Space Nuts Episode 487: Rethinking the Universe - Dark Energy, Comet Atlas, and Pluto's Moon Mystery
Join Andrew Dunkley and Professor Fred Watson as they welcome the newest member to the team and kick off the first episode of 2025 with groundbreaking discussions and cosmic revelations. This episode is packed with intriguing topics, including a revolutionary paper challenging our understanding of dark energy, a mesmerizing comet lighting up our skies, and a fresh perspective on how Pluto acquired its moon, Charon.
Episode Highlights:
- Dark Energy Debate: Explore the bold new paper suggesting the universe might not have dark energy and isn't expanding as we thought. Fred Watson and guest Professor Jonti Horner delve into the implications of this paradigm-shifting research and what it means for the future of cosmology.
- Comet C/2024 G3 Atlas: Discover the celestial wonder of Comet Atlas, a once-in-160,000-year event. Learn about its journey close to the sun and how you can catch a glimpse of this spectacular comet in the night sky.
- Pluto's Moon Charon : Uncover the fascinating story behind Pluto's largest moon, Charon. Jonti Horner explains the new theory of a gentle collision that might have led to Charon's capture, providing fresh insights into the dynamics of our solar system.
- Astronomical Events of 2025: Get a sneak peek into the best celestial events to look forward to this year, including lunar eclipses and meteor showers.
For more Space Nuts, including our continually updating newsfeed and to listen to all our episodes, visit our website (https://www.usq.edu.au/](https://www.usq.edu.au/)
University of Canterbury
[https://www.canterbury.ac.nz/](https://www.canterbury.ac.nz/)
Monthly Notices of the Royal Astronomical Society
[https://academic.oup.com/mnras](https://academic.oup.com/mnras)
Dark Energy Survey
[https://www.darkenergysurvey.org/](https://www.darkenergysurvey.org/)
Solar and Heliospheric Observatory (SOHO)
[https://sohowww.nascom.nasa.gov/](https://sohowww.nascom.nasa.gov/)
Space.com
[https://www.space.com/](https://www.space.com/)
Stellarium
[https://stellarium.org/](https://stellarium.org/)
Become a supporter of this podcast: https://www.spreaker.com/podcast/space-nuts--2631155/support (https://www.spreaker.com/podcast/space-nuts--2631155/support?utm_source=rss&utm_medium=rss&utm_campaign=rss) .
Episode link: https://play.headliner.app/episode/25122266?utm_source=youtube
00:00:00 --> 00:00:02 hello again thanks for joining us this
00:00:02 --> 00:00:05 is Space Nuts my name is Andrew Dunley
00:00:05 --> 00:00:08 Welcome to our first edition of
00:00:08 --> 00:00:11 20205 coming up oh boy it is jam-packed
00:00:11 --> 00:00:13 we' got a lot of catching up to do some
00:00:13 --> 00:00:14 really interesting things one of the
00:00:14 --> 00:00:16 biggest this might be one of the biggest
00:00:16 --> 00:00:19 stories of the Year already a new paper
00:00:19 --> 00:00:21 suggesting the universe has no dark
00:00:21 --> 00:00:25 matter and isn't expanding like we think
00:00:25 --> 00:00:27 so that'll tip the whole thing upside
00:00:27 --> 00:00:29 down we're also going to look at a comet
00:00:29 --> 00:00:31 uh that is in our skies at the moment
00:00:31 --> 00:00:35 Comet C 2024 G3 Atlas uh so we'll talk
00:00:35 --> 00:00:38 about that and don't be a Caren kiss and
00:00:38 --> 00:00:40 tell what's that mean we'll tell you
00:00:40 --> 00:00:44 shortly on this edition of Space Nuts 15
00:00:44 --> 00:00:48 seconds guidance is internal 10 9
00:00:48 --> 00:00:53 ignition sequence start Space Nuts 5 4 3
00:00:53 --> 00:00:58 2 1 2 3 4 5 5 4 3 2 1 Space Nuts asut
00:00:58 --> 00:01:01 reported feels good and it feels real
00:01:01 --> 00:01:03 good to be back in the chair with
00:01:03 --> 00:01:05 Professor Fred Watson astronomer at
00:01:05 --> 00:01:07 large hello Fred hello Andrew how are
00:01:07 --> 00:01:11 you doing I'm doing well uh it's good to
00:01:11 --> 00:01:14 be back um we had a nice break uh just
00:01:14 --> 00:01:16 very quickly Judy and I went to India
00:01:16 --> 00:01:18 Sri Lanka Thailand Malaysia Singapore
00:01:18 --> 00:01:20 and then back home and then we had to go
00:01:20 --> 00:01:23 to a wedding on New Year's Day believe
00:01:23 --> 00:01:25 it or not down in the snowy mountains so
00:01:26 --> 00:01:27 we've had a very eventful break what
00:01:27 --> 00:01:30 about you uh oh well yes I had an
00:01:30 --> 00:01:33 eventful break as well because seven
00:01:33 --> 00:01:38 members of my UK family descended on us
00:01:38 --> 00:01:40 uh not all of them stayed with us but
00:01:40 --> 00:01:43 most of them did because I had a
00:01:43 --> 00:01:45 significant birthday in December and so
00:01:45 --> 00:01:46 they all came to help me celebrate yeah
00:01:46 --> 00:01:51 800's a real Milestone absolutely uh it
00:01:51 --> 00:01:53 does begin with an e but it's not 800
00:01:53 --> 00:01:57 and it's not eight either 18 that's it
00:01:57 --> 00:02:00 it's nearer to that yeah uh just can't
00:02:00 --> 00:02:02 imagine being stuck in a room with that
00:02:02 --> 00:02:05 many Pals all at once but anyway um
00:02:05 --> 00:02:08 you you know they started fighting among
00:02:08 --> 00:02:12 themselves as usual uh but actually uh
00:02:12 --> 00:02:13 compared with the way the Aussies fought
00:02:13 --> 00:02:15 among themselves they were pretty tame I
00:02:15 --> 00:02:18 have to say yeah well that happens a lot
00:02:18 --> 00:02:20 Christmas brings that out inness do does
00:02:20 --> 00:02:22 yeah does absolutely now I uh have a
00:02:22 --> 00:02:25 little bit of a surprise for our
00:02:25 --> 00:02:28 audience uh moving forward uh we have
00:02:28 --> 00:02:30 another guest with us at the moment he
00:02:30 --> 00:02:33 is Professor jonty Horner he's the
00:02:33 --> 00:02:35 profess professor of astrophysics at the
00:02:35 --> 00:02:37 University of Southern Queensland jonty
00:02:37 --> 00:02:39 welcome thank you for having me it's
00:02:39 --> 00:02:41 good to be here uh it's good that you
00:02:41 --> 00:02:43 decided to join us because we thought
00:02:43 --> 00:02:46 you'd say no but anyway uh the reason
00:02:46 --> 00:02:49 you're on board is because um Fred and I
00:02:49 --> 00:02:51 have basically run out of time to do
00:02:51 --> 00:02:53 catch-up episodes for when both of us
00:02:53 --> 00:02:55 are going to be away over the coming
00:02:55 --> 00:02:58 months and so this is technically Fred's
00:02:58 --> 00:03:00 only episode
00:03:00 --> 00:03:03 for the next month or so and you're
00:03:03 --> 00:03:06 going to fill in for him over that time
00:03:06 --> 00:03:08 frame so we're really pleased about that
00:03:08 --> 00:03:09 uh can you tell us a little bit about
00:03:09 --> 00:03:12 yourself um you know professor of
00:03:12 --> 00:03:14 astrophysics very exciting happy to do
00:03:14 --> 00:03:16 so I mean you probably pick up from the
00:03:16 --> 00:03:17 accent that I've got a bit of a shared
00:03:17 --> 00:03:19 Heritage with Fred which I'm sure is the
00:03:19 --> 00:03:21 only reason you invited me on it's to
00:03:21 --> 00:03:24 maintain the arkshire connection um I I
00:03:24 --> 00:03:27 grew up in the north of England um back
00:03:27 --> 00:03:29 in the 80s really and got hooked by
00:03:29 --> 00:03:31 astronomy very young thanks to Patrick
00:03:31 --> 00:03:34 Moore um and I seem to be expanding in a
00:03:34 --> 00:03:35 similar way to him as well so I'm
00:03:36 --> 00:03:38 clearly mimicking his share and joined
00:03:38 --> 00:03:40 my local astronomy society which is a
00:03:40 --> 00:03:42 WRA astronomy society when I was about
00:03:43 --> 00:03:45 eight years old and I now get to be
00:03:45 --> 00:03:46 their president actually even though I'm
00:03:46 --> 00:03:48 in absente which is really kind of a
00:03:48 --> 00:03:50 lovely touching thing you know I'm a
00:03:50 --> 00:03:52 young kid that came through the society
00:03:52 --> 00:03:53 went to talks from professional
00:03:53 --> 00:03:56 astronomers all the time and basically
00:03:56 --> 00:03:58 that let me stay hooked through being a
00:03:58 --> 00:04:00 teenager and meant that I had the
00:04:00 --> 00:04:02 ammunition of the wellwith all I guess
00:04:02 --> 00:04:05 coming from a low socioeconomic area and
00:04:05 --> 00:04:06 you know not the best part of the world
00:04:06 --> 00:04:08 to grow up in at that time thanks to
00:04:08 --> 00:04:11 magua milk snater I I still have the
00:04:11 --> 00:04:14 opportunity to head off to unig get to
00:04:14 --> 00:04:16 study what I want to do and that's
00:04:16 --> 00:04:18 allowed me to have a reasonably
00:04:18 --> 00:04:19 entertaining and challenging at times
00:04:19 --> 00:04:22 career and move around the world rugged
00:04:22 --> 00:04:25 up in Australia in about 2010 and I've
00:04:25 --> 00:04:26 been here ever since so despite the
00:04:26 --> 00:04:28 accent I am officially Australian I just
00:04:28 --> 00:04:31 don't quite found at so well that's kind
00:04:31 --> 00:04:34 of the Potted history we're so thrilled
00:04:34 --> 00:04:36 to have you and people will get to know
00:04:36 --> 00:04:38 you over the coming weeks so welcome
00:04:38 --> 00:04:40 aboard and uh we're going to have a
00:04:40 --> 00:04:42 we're going to have a lot of fun today
00:04:42 --> 00:04:44 uh talking about these uh these topics
00:04:44 --> 00:04:46 and we're going to start with probably
00:04:46 --> 00:04:49 the big one in regard to this this new
00:04:49 --> 00:04:52 paper uh suggesting the universe has no
00:04:52 --> 00:04:55 dark energy and isn't expanding like we
00:04:55 --> 00:05:00 think um your thoughts on this Fred
00:05:00 --> 00:05:03 uh yeah it's entertaining um it's uh
00:05:04 --> 00:05:07 something that I think is going to
00:05:07 --> 00:05:10 cause uh not constellation by any means
00:05:10 --> 00:05:14 but certainly uh give cosmologists the
00:05:14 --> 00:05:17 people who look at the uh history and
00:05:17 --> 00:05:19 evolution of the universe as a whole uh
00:05:19 --> 00:05:23 perhaps reason to pause and say okay
00:05:23 --> 00:05:24 maybe this is a time to have a look at
00:05:25 --> 00:05:26 the Paradigm on which under which we're
00:05:26 --> 00:05:29 working and in fact the um the search
00:05:29 --> 00:05:31 that we're talking about which has been
00:05:31 --> 00:05:34 done by a group uh actually all of them
00:05:34 --> 00:05:36 are at the University of can Canterbury
00:05:36 --> 00:05:38 in New Zealand so it's a gwis who stolen
00:05:38 --> 00:05:41 a march on us with this uh their paper
00:05:41 --> 00:05:42 in monthly notices of the Royal
00:05:42 --> 00:05:45 Astronomical Society is entitled
00:05:45 --> 00:05:47 Supernova evidence for foundational
00:05:47 --> 00:05:51 change to cosmological models and what
00:05:51 --> 00:05:55 they're basically saying is that we now
00:05:55 --> 00:06:00 have such a big uh collection of of
00:06:00 --> 00:06:03 supernova data and these are stars as
00:06:03 --> 00:06:05 you know that explode at the ends of
00:06:05 --> 00:06:09 their lives they explode with a specific
00:06:09 --> 00:06:11 brightness this is the the trick to it
00:06:11 --> 00:06:13 they become standard candles because
00:06:13 --> 00:06:15 they all reach the same Peak brightness
00:06:15 --> 00:06:18 and that allows them to give us a direct
00:06:18 --> 00:06:20 measurement of the geometry of the
00:06:20 --> 00:06:22 universe basically their distance uh and
00:06:23 --> 00:06:26 when you do that with the latest data uh
00:06:26 --> 00:06:30 it turns out that the dark energy model
00:06:30 --> 00:06:34 which is kind of getting a bit creaky
00:06:34 --> 00:06:36 because we've always thought Dark Energy
00:06:36 --> 00:06:38 a springiness of space might be constant
00:06:38 --> 00:06:40 but there's new evidence that suggests
00:06:40 --> 00:06:42 that it's not but that model might
00:06:43 --> 00:06:46 really need to be taken apart uh for a
00:06:46 --> 00:06:48 rethink and the rethink that they're
00:06:48 --> 00:06:54 proposing uh uh is a model that um is
00:06:54 --> 00:06:55 being called I've got the word time
00:06:56 --> 00:06:58 share in my mind but it's actually time
00:06:58 --> 00:07:02 scape uh which suggests that the reason
00:07:02 --> 00:07:04 why we think we see dark energy and
00:07:04 --> 00:07:06 remember that was discovered back in
00:07:06 --> 00:07:09 1998 uh the reason why we think we see
00:07:09 --> 00:07:11 dark energy is that the universe is far
00:07:11 --> 00:07:13 from homogeneous it's not the same in
00:07:13 --> 00:07:15 all directions it's got thick bits and
00:07:15 --> 00:07:17 thin bits in terms of the amount of
00:07:17 --> 00:07:20 matter that it Con contains and the
00:07:20 --> 00:07:22 problem with all our cosmological
00:07:22 --> 00:07:24 modeling is the first premise that we
00:07:24 --> 00:07:27 start from the first foundational fact
00:07:27 --> 00:07:30 oid that we take is that the universe is
00:07:30 --> 00:07:32 the same in all directions it's
00:07:32 --> 00:07:35 isentropic uh and uniform and that is
00:07:35 --> 00:07:36 not the case we know that because we
00:07:36 --> 00:07:38 look out there and we see galaxies in
00:07:38 --> 00:07:40 some places and not in others so we know
00:07:40 --> 00:07:42 that the universe is highly
00:07:42 --> 00:07:43 inhomogeneous and what these people are
00:07:44 --> 00:07:47 saying is perhaps that is the bigger
00:07:47 --> 00:07:50 effect that is manifesting itself in
00:07:50 --> 00:07:52 what we think we're seeing as a an
00:07:52 --> 00:07:54 accelerated expansion of the universe uh
00:07:54 --> 00:07:57 caused by dark energy whereas in reality
00:07:57 --> 00:07:59 uh that's not the case the universe
00:07:59 --> 00:08:02 perhaps is not accelerating in its
00:08:02 --> 00:08:05 expansion but what we can see makes us
00:08:05 --> 00:08:07 think it is so the more measurements
00:08:07 --> 00:08:10 that we can make the more likely we are
00:08:10 --> 00:08:12 to be able to pick between one model and
00:08:12 --> 00:08:15 another uh so are they suggesting this
00:08:15 --> 00:08:18 is some kind of optical illusion in a
00:08:18 --> 00:08:19 sense yes that's right well the whole
00:08:19 --> 00:08:22 universe is an optical illusion in that
00:08:22 --> 00:08:24 you know we we see these things dotted
00:08:24 --> 00:08:26 around and we've got to be be very
00:08:26 --> 00:08:28 careful as to how we interpret that as a
00:08:28 --> 00:08:29 threedimensional
00:08:29 --> 00:08:32 entity and that's always the problem um
00:08:32 --> 00:08:35 my take on it if if you'll forgive me
00:08:35 --> 00:08:37 and I'd love to hear what jonty thinks
00:08:37 --> 00:08:40 about this work as well my take on it is
00:08:40 --> 00:08:42 that there is a lot of evidence not just
00:08:42 --> 00:08:45 from the Supernova observations but from
00:08:45 --> 00:08:47 the geometry of the universe as a whole
00:08:47 --> 00:08:49 when we look at this The Way galaxies
00:08:49 --> 00:08:52 form this kind of honeycomb of material
00:08:52 --> 00:08:55 almost like a foam of galaxies uh when
00:08:55 --> 00:08:57 you Analyze That and look at the
00:08:57 --> 00:08:59 characteristic distances between
00:08:59 --> 00:09:01 galaxies and things of that sort you can
00:09:01 --> 00:09:03 um really work out what the geometry of
00:09:03 --> 00:09:07 the universe is like in some detail and
00:09:07 --> 00:09:10 that allows you to tease out the
00:09:10 --> 00:09:12 constituent components including the
00:09:12 --> 00:09:14 contribution of normal matter which is
00:09:14 --> 00:09:17 only about 5% constitution of dark
00:09:17 --> 00:09:20 matter which is something like 25% and
00:09:20 --> 00:09:22 this mysterious thing called dark energy
00:09:22 --> 00:09:25 which is 70% there's there's there's
00:09:25 --> 00:09:28 Jordy agreeing with everything I'm
00:09:28 --> 00:09:30 saying he yeah he couldn't wait he
00:09:30 --> 00:09:32 couldn't wait to come back couldn't wait
00:09:32 --> 00:09:35 no he's yeah sorry about that all right
00:09:35 --> 00:09:38 Jordy it's
00:09:38 --> 00:09:41 okay so yeah not confusing Jordy with
00:09:41 --> 00:09:44 jonty which on an email and I apolog
00:09:44 --> 00:09:46 Jordy nearly got called jonty I have to
00:09:46 --> 00:09:48 say and would have been after you
00:09:48 --> 00:09:51 jonty um jonty what's your take on this
00:09:51 --> 00:09:53 and I I I do remember reading in one of
00:09:53 --> 00:09:55 our emails when we discussed this topic
00:09:55 --> 00:09:58 that it gave you a headache well I think
00:09:58 --> 00:09:59 most of these things do because we're
00:09:59 --> 00:10:01 trying to visualize things that are at
00:10:01 --> 00:10:03 the very limits of our understanding and
00:10:03 --> 00:10:05 I always find it amazing that we we're
00:10:05 --> 00:10:07 having this podcast here in all this
00:10:07 --> 00:10:08 technology we've developed with this
00:10:08 --> 00:10:10 incredible wealth of understanding we
00:10:10 --> 00:10:11 have the universe that has all been
00:10:11 --> 00:10:13 developed by about two kilograms of
00:10:13 --> 00:10:16 squishy stuff in people's heads and it's
00:10:16 --> 00:10:18 amazing that two kilos of squishy carbon
00:10:18 --> 00:10:21 can work out what the universe is like
00:10:21 --> 00:10:23 but what I love about this is it's a
00:10:23 --> 00:10:24 really nice reminder of how science
00:10:24 --> 00:10:27 actually works so you kind of get the
00:10:27 --> 00:10:28 impression at school that science was
00:10:28 --> 00:10:30 just done and dusted and here's a theory
00:10:30 --> 00:10:31 and that's it but what we're actually
00:10:31 --> 00:10:34 doing is this kind of iterative process
00:10:34 --> 00:10:36 where in astronomy we're not on
00:10:36 --> 00:10:37 experimental science we're an
00:10:37 --> 00:10:38 observational science which is a bit of
00:10:39 --> 00:10:41 a subtlety but what it means is we're
00:10:41 --> 00:10:42 looking out at the universe like
00:10:42 --> 00:10:43 detectives we're Gathering all these
00:10:43 --> 00:10:46 Clues and then we try and piece them
00:10:46 --> 00:10:47 together into a narrative of how things
00:10:47 --> 00:10:50 work and what makes that narrative a
00:10:50 --> 00:10:52 theory is that you can use it to make
00:10:52 --> 00:10:54 predictions if this is correct then you
00:10:54 --> 00:10:56 will see this then you'll see the other
00:10:56 --> 00:10:58 and sometimes people make explicit
00:10:58 --> 00:11:00 predictions like the next generation of
00:11:00 --> 00:11:01 telescopes you need to look for this and
00:11:02 --> 00:11:04 this is a really good test other times
00:11:04 --> 00:11:05 it's a bit more implicit because it's
00:11:05 --> 00:11:08 just saying this is how things behave
00:11:08 --> 00:11:10 and typically those series those
00:11:10 --> 00:11:12 explanations do an exceptionally good
00:11:12 --> 00:11:15 job of explaining everything we already
00:11:15 --> 00:11:18 see and going a little bit beyond it but
00:11:18 --> 00:11:20 there's this really long history of US
00:11:20 --> 00:11:22 hitting a wall where suddenly we've
00:11:22 --> 00:11:24 reached beyond the point where the
00:11:24 --> 00:11:26 theory works because we just didn't have
00:11:26 --> 00:11:28 enough data so the theory was a good
00:11:28 --> 00:11:29 explanation but it's not the final
00:11:29 --> 00:11:31 answer and then you get the
00:11:31 --> 00:11:34 observational that show the theory isn't
00:11:34 --> 00:11:36 quite right and you go back and new
00:11:36 --> 00:11:37 batches of theories come and sometimes
00:11:37 --> 00:11:38 they're just refinement or an
00:11:38 --> 00:11:40 improvement which is what this is doing
00:11:40 --> 00:11:42 essentially it's saying we can no longer
00:11:42 --> 00:11:44 assume the universe is homogeneous
00:11:44 --> 00:11:46 you've got to take account of the pess
00:11:46 --> 00:11:48 there's a few different models that try
00:11:48 --> 00:11:51 and do that in different ways they'll
00:11:51 --> 00:11:52 predict different things we can look at
00:11:52 --> 00:11:53 that in the
00:11:53 --> 00:11:55 future sometimes it knocks a theory over
00:11:55 --> 00:11:58 and you start again from scratch and
00:11:58 --> 00:11:59 this is what we're seeing with seeing
00:11:59 --> 00:12:01 science happening before our very eyes
00:12:01 --> 00:12:02 here and it's because what we're looking
00:12:02 --> 00:12:06 at is the hardest ever things to measure
00:12:06 --> 00:12:08 the most challenging observations really
00:12:08 --> 00:12:10 pushing the boundaries of what we know
00:12:10 --> 00:12:12 and so as we get more detailed answers
00:12:12 --> 00:12:14 you are going to hit a point where the
00:12:14 --> 00:12:16 simpler Theory doesn't work and I mean
00:12:16 --> 00:12:18 it makes my head hurt to call the
00:12:18 --> 00:12:20 current cosmology the simple version
00:12:21 --> 00:12:23 because it really really isn't but it's
00:12:23 --> 00:12:24 a steady Improvement and we've seen it
00:12:24 --> 00:12:27 in the past I use Newton's gravitation
00:12:27 --> 00:12:29 in all the research work I do all the
00:12:30 --> 00:12:32 simulations even though it's wrong it's
00:12:32 --> 00:12:35 wrong because you need to do general
00:12:35 --> 00:12:37 relativity to improve on it that's you
00:12:38 --> 00:12:39 know if we were doing the podcast 120
00:12:39 --> 00:12:41 years ago that would have been the great
00:12:41 --> 00:12:43 Revelation Newton was wrong here's
00:12:43 --> 00:12:45 Einstein but Newton's model was good
00:12:45 --> 00:12:47 enough that it's easier for my
00:12:47 --> 00:12:50 simulations to use it and the
00:12:50 --> 00:12:51 differences are so small we can ignore
00:12:51 --> 00:12:54 them that was 120 years ago this is the
00:12:54 --> 00:12:56 equivalent kind of thing going on now
00:12:56 --> 00:12:58 this is right at the Forefront and it's
00:12:58 --> 00:13:01 brilliant to see how these new surveys
00:13:01 --> 00:13:03 that were put together B off the stuff
00:13:03 --> 00:13:05 20 years ago and now pushing the limits
00:13:05 --> 00:13:07 of where that may or may not work allow
00:13:07 --> 00:13:09 needs to take that next step yeah would
00:13:09 --> 00:13:12 it be fair to say that uh challenging
00:13:12 --> 00:13:15 what we perceive to be the current
00:13:15 --> 00:13:18 reality is the way we can
00:13:18 --> 00:13:22 improve the the potential outcomes or
00:13:22 --> 00:13:24 the potential changes in the way we look
00:13:24 --> 00:13:26 at cosmology or or the universe as a
00:13:26 --> 00:13:29 whole um if if we didn't challenge these
00:13:29 --> 00:13:31 things there'd be no progress would that
00:13:31 --> 00:13:35 be a fair point yeah yeah absolutely so
00:13:35 --> 00:13:39 uh it it's you know essentially what we
00:13:39 --> 00:13:41 try to do here or the authors of this
00:13:42 --> 00:13:45 paper is lift the lid on not not the
00:13:45 --> 00:13:46 elephant in the room in the sense that
00:13:46 --> 00:13:48 you know we think there's something
00:13:48 --> 00:13:50 definitely drastically wrong with dark
00:13:50 --> 00:13:52 energy because it's still very much the
00:13:52 --> 00:13:55 paradig by which astronomers work but
00:13:55 --> 00:13:58 lifting the lid on maybe complacency so
00:13:58 --> 00:14:02 it is challenging our ideas and it will
00:14:02 --> 00:14:04 it will produce new results it may even
00:14:04 --> 00:14:07 produce a paper that says no way the
00:14:07 --> 00:14:09 dark energy model fits the uh the data
00:14:09 --> 00:14:13 better uh than the the the time scape
00:14:13 --> 00:14:15 model um especially when there is new
00:14:15 --> 00:14:17 data and actually those data already
00:14:17 --> 00:14:18 exist it's just that they haven't been
00:14:18 --> 00:14:21 fed into the into the mix yet so there
00:14:21 --> 00:14:24 might be challenges to the new model uh
00:14:24 --> 00:14:27 not very far down the track uh I kind of
00:14:27 --> 00:14:29 hope though that uh this this sort of
00:14:30 --> 00:14:32 thing actually starts to gain a little
00:14:32 --> 00:14:35 bit of traction and that we might see
00:14:35 --> 00:14:37 some glimmer of hope in understanding
00:14:37 --> 00:14:39 what we have hither to thought of as
00:14:39 --> 00:14:40 dark energy because it's been one of the
00:14:40 --> 00:14:44 biggest puzzles faced by astrophysicists
00:14:44 --> 00:14:46 yes that's kind of what this whole paper
00:14:46 --> 00:14:48 is doing actually so the the idea behind
00:14:48 --> 00:14:50 this is two or three different models
00:14:50 --> 00:14:52 were proposed in the last 10 or 15 years
00:14:53 --> 00:14:54 and what this paper is doing is saying
00:14:54 --> 00:14:57 now we have all this observational data
00:14:57 --> 00:14:59 we've got enough data to compare them
00:14:59 --> 00:15:01 models and run a statistical test to see
00:15:01 --> 00:15:04 which fits better essentially and they
00:15:04 --> 00:15:06 find that the time scape one fits a
00:15:06 --> 00:15:08 little bit better for this sample than
00:15:08 --> 00:15:10 dark energy but not enough to be
00:15:10 --> 00:15:13 definitive yet and what's interesting is
00:15:13 --> 00:15:14 there's this fantastic thing called The
00:15:14 --> 00:15:17 Dark Energy survey which I think Tamara
00:15:17 --> 00:15:19 deris down at ukq has led but it's this
00:15:19 --> 00:15:21 incredible Global project that I know
00:15:21 --> 00:15:23 about because of the spin-offs in solar
00:15:23 --> 00:15:25 system astronomy that I've heard about
00:15:25 --> 00:15:27 which is an even bigger data set and I
00:15:27 --> 00:15:29 suspect the next set with this is to say
00:15:29 --> 00:15:31 look the test with the data set we use
00:15:31 --> 00:15:33 here show that this is a worthwhile test
00:15:33 --> 00:15:35 to do now let's use an even bigger data
00:15:35 --> 00:15:37 set so I could easily see you talking
00:15:37 --> 00:15:39 about this again in 12 GS time say
00:15:39 --> 00:15:40 remember that team that said time skate
00:15:40 --> 00:15:42 was interesting they've got a new one
00:15:42 --> 00:15:44 out it's a sequel and it's
00:15:44 --> 00:15:47 really yeah yeah yeah it could be really
00:15:47 --> 00:15:50 exciting down the track and we we
00:15:50 --> 00:15:51 obviously there's going to be a lot of
00:15:51 --> 00:15:53 peer review a lot of discussion a lot of
00:15:53 --> 00:15:55 debate some will debunk it some will say
00:15:55 --> 00:15:56 well actually you know they're on to
00:15:56 --> 00:15:58 something we might yeah who knows where
00:15:58 --> 00:16:00 this will that we'll watch with great
00:16:00 --> 00:16:04 interest this is Space Nuts you can um
00:16:04 --> 00:16:05 follow up that story on the
00:16:05 --> 00:16:07 conversation.com this is Space Nuts
00:16:07 --> 00:16:11 Andrew Dunley with Fred and jonty Horner
00:16:11 --> 00:16:14 and glad to have your
00:16:14 --> 00:16:17 company okay we checked all four systems
00:16:17 --> 00:16:20 and It Go space Nets right jotty uh to
00:16:21 --> 00:16:23 you uh and and uh just before we started
00:16:23 --> 00:16:25 you showed us some fabulous images of
00:16:25 --> 00:16:30 this uh Comet C 2024 G3 Atlas is that
00:16:30 --> 00:16:33 the right title for like if I get that
00:16:33 --> 00:16:35 right it is yeah and ning conventions
00:16:35 --> 00:16:37 for comets are a little bit like bar
00:16:37 --> 00:16:39 codes so you've got two parts the atlas
00:16:39 --> 00:16:41 part is who discovered it and that's the
00:16:41 --> 00:16:44 atlas survey the rest of it is a unique
00:16:44 --> 00:16:45 identifier that tells you when it was
00:16:45 --> 00:16:48 found so the C tells you that this is a
00:16:48 --> 00:16:50 comet that is not a periodic Comet it's
00:16:50 --> 00:16:51 the first time we've seen it if it was a
00:16:52 --> 00:16:54 periodic Comet like comic hot and be a p
00:16:54 --> 00:16:56 and it might even have a number before
00:16:56 --> 00:17:00 it and then the 2024 G3 tells you when
00:17:00 --> 00:17:02 it was found so it was discovered in
00:17:02 --> 00:17:04 2024 the the letter tells you which
00:17:05 --> 00:17:07 fortnite of the year it was found in so
00:17:07 --> 00:17:09 a would be the first fortnite in January
00:17:09 --> 00:17:11 B the second and so on and then three
00:17:11 --> 00:17:14 tells you was the third object in that
00:17:14 --> 00:17:17 fortnite so nice and straightforward and
00:17:17 --> 00:17:18 it rolls off the tongue I mean it's
00:17:18 --> 00:17:20 easier than choing Shan Atlas which was
00:17:20 --> 00:17:24 last year now this comic was found and
00:17:24 --> 00:17:27 people got moderately excited got
00:17:27 --> 00:17:29 moderately excited because it was very
00:17:29 --> 00:17:31 fair when it was found which suggests
00:17:31 --> 00:17:33 that it might be intrinsically
00:17:33 --> 00:17:36 relatively small as IC object does but
00:17:36 --> 00:17:38 when they worked out its orbit they
00:17:38 --> 00:17:40 found that it was going to get within a
00:17:40 --> 00:17:42 tenth of the distance between the Earth
00:17:42 --> 00:17:43 and the Sun of the Sun so it's going to
00:17:43 --> 00:17:46 get really close to the Sun and all
00:17:46 --> 00:17:47 other the things being equal the closer
00:17:47 --> 00:17:49 cometer nucleus gets to the Sun the more
00:17:50 --> 00:17:51 active it gets and therefore the more
00:17:51 --> 00:17:54 spectacular the comet gets so that's an
00:17:54 --> 00:17:56 indication that this comic could get
00:17:56 --> 00:17:57 very very bright around perhelion
00:17:57 --> 00:18:00 closest to the which is literally while
00:18:00 --> 00:18:02 we're recording this podcast it's around
00:18:02 --> 00:18:04 now the reason everybody's being
00:18:04 --> 00:18:06 tentative about it is that being quite a
00:18:06 --> 00:18:07 small object small things that get close
00:18:08 --> 00:18:09 to the Sun tend not to survive they tend
00:18:09 --> 00:18:12 to fall apart disintegrate and so with
00:18:12 --> 00:18:15 this thing people have been far more
00:18:15 --> 00:18:16 cautious than I'm used to with comments
00:18:16 --> 00:18:18 actually I'm used to people hyping them
00:18:18 --> 00:18:19 and me having to play the voice of
00:18:19 --> 00:18:20 reason with this one people have been
00:18:20 --> 00:18:23 really cautious because it might not
00:18:23 --> 00:18:25 survive but now that it's at its closest
00:18:25 --> 00:18:28 to the Sun it's going really well and it
00:18:28 --> 00:18:29 is surviving I mean that doesn't mean
00:18:29 --> 00:18:31 that in two days time it won't
00:18:31 --> 00:18:33 disintegrate so caution there comets are
00:18:33 --> 00:18:35 like cats they have tails to do whatever
00:18:35 --> 00:18:38 they want but it's looking promising at
00:18:38 --> 00:18:40 the minute it's nearly as bright as the
00:18:40 --> 00:18:43 planet Venus but you can't see it
00:18:43 --> 00:18:44 because it's within five degrees of the
00:18:44 --> 00:18:47 sun that's as we record this but in the
00:18:47 --> 00:18:49 next few days it's going to start to
00:18:49 --> 00:18:51 move away from the Sun in the sky very
00:18:51 --> 00:18:53 low on the western Horizon apologies to
00:18:53 --> 00:18:55 people in the northern hemisphere but
00:18:55 --> 00:18:56 this is going to be one which we're
00:18:56 --> 00:18:57 going to have a much better view down
00:18:57 --> 00:19:00 south just because of the orientation of
00:19:00 --> 00:19:02 the comics Orit it's diving very steeply
00:19:02 --> 00:19:04 south below the plane of the solar
00:19:04 --> 00:19:05 system so as it moves away from the sun
00:19:05 --> 00:19:08 it's moving in a sutherly direction what
00:19:08 --> 00:19:11 all that means is that Thursday Friday
00:19:11 --> 00:19:13 Saturday Sunday so that's Thursday the
00:19:13 --> 00:19:15 16th of January through the weekend
00:19:15 --> 00:19:17 maybe into next week there is a chance
00:19:17 --> 00:19:20 we could have a reasonably bright Comet
00:19:20 --> 00:19:23 very low on the western Horizon after
00:19:23 --> 00:19:25 Sunset probably a little bit brighter
00:19:25 --> 00:19:28 than Comet TR chinshan Atlas was but a
00:19:28 --> 00:19:30 little bit harder to see it's a bit more
00:19:30 --> 00:19:33 lost in the sun's glare fading day by
00:19:33 --> 00:19:35 day as it gets higher above the Horizon
00:19:35 --> 00:19:38 so on Thursday for me here in to in
00:19:38 --> 00:19:40 southeast Queensland it'll set about 45
00:19:40 --> 00:19:42 minutes after the sun on Friday it'll
00:19:42 --> 00:19:44 set about an hour after the sun on
00:19:44 --> 00:19:45 Saturday about an hour and a quarter so
00:19:45 --> 00:19:47 you get this feel it's moving away from
00:19:47 --> 00:19:50 the Sun low on the western Horizon I'm
00:19:50 --> 00:19:51 going to get out there and try and
00:19:51 --> 00:19:52 photograph it and there are actually
00:19:52 --> 00:19:54 people getting photos of it in broad
00:19:54 --> 00:19:56 daylight at the minute but the havat
00:19:56 --> 00:19:59 there is don't do that unless you really
00:19:59 --> 00:20:00 know what you're doing because it's a
00:20:00 --> 00:20:01 very good way of damaging your camera
00:20:01 --> 00:20:04 your eyesight and your wallet essenti it
00:20:04 --> 00:20:06 could be very very good they've
00:20:07 --> 00:20:10 described this as a once in 160 year
00:20:10 --> 00:20:13 Comet I also believe it's
00:20:13 --> 00:20:17 uh of all Cloud origin I mean what does
00:20:17 --> 00:20:19 that what does that mean basically um it
00:20:19 --> 00:20:23 means that people are throwing a lassue
00:20:23 --> 00:20:25 around something that astronom probably
00:20:25 --> 00:20:29 wouldn't mention so comets move on these
00:20:29 --> 00:20:31 really elongated orbits around the Sun
00:20:31 --> 00:20:32 and when a comet's trapped on an orbit
00:20:33 --> 00:20:34 that's relatively short period you know
00:20:34 --> 00:20:36 in tens or hundreds or even a few
00:20:36 --> 00:20:39 thousand years it's not getting so far
00:20:39 --> 00:20:40 from the Sun that anything else is going
00:20:40 --> 00:20:42 to Stir It Up other than the planets in
00:20:42 --> 00:20:43 the inner solar system so Comet H is
00:20:44 --> 00:20:46 roughly 76 years and it comes back when
00:20:46 --> 00:20:48 you get to orbital periods of around
00:20:48 --> 00:20:50 100 years or so or even more than
00:20:50 --> 00:20:52 that you're getting Far Enough From the
00:20:52 --> 00:20:55 Sun that you get perturbed by passing
00:20:55 --> 00:20:58 Stars by the tidal effects of the Galaxy
00:20:58 --> 00:21:00 stuff like that so saying that this
00:21:00 --> 00:21:03 thing's on 160 year orbit doesn't
00:21:04 --> 00:21:06 mean that it will be back in 160
00:21:06 --> 00:21:07 years because when it gets furthest from
00:21:07 --> 00:21:09 the Sun it will be nudged around and
00:21:09 --> 00:21:11 will probably not come in on quite the
00:21:11 --> 00:21:13 same orbit the reason that gets thrown
00:21:13 --> 00:21:16 around though is that it's currently on
00:21:16 --> 00:21:18 160 year orbit so therefore it
00:21:18 --> 00:21:20 wasn't seen at any point in the last
00:21:20 --> 00:21:22 160 years it's a little
00:21:22 --> 00:21:25 specious what what it did give
00:21:25 --> 00:21:27 astronomers a bit of faith for though is
00:21:27 --> 00:21:29 that this comet has probably been past
00:21:29 --> 00:21:31 the Sun at least once before because
00:21:31 --> 00:21:34 that orbit is slightly tightly
00:21:34 --> 00:21:36 bound that gives a little bit more
00:21:37 --> 00:21:38 confidence that it would survive
00:21:38 --> 00:21:40 perhelion so the Comets that break up
00:21:40 --> 00:21:41 are either really small fragments of a
00:21:41 --> 00:21:43 bigger Comet and they're too small to
00:21:43 --> 00:21:45 survive all comets coming through for
00:21:46 --> 00:21:48 the very first time have a tendency to
00:21:48 --> 00:21:51 break apart more often so the media
00:21:51 --> 00:21:53 stories use that number because it's a
00:21:53 --> 00:21:55 big number and it makes it sound
00:21:55 --> 00:21:57 exciting it is not the best comic you'll
00:21:57 --> 00:21:59 see in the next 60 years it's
00:21:59 --> 00:22:01 possibly the best Comet of this year but
00:22:01 --> 00:22:03 we don't know till the year's over
00:22:03 --> 00:22:06 yet but having that orbital period that
00:22:06 --> 00:22:08 is indicating it's been through before
00:22:08 --> 00:22:10 gave astronom is a little bit of faith
00:22:10 --> 00:22:11 that it might survive and other the
00:22:11 --> 00:22:13 minute it's looking good there's some
00:22:13 --> 00:22:15 glorious images out online from the
00:22:15 --> 00:22:18 solar helus feric Observatory suro which
00:22:18 --> 00:22:19 points at the sun has a little thing in
00:22:19 --> 00:22:21 the middle to block the Sun out so it
00:22:21 --> 00:22:24 can look at solar eruptions coronal mass
00:22:24 --> 00:22:25 ejections and this comet's in the field
00:22:25 --> 00:22:27 of you at the minute and it's the third
00:22:27 --> 00:22:30 brightest comic that Soho has ever seen
00:22:30 --> 00:22:31 it's brighter than Trin Shan Atlas was
00:22:31 --> 00:22:33 at the minute the only two that were
00:22:33 --> 00:22:36 better was comic mcnaught in early 2007
00:22:36 --> 00:22:39 and um Comet I on in
00:22:39 --> 00:22:42 2012 so it's in steem company could be
00:22:42 --> 00:22:44 really good and it's well worth a look
00:22:44 --> 00:22:46 and you will see some awesome photos I
00:22:46 --> 00:22:48 can almost guarantee that gosh I'm going
00:22:48 --> 00:22:49 to have to get out there with my
00:22:49 --> 00:22:51 telescope and see if I can have a crack
00:22:51 --> 00:22:53 at it uh Fred we've talked about um
00:22:53 --> 00:22:58 comets a lot um and we got pretty
00:22:58 --> 00:23:01 excited late last year when um the comet
00:23:01 --> 00:23:03 made the news and we couldn't see it
00:23:03 --> 00:23:04 because it was cloudy in Sydney it was
00:23:04 --> 00:23:08 cloudy here um I never got one chance to
00:23:08 --> 00:23:11 see it so I'm very hopeful about this
00:23:11 --> 00:23:12 one yeah well the great thing about this
00:23:13 --> 00:23:14 one Andrew is you're not going to get
00:23:14 --> 00:23:16 have to get up at 3:00 in the morning as
00:23:16 --> 00:23:18 as jonty did to photograph the the last
00:23:18 --> 00:23:24 one so uh yeah so um I I'm sure that
00:23:24 --> 00:23:26 fingers will be crossed sadly mine won't
00:23:27 --> 00:23:29 be because two days days time I'll be
00:23:29 --> 00:23:32 very well up in the northern hemisphere
00:23:32 --> 00:23:34 uh in the Arctic Circle in fact so uh
00:23:34 --> 00:23:36 that's going to take me well away from
00:23:36 --> 00:23:38 uh night sky viewing of this comet in
00:23:38 --> 00:23:40 the evening Sky maybe when you take off
00:23:40 --> 00:23:42 you could just take your telescope and
00:23:42 --> 00:23:43 shove it out the window of the plane
00:23:43 --> 00:23:46 that I I just think depending what time
00:23:46 --> 00:23:49 you fly if you're taking off in the
00:23:49 --> 00:23:50 early evening you might get to see it
00:23:50 --> 00:23:52 from the plane window and that's a good
00:23:52 --> 00:23:54 way of been above the clouds it is
00:23:54 --> 00:23:56 indeed yeah it's uh it's an afternoon
00:23:56 --> 00:23:59 flight jonty up to Bangkok and then from
00:23:59 --> 00:24:00 there up to
00:24:00 --> 00:24:03 Stockholm so to be on the western side
00:24:03 --> 00:24:05 of the
00:24:05 --> 00:24:08 aircraft um my seat is already picked so
00:24:08 --> 00:24:10 that I will be next to my
00:24:10 --> 00:24:14 wife you probably need to be looking at
00:24:14 --> 00:24:18 her yes indeed H yeah it's very exciting
00:24:18 --> 00:24:20 so something to keep an eye out for and
00:24:20 --> 00:24:23 jny just quickly uh if people want to
00:24:23 --> 00:24:26 have a a go at seeing this um best time
00:24:26 --> 00:24:29 best way uh the further south you are in
00:24:29 --> 00:24:32 the world the better um actually I think
00:24:32 --> 00:24:34 about where I am really the nearer you
00:24:34 --> 00:24:35 are to the Equator the more steeply
00:24:36 --> 00:24:38 things set and so the higher above the
00:24:38 --> 00:24:40 Horizon they are a given amount of time
00:24:40 --> 00:24:42 before they set so if it's 30 minutes
00:24:42 --> 00:24:43 before something sets and you're at the
00:24:43 --> 00:24:45 poll it's pretty much on the horizon
00:24:45 --> 00:24:47 already if you're on the equator it's
00:24:47 --> 00:24:50 setting vertically but have a play
00:24:50 --> 00:24:51 around with one of the wonderful free
00:24:51 --> 00:24:54 planetarian programs I often use the
00:24:54 --> 00:24:56 larium um because that's a free one you
00:24:56 --> 00:24:57 can just open in a browser window set
00:24:58 --> 00:25:01 you look and Away you go and also what I
00:25:01 --> 00:25:02 did earlier on cuz I'm looking at trying
00:25:02 --> 00:25:04 to get some photos Thursday Friday
00:25:04 --> 00:25:06 Saturday if the weather holds out is
00:25:06 --> 00:25:08 actually hop on to Google Maps have a
00:25:08 --> 00:25:10 look for a place around you because you
00:25:10 --> 00:25:12 can drop that little Peg man in and have
00:25:12 --> 00:25:14 a look what the Horizon's like just
00:25:14 --> 00:25:15 south of West and there you can find
00:25:15 --> 00:25:17 somewhere with the lowest Western
00:25:17 --> 00:25:19 Horizon possible because it is going to
00:25:19 --> 00:25:21 be quite low to the Horizon and if you
00:25:21 --> 00:25:24 can't see with an naked eye lob a camera
00:25:24 --> 00:25:26 especially if you've got a DSLR type
00:25:26 --> 00:25:28 camera bang it on a tripod where it
00:25:28 --> 00:25:29 should be and play around with the
00:25:29 --> 00:25:31 exposure times cuz the images I was
00:25:31 --> 00:25:33 showing before we started recording I
00:25:33 --> 00:25:35 could just see the comic with a naked
00:25:35 --> 00:25:36 eye but it was really obvious through
00:25:36 --> 00:25:38 the back of the camera and it was really
00:25:38 --> 00:25:42 obvious in the lens so that Comet I
00:25:42 --> 00:25:43 could see with the naked eye and it's
00:25:43 --> 00:25:45 like yeah wow I can see it brilliant but
00:25:45 --> 00:25:47 the photos came out better than my view
00:25:47 --> 00:25:50 was right and and get out of town get
00:25:50 --> 00:25:51 somewhere
00:25:51 --> 00:25:53 dark dark dark's a bit less relevant
00:25:53 --> 00:25:55 when you're still so close to Sunset I
00:25:55 --> 00:25:56 mean we're talking about observing here
00:25:56 --> 00:25:58 during Twilight at least
00:25:58 --> 00:26:01 even if you go a a week from now it's
00:26:02 --> 00:26:03 still only setting at about 8:00 p.m. so
00:26:03 --> 00:26:05 it's only an hour and a bit after Sunset
00:26:05 --> 00:26:07 and by then it will be fading relatively
00:26:07 --> 00:26:09 quickly if it goes really well it might
00:26:09 --> 00:26:10 be visible with a naked eye for about a
00:26:11 --> 00:26:13 fortnite but that's tenuously but
00:26:13 --> 00:26:15 basically find somewhere with a low
00:26:15 --> 00:26:17 Western Horizon slightly South of West
00:26:17 --> 00:26:19 actually lower the better because if
00:26:19 --> 00:26:21 there's trees in the way or buildings in
00:26:21 --> 00:26:22 the way or people in the way they're
00:26:22 --> 00:26:24 going to get in the way of the Comet so
00:26:24 --> 00:26:26 ideally want the Western Horizon to be
00:26:26 --> 00:26:29 as low as possible yeah okay well we've
00:26:29 --> 00:26:31 got some plenty of Flat Earth around
00:26:31 --> 00:26:34 this part of the world use a different
00:26:34 --> 00:26:38 terminology plenty of flat ground uh so
00:26:38 --> 00:26:40 U yeah out where we are in the Northwest
00:26:40 --> 00:26:42 it's uh probably or the Central West
00:26:42 --> 00:26:44 it's probably a great place to uh make
00:26:44 --> 00:26:46 some observations um lots of stories
00:26:46 --> 00:26:50 online uh space.com but yeah just do a
00:26:50 --> 00:26:53 search for Comet C 2024 G3 and uh yeah
00:26:53 --> 00:26:56 you won't be disappointed this is Space
00:26:56 --> 00:26:57 Nuts Andrew Dunley here with Professor
00:26:57 --> 00:27:03 Fred and Professor johy
00:27:03 --> 00:27:07 Horner Space Nuts our next story takes
00:27:07 --> 00:27:10 us to the outer solar system uh I I kind
00:27:10 --> 00:27:12 of um introduced this as don't be it
00:27:12 --> 00:27:16 Karen kiss and tell this is actually an
00:27:16 --> 00:27:18 interesting story about how Pluto got
00:27:18 --> 00:27:21 its Moon and um you know we we talk
00:27:21 --> 00:27:23 about how Earth got its moon with that
00:27:23 --> 00:27:26 massive collision with thear now they're
00:27:27 --> 00:27:28 starting to think something different
00:27:28 --> 00:27:32 happened with the moon Caron and Pluto
00:27:32 --> 00:27:35 so um take it away whoever wants to pick
00:27:35 --> 00:27:37 this one up first I think this is
00:27:37 --> 00:27:39 definitely jonty's because he's a
00:27:39 --> 00:27:42 planetary scientist okay there you go
00:27:42 --> 00:27:45 yeah so we've got kind of broadly three
00:27:45 --> 00:27:47 types of moon in the solar system we've
00:27:47 --> 00:27:49 got what we call the regular satellites
00:27:49 --> 00:27:50 which you see around the giant planets
00:27:50 --> 00:27:54 and that's IO Europa ganam clist Titan
00:27:54 --> 00:27:55 and the thinking about them is they form
00:27:55 --> 00:27:57 around their planets like the planets
00:27:57 --> 00:27:59 form around the Sun you get a disc of
00:27:59 --> 00:28:01 material these things are creating that
00:28:01 --> 00:28:03 disc and that's why they're pretty much
00:28:03 --> 00:28:04 in the plane of the Equator of those
00:28:04 --> 00:28:07 planets and they look like minlan
00:28:07 --> 00:28:09 systems essentially you've then got what
00:28:09 --> 00:28:10 are called The Irregular satellites
00:28:10 --> 00:28:12 which are things typically again around
00:28:13 --> 00:28:15 the giant planets that are way way out
00:28:16 --> 00:28:17 as much as 20 30 million kilometers from
00:28:18 --> 00:28:19 the planet moving on really bizarre
00:28:19 --> 00:28:21 orbits really eccentric really inclined
00:28:21 --> 00:28:24 and typically small icy objects and then
00:28:24 --> 00:28:26 we understand because they were captured
00:28:26 --> 00:28:28 really straightforward that's how you
00:28:28 --> 00:28:29 form them they didn't form where they
00:28:29 --> 00:28:32 are they were grabbed then you've got
00:28:32 --> 00:28:33 the audities which are the things that
00:28:34 --> 00:28:35 don't fit either of those models and
00:28:35 --> 00:28:38 they're the moon then Neptunes Moon
00:28:38 --> 00:28:41 Triton and a number of the satellite
00:28:41 --> 00:28:42 systems around smaller objects Pluto and
00:28:43 --> 00:28:46 Kum being kind of the really Prime
00:28:46 --> 00:28:49 obvious example and those ones didn't
00:28:49 --> 00:28:51 form in either of the two kind of
00:28:51 --> 00:28:53 standard ways they have to be formed
00:28:53 --> 00:28:55 somewhere different and it seems to be
00:28:55 --> 00:28:58 that collisions are part of that story
00:28:58 --> 00:29:00 and the real key Point here is that for
00:29:00 --> 00:29:02 the Earth and the moon for PL Pluto and
00:29:02 --> 00:29:05 karon the mass of the Moon compared to
00:29:05 --> 00:29:07 the mass of the planet is really really
00:29:07 --> 00:29:09 really big so for the regular
00:29:09 --> 00:29:11 satellites I'm all their Mass together
00:29:11 --> 00:29:13 and it's still less than 110 of the
00:29:13 --> 00:29:16 mass of that planet The Irregular
00:29:16 --> 00:29:18 satellites are even less but the Moon is
00:29:18 --> 00:29:20 an 81st of the mass of the Earth Caron
00:29:20 --> 00:29:23 is a sixth of the mass of Pluto and that
00:29:23 --> 00:29:25 just doesn't work with a disc that
00:29:25 --> 00:29:28 doesn't make sense equally Capt ing them
00:29:28 --> 00:29:30 gravitationally doesn't work so you need
00:29:30 --> 00:29:32 the dissipative force you need something
00:29:32 --> 00:29:34 to slow them down otherwise they just
00:29:34 --> 00:29:36 fly by get perturbed and escape again
00:29:36 --> 00:29:39 you need something to put the brakes on
00:29:39 --> 00:29:41 added to that you've got the
00:29:41 --> 00:29:43 similarities and the differences between
00:29:43 --> 00:29:45 the Moon and the object that hurts it
00:29:45 --> 00:29:46 and we knew this since the Apollo
00:29:46 --> 00:29:49 Astronauts brought samples back our moon
00:29:49 --> 00:29:51 is almost identical in composition to
00:29:51 --> 00:29:54 the Earth but it's lacking in heavy
00:29:54 --> 00:29:56 elements like iron and nickel and it's
00:29:57 --> 00:29:59 overly rich in the light stuff that
00:29:59 --> 00:30:00 makes up the Earth's crust and that led
00:30:00 --> 00:30:02 people in the ' 80s to come up with the
00:30:03 --> 00:30:04 big smash idea that the Earth was in a
00:30:05 --> 00:30:07 collision with something and this was
00:30:07 --> 00:30:09 after it was differentiated so all the
00:30:09 --> 00:30:11 heavy stuff was in the middle all the
00:30:11 --> 00:30:13 light stuff was in the crust and that
00:30:13 --> 00:30:14 splashed off and formed the moon and so
00:30:14 --> 00:30:16 you get a moon that is formed from the
00:30:16 --> 00:30:19 same material as the Earth is really big
00:30:19 --> 00:30:21 but doesn't have all the iron and
00:30:21 --> 00:30:23 nickel then when it comes to Pluto
00:30:23 --> 00:30:25 you've got a very similar looking system
00:30:25 --> 00:30:26 you've got a very big moon compared to
00:30:26 --> 00:30:29 the planet really close in so it doesn't
00:30:29 --> 00:30:31 look like a capture scenario and that
00:30:31 --> 00:30:33 led to a lot of models through the '90s
00:30:33 --> 00:30:36 coming out with a story that Pluto and
00:30:36 --> 00:30:38 karon and also the Little Moons Nicks
00:30:38 --> 00:30:42 and Hydra keas and sticks and they
00:30:42 --> 00:30:44 formed in a giant Collision just the
00:30:44 --> 00:30:46 same as our moon formed around the earth
00:30:46 --> 00:30:48 there was a big splash and you get this
00:30:48 --> 00:30:50 sack light system with one big one and a
00:30:50 --> 00:30:53 few little bits and that works really
00:30:53 --> 00:30:54 well that is a perfectly valid
00:30:54 --> 00:30:56 explanation but the new model is
00:30:56 --> 00:30:58 slightly different and it only really
00:30:58 --> 00:31:00 works because when you're that far from
00:31:00 --> 00:31:02 the Sun the speeds are lower so that
00:31:02 --> 00:31:05 means you can get gentler collisions
00:31:05 --> 00:31:06 everything goes around slower the
00:31:06 --> 00:31:08 further you are from the Sun and so this
00:31:08 --> 00:31:10 new modeling has said let's have a look
00:31:10 --> 00:31:12 at whether you need it to be a
00:31:12 --> 00:31:14 catastrophic Collision run a lot of
00:31:14 --> 00:31:16 simulations essentially to see what
00:31:16 --> 00:31:19 other the scenarios you can get and they
00:31:19 --> 00:31:21 included in this the fact that Pluto and
00:31:21 --> 00:31:23 Caron will be physically strong objects
00:31:23 --> 00:31:26 they're not Blobs of liquid water
00:31:26 --> 00:31:27 they're solid material that has an
00:31:27 --> 00:31:30 inherent strength to it and they found a
00:31:30 --> 00:31:31 set of scenarios within that where you
00:31:31 --> 00:31:34 can get a gently enough Collision that
00:31:34 --> 00:31:36 Pluto and the thing hitting it that
00:31:36 --> 00:31:39 becomes Caron Collide and semi- merge
00:31:39 --> 00:31:40 giving you an object a bit like a
00:31:40 --> 00:31:42 snowman with a small bulge and a big
00:31:42 --> 00:31:45 bulge but never fully merge but that
00:31:45 --> 00:31:47 Collision dissipates energy you have a
00:31:47 --> 00:31:50 collision that like absorbs and they
00:31:50 --> 00:31:52 bounce off each other but the speed has
00:31:52 --> 00:31:54 been slowed down because the Collision
00:31:54 --> 00:31:56 happened essentially you've got
00:31:56 --> 00:31:59 cushioning for one of a better word that
00:31:59 --> 00:32:01 means that karon doesn't move away from
00:32:01 --> 00:32:04 Pluto quickly enough to escape but
00:32:04 --> 00:32:06 instead gets trapped so you get this
00:32:06 --> 00:32:08 collisional capture and that can set up
00:32:08 --> 00:32:10 the system as it looks and a bit of the
00:32:10 --> 00:32:11 debris that goes off would form those of
00:32:12 --> 00:32:14 the moons and it seems equally valid to
00:32:14 --> 00:32:17 the catastroph more catastrophic
00:32:17 --> 00:32:19 Collision version but what I really like
00:32:19 --> 00:32:22 about it is there's a very clear
00:32:22 --> 00:32:23 prediction you can make from this which
00:32:23 --> 00:32:26 is that if you have the catastrophic
00:32:26 --> 00:32:27 Collision type model like the Earth and
00:32:27 --> 00:32:28 Moon
00:32:28 --> 00:32:30 then Pluto and karon will essentially be
00:32:30 --> 00:32:32 made of the same stuff they'll be
00:32:32 --> 00:32:34 compositionally identical maybe with a
00:32:34 --> 00:32:35 little bit of a difference because of
00:32:36 --> 00:32:37 the differentiation of Pluto you might
00:32:37 --> 00:32:39 get Caron being a little bit underdense
00:32:39 --> 00:32:42 and Pluto being denser with this model
00:32:42 --> 00:32:44 you've got two discrete objects that
00:32:44 --> 00:32:47 form separately and remain fairly
00:32:47 --> 00:32:49 discrete they remain separate objects
00:32:49 --> 00:32:52 with a little bit of mixing which means
00:32:52 --> 00:32:53 that if there were any compositional
00:32:53 --> 00:32:55 differences when they formed they should
00:32:55 --> 00:32:58 still have them now we can't test at the
00:32:58 --> 00:32:59 minute we need to go there and land on
00:32:59 --> 00:33:01 them and drill them and do samples yes
00:33:02 --> 00:33:03 but it's another of those examples we
00:33:03 --> 00:33:04 talked about it with the cosmology
00:33:04 --> 00:33:07 earlier on where theories make
00:33:07 --> 00:33:09 predictions that allow you to test them
00:33:09 --> 00:33:11 and Rule between them and the big test
00:33:11 --> 00:33:13 of this compared to the other model is a
00:33:13 --> 00:33:15 compositions is the densities it's stuff
00:33:15 --> 00:33:18 that we can in theory in the future
00:33:18 --> 00:33:20 check and it's really important because
00:33:20 --> 00:33:23 one of the big problems with our
00:33:23 --> 00:33:24 understanding of the objects Beyond
00:33:24 --> 00:33:26 nature and the trans neptunian objects
00:33:26 --> 00:33:27 of which Pluto is just one of the
00:33:27 --> 00:33:28 biggest
00:33:28 --> 00:33:29 is that there's actually quite a few of
00:33:29 --> 00:33:31 these binaries that have very similar
00:33:31 --> 00:33:34 masses out there so this might not be an
00:33:34 --> 00:33:36 isolated event and the better we can
00:33:36 --> 00:33:38 understand those mechanics the better a
00:33:38 --> 00:33:40 handle we have on planet formation Moon
00:33:40 --> 00:33:43 formation and also these smaller objects
00:33:43 --> 00:33:44 so it's really fascinating and for me
00:33:44 --> 00:33:48 it's one that is setting up future
00:33:48 --> 00:33:50 investigations probably sets the scene
00:33:50 --> 00:33:53 for New Horizons match Mark 2 in 20
00:33:53 --> 00:33:54 years 30 years time when the technolog
00:33:54 --> 00:33:56 is a bit better where we can actually go
00:33:56 --> 00:33:58 there and put a l down and do some
00:33:58 --> 00:34:00 something and actually test this
00:34:00 --> 00:34:02 exciting yeah it's so it was more of a
00:34:03 --> 00:34:05 scrape rather than a crash um similar to
00:34:05 --> 00:34:10 the way my wife Parks a car um but but
00:34:10 --> 00:34:11 this was really quick when you talk
00:34:11 --> 00:34:13 about the age of the solar system the
00:34:13 --> 00:34:15 age of the universe with you know
00:34:15 --> 00:34:18 millions billions of years this was a
00:34:18 --> 00:34:20 really quick encounter it's like 10 to
00:34:20 --> 00:34:24 15 hours of of contact and then they
00:34:24 --> 00:34:26 were apart again it's that's why they're
00:34:26 --> 00:34:28 calling it a kiss I suppose it is and I
00:34:28 --> 00:34:29 mean that time
00:34:29 --> 00:34:32 scale sounds surprisingly short but in
00:34:32 --> 00:34:34 the scheme of an impact that's actually
00:34:34 --> 00:34:36 surprisingly long because if you think
00:34:36 --> 00:34:38 about the collision between the Earth
00:34:38 --> 00:34:40 and the moon if the moon's coming in
00:34:40 --> 00:34:43 well if fear's coming in at the slowest
00:34:43 --> 00:34:44 possible speed you can come in and hit
00:34:44 --> 00:34:47 the earth without being gravitationally
00:34:47 --> 00:34:49 bound it's traveling at 10 kilometers a
00:34:49 --> 00:34:53 second the Earth is 12 kmers across
00:34:53 --> 00:34:55 so that's 12200 seconds for the moon for
00:34:55 --> 00:34:57 the the to go from one side of the Earth
00:34:57 --> 00:34:58 to the other
00:34:58 --> 00:35:02 um 12 seconds is what um 200 minutes
00:35:02 --> 00:35:05 three three and a bit hours yeah Pluto
00:35:05 --> 00:35:07 is much smaller than the earth so 10
00:35:07 --> 00:35:09 hours here is indicative of that slower
00:35:09 --> 00:35:11 speed the only way you can stay in
00:35:11 --> 00:35:13 contact for 10 hours is to be moving
00:35:13 --> 00:35:15 much slower and you just couldn't do
00:35:15 --> 00:35:17 that speed in the inner solar system so
00:35:17 --> 00:35:18 it's a long speed for a collision but
00:35:18 --> 00:35:20 it's a short time in terms of the edge
00:35:20 --> 00:35:21 of the solar
00:35:21 --> 00:35:24 system that's fascinating yeah any
00:35:24 --> 00:35:28 thoughts Fred um only that um you know
00:35:28 --> 00:35:30 sometimes we probably would have had
00:35:30 --> 00:35:32 collisions between objects which are
00:35:32 --> 00:35:35 even more gentle uh so that without
00:35:35 --> 00:35:37 demolishing each other they do stick
00:35:37 --> 00:35:39 together and I'm thinking of aroth the
00:35:39 --> 00:35:42 um the object that was observed by New
00:35:42 --> 00:35:44 Horizons after the Pluto encounter in
00:35:44 --> 00:35:49 2015 um aroth is not actually two blobs
00:35:49 --> 00:35:51 it's two pancakes stuck together
00:35:52 --> 00:35:55 edge-wise uh and so maybe that was a
00:35:55 --> 00:35:57 kiss that turned into a rather longer
00:35:57 --> 00:35:59 Embrace because it's clearly still like
00:36:00 --> 00:36:02 that and there's quite a few examples of
00:36:02 --> 00:36:05 that through the cell system it C
00:36:05 --> 00:36:08 another one which the Japanese send hus
00:36:08 --> 00:36:10 that's s what's called a contact bound
00:36:10 --> 00:36:12 there's quite a few of them around where
00:36:12 --> 00:36:13 things have spiral in but they done it
00:36:13 --> 00:36:15 so gently that they just balance against
00:36:15 --> 00:36:18 each other and these objects are small
00:36:18 --> 00:36:20 enough that their mutual attraction
00:36:20 --> 00:36:22 isn't strong enough to overcome their
00:36:22 --> 00:36:24 physical strength so if you put the
00:36:24 --> 00:36:26 Earth and Venus in physical contact with
00:36:26 --> 00:36:27 each other we wouldn't be recording this
00:36:27 --> 00:36:29 podcasts but they'd eventually kind of
00:36:29 --> 00:36:32 smush together yeah but if they're small
00:36:32 --> 00:36:33 enough the physical strength enough to
00:36:33 --> 00:36:35 resist that and you get these contact
00:36:35 --> 00:36:38 bin fascinating all right uh if you'd
00:36:38 --> 00:36:40 like to read about that story uh you can
00:36:40 --> 00:36:42 also find that on
00:36:42 --> 00:36:44 space.com uh we're just about finished
00:36:44 --> 00:36:46 but uh we um we probably have enough
00:36:47 --> 00:36:49 time to just go very quickly over what
00:36:49 --> 00:36:51 will be the best of the best things to
00:36:51 --> 00:36:55 see astronomically speaking in 2025 any
00:36:55 --> 00:36:57 thoughts
00:36:57 --> 00:37:00 go for it jonty I'll do this I'll do the
00:37:00 --> 00:37:02 space launches you do the
00:37:02 --> 00:37:04 astronomy there's a few things that are
00:37:04 --> 00:37:06 good to watch and I always like the
00:37:06 --> 00:37:07 things that you can look at without
00:37:07 --> 00:37:09 needing specialist equipment so things
00:37:09 --> 00:37:11 like eclipses and meteor showers this
00:37:11 --> 00:37:14 year is absolutely terrible for eclipses
00:37:14 --> 00:37:17 of the sun there's two very very poor
00:37:17 --> 00:37:18 partial eclipses one of which you H see
00:37:18 --> 00:37:21 if you're in Far Northeastern Canada the
00:37:21 --> 00:37:22 other for which you'd need to go to
00:37:22 --> 00:37:23 Antarctica and they're going to be
00:37:23 --> 00:37:26 unimpressive anyway but we've got two
00:37:26 --> 00:37:29 really good total LUN eclipses the first
00:37:29 --> 00:37:31 of which comes at the end of March um
00:37:31 --> 00:37:33 mid-march actually 14th of March and
00:37:33 --> 00:37:34 that's going to be really good for
00:37:34 --> 00:37:36 people in the Americas you're going to
00:37:36 --> 00:37:38 get a proper blood moon as has become
00:37:38 --> 00:37:40 kind of common pance back in the middle
00:37:40 --> 00:37:42 of the night you see the full eclipse
00:37:42 --> 00:37:44 for us here in Australia we get a really
00:37:44 --> 00:37:47 good one unfortunately Before Dawn so
00:37:47 --> 00:37:48 yeah Grumble Grumble about that but
00:37:48 --> 00:37:50 that's on the 8th of September and
00:37:50 --> 00:37:52 that'll be a really good one with like
00:37:52 --> 00:37:54 more than an hour and a half of totality
00:37:54 --> 00:37:55 so the moon Will Be Blood Red for an
00:37:55 --> 00:37:58 hour and a half which is kind of cool
00:37:58 --> 00:38:00 we've also got meia showers active as
00:38:00 --> 00:38:03 always we've got for us here in southern
00:38:03 --> 00:38:05 hemisphere the E quarian are our second
00:38:05 --> 00:38:07 best shower of the Year Northern
00:38:07 --> 00:38:09 Hemisphere gets better ones but for a z
00:38:09 --> 00:38:11 trar are our second best and they're
00:38:11 --> 00:38:13 good particularly in the first week of
00:38:13 --> 00:38:16 May and again they get up before Dawn to
00:38:16 --> 00:38:17 see them unfortunately but it's good
00:38:17 --> 00:38:19 time to go camping as the weather cools
00:38:19 --> 00:38:22 down in our Autumn the Geminids in
00:38:22 --> 00:38:24 December are the best shower of the year
00:38:24 --> 00:38:26 every year they're awesome I love them
00:38:26 --> 00:38:28 they're brilliant from the Northern
00:38:28 --> 00:38:29 Hemisphere but they're also good for the
00:38:29 --> 00:38:30 southern hemisphere it's Northern
00:38:31 --> 00:38:33 Hemisphere gets them a bit better their
00:38:33 --> 00:38:35 Peak on the 13th and 14th of December
00:38:35 --> 00:38:37 and this year the moon's out of the way
00:38:37 --> 00:38:38 so it's perfect unlike last year where
00:38:38 --> 00:38:40 the blind sight was in the way and we
00:38:40 --> 00:38:41 had all this natural light pollution and
00:38:41 --> 00:38:44 it was a bit disappointing yeah this
00:38:44 --> 00:38:46 year they'll be really good so they're
00:38:46 --> 00:38:48 really my highlights and a lovely way to
00:38:48 --> 00:38:50 finish the year with the geminates
00:38:50 --> 00:38:53 excellent they're my birthday meteors CU
00:38:53 --> 00:38:55 that's they peek on my
00:38:55 --> 00:38:58 birthday what lifting up off yeah just
00:38:58 --> 00:39:01 um you know the things to watch for this
00:39:01 --> 00:39:03 year are going to be star it's going to
00:39:03 --> 00:39:06 be Starship Starship Starship Starship
00:39:06 --> 00:39:08 uh we are expecting the seventh test
00:39:08 --> 00:39:12 launch of Starship anytime now possibly
00:39:12 --> 00:39:14 tomorrow uh compared with where we're
00:39:14 --> 00:39:15 recording at the moment so by the time
00:39:15 --> 00:39:17 this recording goes to air it might have
00:39:17 --> 00:39:19 happened the seventh test flight which
00:39:19 --> 00:39:23 will once again we hope bring the uh the
00:39:23 --> 00:39:26 Falcon super heavy back to its Chopstick
00:39:26 --> 00:39:29 Landing down there at bokach chicao and
00:39:29 --> 00:39:31 the other space I like to look out for
00:39:31 --> 00:39:35 perhaps is the eventual return of sun
00:39:35 --> 00:39:37 Williams and Butch Wilmore who've been
00:39:37 --> 00:39:39 stuck up on the International Space
00:39:39 --> 00:39:42 Station since Jun June last year uh
00:39:42 --> 00:39:45 because I think their their return has
00:39:45 --> 00:39:47 now been pushed another month further
00:39:47 --> 00:39:49 down the track I think it's no earlier
00:39:49 --> 00:39:51 than the 25th of March was the last
00:39:51 --> 00:39:53 thing I read uh which considering they
00:39:53 --> 00:39:55 expected to be at the International
00:39:55 --> 00:39:58 Space Station for a week uh is pretty
00:39:58 --> 00:40:00 good going really yeah yeah that's the
00:40:00 --> 00:40:02 thing you never know what you're in for
00:40:02 --> 00:40:04 when you get up the International Space
00:40:04 --> 00:40:06 Station but uh yeah I'm sure they'll be
00:40:06 --> 00:40:08 really happy to get home
00:40:08 --> 00:40:10 eventually um all right that just about
00:40:10 --> 00:40:12 wraps it up for this edition of Space
00:40:12 --> 00:40:14 Nuts don't forget to visit us online at
00:40:14 --> 00:40:17 our website Space Nuts podcast.com or
00:40:17 --> 00:40:20 SPAC nuts. don't forget our shop we've
00:40:20 --> 00:40:22 got a post Christmas sale everything's
00:40:22 --> 00:40:23 the same price as it was before
00:40:23 --> 00:40:27 Christmas so yes have a look at that
00:40:27 --> 00:40:29 uh and don't forget our social media
00:40:29 --> 00:40:32 platforms as well and our uh thanks to
00:40:32 --> 00:40:34 Professor Fred Watson who will be around
00:40:34 --> 00:40:36 for one more episode not just this one
00:40:37 --> 00:40:39 we'll do the Q&A episode with him soon
00:40:39 --> 00:40:42 but then he'll be off um up around
00:40:42 --> 00:40:45 Finlandia or somewhere like that and uh
00:40:45 --> 00:40:48 jonty will be sitting in his chair for
00:40:48 --> 00:40:50 uh a few weeks so Professor Fred Watson
00:40:50 --> 00:40:52 and Professor johy horer thank you so
00:40:52 --> 00:40:55 much as always great pleasure Andrew
00:40:55 --> 00:40:58 keep up the good work I never have all
00:40:58 --> 00:41:00 right um thank you jent we'll catch you
00:41:00 --> 00:41:03 on the next episode this is Space Nuts
00:41:03 --> 00:41:05 And from me Andrew Dunley OB by the way
00:41:05 --> 00:41:06 uh Hugh in the studio is here today
00:41:06 --> 00:41:08 hello Hugh what where have you been for
00:41:08 --> 00:41:10 the last six months it's good to have
00:41:10 --> 00:41:12 you along and guess what he did nothing
00:41:12 --> 00:41:14 and for me Andrew Dunley thanks for your
00:41:14 --> 00:41:15 company we'll see you on the very next
00:41:15 --> 00:41:18 episode of Space Nuts bye-bye Space Nuts
00:41:18 --> 00:41:22 you'll be listening to the Space Nuts
00:41:22 --> 00:41:25 podcast available at Apple podcasts
00:41:25 --> 00:41:28 Spotify iHeart Radio or your favorite
00:41:28 --> 00:41:30 podcast player you can also stream on
00:41:30 --> 00:41:33 demand at b.com this has been another
00:41:33 --> 00:41:38 quality podcast production from ds.com