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Comets, Meteors, and Celestial Wonders In this engaging episode of Space Nuts , hosts Andrew Dunkley and Professor Jonti Horner dive deep into the fascinating world of comets and meteors. With Professor Fred Watson away, Jonti brings his expertise to explore these celestial phenomena, their historical significance, and the science behind them.
Episode Highlights:
- Understanding Comets and Meteors: Andrew and Jonti kick off the episode by discussing the importance of comets and meteors in both ancient cultures and modern astronomy. They delve into how these celestial objects have been perceived throughout history and their impact on human events.
- Recent Discoveries and Predictions: The hosts share insights on recent comet discoveries, including the intriguing Comet Chichin Chan, and discuss what we can expect from this comet in the near future. They also touch on the challenges of predicting comet brightness and visibility.
- Meteor Showers Explained: Jonti explains how meteor showers occur, the significance of radiant points, and what conditions are best for viewing these spectacular events. They discuss the most notable meteor showers and when listeners can catch them in action.
- The Impact of Media on Public Perception: The conversation takes a turn as Andrew and Jonti address the role of media in shaping public understanding of astronomical events, particularly the sensationalism surrounding potential alien encounters and the importance of relying on scientific facts.
For more Space Nuts, including our continuously updating newsfeed and to listen to all our episodes, visit our website. (https://www.spacenutspodcast.com/) Follow us on social media at SpaceNutsPod on Facebook, Instagram, and more. We love engaging with our community, so be sure to drop us a message or comment on your favourite platform.
If you’d like to help support Space Nuts and join our growing family of insiders for commercial-free episodes and more, visit spacenutspodcast.com/about (https://www.spacenutspodcast.com/about) .
Stay curious, keep looking up, and join us next time for more stellar insights and cosmic wonders. Until then, clear skies and happy stargazing.
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Episode link: https://play.headliner.app/episode/33283432?utm_source=youtube
00:00:00 --> 00:00:01 Hello again. Thank you for joining us on
00:00:01 --> 00:00:04 another episode of Space Nuts. My name
00:00:04 --> 00:00:06 is Andrew Dunley, your host. It's great
00:00:06 --> 00:00:08 to have your company. As I mentioned
00:00:08 --> 00:00:11 last episode, Fred is away for a few
00:00:11 --> 00:00:13 weeks or a couple of years. No, it's a
00:00:13 --> 00:00:16 few weeks. And uh in hisstead, we'll be
00:00:16 --> 00:00:19 joined by Professor Jonty, who you know
00:00:19 --> 00:00:21 and love because he's been with us
00:00:21 --> 00:00:24 before and uh he's a part of the team.
00:00:24 --> 00:00:27 So, uh, we will be doing over the next,
00:00:27 --> 00:00:30 uh, several episodes, um, taking a
00:00:30 --> 00:00:31 different approach. Uh, we we're going
00:00:31 --> 00:00:35 to focus on specific topics within each
00:00:35 --> 00:00:38 of the episodes. Uh, we could call them
00:00:38 --> 00:00:41 specials if you like. And today, our
00:00:41 --> 00:00:44 focus will be on comets and meteors.
00:00:44 --> 00:00:47 Stick around. We're doing all of that on
00:00:47 --> 00:00:49 this episode of Space Nuts.
00:00:49 --> 00:00:54 >> 15 seconds. Guidance is internal. 10 9
00:00:54 --> 00:00:55 Ignition sequence start.
00:00:55 --> 00:00:56 >> Space Nuts.
00:00:56 --> 00:00:59 >> 5 4 3 2
00:00:59 --> 00:01:01 >> 1 2 3 4 5 5 4 3 2 1
00:01:01 --> 00:01:02 >> Space Nuts.
00:01:02 --> 00:01:05 >> Astronauts report. It feels good.
00:01:05 --> 00:01:06 >> And it's great to have him back.
00:01:06 --> 00:01:08 Professor Jonty her, professor of
00:01:08 --> 00:01:11 astrophysics at the University of
00:01:11 --> 00:01:13 Southern Queensland. Jonty, hello.
00:01:14 --> 00:01:15 >> Ah, hey. How are you going?
00:01:15 --> 00:01:17 >> Good. Great to see you again.
00:01:17 --> 00:01:19 >> Well, it's good to be back. It's
00:01:19 --> 00:01:20 something nice to keep me entertained
00:01:20 --> 00:01:21 while I'm having a little bit of a a
00:01:21 --> 00:01:23 restful couple of weeks. I'm, you know,
00:01:23 --> 00:01:25 I've got a bit of leave so I'm um
00:01:25 --> 00:01:27 recovering from a minor surgery and
00:01:27 --> 00:01:29 therefore I can give my entire forecast
00:01:29 --> 00:01:31 to talking about fun things rather than
00:01:31 --> 00:01:33 doing Adam in effectively. But means I
00:01:33 --> 00:01:34 get to see a little bit of the life Fred
00:01:34 --> 00:01:35 gets to live.
00:01:35 --> 00:01:38 >> Yeah, maybe. Yes. Although he he doesn't
00:01:38 --> 00:01:41 seem to slow down much. Um, in fact, I
00:01:41 --> 00:01:42 think the worst thing you can do when
00:01:42 --> 00:01:44 you retire is slow down because um that
00:01:44 --> 00:01:46 the brain matter decides to give up the
00:01:46 --> 00:01:49 ghost and that's when it's all over Red
00:01:49 --> 00:01:52 Rover. But, uh, no, he he's going going
00:01:52 --> 00:01:54 great guns and um, you didn't mention
00:01:54 --> 00:01:55 that you're having a little bit of a
00:01:56 --> 00:01:59 recuperation. Um, are you in a position
00:01:59 --> 00:02:01 to talk about that or is it too
00:02:01 --> 00:02:03 embarrassing? Oh, well, it's one of
00:02:03 --> 00:02:05 those things that when I when I first
00:02:05 --> 00:02:06 had this pointed out, I a bit
00:02:06 --> 00:02:08 embarrassed about it, but I don't think
00:02:08 --> 00:02:12 as blossing
00:02:12 --> 00:02:14 past a little bit of embarrassment. So,
00:02:14 --> 00:02:17 I'm in my late 40s and I went to the
00:02:17 --> 00:02:19 doctor about a year ago cuz I had a
00:02:19 --> 00:02:20 little bit of bleeding when I was
00:02:20 --> 00:02:21 sitting down and stuff like this. And
00:02:21 --> 00:02:24 nothing dramatic. Um, but I found out
00:02:24 --> 00:02:26 two things. Firstly, in Australia, and I
00:02:26 --> 00:02:27 don't know about the rest of the world,
00:02:27 --> 00:02:28 you should look this up, but when you're
00:02:28 --> 00:02:31 in your 40s, the Medicare system here
00:02:32 --> 00:02:33 affords the opportunity for you to get
00:02:33 --> 00:02:34 health checks.
00:02:34 --> 00:02:34 >> Yep.
00:02:34 --> 00:02:36 >> Which is brilliant. So, you basically
00:02:36 --> 00:02:38 get what in the UK they'd call an MOT
00:02:38 --> 00:02:40 for a car. You get everything run over
00:02:40 --> 00:02:42 and you get your blood pressure done and
00:02:42 --> 00:02:43 your heart rate done and everything
00:02:43 --> 00:02:45 else. And then you go back every 3
00:02:45 --> 00:02:47 months and do it again and again and
00:02:47 --> 00:02:48 again. And it's basically, you're at an
00:02:48 --> 00:02:50 age where things start to break. Let's
00:02:50 --> 00:02:52 get on top of it early so that you can
00:02:52 --> 00:02:54 enjoy the rest of your life in peace.
00:02:54 --> 00:02:55 effectively. I think it's a really good
00:02:55 --> 00:02:57 idea and I suspect from a government
00:02:57 --> 00:02:59 point of view makes a lot of sense cuz
00:02:59 --> 00:03:01 if you find things easy earlier they're
00:03:01 --> 00:03:04 easier and quicker and cheaper to solve.
00:03:04 --> 00:03:06 Um, what it turned out from that was I
00:03:06 --> 00:03:07 spent about two months going back and
00:03:07 --> 00:03:09 forth with a doctor who thought I had
00:03:09 --> 00:03:10 one thing wrong, which is not what it
00:03:10 --> 00:03:12 was. And then I got got sent to this
00:03:12 --> 00:03:14 specialist who said, "You've got
00:03:14 --> 00:03:15 something called a fistula down near
00:03:15 --> 00:03:17 your backside."
00:03:17 --> 00:03:19 >> Which not life-threatening, not the end
00:03:19 --> 00:03:20 of the world, not doomed, but it's
00:03:20 --> 00:03:23 uncomfortable. Um, and you know, it's
00:03:23 --> 00:03:24 been slightly embarrassing in that I've
00:03:24 --> 00:03:27 had to learn more about sanitary pads
00:03:27 --> 00:03:29 than, you know, um, you would have
00:03:29 --> 00:03:31 expected, you know, which the women in
00:03:31 --> 00:03:32 the audience are going about bloody
00:03:32 --> 00:03:35 time. a man learned about this. Um, but
00:03:35 --> 00:03:37 it's a weird one because it's not
00:03:37 --> 00:03:38 life-threatening. It's nothing of a
00:03:38 --> 00:03:40 problem. Something 10 or 20% of guys
00:03:40 --> 00:03:42 apparently get them, but they can take
00:03:42 --> 00:03:45 multiple surgeries to fix. And when I
00:03:45 --> 00:03:46 went in for the first surgery in
00:03:46 --> 00:03:48 January, the there was another guy there
00:03:48 --> 00:03:50 who was on surgery number seven.
00:03:50 --> 00:03:51 >> Wow.
00:03:51 --> 00:03:53 >> Um, which Yeah. deep and joyous. Um,
00:03:53 --> 00:03:55 it's kind of day surgery, but you get a
00:03:55 --> 00:03:56 full general and you go under and doctor
00:03:56 --> 00:03:58 does snippy snippy things and you get a
00:03:58 --> 00:03:59 couple of weeks off work, which is where
00:03:59 --> 00:04:01 I am now. So, I've just had surgery
00:04:01 --> 00:04:04 number two and the doctor is hopeful,
00:04:04 --> 00:04:05 confident, whatever that surgery number
00:04:05 --> 00:04:08 three will be the final fix. And it's
00:04:08 --> 00:04:09 one of these weird things cuz people
00:04:09 --> 00:04:10 say, "What's wrong with you?" And if
00:04:10 --> 00:04:12 it's a sore arm, you just say, "I've
00:04:12 --> 00:04:13 hurt my arm or you've broken your arm or
00:04:13 --> 00:04:15 something like that." Or in Australia, a
00:04:15 --> 00:04:17 really common one, a melanoma. People
00:04:17 --> 00:04:19 have been in the sun too much. Going
00:04:19 --> 00:04:20 into hospital, what do you get? Oh, I've
00:04:20 --> 00:04:22 got a melanoma taken off. But as soon as
00:04:22 --> 00:04:23 it's anywhere between about your belly
00:04:23 --> 00:04:25 button and your knee, people are bashful
00:04:25 --> 00:04:27 about talking about it. And I
00:04:27 --> 00:04:28 >> first few months I was mortified and
00:04:28 --> 00:04:30 like wouldn't talk about it. And I
00:04:30 --> 00:04:32 realization is that if you don't talk
00:04:32 --> 00:04:34 about it, people don't get checked and
00:04:34 --> 00:04:37 we as men are terrible for that. And so,
00:04:37 --> 00:04:38 yeah, worth talking about. I'm a bit
00:04:38 --> 00:04:40 embarrassed about it, but I shouldn't
00:04:40 --> 00:04:42 be. And it's good to tune up. And it
00:04:42 --> 00:04:44 means that in 40 years time, I'll still
00:04:44 --> 00:04:45 be up and kicking and having a lot of
00:04:45 --> 00:04:47 fun rather than in discomfort and
00:04:47 --> 00:04:49 grumbling about a problem I could have
00:04:49 --> 00:04:49 got fixed.
00:04:50 --> 00:04:53 >> Yeah. Yeah. And um I think you're right.
00:04:53 --> 00:04:55 I think men do tend to keep things to
00:04:55 --> 00:04:57 themselves. uh a lot of them go into
00:04:57 --> 00:05:00 denial uh or they just think well no
00:05:00 --> 00:05:03 that won't happen to me so no problem
00:05:03 --> 00:05:05 but uh when I was diagnosed with
00:05:05 --> 00:05:08 prostate cancer it was like a bolt from
00:05:08 --> 00:05:12 the blue and I didn't I I I never
00:05:12 --> 00:05:14 expected to get it because there was
00:05:14 --> 00:05:16 next to no history of it in my family so
00:05:16 --> 00:05:18 um that was that was a bit of a shock
00:05:18 --> 00:05:21 and this is what how long is it now 3
00:05:21 --> 00:05:25 years 3 years and I'm still working my
00:05:25 --> 00:05:29 way through it. So, um, but the latest
00:05:29 --> 00:05:31 scans are all good. So, fingers crossed
00:05:31 --> 00:05:34 that we've, you know, reached a a good
00:05:34 --> 00:05:36 position. But, um, it it's just an
00:05:36 --> 00:05:38 ongoing thing in your life. You just got
00:05:38 --> 00:05:41 to get used to it. But, you my my advice
00:05:41 --> 00:05:42 to men is go and get checked. If you're
00:05:42 --> 00:05:46 over 50, go and get a prostate exam. Go
00:05:46 --> 00:05:49 and get your PSA tests done because if
00:05:49 --> 00:05:50 you don't
00:05:50 --> 00:05:53 and then they find it, it might be too
00:05:53 --> 00:05:57 far along. Um and then then the then the
00:05:57 --> 00:05:59 treatment becomes more dramatic.
00:05:59 --> 00:06:01 >> So anyway um it's a good thing to bring
00:06:01 --> 00:06:01 up.
00:06:02 --> 00:06:03 >> It is and it goes for the mental health
00:06:03 --> 00:06:05 stuff as well. I have a former partner
00:06:05 --> 00:06:07 of mine kind of 20 years ago who was
00:06:07 --> 00:06:09 very severely bipolar. Had a lot of
00:06:09 --> 00:06:11 challenges and she was continually
00:06:11 --> 00:06:13 frustrated by people's responses to that
00:06:13 --> 00:06:16 in public in that it's a hidden illness.
00:06:16 --> 00:06:18 It's there. She's getting treatment. But
00:06:18 --> 00:06:20 what she always said is, "It's real
00:06:20 --> 00:06:21 frustrating. If I if I had a broken leg
00:06:21 --> 00:06:23 or I had an injury to my arm and people
00:06:23 --> 00:06:26 could see it, they'd be supportive." But
00:06:26 --> 00:06:27 with mental health, she got a hell of a
00:06:27 --> 00:06:29 lot of, "Oh, just get over it or toughen
00:06:29 --> 00:06:30 up or
00:06:30 --> 00:06:30 >> Yep."
00:06:30 --> 00:06:31 >> And
00:06:31 --> 00:06:34 >> and you know, she was female, so she's
00:06:34 --> 00:06:35 more likely to go to the doctor and talk
00:06:35 --> 00:06:38 about it statistically. Men with mental
00:06:38 --> 00:06:39 health challenges tend to avoid that
00:06:40 --> 00:06:41 even more than they'll go to the doctor
00:06:41 --> 00:06:44 with physical health challenges. And
00:06:44 --> 00:06:45 it's something I'd like to see change. I
00:06:45 --> 00:06:47 come from a workingass background in
00:06:47 --> 00:06:49 Yorkshire where men don't talk about
00:06:49 --> 00:06:50 anything. You know, you're meant to be
00:06:50 --> 00:06:52 stoic and the only the only expression
00:06:52 --> 00:06:54 of emotion you're allowed is rage or a
00:06:54 --> 00:06:57 single manly tear. You know, it's
00:06:57 --> 00:06:58 >> really crazy the way we're conditioned.
00:06:58 --> 00:07:00 And even though I'm, you know, I went to
00:07:00 --> 00:07:02 uni, I've had a life, I've grown up, all
00:07:02 --> 00:07:03 this stuff still there at the back of
00:07:03 --> 00:07:04 your head and you've got to fight
00:07:04 --> 00:07:06 against it because the instinct is, ah,
00:07:06 --> 00:07:08 there's nothing wrong. I won't bother.
00:07:08 --> 00:07:08 >> Yeah.
00:07:08 --> 00:07:11 >> Yeah. And uh yeah, you see it way too
00:07:11 --> 00:07:13 often. Um, I I know it's a departure
00:07:14 --> 00:07:15 from what this podcast is all about, but
00:07:15 --> 00:07:17 I I
00:07:17 --> 00:07:21 when given the opportunity will, um,
00:07:21 --> 00:07:25 openly say to men, um, you know, don't
00:07:25 --> 00:07:27 don't hesitate to go to the doctor, not
00:07:28 --> 00:07:30 not when you think something's wrong,
00:07:30 --> 00:07:32 just preemptively go and get once a
00:07:32 --> 00:07:33 year, go and get checked and make sure
00:07:33 --> 00:07:35 everything's where it's supposed to be
00:07:35 --> 00:07:37 or whatever. Um,
00:07:38 --> 00:07:39 >> we do it do it for our cars, we do it
00:07:39 --> 00:07:40 for our pets.
00:07:40 --> 00:07:42 >> Yeah. Yeah, do it for yourself as well.
00:07:42 --> 00:07:43 >> Yeah, exactly.
00:07:43 --> 00:07:44 >> And yeah, I think it's probably a record
00:07:44 --> 00:07:45 for the quickest we've ever got off
00:07:45 --> 00:07:47 topic and possibly we should have a
00:07:47 --> 00:07:49 trigger warning at the front of it and
00:07:49 --> 00:07:50 all the rest of it, but no, good way to
00:07:50 --> 00:07:52 start even though it is off topic.
00:07:52 --> 00:07:54 >> It's okay. We'll get on to topic right
00:07:54 --> 00:07:57 now because uh what uh as I mentioned
00:07:57 --> 00:08:00 these these uh next uh several uh
00:08:00 --> 00:08:02 episodes are going to be dedicated to
00:08:02 --> 00:08:06 singular topics each and today it's uh
00:08:06 --> 00:08:09 well related topics, comets and meteors.
00:08:09 --> 00:08:11 Uh, this is a this is a pet topic of
00:08:11 --> 00:08:13 yours. I imagine
00:08:13 --> 00:08:14 >> it is. I I've always been a bit more
00:08:14 --> 00:08:16 into the nearby stuff than the more
00:08:16 --> 00:08:18 distant stuff. So, it always tickles me
00:08:18 --> 00:08:20 a little bit that when questions come in
00:08:20 --> 00:08:22 when I'm on the show, we get all the big
00:08:22 --> 00:08:24 bang and cosmology ones. And I'm sure if
00:08:24 --> 00:08:25 you got someone like the wonderful
00:08:25 --> 00:08:27 Tamara Davis on to talk cosmology, she'd
00:08:27 --> 00:08:29 get all the planets questions. It's
00:08:29 --> 00:08:30 always the way it goes. Yeah.
00:08:30 --> 00:08:32 >> But comets and meteors a big part of
00:08:32 --> 00:08:34 what hooked me into astronomy as a kid.
00:08:34 --> 00:08:37 And my thinking behind this is that
00:08:37 --> 00:08:39 we're recording in advance. You know, um
00:08:39 --> 00:08:42 obviously Fred is away, but you've got
00:08:42 --> 00:08:44 recordings with Fred already. And so the
00:08:44 --> 00:08:46 news that we would normally talk about
00:08:46 --> 00:08:49 hasn't happened yet. So I I have many
00:08:49 --> 00:08:50 talents, but seeing Into the Future
00:08:50 --> 00:08:52 isn't one of them to that degree. And so
00:08:52 --> 00:08:54 I thought it better to have a discussion
00:08:54 --> 00:08:55 about the general stuff in a bit more
00:08:55 --> 00:08:57 depth
00:08:57 --> 00:08:59 than go into particular news topics. And
00:08:59 --> 00:09:01 it's it could almost be a bit of an
00:09:01 --> 00:09:03 explainer, a bit of the background, and
00:09:03 --> 00:09:05 hopefully at least gives my insight into
00:09:05 --> 00:09:07 why a given topic's interesting, but
00:09:07 --> 00:09:09 also what people can look out for in the
00:09:09 --> 00:09:12 future and how they can get more into
00:09:12 --> 00:09:14 more out of that particular topic, if
00:09:14 --> 00:09:15 that makes sense.
00:09:15 --> 00:09:16 >> Yeah.
00:09:16 --> 00:09:18 >> Um, a little bit different. I understand
00:09:18 --> 00:09:20 for some listeners it might be a bit bit
00:09:20 --> 00:09:22 of an abrupt departure and a change. So,
00:09:22 --> 00:09:23 it'll be interesting to see what
00:09:23 --> 00:09:25 feedback you get. But hopefully people
00:09:25 --> 00:09:27 like it as a little bit of a change in a
00:09:27 --> 00:09:28 breath of fresh air. And if they don't,
00:09:28 --> 00:09:30 well, there's only a couple of episodes
00:09:30 --> 00:09:31 and Fred's back anyway, so you'll have
00:09:32 --> 00:09:33 to deal with it and we'll see.
00:09:33 --> 00:09:35 >> I'm sure it'll be fine. Comets and
00:09:35 --> 00:09:39 meteors are a very uh popular topic. So,
00:09:39 --> 00:09:41 um, where do we start? Maybe maybe look
00:09:41 --> 00:09:43 at a bit of the history of this.
00:09:43 --> 00:09:45 >> Yeah, I think that is a always a good
00:09:45 --> 00:09:46 place to start because it sets the
00:09:46 --> 00:09:49 context of where we are now. And for
00:09:49 --> 00:09:51 both comets and meteors, there's a kind
00:09:51 --> 00:09:54 of global connection society that really
00:09:54 --> 00:09:57 predates by a long long way our
00:09:57 --> 00:09:59 scientific knowledge essentially the
00:09:59 --> 00:10:01 modern scientific viewpoint and the
00:10:01 --> 00:10:03 scientific method. All cultures across
00:10:03 --> 00:10:05 the world from our wonderful traditional
00:10:05 --> 00:10:07 owners here in Australia to the peoples
00:10:07 --> 00:10:09 of every continent and every land both
00:10:09 --> 00:10:12 current and past historically had a
00:10:12 --> 00:10:14 really firm connection to the night sky.
00:10:14 --> 00:10:15 They knew the night sky better than most
00:10:15 --> 00:10:17 people these days do because it wasn't
00:10:17 --> 00:10:19 light pollution. There weren't TVs and
00:10:19 --> 00:10:21 Xboxes. So the sky was something people
00:10:21 --> 00:10:24 were much more exposed to.
00:10:24 --> 00:10:25 A lot of cultures had this kind of idea
00:10:25 --> 00:10:28 of as above so below, as below so above.
00:10:28 --> 00:10:30 So they were very firmly of the idea
00:10:30 --> 00:10:32 that major events on the earth were
00:10:32 --> 00:10:35 reflected in the sky and major events in
00:10:35 --> 00:10:37 the sky would have their counterparts on
00:10:37 --> 00:10:40 the earth. And that's where astrology
00:10:40 --> 00:10:42 was born. And for a long time astrology
00:10:42 --> 00:10:44 and astronomy were one and the same. You
00:10:44 --> 00:10:46 know, people doing astronomy studies
00:10:46 --> 00:10:47 were doing it because they wanted to
00:10:48 --> 00:10:49 understand the events that would
00:10:49 --> 00:10:51 influence what's on the earth. And there
00:10:51 --> 00:10:53 are good examples of this in terms of
00:10:53 --> 00:10:55 the nominally fixed stars. Things like
00:10:55 --> 00:10:58 the ancient Egyptians using the rising
00:10:58 --> 00:11:00 of Sirius in the dawn sky after it
00:11:00 --> 00:11:02 disappeared in the evenings as a
00:11:02 --> 00:11:04 predictor of the flooding of the Nile,
00:11:04 --> 00:11:05 for example, the use of the night sky as
00:11:05 --> 00:11:08 a calendar. Lots of stuff like that. But
00:11:08 --> 00:11:10 because people were so aware of the
00:11:10 --> 00:11:13 night sky, anything that was ephemeral,
00:11:13 --> 00:11:15 anything that was transitory that
00:11:15 --> 00:11:16 appeared and then disappeared that was
00:11:16 --> 00:11:19 unexpected was often seen as kind of a
00:11:19 --> 00:11:22 potent or an omen. Something that was an
00:11:22 --> 00:11:24 indication either of major change and
00:11:24 --> 00:11:26 upheaval currently happening or one soon
00:11:26 --> 00:11:28 to come. And really bright comets and
00:11:28 --> 00:11:30 spectacular meteor showers kind of often
00:11:30 --> 00:11:33 filled this role. And you can go back
00:11:33 --> 00:11:35 through ancient history where we have
00:11:35 --> 00:11:37 the records and see good examples of
00:11:37 --> 00:11:40 this. I've got in one of my talks talks
00:11:40 --> 00:11:45 about a guy called Mithridatis um up 6 I
00:11:45 --> 00:11:46 think his name was. He was one of the
00:11:46 --> 00:11:48 great enemies of the Roman Empire. And
00:11:48 --> 00:11:51 there are quotes ascribed to him saying
00:11:51 --> 00:11:53 things like um even the heavens
00:11:53 --> 00:11:55 predicted the greatness of this man. For
00:11:55 --> 00:11:57 in the year in which he was born and the
00:11:57 --> 00:11:59 year in which he came to reign, a comet
00:11:59 --> 00:12:02 shone through both periods for 70 days
00:12:02 --> 00:12:04 as bright as the sun. Each rising and
00:12:04 --> 00:12:06 setting took four hours each. And that's
00:12:06 --> 00:12:08 kind of hyperbolic, but it gives this
00:12:08 --> 00:12:11 idea that people saw something in the
00:12:11 --> 00:12:14 sky that was unusual and tied it to
00:12:14 --> 00:12:16 events on Earth. Another good example
00:12:16 --> 00:12:18 would be the alleged comet called
00:12:18 --> 00:12:23 Caesar's comet in 44 BC 43US 43
00:12:23 --> 00:12:26 which is recorded in Roman writings from
00:12:26 --> 00:12:29 a century or two later talking about
00:12:30 --> 00:12:31 after the death of Caesar a comet blazed
00:12:32 --> 00:12:34 in the sky for seven days that was
00:12:34 --> 00:12:36 spectacularly bright. then disappeared
00:12:36 --> 00:12:38 and was never seen again. Now, that
00:12:38 --> 00:12:39 comet is a really good example of the
00:12:40 --> 00:12:42 challenge people have with historical
00:12:42 --> 00:12:43 records
00:12:44 --> 00:12:45 >> because on the one hand, you've got
00:12:45 --> 00:12:46 these clear reports from the Roman
00:12:46 --> 00:12:49 Empire. None of them at the time though,
00:12:49 --> 00:12:51 all of them a bit later on. But that
00:12:51 --> 00:12:53 comet is not recorded from anywhere else
00:12:53 --> 00:12:54 on the planet and there were cultures
00:12:54 --> 00:12:56 around the globe leaving records like
00:12:56 --> 00:12:58 ancient China and ancient Korea who
00:12:58 --> 00:13:01 would have seen it. So, was that comet
00:13:01 --> 00:13:03 real? Or was it a case of after the
00:13:03 --> 00:13:05 event people inventing a night sky
00:13:05 --> 00:13:08 phenomena to tie with the soul of the
00:13:08 --> 00:13:10 emperor rising to heaven? It's one of
00:13:10 --> 00:13:12 the challenges people in the kind of
00:13:12 --> 00:13:13 cultural astronomy space face, I think,
00:13:13 --> 00:13:15 in terms of disentangling
00:13:15 --> 00:13:17 the narrative from the events that
00:13:17 --> 00:13:19 prompted it, if that kind of makes
00:13:19 --> 00:13:19 sense.
00:13:19 --> 00:13:22 >> Yeah. But what's certainly true is that
00:13:22 --> 00:13:24 for as long as we've looked at the sky,
00:13:24 --> 00:13:26 really bright comets and unusually
00:13:26 --> 00:13:29 powerful meteor showers were things that
00:13:29 --> 00:13:31 people took note of. And recently there
00:13:31 --> 00:13:33 was a lot of meteor media coverage of
00:13:33 --> 00:13:36 the April Lyid meteor shower, which is
00:13:36 --> 00:13:37 not one of the strongest of the year,
00:13:37 --> 00:13:40 but one of the reasonable moderate ones.
00:13:40 --> 00:13:41 It's a kind of one that if you're a
00:13:41 --> 00:13:43 meteor enthusiast, you'll go out and
00:13:43 --> 00:13:44 watch, but isn't worth going out if
00:13:44 --> 00:13:46 you're not that interested cuz there's
00:13:46 --> 00:13:48 too few. M
00:13:48 --> 00:13:49 >> I had to grumble about some of the
00:13:49 --> 00:13:50 coverage here in Australia cuz it's not
00:13:50 --> 00:13:53 a great shower for us. But that meteor
00:13:53 --> 00:13:55 shower was recognized by the traditional
00:13:55 --> 00:13:57 owners in Australia and there are
00:13:57 --> 00:13:59 stories from Victoria from I think the
00:13:59 --> 00:14:01 Bong people although I stand to be
00:14:01 --> 00:14:03 corrected on that that associate this
00:14:03 --> 00:14:04 meteor shower with the Malifile one of
00:14:04 --> 00:14:07 the big grand nesting birds in Australia
00:14:07 --> 00:14:09 which nests around that time of year.
00:14:09 --> 00:14:11 The meteors seen shrieking from low in
00:14:11 --> 00:14:12 the northern sky were viewed as being
00:14:12 --> 00:14:15 the dust being kicked up by the nesting
00:14:15 --> 00:14:17 bird celestially. So they recorded this
00:14:17 --> 00:14:18 meteor shower, even though it isn't a
00:14:18 --> 00:14:22 particularly strong one. But our oldest
00:14:22 --> 00:14:24 written record of any meteor shower is
00:14:24 --> 00:14:26 the Aprils and it's dated back to
00:14:26 --> 00:14:29 something like 687 B.CE when stars fell
00:14:29 --> 00:14:31 like rain when there was a major storm
00:14:31 --> 00:14:33 from the Lyids and it was significant
00:14:33 --> 00:14:36 enough for people to record. So comets
00:14:36 --> 00:14:39 and meteors way before the modern
00:14:39 --> 00:14:41 scientific understanding of them really
00:14:41 --> 00:14:45 had this important cultural role. Um,
00:14:45 --> 00:14:46 even in the Battle of Hastings, if you
00:14:46 --> 00:14:48 ever go to see the bio tapestry, this
00:14:48 --> 00:14:51 wonderful woven record of the Battle of
00:14:51 --> 00:14:52 Hastings and the invasion of William the
00:14:52 --> 00:14:55 Conqueror, Comet Hi features prominently
00:14:55 --> 00:14:58 on that because in 1066,
00:14:58 --> 00:14:59 >> you had the second best apparition of
00:14:59 --> 00:15:01 Comet Halley in the last 2 years.
00:15:01 --> 00:15:03 Arguably, it was very spectacular in the
00:15:03 --> 00:15:05 sky at the time the conquest was going
00:15:05 --> 00:15:07 on. And that was considered important
00:15:07 --> 00:15:10 enough to be recorded in the tapestry
00:15:10 --> 00:15:12 that was woven at the time. You know,
00:15:12 --> 00:15:14 it's amazing that you've got this panel
00:15:14 --> 00:15:16 where there's all the peasants pointing
00:15:16 --> 00:15:18 up at this thing in the sky and somebody
00:15:18 --> 00:15:20 whispering King Harold's ear about the
00:15:20 --> 00:15:22 comet that's visible. So yeah, don't
00:15:22 --> 00:15:24 know whether the invading forces took it
00:15:24 --> 00:15:26 as a good sign or a bad sign, but they
00:15:26 --> 00:15:27 thought it was important enough to
00:15:27 --> 00:15:29 include.
00:15:29 --> 00:15:31 >> So that in itself's fairly breathtaking.
00:15:31 --> 00:15:32 And so when we see these objects, it's a
00:15:32 --> 00:15:35 lovely connection to thousands of years
00:15:35 --> 00:15:37 of our heritage of people looking at the
00:15:37 --> 00:15:41 night sky in wonder. I think the first
00:15:41 --> 00:15:45 step we had really in moving from
00:15:45 --> 00:15:48 cultural commentary astronomy to modern
00:15:48 --> 00:15:50 scientific astronomy in a way came with
00:15:50 --> 00:15:53 the great comet of 1577
00:15:53 --> 00:15:56 which was another of the really amazing
00:15:56 --> 00:15:58 spectacular bright comets that was
00:15:58 --> 00:16:01 widely observed hence why it's a great
00:16:01 --> 00:16:03 comet but it was observed by the great
00:16:03 --> 00:16:06 astronomer Tiko Brahhe and I'm sure
00:16:06 --> 00:16:08 Brahe is featured on the podcast many
00:16:08 --> 00:16:10 times before, but the quirky individual
00:16:10 --> 00:16:12 he was. It's well worth looking up his
00:16:12 --> 00:16:15 Wikipedia record. Is this wealthy
00:16:15 --> 00:16:18 nobleman with a silver replacement nose
00:16:18 --> 00:16:20 after he lost half his nose in a duel?
00:16:20 --> 00:16:21 He's that guy.
00:16:21 --> 00:16:22 >> Yes.
00:16:22 --> 00:16:24 >> Yes. Um he had a pet moose that died
00:16:24 --> 00:16:25 when it fell down the steps because it
00:16:25 --> 00:16:27 got drunk at a banquet. He
00:16:27 --> 00:16:31 >> really odd odd man. Um but probably
00:16:31 --> 00:16:33 viewed as being the last great pre-
00:16:33 --> 00:16:36 telescope astron astronomical observer
00:16:36 --> 00:16:38 if that makes sense. Naked eye observer.
00:16:38 --> 00:16:40 Now, at this time, comets were kind of
00:16:40 --> 00:16:42 thought to be probably atmospheric
00:16:42 --> 00:16:44 phenomenon. They were nearby, high in
00:16:44 --> 00:16:46 the atmosphere,
00:16:46 --> 00:16:48 and so that was what was going on.
00:16:48 --> 00:16:50 People had that kind of idea. He
00:16:50 --> 00:16:53 realized that if that were true, these
00:16:53 --> 00:16:55 things would display a noticeable
00:16:55 --> 00:16:57 parallax if people observed them from
00:16:57 --> 00:16:58 different locations.
00:16:58 --> 00:16:59 >> Uhhuh.
00:16:59 --> 00:17:01 >> So, in other words, people looking from
00:17:01 --> 00:17:03 different locations would see the comet
00:17:03 --> 00:17:05 in a different place in the sky because
00:17:05 --> 00:17:07 it was in the foreground. It's the same
00:17:07 --> 00:17:09 technique we use to measure the distance
00:17:09 --> 00:17:11 to the nearest stars. If you put your
00:17:11 --> 00:17:12 finger in front of your face and look at
00:17:12 --> 00:17:14 it through one eye and then look through
00:17:14 --> 00:17:15 the other, you'll see your finger
00:17:15 --> 00:17:17 blinking side to side. And the further
00:17:18 --> 00:17:20 away your finger is, the less it moves.
00:17:20 --> 00:17:21 >> We use that to measure the distance to
00:17:21 --> 00:17:23 stars by observing from one side of the
00:17:23 --> 00:17:25 Earth's orbit than the other. But what
00:17:25 --> 00:17:27 Brah did was collect observations from
00:17:27 --> 00:17:29 around Europe of where the comet was in
00:17:29 --> 00:17:33 the sky. With those observations, he
00:17:33 --> 00:17:34 would have been able to detect a
00:17:34 --> 00:17:37 parallax for the comet if it were closer
00:17:37 --> 00:17:39 than the orbit of the moon. So if it was
00:17:39 --> 00:17:40 atmospheric, absolutely definitely would
00:17:40 --> 00:17:43 do. But no measurable parallax was
00:17:43 --> 00:17:45 found, which showed the comet had to be
00:17:45 --> 00:17:47 at least a couple of million km away.
00:17:47 --> 00:17:48 And in fact, it was probably several
00:17:48 --> 00:17:51 tens of millions of kilome distant. He
00:17:51 --> 00:17:53 got this beautiful figure and I've I use
00:17:53 --> 00:17:56 this in my talks occasionally that is
00:17:56 --> 00:17:58 his drawing of the motion of the comet
00:17:58 --> 00:18:00 and it's fascinating from cultural point
00:18:00 --> 00:18:02 of view because it's clearly at the time
00:18:02 --> 00:18:03 when you still have the geocentric model
00:18:04 --> 00:18:05 the earth was the center of the
00:18:05 --> 00:18:07 universe. So you've got the Earth in the
00:18:07 --> 00:18:09 middle, the Sun going around the Earth,
00:18:09 --> 00:18:10 but then Mercury, Venus, and the Moon
00:18:10 --> 00:18:12 going around the Sun,
00:18:12 --> 00:18:14 >> this kind of weird hybrid thing, but
00:18:14 --> 00:18:15 you've got the path of the comet moving
00:18:15 --> 00:18:17 through there that he's determined. And
00:18:17 --> 00:18:19 what's really interesting to me, what's
00:18:20 --> 00:18:22 really fascinating is he's got the tails
00:18:22 --> 00:18:24 pointing away from the sun all the time.
00:18:24 --> 00:18:26 So he's got the phenomenology of where
00:18:26 --> 00:18:28 the comet is in the solar system,
00:18:28 --> 00:18:31 modular, the the sun's going around the
00:18:31 --> 00:18:33 Earth, and the tails pointing the right
00:18:33 --> 00:18:36 way as it moves. tales of comets always
00:18:36 --> 00:18:38 pointing away from the sun. And to me
00:18:38 --> 00:18:41 that kind of marks the dawn of the
00:18:41 --> 00:18:44 modern scientific view of comets from
00:18:44 --> 00:18:46 the cultural we don't know what they are
00:18:46 --> 00:18:49 but they are important.
00:18:49 --> 00:18:51 >> I think that's a real kind of boundary
00:18:51 --> 00:18:52 point for me.
00:18:52 --> 00:18:54 >> Yeah. Yeah. Fascinating. I was actually
00:18:54 --> 00:18:56 going to ask you about the uh you know
00:18:56 --> 00:18:58 the point in time where we went from the
00:18:58 --> 00:19:01 mythology to the understanding that this
00:19:01 --> 00:19:04 this was something else and yeah you
00:19:04 --> 00:19:06 covered that beautifully. Going to just
00:19:06 --> 00:19:08 take a breath on Space Nuts. Uh you're
00:19:08 --> 00:19:10 with Andrew Dunley and Professor Jonty
00:19:10 --> 00:19:13 Horner.
00:19:13 --> 00:19:14 Let's take a short break from the show
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00:21:01 --> 00:21:02 >> G. And I feel
00:21:02 --> 00:21:03 >> Space Nuts.
00:21:03 --> 00:21:05 >> I did say a breath. That was quick. Um,
00:21:05 --> 00:21:07 let's continue talking about comets and
00:21:07 --> 00:21:10 meteors. There have been a lot of them
00:21:10 --> 00:21:14 in the news of late uh comet pan stars
00:21:14 --> 00:21:17 is um you know it was very very uh
00:21:17 --> 00:21:22 popular late April. uh and uh we we've
00:21:22 --> 00:21:25 seen in recent times u a new kind of
00:21:25 --> 00:21:27 comet and those are the ones that are
00:21:27 --> 00:21:31 coming from other systems uh not not the
00:21:31 --> 00:21:34 ones that are con continually rotating
00:21:34 --> 00:21:35 through our own solar system. We've had
00:21:35 --> 00:21:39 these exo comets that have been quite
00:21:39 --> 00:21:42 intriguing and and uh opening up all
00:21:42 --> 00:21:44 sorts of new ideas and questions about
00:21:44 --> 00:21:47 uh comets and other other parts of the
00:21:47 --> 00:21:49 the universe and what we could learn
00:21:49 --> 00:21:53 from them. Um and and new comets are
00:21:53 --> 00:21:54 being discovered all the time. That
00:21:54 --> 00:21:56 doesn't mean they haven't been here
00:21:56 --> 00:21:58 before, but it does mean that they've
00:21:58 --> 00:22:02 got very longitudinal travel times. So,
00:22:02 --> 00:22:04 um, you know, some we won't ever see
00:22:04 --> 00:22:06 because we'll have been and gone before
00:22:06 --> 00:22:10 they get here, and others we'll maybe
00:22:10 --> 00:22:12 see several times during our lifetimes.
00:22:12 --> 00:22:15 >> Absolutely. Now, historically, people
00:22:15 --> 00:22:17 broke the comets we found down into two
00:22:17 --> 00:22:20 categories. We had short period comets,
00:22:20 --> 00:22:22 which are comets. The definition when I
00:22:22 --> 00:22:24 was a kid was comets whose orbital
00:22:24 --> 00:22:26 periods were less than 200 years.
00:22:26 --> 00:22:27 Shorter than that and you were a short
00:22:27 --> 00:22:29 period comet. Longer than that, and you
00:22:29 --> 00:22:31 were a long period comet. Now there are
00:22:31 --> 00:22:33 subtleties within that. Within the short
00:22:33 --> 00:22:34 period comets we have comets like comet
00:22:34 --> 00:22:36 Halley which are called the Halley type
00:22:36 --> 00:22:38 comets which come around with a period
00:22:38 --> 00:22:40 comparable to a human lifetime or a bit
00:22:40 --> 00:22:42 longer. And the two brightest and most
00:22:42 --> 00:22:43 famous of those are comet Halley and
00:22:43 --> 00:22:44 comet Swift Tuttle.
00:22:44 --> 00:22:46 >> You then have the Jupiter family comets
00:22:46 --> 00:22:48 which are comets whose orbits are just a
00:22:48 --> 00:22:50 few years and are typically under
00:22:50 --> 00:22:52 Jupiter's control. And when I was a kid,
00:22:52 --> 00:22:54 anything longer than 200 years was
00:22:54 --> 00:22:57 considered long period. Now that kind of
00:22:57 --> 00:22:58 got smashed into the ground a bit in the
00:22:58 --> 00:23:01 early 2000s when comet Eaya Jang was
00:23:01 --> 00:23:04 cited because comet Eaya Jang was very
00:23:04 --> 00:23:06 well observed. Its orbit was well
00:23:06 --> 00:23:07 calculated. It was found to have a
00:23:07 --> 00:23:10 period of 366 years I think it is and
00:23:10 --> 00:23:13 that allowed people to identify the
00:23:13 --> 00:23:14 previous observations of that comet from
00:23:14 --> 00:23:17 the last time it was around. So that's
00:23:17 --> 00:23:19 currently the record holder where we're
00:23:19 --> 00:23:22 absolutely certain that it's been seen
00:23:22 --> 00:23:25 on multiple occasions and it has a a
00:23:25 --> 00:23:27 periodic comet designation. Now now a
00:23:27 --> 00:23:29 subtlety to that is we do have the crot
00:23:30 --> 00:23:31 sungrazing comets and I can talk more
00:23:31 --> 00:23:33 about them a little later where we have
00:23:33 --> 00:23:36 a strong identification between an
00:23:36 --> 00:23:38 observation of the comet say with comedy
00:23:38 --> 00:23:40 Keki in 1965
00:23:40 --> 00:23:44 and a previous apparition in the 1100s
00:23:44 --> 00:23:46 which is about an 800year return. Yeah,
00:23:46 --> 00:23:48 >> that's a bit woolly because the comets
00:23:48 --> 00:23:50 we observe now are fragments of one
00:23:50 --> 00:23:53 comet back then and so therefore several
00:23:53 --> 00:23:55 comets tied to that initial apparition.
00:23:55 --> 00:23:57 So there's all that complexity there. We
00:23:57 --> 00:24:00 then have the long period comets which
00:24:00 --> 00:24:03 like I say were 200 years or more. It
00:24:03 --> 00:24:05 still kind of is but with those objects
00:24:06 --> 00:24:07 that are both long period and short
00:24:07 --> 00:24:08 period thanks to a jang. You've got
00:24:08 --> 00:24:10 these objects whose orbital periods are
00:24:10 --> 00:24:12 so long that they are marketkedly longer
00:24:12 --> 00:24:15 than a human lifetime. even if they're
00:24:15 --> 00:24:16 comets that have been through before. So
00:24:16 --> 00:24:18 a good example of a really bright comet
00:24:18 --> 00:24:21 that is considered long period but has
00:24:21 --> 00:24:23 been through many times before is comet
00:24:23 --> 00:24:25 Hailbop. Comet Hailbop was spectacular
00:24:25 --> 00:24:28 in 9697. It was visible with a naked eye
00:24:28 --> 00:24:30 for 18 months shattering all the
00:24:30 --> 00:24:32 records. It will be back in about the
00:24:32 --> 00:24:34 year 4400. It was the last round when
00:24:34 --> 00:24:36 the Egyptians were building pyramids.
00:24:36 --> 00:24:39 And that is perversely a long period
00:24:39 --> 00:24:40 comet with a relatively short period
00:24:40 --> 00:24:43 orbit for a long period of comet. And so
00:24:43 --> 00:24:45 scientifically we'd call that
00:24:45 --> 00:24:48 dynamically old or not a new comet
00:24:48 --> 00:24:49 because it's been around a number of
00:24:49 --> 00:24:52 times. At the very long period end of
00:24:52 --> 00:24:54 the long period comets you get things
00:24:54 --> 00:24:56 that are coming in from halfway to the
00:24:56 --> 00:24:58 nearest star from a region we describe
00:24:58 --> 00:25:01 as the or cloud or the opic cloud. And
00:25:01 --> 00:25:03 those things on their way in have
00:25:04 --> 00:25:06 calculated orbital periods of hundreds
00:25:06 --> 00:25:09 of thousands or even millions of years.
00:25:09 --> 00:25:10 And many of those actually only come
00:25:10 --> 00:25:12 through once and then they get nudged
00:25:12 --> 00:25:14 and ejected from the solar system never
00:25:14 --> 00:25:15 to return
00:25:15 --> 00:25:17 >> going out to wander among the stars. And
00:25:18 --> 00:25:19 it's objects like that that will become
00:25:19 --> 00:25:22 the interstellar comets for other stars
00:25:22 --> 00:25:24 in the same way that this third group of
00:25:24 --> 00:25:26 comets that you alluded to that we found
00:25:26 --> 00:25:28 recently are interstellar comets in our
00:25:28 --> 00:25:30 system. So these are the objects coming
00:25:30 --> 00:25:32 through so quickly that they are not
00:25:32 --> 00:25:34 gravitationally bound to the sun, but
00:25:34 --> 00:25:36 also so quickly that there is no
00:25:36 --> 00:25:38 possibility that they ever were. They've
00:25:38 --> 00:25:40 been flung in so quickly that they must
00:25:40 --> 00:25:44 come from another place. The most recent
00:25:44 --> 00:25:46 one was ThreeI Atlas, which got talked
00:25:46 --> 00:25:49 about a huge amount. Yes. Was definitely
00:25:49 --> 00:25:51 not an alien spaceship. And to avoid
00:25:51 --> 00:25:53 getting too political, just a very brief
00:25:53 --> 00:25:55 comment on that because it needs to be
00:25:55 --> 00:25:57 stated and restated, which is that the
00:25:57 --> 00:25:59 arguments of that being an alien
00:25:59 --> 00:26:02 spaceship were the work of one person. M
00:26:02 --> 00:26:04 >> one person who is not a solar system
00:26:04 --> 00:26:06 astronomer historically but has reached
00:26:06 --> 00:26:08 that age and level of senility that they
00:26:08 --> 00:26:10 believe they can be an expert in things
00:26:10 --> 00:26:12 that they are not and has a certain
00:26:12 --> 00:26:14 financial interest in keeping people
00:26:14 --> 00:26:16 interested in aliens because they buy
00:26:16 --> 00:26:20 his book. And the community of
00:26:20 --> 00:26:22 astronomers has been very upset and very
00:26:22 --> 00:26:24 stressed about that cuz it diverts
00:26:24 --> 00:26:25 attention from what is a really
00:26:25 --> 00:26:28 fascinating object on the fact that it's
00:26:28 --> 00:26:30 really fascinating but also breeds a
00:26:30 --> 00:26:31 certain amount of fear. And I genuinely
00:26:31 --> 00:26:34 had people reaching out to me when he
00:26:34 --> 00:26:36 was pushing this narrative of it being
00:26:36 --> 00:26:37 aliens that were going to invade because
00:26:37 --> 00:26:39 they were frightened. They were
00:26:39 --> 00:26:41 genuinely worried because a Harvard
00:26:41 --> 00:26:43 astronomer was saying aliens were going
00:26:43 --> 00:26:45 to come and beat us all up.
00:26:45 --> 00:26:47 >> Yeah. And it's problematic because it
00:26:47 --> 00:26:49 hides the science, but it's also more
00:26:49 --> 00:26:51 widely problematic at a time when we
00:26:51 --> 00:26:53 have lowering levels of engagement with
00:26:54 --> 00:26:56 science and very much lowering levels of
00:26:56 --> 00:26:59 trust in science and scientists. It's
00:26:59 --> 00:27:01 very bad to have someone acting
00:27:01 --> 00:27:02 disingenuously,
00:27:02 --> 00:27:05 telling lies or muddying the water and
00:27:06 --> 00:27:07 then arguing that everybody else is
00:27:07 --> 00:27:09 wrong and mean to me and I'm the only
00:27:09 --> 00:27:11 one telling the truth. And it's part of
00:27:11 --> 00:27:13 that whole fake news thing that I think
00:27:13 --> 00:27:16 is dangerous and damaging. You know, we
00:27:16 --> 00:27:18 need people to
00:27:18 --> 00:27:19 >> have trust and faith in science because
00:27:19 --> 00:27:21 it's so integral to our lives. And it's
00:27:21 --> 00:27:23 good to question, but it's bad when
00:27:23 --> 00:27:25 people say things that they
00:27:25 --> 00:27:26 fundamentally know are not true just to
00:27:26 --> 00:27:28 get hits or clicks or money.
00:27:28 --> 00:27:32 >> Yeah. I and it's important to debunk
00:27:32 --> 00:27:36 that kind of uh approach because I I've
00:27:36 --> 00:27:38 had people come up to me very recently
00:27:38 --> 00:27:40 who know I do this podcast
00:27:40 --> 00:27:42 uh who've said to me, "Oh, what do you
00:27:42 --> 00:27:44 think of that alien spaceship?" And I
00:27:44 --> 00:27:47 go, "It's it's bullshit." That's what I
00:27:47 --> 00:27:50 think because it's it's somebody trying
00:27:50 --> 00:27:51 to get media attention. It's got
00:27:51 --> 00:27:53 nothing. It's a rock. It it's actually
00:27:53 --> 00:27:56 it's it's an it's an ice conglomerate.
00:27:56 --> 00:27:58 It's it's not a it's not a spaceship at
00:27:58 --> 00:28:00 all. It's not behaving like a spaceship
00:28:00 --> 00:28:02 would. It's behaving like something
00:28:02 --> 00:28:04 passing through our solar system
00:28:04 --> 00:28:06 >> and
00:28:06 --> 00:28:08 and people people the thing is Johnny
00:28:08 --> 00:28:10 people are buying this rubbish.
00:28:10 --> 00:28:12 >> But there's a old saying that you know a
00:28:12 --> 00:28:14 lie can run around a lie can run around
00:28:14 --> 00:28:16 the world before the truth has got its
00:28:16 --> 00:28:17 boots on.
00:28:17 --> 00:28:19 >> Especially when it's an attractive lie.
00:28:19 --> 00:28:21 It's I mean again digging into my
00:28:21 --> 00:28:23 memories of Terry Pratchett stuff which
00:28:23 --> 00:28:25 happens a lot. It's the old quote when
00:28:25 --> 00:28:27 they're talking about newspapers and
00:28:27 --> 00:28:29 nobody really ever wants to hear a story
00:28:29 --> 00:28:31 about dog bites man because it happens
00:28:31 --> 00:28:32 all the time. But if you got a story
00:28:32 --> 00:28:34 that says man bites dog, everybody's
00:28:34 --> 00:28:34 fascinated.
00:28:34 --> 00:28:35 >> Yeah.
00:28:35 --> 00:28:37 >> And this story has all the elements.
00:28:37 --> 00:28:39 It's so salacious that it gets coverage
00:28:39 --> 00:28:42 and people who don't normally read or
00:28:42 --> 00:28:44 digest science are not interested will
00:28:44 --> 00:28:46 see this and hook into it. And when the
00:28:46 --> 00:28:48 by line is Harvard astronomer that gives
00:28:48 --> 00:28:50 it a huge amount of credence. It does
00:28:50 --> 00:28:53 >> and nobody hears the rebuttals. It's
00:28:53 --> 00:28:55 A bit like, you know, when there are
00:28:55 --> 00:28:56 claims of life on a planet around
00:28:56 --> 00:28:59 another star, nobody remembers the t the
00:28:59 --> 00:29:01 follow-ups that say actually it wasn't.
00:29:01 --> 00:29:03 They just remember, oh, we found aliens
00:29:03 --> 00:29:05 and we haven't.
00:29:05 --> 00:29:08 >> I mean, I think that the story that uh
00:29:08 --> 00:29:11 the most recent story that I recall
00:29:11 --> 00:29:14 where that that claim was made was um
00:29:14 --> 00:29:17 the one about the something they what
00:29:17 --> 00:29:18 was it they found in the in the
00:29:18 --> 00:29:20 atmosphere of Venus? It was
00:29:20 --> 00:29:22 >> phosphine. Yes. Now I I can go on a
00:29:22 --> 00:29:24 little bit of a side rant about that. My
00:29:24 --> 00:29:27 heart broke. Um the lead author on that
00:29:27 --> 00:29:29 study was Jane Greavves in the UK who's
00:29:29 --> 00:29:31 someone I knew very well when I was in
00:29:31 --> 00:29:32 the UK and she's a fabulous science and
00:29:32 --> 00:29:35 just all around wonderful individual and
00:29:35 --> 00:29:39 the story was led by a UK team who if
00:29:39 --> 00:29:41 you actually read the paper don't say
00:29:41 --> 00:29:44 anything that is this is life. What they
00:29:44 --> 00:29:46 say is we found a very weak signal
00:29:46 --> 00:29:49 >> of this gas in Venus's atmosphere. It's
00:29:49 --> 00:29:50 right down in the noise. So there is a
00:29:50 --> 00:29:53 chance it's a false positive anyway. So
00:29:53 --> 00:29:54 there needs to be a bit bit of extra
00:29:54 --> 00:29:56 work done. It's a little bit interesting
00:29:56 --> 00:29:59 because on the earth the only processes
00:29:59 --> 00:30:03 that produce this peculiar gas are
00:30:03 --> 00:30:05 technology and industry or life.
00:30:05 --> 00:30:06 >> Yeah.
00:30:06 --> 00:30:07 >> We don't know of any other way that it's
00:30:07 --> 00:30:08 made. But that doesn't mean that there
00:30:08 --> 00:30:10 aren't other ways that it's made.
00:30:10 --> 00:30:11 >> Isn't that a tasty morsel for the
00:30:12 --> 00:30:12 popular press?
00:30:12 --> 00:30:14 >> Absolutely. But what happened then was
00:30:14 --> 00:30:17 that there is an American
00:30:17 --> 00:30:19 outreach journal um science
00:30:19 --> 00:30:21 communication journal that broke embargo
00:30:21 --> 00:30:24 on this story. Didn't talk to Jane and
00:30:24 --> 00:30:26 her colleagues, but instead ran a story
00:30:26 --> 00:30:28 saying British scientists find life on
00:30:28 --> 00:30:29 Venus, which is not what they'd said at
00:30:29 --> 00:30:30 all. No,
00:30:30 --> 00:30:32 >> that's what started the absolute bum
00:30:32 --> 00:30:35 fight. And the vitrial and the hate and
00:30:35 --> 00:30:36 the death threats, believe it or not,
00:30:36 --> 00:30:39 that Jen Greavves got because of this
00:30:39 --> 00:30:41 >> were astonishing. It was absolutely
00:30:41 --> 00:30:43 terrible. And instead of being able to
00:30:43 --> 00:30:45 manage the deployment of this wonderful
00:30:45 --> 00:30:47 story about this fascinating new result
00:30:47 --> 00:30:49 they got, they spent all their time in
00:30:49 --> 00:30:53 damage control because this publication
00:30:54 --> 00:30:56 chose to break the embargo early and run
00:30:56 --> 00:30:58 a story that was not factually true but
00:30:58 --> 00:30:59 again would get them clicks.
00:30:59 --> 00:31:02 >> Yep. Yeah. And and that's unfortunately
00:31:02 --> 00:31:05 the modern media and um the the
00:31:05 --> 00:31:07 internet's to blame. Well, it's not the
00:31:07 --> 00:31:08 internet that's to blame. It's the
00:31:08 --> 00:31:11 people who use it that are to blame. And
00:31:11 --> 00:31:13 it's one of the um one of the things you
00:31:13 --> 00:31:16 really got to be careful of when you are
00:31:16 --> 00:31:18 following a story, whether it's an exoc
00:31:18 --> 00:31:22 comet that's not a spaceship or uh life
00:31:22 --> 00:31:25 that's not in Venus's atmosphere. Um and
00:31:25 --> 00:31:28 and even to a lesser degree, and you and
00:31:28 --> 00:31:30 I mentioned this before we started, the
00:31:30 --> 00:31:33 way the media gets its information
00:31:33 --> 00:31:37 confused, such as uh reporting on uh you
00:31:37 --> 00:31:40 upcoming spectacular meteor showers that
00:31:40 --> 00:31:42 uh everyone gets excited about and then
00:31:42 --> 00:31:43 they realize they're on the wrong side
00:31:43 --> 00:31:44 of the planet.
00:31:44 --> 00:31:46 >> Absolutely. And this is a caution I give
00:31:46 --> 00:31:48 to everybody both for comets and for
00:31:48 --> 00:31:49 meteors actually, but particularly for
00:31:50 --> 00:31:51 those of us in the southern hemisphere.
00:31:51 --> 00:31:55 Um, meteor showers and comets are things
00:31:55 --> 00:31:57 that are best seen from some latitudes
00:31:57 --> 00:31:59 and not from others. And for each comet
00:31:59 --> 00:32:00 or for each meteor shower, that's
00:32:00 --> 00:32:02 different. Now, I'll talk later on about
00:32:02 --> 00:32:04 a newly discovered comet that might be
00:32:04 --> 00:32:07 very spectacular in late 2028.
00:32:07 --> 00:32:09 That comet is primarily going to be a
00:32:09 --> 00:32:11 southern hemisphere object. So, it will
00:32:11 --> 00:32:13 probably be better for us in Australia
00:32:13 --> 00:32:14 and New Zealand than it will be for
00:32:14 --> 00:32:16 people in the UK or the US, just as an
00:32:16 --> 00:32:18 example.
00:32:18 --> 00:32:19 when events are happening that are
00:32:20 --> 00:32:21 primarily good for the northern
00:32:21 --> 00:32:22 hemisphere. The northern hemisphere has
00:32:22 --> 00:32:24 more people and more media. And what
00:32:24 --> 00:32:26 I've seen happen more and more is that
00:32:26 --> 00:32:30 the media in Australia and I know the
00:32:30 --> 00:32:31 Australian stuff because that's local to
00:32:31 --> 00:32:33 us. It's probably just the same in New
00:32:33 --> 00:32:35 Zealand, South Africa, South America,
00:32:35 --> 00:32:37 all these other places. But the media
00:32:37 --> 00:32:38 there will pick up these stories and
00:32:38 --> 00:32:41 just run them without running the sanity
00:32:42 --> 00:32:44 featur filter. So the April lyids are a
00:32:44 --> 00:32:46 really good example of this, but a
00:32:46 --> 00:32:47 better one is probably the Percid meteor
00:32:47 --> 00:32:50 shower in August. Now, as a little bit
00:32:50 --> 00:32:52 of background here, when we've got a
00:32:52 --> 00:32:54 meteor shower, we're getting bits of
00:32:54 --> 00:32:55 dust and debris hitting the Earth's
00:32:55 --> 00:32:58 atmosphere and ablating at an altitude
00:32:58 --> 00:33:01 of about 80 km. Now, ablation is a
00:33:02 --> 00:33:03 slightly weird thing. People often
00:33:03 --> 00:33:05 describe this as burning up, but it's
00:33:05 --> 00:33:06 not burning up in the sense of a flame
00:33:06 --> 00:33:09 being lit and a fire burning. It's
00:33:09 --> 00:33:10 rather that these things push into the
00:33:10 --> 00:33:12 atmosphere at really high speed, pile
00:33:12 --> 00:33:13 the air up in front of them, getting the
00:33:14 --> 00:33:16 air superheated, creating a load of
00:33:16 --> 00:33:18 plasma, and the heat from that bakes and
00:33:18 --> 00:33:20 vaporizes the bit of debris. So, it's
00:33:20 --> 00:33:22 not burning up in the traditional sense.
00:33:22 --> 00:33:24 And anytime you see a meteor, you see a
00:33:24 --> 00:33:25 shooting star, that's what you're
00:33:25 --> 00:33:27 seeing. And the bigger the bit of dust,
00:33:27 --> 00:33:29 the brighter it will be. The faster it's
00:33:29 --> 00:33:31 moving at a given size, the more energy
00:33:31 --> 00:33:32 it's got. So, again, the brighter it'll
00:33:32 --> 00:33:33 be.
00:33:33 --> 00:33:33 >> Yeah.
00:33:33 --> 00:33:36 >> And you see shooting stars on any night
00:33:36 --> 00:33:39 of the year. typically three or four an
00:33:39 --> 00:33:41 hour in the evenings, five or six an
00:33:41 --> 00:33:43 hour in the mornings potentially. And
00:33:43 --> 00:33:44 that difference is just because in the
00:33:44 --> 00:33:45 mornings you're facing the direction the
00:33:45 --> 00:33:47 earth's moving. So you getting
00:33:47 --> 00:33:49 collisions that are headon. So the
00:33:49 --> 00:33:51 average collision speed is higher. So a
00:33:51 --> 00:33:53 grain of dust that's the same size will
00:33:53 --> 00:33:55 be a bit brighter. Therefore, the things
00:33:55 --> 00:33:56 that in the evening that will be too
00:33:56 --> 00:33:58 faint to see become visible. So you get
00:33:58 --> 00:34:00 a slight increase in the rate towards
00:34:00 --> 00:34:03 morning than in the evening. Um, it's
00:34:03 --> 00:34:04 also you're probably getting a slightly
00:34:04 --> 00:34:05 increased amount of stuff entering the
00:34:06 --> 00:34:07 atmosphere cuz you always see more flies
00:34:07 --> 00:34:08 hit your windscreen than your air
00:34:08 --> 00:34:11 windscreen. Same kind of idea.
00:34:11 --> 00:34:13 >> When we get a meteor shower, what's
00:34:13 --> 00:34:16 happening is we're passing through the
00:34:16 --> 00:34:18 area of space where the Earth passes
00:34:18 --> 00:34:20 near the orbit of either a comet or an
00:34:20 --> 00:34:22 asteroid. And typically, it's a comet.
00:34:22 --> 00:34:24 >> Now, every time a comet goes around the
00:34:24 --> 00:34:27 sun, that dirty snowball or snowy dirt
00:34:27 --> 00:34:29 ball gets hot. The volatile material on
00:34:30 --> 00:34:32 the surface is too hot to stay solid. So
00:34:32 --> 00:34:34 becomes a gas in a process called
00:34:34 --> 00:34:36 sublimation. And you get jets erupting
00:34:36 --> 00:34:40 from the comet, shrouding in gas, which
00:34:40 --> 00:34:41 is then blown away from the sun to give
00:34:41 --> 00:34:44 you the tails. Those jets erupting into
00:34:44 --> 00:34:47 space carry with them dust.
00:34:47 --> 00:34:49 Now biggest bits of dust are pushed away
00:34:49 --> 00:34:50 so gently they'll fall back to the comet
00:34:50 --> 00:34:52 and clog it up. And some comets
00:34:52 --> 00:34:54 eventually turn off because of this.
00:34:54 --> 00:34:56 also is the reason most comets are only
00:34:56 --> 00:34:58 active from a few few locations on the
00:34:58 --> 00:35:00 surface, not uniformly because most of
00:35:00 --> 00:35:02 the surface is clogged up and you've
00:35:02 --> 00:35:03 just got a few active areas where
00:35:03 --> 00:35:05 volatile material is exposed.
00:35:05 --> 00:35:06 >> Yeah.
00:35:06 --> 00:35:07 >> But that dust that's ejected from the
00:35:07 --> 00:35:10 comet is ejected with speeds measured in
00:35:10 --> 00:35:12 meters/s or centimeters/s
00:35:12 --> 00:35:14 from an object that's traveling at a
00:35:14 --> 00:35:15 speed measured in tens of kilometers/ a
00:35:15 --> 00:35:18 second. So, what that means is that that
00:35:18 --> 00:35:21 dust is moving away from the comet at a
00:35:21 --> 00:35:23 speed almost identical to the speed the
00:35:23 --> 00:35:25 comet's traveling itself. I guess it's
00:35:25 --> 00:35:28 like if you you're driving along the
00:35:28 --> 00:35:29 road and you drop a tennis ball out of
00:35:29 --> 00:35:31 the window until the wind resistance
00:35:32 --> 00:35:33 pushes it back. If there wasn't a wind
00:35:33 --> 00:35:35 resistance there, it would move along
00:35:35 --> 00:35:37 with the car just drifting away very
00:35:37 --> 00:35:39 slightly based on the speed you pushed
00:35:39 --> 00:35:41 it out of the window. Same idea.
00:35:41 --> 00:35:43 >> Yeah. I actually saw a a really great
00:35:43 --> 00:35:47 experiment once where they were um how
00:35:48 --> 00:35:49 did they do it? They had a guy on the
00:35:49 --> 00:35:53 back of a truck and they were driving at
00:35:53 --> 00:35:57 like 100 kilometers an hour and they
00:35:57 --> 00:35:59 shot him off the truck in the opposite
00:35:59 --> 00:36:03 direction at the same speed and he just
00:36:03 --> 00:36:04 stopped where he landed.
00:36:04 --> 00:36:06 >> Oh, it's brilliant. I think Mythbusters
00:36:06 --> 00:36:07 did something similar.
00:36:07 --> 00:36:08 >> It's amazing.
00:36:08 --> 00:36:11 >> Our common sense is physics really.
00:36:11 --> 00:36:13 >> Yeah, simple physics is great, but our
00:36:13 --> 00:36:15 common sense breaks down in some
00:36:15 --> 00:36:17 situations because our common sense is a
00:36:17 --> 00:36:19 naturally inherited thing about the
00:36:19 --> 00:36:22 world at the speeds we experience it.
00:36:22 --> 00:36:23 >> And so we tend to think if you're
00:36:23 --> 00:36:25 running forwards at 10 km an hour and
00:36:25 --> 00:36:27 you throw something forwards, it will
00:36:27 --> 00:36:29 travel a bit faster. That breaks down
00:36:29 --> 00:36:30 when you get to relativity. There's all
00:36:30 --> 00:36:33 these weird things around it. where our
00:36:33 --> 00:36:35 common sense gets it wrong for comets
00:36:35 --> 00:36:37 and for the dust. And it took me a long
00:36:37 --> 00:36:38 while to get my head around this because
00:36:38 --> 00:36:40 it's a bit counterintuitive.
00:36:40 --> 00:36:43 If you eject dust from a comet, you can
00:36:43 --> 00:36:44 eject the dust forward or backwards. So
00:36:44 --> 00:36:46 you can imagine this jet from the comet
00:36:46 --> 00:36:48 working a bit like a geyser turning off
00:36:48 --> 00:36:50 when it gets dark and it gets cold and
00:36:50 --> 00:36:51 then turning off again in the morning
00:36:51 --> 00:36:53 when it gets hot again.
00:36:53 --> 00:36:55 >> That can throw dust forwards, sidewards,
00:36:55 --> 00:36:58 and backwards or any combination of the
00:36:58 --> 00:37:00 above. So that means this comet is
00:37:00 --> 00:37:01 throwing out dust at a speed of
00:37:01 --> 00:37:04 meters/s, a bit like a sprinkler into
00:37:04 --> 00:37:07 space. The dust that has a forward
00:37:07 --> 00:37:09 component to its speed. So it could be
00:37:09 --> 00:37:11 going sidewards but a little forward or
00:37:11 --> 00:37:12 it could be going head-on in front of
00:37:12 --> 00:37:14 the comet. That is now traveling around
00:37:14 --> 00:37:17 the sun faster than the comet is, which
00:37:17 --> 00:37:19 means it will move onto an orbit with a
00:37:19 --> 00:37:21 longer period than the comet. So the
00:37:21 --> 00:37:23 next time the comet comes around, that
00:37:23 --> 00:37:24 grain of dust will arrive after the
00:37:24 --> 00:37:27 comet. So dust thrown forward ends up
00:37:27 --> 00:37:29 behind. And similarly does thrown
00:37:29 --> 00:37:30 backwards is moving slower than the
00:37:30 --> 00:37:32 comet which puts it on a slightly
00:37:32 --> 00:37:34 shorter period orbit and therefore it
00:37:34 --> 00:37:36 will arrive ahead of the comet next
00:37:36 --> 00:37:37 time. And that little bit of sidewards
00:37:37 --> 00:37:39 motion also means it will spread out a
00:37:39 --> 00:37:42 little bit in space. What this means
00:37:42 --> 00:37:44 over time periods is that comets every
00:37:44 --> 00:37:46 time they come round essentially shed
00:37:46 --> 00:37:48 what becomes like a javelin shape, a
00:37:48 --> 00:37:51 spear of dust into space with a comet at
00:37:51 --> 00:37:53 the center
00:37:53 --> 00:37:55 like a spike. And that spike gradually
00:37:55 --> 00:37:57 diffuses over time, spreads out further
00:37:57 --> 00:37:59 and further ahead and behind the comet.
00:37:59 --> 00:38:01 And so over a long time scale, you
00:38:01 --> 00:38:03 eventually end up with the comet's orbit
00:38:03 --> 00:38:05 shrouded in dust. And the dust can be
00:38:05 --> 00:38:06 quite spread out over millions of
00:38:06 --> 00:38:07 kilometers.
00:38:07 --> 00:38:08 >> Yeah,
00:38:08 --> 00:38:10 >> these orbits are oriented randomly in
00:38:10 --> 00:38:12 space. So many of them don't intersect
00:38:12 --> 00:38:14 the Earth. Even if the comet gets closer
00:38:14 --> 00:38:16 to the sun than we are at its closest,
00:38:16 --> 00:38:18 passes above or below the Earth's orbit,
00:38:18 --> 00:38:21 nothing happens. But for a subset of
00:38:21 --> 00:38:25 them, the comet will in its orbit have
00:38:25 --> 00:38:26 the potential to get very close to the
00:38:26 --> 00:38:28 Earth. So its orbit and the Earth get
00:38:28 --> 00:38:30 very close together. And in those cases,
00:38:30 --> 00:38:32 every time we go around the sun, if that
00:38:32 --> 00:38:34 comet's been laying dust down for a
00:38:34 --> 00:38:36 while, we'll run into the dust every
00:38:36 --> 00:38:38 time we go around. And that dust will
00:38:38 --> 00:38:39 hit the Earth's atmosphere, which means
00:38:40 --> 00:38:41 we're going through a dirtier bit of the
00:38:41 --> 00:38:43 solar system, and we get more meteors.
00:38:43 --> 00:38:45 That's when we get a meteor shower. But
00:38:45 --> 00:38:47 the other telltale thing for the meteor
00:38:47 --> 00:38:49 shower is all the dust grains that hit
00:38:49 --> 00:38:52 the earth in a meteor shower are moving
00:38:52 --> 00:38:53 essentially parallel to each other.
00:38:53 --> 00:38:54 They're all following the same orbit
00:38:54 --> 00:38:56 around the sun hitting the earth from
00:38:56 --> 00:38:59 the same direction at the same speed.
00:38:59 --> 00:39:01 So all this dust is coming towards you
00:39:01 --> 00:39:03 from a single point in space. So from
00:39:03 --> 00:39:05 your point of view looking at the sky
00:39:05 --> 00:39:06 when you see those meteors part of a
00:39:06 --> 00:39:09 meteor shower they appear to appear
00:39:09 --> 00:39:12 anywhere in the sky. But if you trace
00:39:12 --> 00:39:13 them back they'll all point to a single
00:39:13 --> 00:39:15 point in the sky. something we call the
00:39:15 --> 00:39:18 radiant and that's effectively the point
00:39:18 --> 00:39:19 in space they're traveling towards us
00:39:19 --> 00:39:21 from and they diverge because of
00:39:21 --> 00:39:23 perspective they're coming closer to you
00:39:23 --> 00:39:26 so every meteor shower has a radiant in
00:39:26 --> 00:39:28 the sky the April lids have their
00:39:28 --> 00:39:31 radiant in Lyra although for a fair part
00:39:31 --> 00:39:32 of their time it's actually in Hercules
00:39:32 --> 00:39:35 it drifts a bit the perids have their
00:39:35 --> 00:39:37 radiant in Perseus the Geminids in
00:39:37 --> 00:39:40 Gemini and so on
00:39:40 --> 00:39:42 >> so that's all well and good if the
00:39:42 --> 00:39:45 radiant is below the horizon horizon.
00:39:45 --> 00:39:46 That means the meteors are hitting the
00:39:46 --> 00:39:47 other side of the Earth and you can't
00:39:47 --> 00:39:50 see them because the Earth's in the way.
00:39:50 --> 00:39:52 So, first point with a meteor shower is
00:39:52 --> 00:39:55 unlike some of the media reports, you
00:39:55 --> 00:39:56 can't see meteors for that meteor shower
00:39:56 --> 00:39:58 at any time of night. You can only see
00:39:58 --> 00:39:59 them when the radiant's above the
00:39:59 --> 00:40:03 horizon. Point number one. Point the
00:40:03 --> 00:40:05 second is the higher in the sky that
00:40:05 --> 00:40:07 radiant is, the more head on into the
00:40:07 --> 00:40:09 stream you're going. So, the more
00:40:09 --> 00:40:11 meteors you'll see. Now, the analogy I
00:40:11 --> 00:40:13 I'd use here is if you imagine getting
00:40:13 --> 00:40:15 your hose pipe and having it on that
00:40:16 --> 00:40:17 shower mode, you know, where water's
00:40:17 --> 00:40:20 coming out from many holes all at once.
00:40:20 --> 00:40:21 If you hold that hose pipe vertically
00:40:22 --> 00:40:23 and turn the tap on, all the water from
00:40:24 --> 00:40:25 that hose pipe will hit a relatively
00:40:25 --> 00:40:27 small area of the ground.
00:40:27 --> 00:40:30 >> If you turn that hose pipe to 45°, that
00:40:30 --> 00:40:32 water will spread out over a larger
00:40:32 --> 00:40:33 surface area.
00:40:33 --> 00:40:35 >> Yep. Now, if you imagine the meteors,
00:40:35 --> 00:40:37 the dust in a meteor shower coming in
00:40:37 --> 00:40:40 towards the Earth, the more directly
00:40:40 --> 00:40:42 overhead your point that they're coming
00:40:42 --> 00:40:45 from is, the more meteors you'll get in
00:40:45 --> 00:40:47 a certain volume of the atmosphere. And
00:40:47 --> 00:40:49 the lower to the horizon that point is,
00:40:49 --> 00:40:50 the more you'll spread those same number
00:40:50 --> 00:40:53 of grains of dust out. So, the higher in
00:40:53 --> 00:40:56 the sky the radiant is, the more dust is
00:40:56 --> 00:40:58 hitting the part of the atmosphere you
00:40:58 --> 00:40:59 can see from your location. So, the more
00:40:59 --> 00:41:02 meteors you get. And what this means is
00:41:02 --> 00:41:03 the lower in the sky the radiant is the
00:41:04 --> 00:41:06 fewer meteors you see. And so you see
00:41:06 --> 00:41:08 the most meteors for a given meteor
00:41:08 --> 00:41:10 shower when the radiant is near what we
00:41:10 --> 00:41:11 call culmination where it's nearly
00:41:11 --> 00:41:13 highest in the sky.
00:41:13 --> 00:41:14 >> For the southern hemisphere when it's
00:41:14 --> 00:41:16 nearly due north for the northern
00:41:16 --> 00:41:19 hemisphere the radiant nearly due south.
00:41:19 --> 00:41:22 So all well and good. But what that
00:41:22 --> 00:41:24 means is that from different locations
00:41:24 --> 00:41:26 on the earth a given meteor shower will
00:41:26 --> 00:41:27 give you a different strength of
00:41:27 --> 00:41:32 display. The April lyids, their radiant
00:41:32 --> 00:41:34 is 34 degrees north of the equator. So
00:41:34 --> 00:41:37 that means if you lived 34 degrees north
00:41:37 --> 00:41:39 of the equator, at about 2:00 a.m. in
00:41:39 --> 00:41:40 the morning, the radiant would be
00:41:40 --> 00:41:42 overhead and you're in the best place on
00:41:42 --> 00:41:44 the planet to see the meteors. If you
00:41:44 --> 00:41:47 had perfect vision, perfectly dark sky,
00:41:47 --> 00:41:50 you'd see a number of meteors 15 to 20
00:41:50 --> 00:41:52 per hour for the Aprils. And that's
00:41:52 --> 00:41:54 called the zenithl hourly rate. That's
00:41:54 --> 00:41:55 the number of meters you'd see in
00:41:56 --> 00:41:58 perfect conditions with perfect eyesight
00:41:58 --> 00:42:00 with no light pollution if the radiant
00:42:00 --> 00:42:02 was overhead. The lower the radiant is
00:42:02 --> 00:42:03 in the sky, the more that number
00:42:03 --> 00:42:07 shrinks. So the ZHR is the theoretical
00:42:07 --> 00:42:10 maximum number you'd see. So good meteor
00:42:10 --> 00:42:12 shower, not a great one from the
00:42:12 --> 00:42:13 northern hemisphere, but for us in
00:42:13 --> 00:42:17 Brisbane, let's say 26° south, the
00:42:17 --> 00:42:19 radiant of the April Lyids at its
00:42:19 --> 00:42:21 highest in the sky is only 30° above the
00:42:21 --> 00:42:24 horizon. That means that the volume of
00:42:24 --> 00:42:26 space where the dust is arriving is
00:42:26 --> 00:42:28 doubled. So you'd only see half the
00:42:28 --> 00:42:30 number of meteors.
00:42:30 --> 00:42:32 >> So instead of 20 per hour, you're down
00:42:32 --> 00:42:35 to 10 an hour immediately before
00:42:35 --> 00:42:37 anything else kicks in. And the further
00:42:37 --> 00:42:39 south you go, the lower the rates are.
00:42:39 --> 00:42:41 But the problem is the journalist
00:42:41 --> 00:42:42 covering this will pick up on a northern
00:42:42 --> 00:42:45 hemisphere article and just repeat it.
00:42:45 --> 00:42:46 There's this meteor shower happening.
00:42:46 --> 00:42:48 You can see them all night every night.
00:42:48 --> 00:42:49 Well, that's not right. If the radiant's
00:42:50 --> 00:42:51 below the horizon, you can't see them.
00:42:51 --> 00:42:53 and you'll see 100 per hour and that's
00:42:53 --> 00:42:55 because they've seen the zenithal rate
00:42:55 --> 00:42:57 quoted as 100 per hour and they just use
00:42:58 --> 00:42:59 it as a number.
00:42:59 --> 00:42:59 >> Yeah.
00:42:59 --> 00:43:01 >> Unless you are incredibly incredibly
00:43:01 --> 00:43:04 fortunate, you will never see the same
00:43:04 --> 00:43:07 number of meteors as the ZHR predicts
00:43:07 --> 00:43:09 because the radiant won't be directly
00:43:09 --> 00:43:11 overhead. So the rate gets lower. Your
00:43:12 --> 00:43:13 eyes are not perfect unless you're one
00:43:13 --> 00:43:15 of the very rare observers. The rates
00:43:15 --> 00:43:17 will get lower.
00:43:17 --> 00:43:18 >> There might be light pollution. The
00:43:18 --> 00:43:21 phentto meteors are not seen. the rates
00:43:21 --> 00:43:23 get lower. The moon might be in the sky.
00:43:23 --> 00:43:24 The faint meters are not seen. The rates
00:43:24 --> 00:43:28 are lower. So you will never see a
00:43:28 --> 00:43:29 number of meters in the sky equal to the
00:43:29 --> 00:43:32 ZHR unless the meteor shower is more
00:43:32 --> 00:43:34 active than predicted in which case the
00:43:34 --> 00:43:37 ZHR will be higher and you'd see more.
00:43:37 --> 00:43:39 Where this really comes in is for meteor
00:43:39 --> 00:43:41 showers like the perids. The perids are
00:43:41 --> 00:43:43 one of the big three. There are three
00:43:43 --> 00:43:45 awesome meteor showers a year that are
00:43:45 --> 00:43:48 by far the best in a given year. They're
00:43:48 --> 00:43:51 the highest rate. So most dust coming in
00:43:51 --> 00:43:53 or the highest speed. The quadrantids in
00:43:53 --> 00:43:55 early January
00:43:55 --> 00:43:57 are very very shortlived. They're a wage
00:43:57 --> 00:43:58 shower. You've got a very low rate of
00:43:58 --> 00:43:59 meteors for most of the time they're
00:43:59 --> 00:44:01 active and then a very narrow spike that
00:44:01 --> 00:44:04 can be very big. But if you manage to
00:44:04 --> 00:44:05 see that spike, there's a lot of
00:44:05 --> 00:44:07 meteors. They're only really visible
00:44:07 --> 00:44:09 from the northern hemisphere. The perids
00:44:10 --> 00:44:12 in August are probably the most storied
00:44:12 --> 00:44:16 meteor shower with long history of
00:44:16 --> 00:44:17 observations
00:44:17 --> 00:44:19 linked to comet Swift Tuttle which goes
00:44:19 --> 00:44:22 around every 120 130 years incidentally
00:44:22 --> 00:44:24 will be incredibly spectacular in the
00:44:24 --> 00:44:26 year 2126 if people hang around to see
00:44:26 --> 00:44:26 it.
00:44:26 --> 00:44:28 >> Yeah. Okay. I'll I'll write that in my
00:44:28 --> 00:44:29 diary.
00:44:29 --> 00:44:31 >> Um Percids are brilliant but their
00:44:31 --> 00:44:34 radiant is at about 55° north in the
00:44:34 --> 00:44:36 sky.
00:44:36 --> 00:44:37 Fabulous from Northern Europe, fabulous
00:44:37 --> 00:44:39 from North America, places north of the
00:44:39 --> 00:44:41 equator to get a really good show. But
00:44:41 --> 00:44:44 we get articles every year on commercial
00:44:44 --> 00:44:45 media here in Australia saying the
00:44:45 --> 00:44:47 persons are happening. Go out tonight
00:44:47 --> 00:44:49 and you'll see 100 meters an hour. And
00:44:49 --> 00:44:51 for most of Australia, the radiant never
00:44:51 --> 00:44:54 even rises. Never. You know, south of
00:44:54 --> 00:44:56 about 35° south, the radiant will never
00:44:56 --> 00:44:57 rise. I think that's about the latitude
00:44:58 --> 00:44:59 of Sydney.
00:44:59 --> 00:45:01 >> North of that, it will rise, but it'll
00:45:01 --> 00:45:02 be very low to the horizon. And so
00:45:02 --> 00:45:04 you'll see a much lower rate unless
00:45:04 --> 00:45:05 you're in the top top end. If you're in
00:45:06 --> 00:45:07 the top end of Australia, it's a bit
00:45:07 --> 00:45:10 different. And so when you see articles
00:45:10 --> 00:45:12 like this, you need to engage your
00:45:12 --> 00:45:14 science brain and say the journal is
00:45:14 --> 00:45:15 wrong.
00:45:15 --> 00:45:15 >> Yeah.
00:45:15 --> 00:45:19 >> Where's my location? What's the radiance
00:45:19 --> 00:45:21 declination, which is latitude in the
00:45:21 --> 00:45:23 sky effectively? Figure out how high in
00:45:23 --> 00:45:24 the sky it'll get, and that will give
00:45:24 --> 00:45:26 you a feel for what you might actually
00:45:26 --> 00:45:29 see. Now, if you want to um look at the
00:45:29 --> 00:45:31 meteor shower calendar and figure out
00:45:31 --> 00:45:32 when there are good ones happening, the
00:45:32 --> 00:45:35 International Meteor organization is my
00:45:35 --> 00:45:37 go-to on this. They're a fabulous
00:45:37 --> 00:45:38 organization that put together every
00:45:38 --> 00:45:41 year a calendar. And that calendar lists
00:45:41 --> 00:45:42 all the meteor showers from the
00:45:42 --> 00:45:43 incredibly minor ones that give one
00:45:43 --> 00:45:45 meteor every two hours, you know, to the
00:45:46 --> 00:45:48 major ones. And every year it writes
00:45:48 --> 00:45:50 about the conditions in terms of
00:45:50 --> 00:45:52 moonlight as well. Because if the moon
00:45:52 --> 00:45:55 is bright, you will see far fewer
00:45:55 --> 00:45:57 meteors. And coming up in a couple of
00:45:57 --> 00:45:59 weeks from when we're having this
00:45:59 --> 00:46:01 discussion, but in the past as we
00:46:01 --> 00:46:03 actually go live to air, you've got the
00:46:03 --> 00:46:05 peak of the Aquarids. Now the Aquarids
00:46:05 --> 00:46:07 are one of the few showers that's better
00:46:07 --> 00:46:08 for southern hemisphere than northern
00:46:08 --> 00:46:10 hemisphere. Fragments of comet Hali and
00:46:10 --> 00:46:13 they're at their peak around the 3rd to
00:46:13 --> 00:46:16 the 7th of May. Have quite a broad peak.
00:46:16 --> 00:46:18 But this year the moon is a waning
00:46:18 --> 00:46:21 gibbus. So at the time of night when you
00:46:21 --> 00:46:22 could see these meteors, the sky will be
00:46:22 --> 00:46:25 really bright and so far fewer will be
00:46:25 --> 00:46:27 visible than normal and you can get that
00:46:27 --> 00:46:29 from these calendars. But the highlight
00:46:29 --> 00:46:30 of every year for me showers is the
00:46:30 --> 00:46:34 Geminids in December and they are pretty
00:46:34 --> 00:46:36 much global as a phenomenon and they're
00:46:36 --> 00:46:38 brilliant everywhere. Obviously better
00:46:38 --> 00:46:39 for the northern hemisphere than the
00:46:39 --> 00:46:42 south. That's like a recurring theme,
00:46:42 --> 00:46:45 but they are great every year and this
00:46:45 --> 00:46:47 year moon will be effectively new. So,
00:46:48 --> 00:46:49 if you want to go see the Geminids
00:46:49 --> 00:46:51 peaking on the 14th or 15th of December,
00:46:51 --> 00:46:53 they're the highlight this year and
00:46:53 --> 00:46:54 pretty much every year.
00:46:54 --> 00:46:56 >> Okay. Uh, we're going to take another
00:46:56 --> 00:46:58 breath and then we'll come back and wrap
00:46:58 --> 00:47:00 it all up in this episode of Space Nuts
00:47:00 --> 00:47:05 with Andrew Dunley and Jonty Horner.
00:47:05 --> 00:47:07 >> Swift
00:47:07 --> 00:47:09 base here. The angle has landed.
00:47:09 --> 00:47:13 >> Space Nuts. One of my big frustrations
00:47:13 --> 00:47:16 uh when I want to observe comets is I
00:47:16 --> 00:47:19 live on a very flat area of the planet.
00:47:19 --> 00:47:22 Uh we don't have mountains nearby. We
00:47:22 --> 00:47:24 barely have hills and a lot of the
00:47:24 --> 00:47:29 comets are visible in the low horizon
00:47:29 --> 00:47:33 just after sunset or thereabouts. And
00:47:33 --> 00:47:35 they're short-lived and they're they're
00:47:35 --> 00:47:38 below the horizon way too quick. uh
00:47:38 --> 00:47:40 which makes astrophotography a real pain
00:47:40 --> 00:47:44 in the butt for me. But it is just a a
00:47:44 --> 00:47:49 quirk of where I live. Um I believe the
00:47:49 --> 00:47:51 that we do have some pretty spectacular
00:47:51 --> 00:47:54 ones coming up. I I the one that I've
00:47:54 --> 00:47:56 seen in my life that was the most
00:47:56 --> 00:48:00 spectacular for me was in 2007, January
00:48:00 --> 00:48:01 2007.
00:48:01 --> 00:48:05 Uh the it was Comet McNort. It was
00:48:05 --> 00:48:08 amazing. like naked eye comet wise it
00:48:08 --> 00:48:12 was unmissable. Uh it dominated the sky
00:48:12 --> 00:48:14 for quite some time. Uh we don't see
00:48:14 --> 00:48:17 many like that though do we? We don't.
00:48:17 --> 00:48:18 Now comet McNaugh was probably the
00:48:18 --> 00:48:21 brightest comet since the 1960s and it
00:48:21 --> 00:48:24 was truly a great comet. Now when we
00:48:24 --> 00:48:26 talk about the brightest comets and the
00:48:26 --> 00:48:29 ones people want to see great comet is
00:48:29 --> 00:48:30 the Appalachian people attached to
00:48:30 --> 00:48:32 comets and it's got a woollyish
00:48:32 --> 00:48:33 definition. It's basically the comet was
00:48:34 --> 00:48:35 bright enough and spectacular enough
00:48:36 --> 00:48:37 that even people who weren't that
00:48:37 --> 00:48:39 interested could just step outside and
00:48:39 --> 00:48:40 see it. Comet McNot's definitely like
00:48:40 --> 00:48:43 that. Arguably Comet Chuchchin Chan
00:48:43 --> 00:48:46 Atlas in 2024 and Comet Atlas in early
00:48:46 --> 00:48:50 2025 just made that threshold. So if you
00:48:50 --> 00:48:51 saw those comets, you'd probably say
00:48:51 --> 00:48:53 they are right at the lower end of what
00:48:54 --> 00:48:56 we consider a great comet. M
00:48:56 --> 00:48:58 >> on average if you go back through
00:48:58 --> 00:49:00 historical comic records you'd probably
00:49:00 --> 00:49:02 get about 10 great comics per century
00:49:02 --> 00:49:05 with very wide variance and that's not
00:49:05 --> 00:49:07 one every 10 years though like buses you
00:49:07 --> 00:49:09 wait 30 years and two come along at once
00:49:09 --> 00:49:12 and you saw that back in 1996 with comet
00:49:12 --> 00:49:14 Hailbop and comet H high kitaki which
00:49:14 --> 00:49:16 were visible in the sky at the same time
00:49:16 --> 00:49:18 as great comets.
00:49:18 --> 00:49:19 >> It's really hard to predict when they're
00:49:19 --> 00:49:21 going to come in but we've seen some
00:49:21 --> 00:49:23 really fascinating advances in the last
00:49:23 --> 00:49:26 few years on two fronts. Firstly, our
00:49:26 --> 00:49:28 ability to find things early has
00:49:28 --> 00:49:31 improved. We've got better telescopes,
00:49:31 --> 00:49:34 more automated surveys, and comet maps
00:49:34 --> 00:49:35 earlier this year, which turned out to
00:49:35 --> 00:49:36 be a bit of a disappointment for many
00:49:36 --> 00:49:37 people, is a really good example of
00:49:38 --> 00:49:39 that. That's a member of the CO
00:49:39 --> 00:49:42 sungrazing family. And the CO sungrazers
00:49:42 --> 00:49:44 have numbered many of the brightest
00:49:44 --> 00:49:46 great comets of the last couple of
00:49:46 --> 00:49:49 thousand years. Comet maps was the
00:49:49 --> 00:49:50 earliest we've ever found a crot
00:49:50 --> 00:49:53 sungrazer on the way in earlier even
00:49:53 --> 00:49:56 than comedy kayeki which was probably
00:49:56 --> 00:49:58 the brightest comet in the 20th century
00:49:58 --> 00:50:00 back in the late 1960s and so people's
00:50:00 --> 00:50:02 hopes were high but in reality it was
00:50:02 --> 00:50:04 quite a small fragment of the crot's
00:50:04 --> 00:50:07 parents sunraer these crots comets are
00:50:07 --> 00:50:08 all fragments of a bigger comet in the
00:50:08 --> 00:50:10 past and it just fell apart on its way
00:50:10 --> 00:50:13 in nothing to see here but our ability
00:50:14 --> 00:50:17 to find things earlier means that we get
00:50:17 --> 00:50:18 more warning
00:50:18 --> 00:50:19 when a bright comet's coming. Now,
00:50:19 --> 00:50:21 that's not absolutely guaranteed. We had
00:50:21 --> 00:50:23 a comet and the name of it slipped my
00:50:23 --> 00:50:27 mind um comet 12 18 months ago. Um no, I
00:50:27 --> 00:50:31 think it was like last September that
00:50:31 --> 00:50:33 was discovered when it was almost naked
00:50:33 --> 00:50:35 eye visibility. It just about became
00:50:35 --> 00:50:37 naked eye visible. Wasn't great by any
00:50:37 --> 00:50:37 means.
00:50:38 --> 00:50:38 >> Swan,
00:50:38 --> 00:50:39 >> but we got no warning. That's it. Comet
00:50:40 --> 00:50:42 swan. And the reason that that was found
00:50:42 --> 00:50:44 so late was it came at us from behind
00:50:44 --> 00:50:46 the sun and suddenly popped into view.
00:50:46 --> 00:50:49 So that does still happen. But with
00:50:49 --> 00:50:50 facilities like Vera Rubin coming
00:50:50 --> 00:50:52 online, we're going to find comets
00:50:52 --> 00:50:54 earlier and earlier, which means we get
00:50:54 --> 00:50:56 more prior warning, but it also means
00:50:56 --> 00:50:58 that the uncertainty about how bright
00:50:58 --> 00:50:59 they're going to get is possibly even
00:50:59 --> 00:51:02 higher cuz we're almost finding them now
00:51:02 --> 00:51:03 before they've really started to become
00:51:03 --> 00:51:05 active while they're far enough from the
00:51:05 --> 00:51:06 sun that we're almost seeing a bare
00:51:06 --> 00:51:09 nucleus or we're seeing a much smaller
00:51:09 --> 00:51:10 comet that's have a little bit of an
00:51:10 --> 00:51:12 outburst at that distance. And whether
00:51:12 --> 00:51:14 that far away, we effectively can't tell
00:51:14 --> 00:51:16 the difference. they're still like a
00:51:16 --> 00:51:18 single pixel. There's a really good
00:51:18 --> 00:51:20 example of this in the form of comet
00:51:20 --> 00:51:22 Chuch Chin Chan. Um, not comet Chuchchan
00:51:22 --> 00:51:24 Atlas from a couple of years ago, but
00:51:24 --> 00:51:25 comet Chuch Chin Chan that has just been
00:51:25 --> 00:51:27 discovered in the last couple of months.
00:51:27 --> 00:51:30 Comet C/2026C1.
00:51:30 --> 00:51:32 As we record this, that comet is still
00:51:32 --> 00:51:34 more distant from the sun than the orbit
00:51:34 --> 00:51:36 of Saturn.
00:51:36 --> 00:51:38 >> It was found a couple of months ago. It
00:51:38 --> 00:51:39 will not be at its closest to some
00:51:39 --> 00:51:42 perihelion until November 2028. So,
00:51:42 --> 00:51:45 we've got two and a half years to wait.
00:51:45 --> 00:51:47 Now, what factors into a comet's
00:51:47 --> 00:51:49 brightness is very complicated. Um, but
00:51:49 --> 00:51:51 it can boil down to a few different
00:51:51 --> 00:51:53 things. Firstly, if everything else is
00:51:53 --> 00:51:55 equal. So, imagine we only change one
00:51:55 --> 00:51:58 thing. Typically, the bigger the nucleus
00:51:58 --> 00:51:59 of the comet, the bigger its surface
00:52:00 --> 00:52:03 area is, so the more dust and gas it can
00:52:03 --> 00:52:05 produce. And we see the comet from the
00:52:05 --> 00:52:06 light that is reflected from the dust
00:52:06 --> 00:52:08 and gas. That's what makes the tails in
00:52:08 --> 00:52:10 the coma. The snowballs at the head are
00:52:10 --> 00:52:12 actually pretty small. Comet McNaugh was
00:52:12 --> 00:52:14 only about 5 km across for the nucleus,
00:52:14 --> 00:52:17 but it grew tails more than 300 million
00:52:17 --> 00:52:18 km long.
00:52:18 --> 00:52:21 >> Yeah, that's different. Incredible.
00:52:21 --> 00:52:23 >> So, if you have two comet nuclei that
00:52:23 --> 00:52:25 are in all senses identical other than
00:52:25 --> 00:52:27 their size, the bigger one will
00:52:27 --> 00:52:29 typically be more active and produce
00:52:29 --> 00:52:32 more gas and dust. However, some comets
00:52:32 --> 00:52:34 have a larger fraction of their surface
00:52:34 --> 00:52:36 active than others. Some comets are
00:52:36 --> 00:52:38 almost dormant because they're clogged
00:52:38 --> 00:52:39 up and there's very little activity even
00:52:39 --> 00:52:42 from a larger nucleus. So already a bit
00:52:42 --> 00:52:44 complex, but first rule of thumb, the
00:52:44 --> 00:52:46 bigger the nucleus, the more likelihood
00:52:46 --> 00:52:47 there is that it will be able to produce
00:52:47 --> 00:52:48 a lot of gas and dust and be more
00:52:48 --> 00:52:51 spectacular. With comet Chuch Chen Shan,
00:52:51 --> 00:52:53 that's interesting. We found it so far
00:52:53 --> 00:52:55 away, which suggests it is either a
00:52:55 --> 00:52:57 comet with quite a large nucleus because
00:52:57 --> 00:52:59 it's probably not that active at that
00:52:59 --> 00:53:01 distance, but it may have just had a bit
00:53:01 --> 00:53:04 of an outburst of activity driven by
00:53:04 --> 00:53:06 something like carbon monoxide, which
00:53:06 --> 00:53:08 can turn from solid to gas at a very low
00:53:08 --> 00:53:09 temperature. So, it might be
00:53:09 --> 00:53:11 masquerading as a bigger comet than it
00:53:11 --> 00:53:13 is, and we don't know.
00:53:13 --> 00:53:13 >> Okay.
00:53:13 --> 00:53:15 >> The next thing that factors into how
00:53:15 --> 00:53:16 bright a comet gets is how close it gets
00:53:16 --> 00:53:18 to the sun. So the closer it gets to the
00:53:18 --> 00:53:19 sun,
00:53:19 --> 00:53:21 >> the hotter its surface gets and the more
00:53:21 --> 00:53:23 strongly it will be active. So with
00:53:23 --> 00:53:26 comet McNaut, you had a 5 km nucleus
00:53:26 --> 00:53:28 which is fairly respectable but not as
00:53:28 --> 00:53:31 big as Hailbot which was 50 km. Hailbot
00:53:31 --> 00:53:33 was ridiculous. But comet McNaut got
00:53:33 --> 00:53:35 very close into the sun. So it got
00:53:35 --> 00:53:38 really incredibly intensely active was
00:53:38 --> 00:53:39 throwing off huge amounts of gas and
00:53:39 --> 00:53:42 dust. So that contributed again to more
00:53:42 --> 00:53:44 stuff to reflect sunlight and also being
00:53:44 --> 00:53:46 nearer to the sun, the intensity of
00:53:46 --> 00:53:47 light reflecting off it's higher as
00:53:47 --> 00:53:49 well. So kind of get a double whammy
00:53:49 --> 00:53:51 there. The other factor is how close
00:53:51 --> 00:53:53 they get to the earth. So if you have
00:53:53 --> 00:53:55 two comets that are the same size and
00:53:55 --> 00:53:57 the same distance from the sun and one
00:53:57 --> 00:53:59 is closer to the earth than the other,
00:53:59 --> 00:54:00 the one closer to the earth will be
00:54:00 --> 00:54:01 brighter, but will also potentially be
00:54:01 --> 00:54:03 more spread out and more diffuse in the
00:54:03 --> 00:54:05 sky. So that brightness might be spread
00:54:05 --> 00:54:07 over a different area.
00:54:07 --> 00:54:09 You've then got subtleties of how dusty
00:54:09 --> 00:54:12 or gassy they are. Some comets like
00:54:12 --> 00:54:15 comet Pan Stars seem to be more gassy.
00:54:15 --> 00:54:16 Some comets like Chuch Chin Chan Atlas
00:54:16 --> 00:54:17 was more dusty and that can have an
00:54:18 --> 00:54:20 impact on how they brighten. Bringing
00:54:20 --> 00:54:21 all this back together though for comet
00:54:21 --> 00:54:24 Chuch Chin Chan. At its closest to the
00:54:24 --> 00:54:26 Sun, it will be a little bit further
00:54:26 --> 00:54:28 from the Sun than the Earth is. So, it's
00:54:28 --> 00:54:29 not like comet McNaugh that's going to
00:54:29 --> 00:54:32 get really close in. But 1 AU from the
00:54:32 --> 00:54:33 Sun's fairly respectable. it can still
00:54:33 --> 00:54:35 maintain a fairly decent level of
00:54:35 --> 00:54:37 activity at that distance. Comet hellbop
00:54:37 --> 00:54:38 didn't get much closer than that and was
00:54:38 --> 00:54:40 fantastic.
00:54:40 --> 00:54:41 So that's in its favor. It's going to
00:54:41 --> 00:54:43 get close enough in that you could get a
00:54:43 --> 00:54:46 decent level of activity.
00:54:46 --> 00:54:48 Also, because it's only going to get
00:54:48 --> 00:54:50 that close to the sun, it'll take a bit
00:54:50 --> 00:54:51 longer to pass through the inner solar
00:54:51 --> 00:54:53 system. Comets that get really close to
00:54:53 --> 00:54:55 the sun get traveling incredibly quickly
00:54:55 --> 00:54:57 at that point. So they tend to whip in
00:54:57 --> 00:54:58 and whip out fairly quickly. Whereas
00:54:58 --> 00:55:00 with cometry chinchan, it's going to
00:55:00 --> 00:55:03 hang around for a fair while. It is
00:55:03 --> 00:55:05 potentially quite a large cometry
00:55:05 --> 00:55:07 nucleus, but we don't know yet. This is
00:55:07 --> 00:55:10 the the caution I give. If it turns out
00:55:10 --> 00:55:11 that we've caught it during an outburst,
00:55:11 --> 00:55:13 it may be a bit of a disappointment. If
00:55:13 --> 00:55:14 we've actually seen it as a bare
00:55:14 --> 00:55:18 nucleus, that orers very very very well.
00:55:18 --> 00:55:20 What this all suggests is that comet
00:55:20 --> 00:55:23 chaan has the potential to be bright in
00:55:23 --> 00:55:26 late 2028. Depending on which fit to its
00:55:26 --> 00:55:28 current brightness you use, it could
00:55:28 --> 00:55:30 become barely naked eye visible, which
00:55:30 --> 00:55:33 is still pretty good. You know, we see
00:55:33 --> 00:55:35 20 or 30 comets a year and very only
00:55:36 --> 00:55:37 maybe one will get to naked eye
00:55:37 --> 00:55:39 visibility. Or it could get as bright as
00:55:39 --> 00:55:40 the brightest stars. And if it gets as
00:55:40 --> 00:55:43 bright as the brightest stars, then it
00:55:43 --> 00:55:45 gets into great comet type territory.
00:55:45 --> 00:55:47 That's a factor of a 100 difference in
00:55:47 --> 00:55:49 brightness between those two extremes.
00:55:50 --> 00:55:51 And it could get brighter than the
00:55:51 --> 00:55:52 brightest extreme there or fainter than
00:55:52 --> 00:55:55 the faintest extreme. We just don't know
00:55:55 --> 00:55:57 yet. But having found it so early or as
00:55:57 --> 00:56:00 well, but typically predicting the next
00:56:00 --> 00:56:01 great comet is a fool's bargain until
00:56:02 --> 00:56:04 it's discovered. What we can say is that
00:56:04 --> 00:56:07 there are a few periodic comets that
00:56:07 --> 00:56:09 will be great in the future. Comet
00:56:09 --> 00:56:11 Halley will be a lot better in 2061 than
00:56:12 --> 00:56:15 it was in 1986. In 1986, we had the
00:56:15 --> 00:56:16 worst operation of comet Hali for 2
00:56:16 --> 00:56:17 years.
00:56:17 --> 00:56:18 >> Tell me about it.
00:56:18 --> 00:56:21 >> Yeah. Bit disappointing. 2061 will be
00:56:21 --> 00:56:22 better.
00:56:22 --> 00:56:24 >> Oh, good. Well, I don't know if I'll be
00:56:24 --> 00:56:27 around by then, but um probably not.
00:56:27 --> 00:56:29 I'll be 99.
00:56:29 --> 00:56:31 >> Make everybody feel really cheerful.
00:56:31 --> 00:56:32 It's now closer to Comet Hall's next
00:56:32 --> 00:56:34 apparition than the last one. It turned
00:56:34 --> 00:56:35 around, I think, last year. So, it's on
00:56:35 --> 00:56:36 its way back. Yeah.
00:56:36 --> 00:56:38 >> Comet Halley will be even better in
00:56:38 --> 00:56:40 2135.
00:56:40 --> 00:56:42 Will be really good that year. And that
00:56:42 --> 00:56:43 will be the best apparition for a couple
00:56:43 --> 00:56:45 of hundred years. Comet Swift Tuttle
00:56:45 --> 00:56:48 will be incredible in 2126. We know that
00:56:48 --> 00:56:49 cuz we know pretty much exactly when
00:56:49 --> 00:56:50 it'll come back. We know where it will
00:56:50 --> 00:56:52 be compared to the Earth and the Sun.
00:56:52 --> 00:56:55 There is a suggestion that in 2097 we
00:56:55 --> 00:56:57 may have the comet of the century or
00:56:57 --> 00:56:58 close to it. This is research that came
00:56:58 --> 00:57:01 out last year. One of the greatest
00:57:01 --> 00:57:03 comets of the last thousand years was
00:57:03 --> 00:57:07 comet dishes in 1744. Also called comet
00:57:07 --> 00:57:09 Clinkenberg. Comet that is famous for
00:57:09 --> 00:57:12 having had six tails. Incredibly bright
00:57:12 --> 00:57:15 almost visible in broad daylight. A
00:57:15 --> 00:57:16 couple of astronomers, I think the lead
00:57:16 --> 00:57:19 researcher on this was Mike Meyer,
00:57:19 --> 00:57:20 published a paper last year that went
00:57:20 --> 00:57:23 back through historical observations and
00:57:23 --> 00:57:25 found a number of previous comets over
00:57:25 --> 00:57:27 the last 2 years that were all
00:57:27 --> 00:57:29 incredibly bright, really spectacular,
00:57:29 --> 00:57:31 but seem to have been moving the same as
00:57:31 --> 00:57:33 that comet, linked them together, and
00:57:33 --> 00:57:35 it's a very compelling tale that if
00:57:35 --> 00:57:38 their research is correct, that comet
00:57:38 --> 00:57:40 actually has an orbital period of just a
00:57:40 --> 00:57:43 little bit less, just around 450 years,
00:57:43 --> 00:57:45 I think 400 years. No, 350 years,
00:57:45 --> 00:57:47 wouldn't it? Do the mental arithmetic.
00:57:47 --> 00:57:50 Yeah, about 350 years, which means it
00:57:50 --> 00:57:53 should return in 2097.
00:57:53 --> 00:57:56 And if it does, it will be awesome. Um,
00:57:56 --> 00:57:57 sadly, I don't think you or I will be
00:57:58 --> 00:57:59 around for that.
00:57:59 --> 00:58:00 >> Probably not.
00:58:00 --> 00:58:01 >> Probably not. But things like that we
00:58:01 --> 00:58:02 can predict. But most
00:58:02 --> 00:58:04 >> Fred will be, but
00:58:04 --> 00:58:06 >> absolutely. Fred is indestructible, and
00:58:06 --> 00:58:09 I'll stand by that. But most of the big
00:58:09 --> 00:58:11 cometry nuclei coming through are on
00:58:11 --> 00:58:13 such long period orbits with the
00:58:13 --> 00:58:15 exception of Halley and Swift Tuttle
00:58:15 --> 00:58:17 that their apparitions are so infrequent
00:58:17 --> 00:58:18 that we've not identified them as
00:58:18 --> 00:58:20 periodic visitors and many of them have
00:58:20 --> 00:58:22 periods of thousands or tens of
00:58:22 --> 00:58:24 thousands of years. So we typically only
00:58:24 --> 00:58:27 find them on their way in a few weeks or
00:58:27 --> 00:58:30 a few months before apparition in case
00:58:30 --> 00:58:32 of comet hellopet was 2 years which was
00:58:32 --> 00:58:34 exceptional at the time. KZ of comet
00:58:34 --> 00:58:36 Chuchin Shan it's more than two and a
00:58:36 --> 00:58:39 half years away but our technology has
00:58:39 --> 00:58:41 improved hugely so I don't think it's
00:58:41 --> 00:58:43 fair necessarily to say that Chuchin
00:58:43 --> 00:58:45 Shan will be another hail bop
00:58:45 --> 00:58:47 >> but if you look at the brighter end of
00:58:47 --> 00:58:48 the predictions it could be naked eye
00:58:48 --> 00:58:50 visible for 3 four 5 months
00:58:50 --> 00:58:51 >> wow
00:58:51 --> 00:58:52 >> which would be awesome and it would
00:58:52 --> 00:58:54 potentially be circumpolar for us in the
00:58:54 --> 00:58:56 southern hemisphere because at its
00:58:56 --> 00:58:57 closest to the sun of the earth it's
00:58:57 --> 00:58:59 going to be way south not going to be
00:58:59 --> 00:59:01 good for the northern hemisphere but we
00:59:01 --> 00:59:03 can't really predict that it's the same
00:59:03 --> 00:59:05 with meteor showers, we can predict the
00:59:05 --> 00:59:06 annual ones roughly how good they're
00:59:06 --> 00:59:07 going to be.
00:59:07 --> 00:59:08 >> Y
00:59:08 --> 00:59:10 >> and if you go back to when I was a kid,
00:59:10 --> 00:59:11 we couldn't really predict meteor
00:59:12 --> 00:59:13 storms, meteor outbursts, and that's one
00:59:13 --> 00:59:15 of the things people really love to see.
00:59:15 --> 00:59:17 So Geminids are great. Northern
00:59:17 --> 00:59:19 hemisphere, you'll see maybe even 80 or
00:59:19 --> 00:59:20 100 an hour at their peak in the early
00:59:20 --> 00:59:22 hours of the morning. I've seen 50 an
00:59:22 --> 00:59:25 hour from our latitude near Brisbane.
00:59:25 --> 00:59:27 They're really good. But what people
00:59:27 --> 00:59:28 really want to see are meteor storms,
00:59:28 --> 00:59:31 and they're much rarer. There's a few
00:59:31 --> 00:59:33 amazing ones historically. There was the
00:59:33 --> 00:59:36 one in 1833 that was linked to the
00:59:36 --> 00:59:39 Leonid meteor shower that had a rate in
00:59:39 --> 00:59:43 excess of 100 an hour was best seen
00:59:43 --> 00:59:47 from the contiguous US and it was bright
00:59:47 --> 00:59:49 enough there were sufficient meteors in
00:59:49 --> 00:59:52 the sky that miners in the US were woken
00:59:52 --> 00:59:54 from their campsites by the light
00:59:54 --> 00:59:56 shining through their tents and people
00:59:56 --> 00:59:57 were convinced that the end times had
00:59:58 --> 01:00:00 come the apocalypse was here because he
01:00:00 --> 01:00:02 were getting as many as 20 meteors per
01:00:02 --> 01:00:03 second.
01:00:03 --> 01:00:04 >> Incredible.
01:00:04 --> 01:00:06 >> Um, now that in the way that kind of
01:00:06 --> 01:00:09 Taiko's observations in 1577 were
01:00:09 --> 01:00:11 probably the birth of modern cometry
01:00:11 --> 01:00:14 astronomy, 1833, I think, was possibly
01:00:14 --> 01:00:16 the birth of modern meteor astronomy
01:00:16 --> 01:00:17 because there had been a storm from the
01:00:17 --> 01:00:20 lineage in 1799. People predicted that
01:00:20 --> 01:00:23 there might be another one in 1866
01:00:23 --> 01:00:24 because maybe this was happening every
01:00:24 --> 01:00:26 33 years when the comet came back and
01:00:26 --> 01:00:29 indeed that happened in 1866.
01:00:29 --> 01:00:32 And so that was a bit like the birth of
01:00:32 --> 01:00:34 modern meteor science. And after that,
01:00:34 --> 01:00:35 people said, "Well, there'll be one in
01:00:35 --> 01:00:38 1899." And there wasn't. So that then
01:00:38 --> 01:00:41 tricked people up. So thanks to that,
01:00:41 --> 01:00:42 we've gradually developed a better
01:00:42 --> 01:00:44 understanding of the physics of how
01:00:44 --> 01:00:46 meteor showers work. And I'm aware time
01:00:46 --> 01:00:48 is running away from us. But it for
01:00:48 --> 01:00:50 people interested in this, in the run-up
01:00:50 --> 01:00:53 to the Leonid heavy leanid activity in
01:00:53 --> 01:00:56 1999 through to 2002, there was some
01:00:56 --> 01:01:00 amazing research done by um David Asher
01:01:00 --> 01:01:02 from Amar Observatory and I think fondly
01:01:02 --> 01:01:04 on David because he was a lovely mentor
01:01:04 --> 01:01:07 to me when I visited Amar in 1999. very
01:01:07 --> 01:01:09 quiet guy but incredibly talented
01:01:09 --> 01:01:12 scientist and he did this remarkable
01:01:12 --> 01:01:15 work making predictions of when we would
01:01:15 --> 01:01:17 and wouldn't get Leonid storms by
01:01:17 --> 01:01:19 modeling the ejection of dust from the
01:01:20 --> 01:01:22 cometry nucleus and evolving the dust
01:01:22 --> 01:01:24 forward in time and go back way earlier
01:01:24 --> 01:01:27 on I mentioned these javelin sh spikes
01:01:27 --> 01:01:29 he event he effectively modeled those
01:01:29 --> 01:01:31 and figured out where the spikes will be
01:01:31 --> 01:01:32 and a slight nudge up or down means that
01:01:32 --> 01:01:34 the earth will run through the spike or
01:01:34 --> 01:01:36 not and the great lean zones are
01:01:36 --> 01:01:38 produced by dust left behind just one or
01:01:38 --> 01:01:41 two revolutions ago. So the activity
01:01:41 --> 01:01:45 between 1999 and 2002 resulted from a
01:01:45 --> 01:01:47 few different streams. The older they
01:01:47 --> 01:01:49 are, the more diffuse they get. But now
01:01:49 --> 01:01:51 we have the ability for comets we know
01:01:51 --> 01:01:54 well and meteor showers we know well to
01:01:54 --> 01:01:55 figure out where those spikes are
01:01:55 --> 01:01:57 roughly going to be, how long they are,
01:01:57 --> 01:02:00 and make predictions going forward. Now,
01:02:00 --> 01:02:01 there aren't any great meteor storms
01:02:02 --> 01:02:03 predicted in the relatively near future.
01:02:03 --> 01:02:05 The Leonids are not likely to give major
01:02:05 --> 01:02:09 storms in 2033 or 2066, but will give
01:02:09 --> 01:02:11 increased activity. The reason for that
01:02:11 --> 01:02:13 is Jupiter and Saturn are pulling those
01:02:13 --> 01:02:16 javelins around and making them miss the
01:02:16 --> 01:02:18 Earth. The leanings will probably return
01:02:18 --> 01:02:21 in force in I think 2097 with a
01:02:21 --> 01:02:23 possibility of a storm of like 20 an
01:02:23 --> 01:02:26 hour. But we're getting to understand
01:02:26 --> 01:02:28 that. So with meteor showers, we can
01:02:28 --> 01:02:30 predict the annual showers. They're very
01:02:30 --> 01:02:32 reliable. They gradually get better and
01:02:32 --> 01:02:34 worse with time as the streams move
01:02:34 --> 01:02:35 around and we insect more of the
01:02:35 --> 01:02:38 material or less, but they're pretty
01:02:38 --> 01:02:39 reliable.
01:02:39 --> 01:02:41 Outbursts are harder to predict, but
01:02:41 --> 01:02:44 we're getting better at doing it. But
01:02:44 --> 01:02:46 predicting an outburst from a shower
01:02:46 --> 01:02:48 we've never seen before or a shower
01:02:48 --> 01:02:50 that's incredibly rare, we typically
01:02:50 --> 01:02:53 can't do until it happens because we
01:02:53 --> 01:02:55 need to have a feel for what it's done
01:02:55 --> 01:02:57 in the past. So, we occasionally will
01:02:57 --> 01:02:58 get an outburst of a meteor shower we've
01:02:58 --> 01:03:01 never seen before. and you can't predict
01:03:01 --> 01:03:02 that. And that's when it's really
01:03:02 --> 01:03:04 exciting because then you can start to
01:03:04 --> 01:03:06 learn about a new meteor shower being
01:03:06 --> 01:03:08 born. You can learn about the comet that
01:03:08 --> 01:03:10 birthed it. Put all that together. And
01:03:10 --> 01:03:11 that's one of the things where I'll go
01:03:12 --> 01:03:13 out and I love my meteor showers. I'll
01:03:13 --> 01:03:15 sit out under the sky and watch them.
01:03:15 --> 01:03:16 But I would love to just be outside when
01:03:16 --> 01:03:18 there's an unexpected outburst when we
01:03:18 --> 01:03:20 see something new like a meteor shower
01:03:20 --> 01:03:22 being born for the first time. Just
01:03:22 --> 01:03:24 >> and and and that's what we recommend to
01:03:24 --> 01:03:26 all our space listeners. uh get up at
01:03:26 --> 01:03:30 2:00 every morning every day and go out
01:03:30 --> 01:03:32 and just wait. And you know, one day
01:03:32 --> 01:03:34 you'll get lucky. Might take 20 years,
01:03:34 --> 01:03:34 but
01:03:34 --> 01:03:36 >> doesn't have to be 2 a.m. I mean, there
01:03:36 --> 01:03:38 is a little bit of a preference for
01:03:38 --> 01:03:41 meteor showers to be more active in the
01:03:41 --> 01:03:43 morning hours and the evening hours, but
01:03:43 --> 01:03:45 that's purely a geometry thing. Yeah,
01:03:45 --> 01:03:46 >> it's linked a little bit to the
01:03:46 --> 01:03:47 direction of the Earth's motion and the
01:03:47 --> 01:03:48 direction things are crossing the
01:03:48 --> 01:03:51 Earth's orbit in that if you think about
01:03:51 --> 01:03:52 something crossing the Earth's orbit at
01:03:52 --> 01:03:55 right angles to the Earth because the
01:03:55 --> 01:03:57 Earth's moving forward at 30 km a
01:03:57 --> 01:03:59 second, the direction you would see that
01:03:59 --> 01:04:00 coming from is actually a bit ahead of
01:04:00 --> 01:04:01 you because you've got the addition of
01:04:01 --> 01:04:03 the speed the debris is going and the
01:04:03 --> 01:04:06 speed the Earth's moving. M so meteor
01:04:06 --> 01:04:07 showers
01:04:08 --> 01:04:10 that are visible with radiance that will
01:04:10 --> 01:04:12 be in the morning sky. You've got a
01:04:12 --> 01:04:14 little bit of an additive effect between
01:04:14 --> 01:04:15 the speed the debris is going and the
01:04:15 --> 01:04:17 speed the earth's moving which means the
01:04:17 --> 01:04:19 average impact speed of the debris is
01:04:19 --> 01:04:21 higher and you get more meteors. But
01:04:21 --> 01:04:23 also you get this effect of the earth's
01:04:23 --> 01:04:24 motion being a bit like you're driving
01:04:24 --> 01:04:26 into a snowstorm. You know if you're
01:04:26 --> 01:04:28 driving into a snowstorm where there's
01:04:28 --> 01:04:29 no wind and the snowflakes are falling
01:04:30 --> 01:04:32 down vertically you will perceive them
01:04:32 --> 01:04:33 as coming from in front of your car not
01:04:33 --> 01:04:36 overhead. And so there's a preference
01:04:36 --> 01:04:37 for meteor showers to be slightly more
01:04:37 --> 01:04:39 likely to have activity that peaks in
01:04:39 --> 01:04:41 the morning hours and the evening, but
01:04:41 --> 01:04:43 that's not a guarantee. There are some
01:04:43 --> 01:04:45 meteor showers that are at the highest
01:04:45 --> 01:04:46 where the radiant culminates in the
01:04:46 --> 01:04:49 evening sky. It just depends. Some like
01:04:50 --> 01:04:51 the Aquarids are only visible for a
01:04:51 --> 01:04:53 couple of hours before dawn. There's
01:04:53 --> 01:04:54 even a few meteor showers that are
01:04:54 --> 01:04:56 daylight showers where the radiance's
01:04:56 --> 01:04:57 only really above the horizon during the
01:04:58 --> 01:04:59 hours of daylight. And we know about
01:04:59 --> 01:05:01 them primarily from radio observations.
01:05:01 --> 01:05:04 Radar pe well not radar people listening
01:05:04 --> 01:05:06 to radio reflecting off the ionized
01:05:06 --> 01:05:09 streaks that the meteors leave in the
01:05:09 --> 01:05:11 ionosphere that allows you to see over
01:05:11 --> 01:05:13 the horizon to radio stations that are
01:05:13 --> 01:05:14 broadcasting that you don't normally
01:05:14 --> 01:05:16 get. So you can hear meteor showers.
01:05:16 --> 01:05:17 >> Yeah.
01:05:17 --> 01:05:18 >> So we know there are daytime showers
01:05:18 --> 01:05:20 that we cannot see at night and some of
01:05:20 --> 01:05:22 them are possibly as active as the
01:05:22 --> 01:05:24 Geminis of the Percids. If you know if
01:05:24 --> 01:05:26 we could turn the sun off I mean that
01:05:26 --> 01:05:28 would be a bad thing. Please don't do
01:05:28 --> 01:05:29 it. If you're a super villain listening,
01:05:29 --> 01:05:32 do not take this as an idea. But if we
01:05:32 --> 01:05:34 could turn the sun off and see, there
01:05:34 --> 01:05:35 are a couple of meteor showers in the
01:05:35 --> 01:05:36 daytime that could be pretty
01:05:36 --> 01:05:38 spectacular.
01:05:38 --> 01:05:41 It is all very fascinating. And I
01:05:41 --> 01:05:43 suppose the best advice would be to uh
01:05:43 --> 01:05:45 go and look for the the better sources
01:05:46 --> 01:05:47 of forecasting rather than trying to
01:05:48 --> 01:05:50 figure it out for yourself. And uh and
01:05:50 --> 01:05:51 you've mentioned a couple of them
01:05:51 --> 01:05:54 already, uh comet maps and what was the
01:05:54 --> 01:05:56 other one about meteors? For meteors, I
01:05:56 --> 01:05:58 really strongly recommend the
01:05:58 --> 01:05:59 International Meteor Organization. If
01:06:00 --> 01:06:02 you go to their website, hover over the
01:06:02 --> 01:06:04 resources link, click on it to get the
01:06:04 --> 01:06:05 drop down. Click on meteor shower
01:06:06 --> 01:06:07 calendar. They have on the right hand
01:06:07 --> 01:06:10 side the best showers of the year with
01:06:10 --> 01:06:12 information and what the moon will be
01:06:12 --> 01:06:13 like. But there's also on the left side
01:06:13 --> 01:06:15 a PDF that you can download that goes
01:06:16 --> 01:06:17 into much more minute detail and talks
01:06:17 --> 01:06:19 about even the more minor showers. And
01:06:20 --> 01:06:21 that's a very good point of truth for
01:06:21 --> 01:06:24 meteor showers. Well, I I kind of
01:06:24 --> 01:06:25 describe them being like three tiers of
01:06:25 --> 01:06:28 meteor showers, ignoring the outbursts.
01:06:28 --> 01:06:29 There are the big three, which are the
01:06:29 --> 01:06:31 quadrantids, the perids, and the
01:06:31 --> 01:06:33 geminids, which are even if you're not
01:06:33 --> 01:06:35 that interested at all in space. And if
01:06:36 --> 01:06:37 you are, thanks for listening to the
01:06:37 --> 01:06:39 podcast anyway, but it's not really our
01:06:39 --> 01:06:41 target audience. But even people who are
01:06:41 --> 01:06:43 not that interested, that's a spectacle
01:06:43 --> 01:06:44 you can go out and see with them and
01:06:44 --> 01:06:46 share with them. Just make sure that you
01:06:46 --> 01:06:48 figure out when the radiant rises from
01:06:48 --> 01:06:49 your location because you don't want to
01:06:49 --> 01:06:51 turn people off by looking at a time
01:06:51 --> 01:06:53 when you can't see meteors. So for the
01:06:53 --> 01:06:55 Geminids, the best time is around 2:00
01:06:55 --> 01:06:57 a.m. But depending on where you are in
01:06:57 --> 01:07:00 the world, from our latitude, you're
01:07:00 --> 01:07:02 looking at you can't see any before
01:07:02 --> 01:07:04 9:30, 10:00 at night. Obviously, if
01:07:04 --> 01:07:05 you're somewhere with daylight savings
01:07:05 --> 01:07:07 in the Southern Hemisphere, add an hour
01:07:07 --> 01:07:09 to that. So for you down in New South
01:07:09 --> 01:07:11 Wales where the clocks change, you're
01:07:11 --> 01:07:13 talking after 11:00 p.m. for you. But if
01:07:13 --> 01:07:15 you're in Northern Europe, the Geminid
01:07:15 --> 01:07:17 radiant never sets. So where I grew up
01:07:17 --> 01:07:18 in the UK, as soon as it got dark, I
01:07:18 --> 01:07:20 could see them. The rates still got
01:07:20 --> 01:07:21 better through the night. Similarly for
01:07:21 --> 01:07:24 the Percids in particular, Percids are a
01:07:24 --> 01:07:26 northern hemisphere only thing. It's
01:07:26 --> 01:07:27 light until quite late. Certainly for
01:07:28 --> 01:07:29 the high northern latitudes like the UK,
01:07:29 --> 01:07:31 but as soon as it gets dark, you can see
01:07:31 --> 01:07:33 them. So they're the showers that are
01:07:33 --> 01:07:35 well worth going out to look at as a
01:07:35 --> 01:07:37 beginner. And you just sit out there. I
01:07:38 --> 01:07:39 would figure out where the radiant is
01:07:39 --> 01:07:41 and look 30 or 40 degrees to the left or
01:07:41 --> 01:07:43 right of it to get the best balance
01:07:43 --> 01:07:45 between a lot of meteors but decent ones
01:07:45 --> 01:07:48 to see and just get a comfy chair, lie
01:07:48 --> 01:07:51 back, wrap up warm with the people you
01:07:51 --> 01:07:53 love and tell stories and relax and
01:07:53 --> 01:07:54 occasionally you'll see something good
01:07:54 --> 01:07:55 and it's quite addictive. You think, you
01:07:55 --> 01:07:57 know, I'll go to bed but I just want to
01:07:57 --> 01:07:59 see one more and then well that was
01:07:59 --> 01:08:00 rubbish so I want to see another one
01:08:00 --> 01:08:02 that's actually good. You've then got
01:08:02 --> 01:08:05 like the mid-tier showers which can be
01:08:05 --> 01:08:06 decent but you need to be a bit more
01:08:06 --> 01:08:08 dedicated for. These are the ones where
01:08:08 --> 01:08:10 you might see 10 or 15 an hour instead
01:08:10 --> 01:08:13 of 50 an hour. And I wouldn't recommend
01:08:13 --> 01:08:14 people who are beginners go out and see
01:08:14 --> 01:08:16 them because it's there's not enough
01:08:16 --> 01:08:18 happening. And that's why I worry about
01:08:18 --> 01:08:21 coverage for the April liids even in the
01:08:21 --> 01:08:23 northern hemisphere because they're just
01:08:23 --> 01:08:25 not that good. If you're someone who's
01:08:25 --> 01:08:27 really keen, you'll enjoy them, but for
01:08:27 --> 01:08:29 most people they'll be a let down and
01:08:29 --> 01:08:30 you don't want to turn people off the
01:08:30 --> 01:08:32 subject. Then there are the minor
01:08:32 --> 01:08:34 showers that you frankly need to be very
01:08:34 --> 01:08:36 obsessive to follow. And I've seen
01:08:36 --> 01:08:38 stories of a lot of the science of this
01:08:38 --> 01:08:41 has been done by amateur astronomers and
01:08:41 --> 01:08:42 quite often by people who are quite
01:08:42 --> 01:08:46 obsessive about the topic. And I saw one
01:08:46 --> 01:08:48 guy who was in North America where it
01:08:48 --> 01:08:51 gets brutal, brutal cold in the winter,
01:08:51 --> 01:08:54 who built himself a an insulated coffin
01:08:54 --> 01:08:56 with an incredibly transparent glass lid
01:08:56 --> 01:08:58 that he would carry out with him that
01:08:58 --> 01:08:59 was big enough for him to have a
01:09:00 --> 01:09:01 notebook and write down the details of
01:09:01 --> 01:09:03 every meteor he saw. So he could lie out
01:09:03 --> 01:09:05 in minus40°
01:09:05 --> 01:09:08 and I think that's um units ambivalent.
01:09:08 --> 01:09:09 I think Fahrenheit and centigrade are
01:09:09 --> 01:09:11 very similar at that point. But he's in
01:09:11 --> 01:09:13 an insulated box that keeps him warm and
01:09:13 --> 01:09:15 he'd lie out all night recording 2
01:09:15 --> 01:09:17 meters 3 meters an hour.
01:09:17 --> 01:09:20 >> That isn't for me, but it is for people.
01:09:20 --> 01:09:22 But when you see a meteor shower with a
01:09:22 --> 01:09:25 ZHR of less than about 20, I'd probably
01:09:25 --> 01:09:27 leave that unless you're really keen. If
01:09:27 --> 01:09:30 it's got a ZHR of 50 plus, well worth
01:09:30 --> 01:09:31 looking out for. But look for when the
01:09:31 --> 01:09:33 time of maximum is. For most meteor
01:09:33 --> 01:09:35 showers, they've got what we call a full
01:09:35 --> 01:09:38 width half maximum of about 24 hours.
01:09:38 --> 01:09:41 What that means is that the rate only
01:09:41 --> 01:09:42 stays above half of the peak rate for
01:09:42 --> 01:09:45 about 24 hours. For 48 hours, then it
01:09:45 --> 01:09:46 would stay above a quarter of the rate
01:09:46 --> 01:09:48 and so on. For the quadrantids, it's
01:09:48 --> 01:09:50 full width at quarter maximum of about
01:09:50 --> 01:09:53 12 hours. So that means if you're 6
01:09:53 --> 01:09:55 hours away from the peak, the rate is
01:09:55 --> 01:09:57 already down to a quarter of that peak.
01:09:57 --> 01:09:59 It's a very sharp peak. And if you're
01:09:59 --> 01:10:00 looking at the wrong time, the show
01:10:00 --> 01:10:02 won't be as good as you'd like it to be,
01:10:02 --> 01:10:05 and you'll be disappointed.
01:10:05 --> 01:10:06 So much to consider, Jonty, but uh
01:10:06 --> 01:10:10 fascinating cockpits and meteors. Um
01:10:10 --> 01:10:11 there's so much to talk about and we
01:10:11 --> 01:10:13 probably didn't really cover absolutely
01:10:13 --> 01:10:15 everything, although we did uh we did
01:10:15 --> 01:10:18 hit on quite a fair bit of info. And of
01:10:18 --> 01:10:19 course, we do welcome questions and
01:10:20 --> 01:10:22 comments. So, please u go to our website
01:10:22 --> 01:10:26 and um click that little AMA button at
01:10:26 --> 01:10:27 the top and you can send us questions
01:10:27 --> 01:10:30 and comments uh in text and audio form.
01:10:30 --> 01:10:32 Don't forget to tell us who you are and
01:10:32 --> 01:10:33 where you're from. But we're going to
01:10:33 --> 01:10:35 wrap it up there. Jonty, thank you so
01:10:35 --> 01:10:37 much. We'll catch you on the next show.
01:10:37 --> 01:10:38 >> Thank you very much.
01:10:38 --> 01:10:40 >> Professor Jonty her, professor of
01:10:40 --> 01:10:43 astrophysics at the University of
01:10:43 --> 01:10:46 Southern Queensland, our special guest
01:10:46 --> 01:10:48 commentator, while Fred's uh on the
01:10:48 --> 01:10:49 other side of the planet looking at
01:10:49 --> 01:10:53 meteors. And uh just a special word for
01:10:53 --> 01:10:55 uh for Hugh in the studio. He's been a
01:10:55 --> 01:10:58 little unwell lately. Hugh, get well
01:10:58 --> 01:11:00 soon, mate. We're all thinking of you.
01:11:00 --> 01:11:01 And from me, Andrew Dunley, thanks for
01:11:01 --> 01:11:03 your company. We'll catch you on the
01:11:03 --> 01:11:05 next episode of Space Nuts.
01:11:05 --> 01:11:06 >> Space Nuts.
01:11:06 --> 01:11:08 >> You'll be listening to the Space Nuts
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