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Space Nuts Episode 497: Earth's Core Dynamics, Hypervelocity Stars, and Cosmic Dust
Join Andrew Dunkley and Professor Jonti Horner in this captivating episode of Space Nuts as they delve into the intriguing dynamics of our planet's core, the discovery of a hyperactive star with a planet, and the fascinating phenomenon of cosmic dust. From the slowing of Earth's inner core to the implications of interstellar objects entering our solar system, this episode is filled with insights that will ignite your curiosity about the universe.
Episode Highlights:
- Earth's Core Dynamics: Andrew and Jonti discuss the recent findings regarding the Earth's inner core, revealing that it has been slowing down. They explore how researchers used data from repeating earthquakes to uncover the complexities of the core's rotation and its implications for our understanding of Earth's geology.
- Hypervelocity Stars: The duo introduces the concept of hypervelocity stars and highlights a newly discovered star that is moving at an astonishing speed of nearly 2 million kilometers per hour. They discuss the significance of this find and its connection to the planet orbiting this remarkable star.
- Cosmic Dust from Neighboring Systems: Andrew and Jonti explore the idea of "space dandruff," where neighboring solar systems contribute to the influx of cosmic dust in our own. They discuss simulations that suggest a million objects from the Alpha Centauri system are currently passing through our solar system, and the potential for detecting these interstellar visitors.
- Debate on Planetary Classification: The episode wraps up with a discussion on a newly discovered object that challenges the boundaries between planets and brown dwarfs. Jonti explains the ongoing debate regarding the definitions of these celestial bodies and how new discoveries are prompting scientists to reconsider traditional classifications.
For more Space Nuts, including our continually 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, X, YouTube Music Music, Tumblr, Instagram, and TikTok. We love engaging with our community, so be sure to drop us a message or comment on your favorite 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.
00:00 - Introduction to the episode and topics
02:15 - Discussion on Earth's core dynamics and slowing rotation
10:30 - Exploration of hypervelocity stars and their implications
18:00 - The phenomenon of cosmic dust from neighboring systems
26:45 - Debate on planetary classification and the discovery of Gaia 4B
30:00 - Closing thoughts and listener engagement
✍️ Episode References
Earth's Inner Core Research
https://www.nature.com/articles (https://www.nature.com/articles)
Hypervelocity Stars and Planet Discovery
https://www.space.com/hypervelocity-stars (https://www.space.com/hypervelocity-stars)
Cosmic Dust Studies
https://www.sciencedirect.com/science/article/pii/S0019103519302003 (https://www.sciencedirect.com/science/article/pii/S0019103519302003)
Become a supporter of this podcast: https://www.spreaker.com/podcast/space-nuts-exploring-the-cosmos--2631155/support (https://www.spreaker.com/podcast/space-nuts-exploring-the-cosmos--2631155/support?utm_source=rss&utm_medium=rss&utm_campaign=rss) .
Episode link: https://play.headliner.app/episode/25683677?utm_source=youtube
00:00:00 --> 00:00:02 hi there thanks for joining us this is
00:00:02 --> 00:00:05 Space Nuts my name is Andrew Dunley your
00:00:05 --> 00:00:07 host great to have your company coming
00:00:07 --> 00:00:09 up on this episode we are going to look
00:00:09 --> 00:00:12 at Earth's core and uh it's sort of hit
00:00:12 --> 00:00:14 the news lately but this is not a new
00:00:14 --> 00:00:16 story but we thought we better talk
00:00:16 --> 00:00:18 about it just in case you're wondering
00:00:18 --> 00:00:22 uh Earth's core uh is uh is slowing down
00:00:22 --> 00:00:24 or or not doing what you'd think it
00:00:24 --> 00:00:26 would normally do so we'll talk about
00:00:26 --> 00:00:29 that there's a hyperactive star out
00:00:29 --> 00:00:30 there and it's got a Planet what does
00:00:30 --> 00:00:32 that mean uh it means it's pretty darn
00:00:32 --> 00:00:35 quick uh we're going to talk space
00:00:35 --> 00:00:39 dandruff yes it's true and a new planet
00:00:39 --> 00:00:41 that's sparking a bit of debate on its
00:00:42 --> 00:00:44 status if we got time if we've got time
00:00:44 --> 00:00:46 we'll do that one that's all coming up
00:00:46 --> 00:00:49 on this episode of Space Nuts 15 seconds
00:00:49 --> 00:00:53 guidance is internal 10 9 ignition
00:00:53 --> 00:00:59 sequence Space Nuts 5 4 3 2 1 2 3 4 5 5
00:00:59 --> 00:01:00 4 3
00:01:00 --> 00:01:04 Space Nuts asut report it feels good he
00:01:04 --> 00:01:06 back for more Professor johy Horner
00:01:06 --> 00:01:08 professor of astrophysics at the
00:01:08 --> 00:01:10 University of Sal Queensland hi Johnny
00:01:10 --> 00:01:13 hey how are you going I am well how are
00:01:13 --> 00:01:15 you I'm getting there I'm not a morning
00:01:15 --> 00:01:18 person was I was saying I got working up
00:01:18 --> 00:01:19 earlier than I was planning this morning
00:01:19 --> 00:01:21 by phone call that said can you go on
00:01:21 --> 00:01:23 live on the radio in five minutes Sor
00:01:23 --> 00:01:25 got be a zombie on live radio which all
00:01:25 --> 00:01:28 was good fun those pisty journalists
00:01:28 --> 00:01:31 here groy ever since I have great
00:01:31 --> 00:01:32 sympathy for anybody who works a Morning
00:01:32 --> 00:01:34 Show and we I think we're talking about
00:01:34 --> 00:01:38 this last week but must be hard but I
00:01:38 --> 00:01:40 I'm not at my best at 20 to 7 in the
00:01:40 --> 00:01:42 morning this is a more reasonable time
00:01:42 --> 00:01:44 but this is still morning it's 20 to 12
00:01:44 --> 00:01:45 at the
00:01:45 --> 00:01:48 minute conscious I used to work with a
00:01:48 --> 00:01:50 journalist who um used to have to do the
00:01:50 --> 00:01:52 police rounds first thing in the morning
00:01:52 --> 00:01:54 to get any news from around the the
00:01:54 --> 00:01:56 various police districts you know car
00:01:56 --> 00:01:59 crashes all that horrible stuff um fires
00:01:59 --> 00:02:00 Etc
00:02:00 --> 00:02:02 uh and after a council meeting they used
00:02:02 --> 00:02:04 to have to ring the mayor at sparrows in
00:02:04 --> 00:02:07 the morning we had one particular mayor
00:02:07 --> 00:02:10 who um was always nearly asleep when
00:02:11 --> 00:02:13 they called and they could never get a
00:02:13 --> 00:02:15 good quote from him because he was just
00:02:15 --> 00:02:16 non-comp
00:02:16 --> 00:02:19 menst not of the day it was a
00:02:19 --> 00:02:21 frustration for the journalist I can
00:02:21 --> 00:02:22 tell you I'm gonna do something at 5
00:02:22 --> 00:02:24 a.m. I'd rather have stayed up all night
00:02:24 --> 00:02:27 to do it then set my alarm early yes yes
00:02:27 --> 00:02:30 well I never had a choice for the odd
00:02:30 --> 00:02:32 years but anyway that that was my that
00:02:32 --> 00:02:34 was my choice even though I didn't have
00:02:34 --> 00:02:35 a choice and now you have your freedom
00:02:36 --> 00:02:37 so that's I
00:02:37 --> 00:02:41 do now um let's get down to business uh
00:02:41 --> 00:02:43 Earth's core the rotation thereof this
00:02:43 --> 00:02:45 is a story that's been around a little
00:02:45 --> 00:02:46 while but it keeps popping up it popped
00:02:46 --> 00:02:48 up again on the weekend and I thought
00:02:48 --> 00:02:51 well let's talk about it um we may have
00:02:51 --> 00:02:53 talked about it with Fred I I got an
00:02:53 --> 00:02:55 inkling that when it first came up we
00:02:55 --> 00:02:59 went there but um yes it's something
00:02:59 --> 00:03:00 that the the press is certainly honing
00:03:00 --> 00:03:04 in on yeah Well's a few little fact toes
00:03:04 --> 00:03:05 about this that really caught my
00:03:06 --> 00:03:07 actually when you sent me the link
00:03:07 --> 00:03:09 through I've managed to miss this one
00:03:09 --> 00:03:12 these are researchers at the University
00:03:12 --> 00:03:15 of Southern California so USC and
00:03:15 --> 00:03:17 they've been looking at earthquake data
00:03:17 --> 00:03:19 so if we want to study the interior of
00:03:19 --> 00:03:21 the Earth with the best will in the
00:03:21 --> 00:03:23 world we can't drill down there you know
00:03:23 --> 00:03:25 the deepest Hull ever drilled was less
00:03:25 --> 00:03:27 than 10 kilm I believe and the Earth is
00:03:27 --> 00:03:29 frustratingly opaque we can't see the
00:03:29 --> 00:03:32 interior the grounds in the way so we've
00:03:32 --> 00:03:33 learned everything that we know about
00:03:33 --> 00:03:35 the interior structure of the Earth the
00:03:35 --> 00:03:37 cor the mantle how they all behave
00:03:37 --> 00:03:39 through earthquakes so you get an
00:03:39 --> 00:03:41 earthquake and seismic waves travel
00:03:41 --> 00:03:43 outwards in all directions there are two
00:03:43 --> 00:03:44 different types of seismic waves in a
00:03:44 --> 00:03:47 very rough sense and when they go from
00:03:47 --> 00:03:48 one medium to another their speed
00:03:49 --> 00:03:50 changes and they refract in just the
00:03:50 --> 00:03:52 same way like does when it enters a
00:03:52 --> 00:03:55 swimming pool same kind of IA so if
00:03:55 --> 00:03:57 you're measuring these earthquakes using
00:03:57 --> 00:04:00 seismal grass from all around the world
00:04:00 --> 00:04:01 you can back out what the interior of
00:04:01 --> 00:04:04 the earth looks like in its properties
00:04:04 --> 00:04:05 by the time it takes a different types
00:04:05 --> 00:04:07 of seismic waves to reach you
00:04:07 --> 00:04:09 essentially and by doing that over an
00:04:09 --> 00:04:10 incredible long time we've got a very
00:04:10 --> 00:04:13 detailed picture of the Earth's interior
00:04:13 --> 00:04:14 even down to you know the temperatures
00:04:14 --> 00:04:17 the pressures the compositions and
00:04:17 --> 00:04:18 people are monitoring this all the time
00:04:18 --> 00:04:21 but the finer the detail you want the
00:04:21 --> 00:04:23 more challenging it is to disentangle
00:04:23 --> 00:04:24 the information about the earthquake
00:04:24 --> 00:04:25 itself from the information you're
00:04:25 --> 00:04:27 learning about the interior and this is
00:04:27 --> 00:04:30 something we see a lot with fing exop
00:04:30 --> 00:04:32 planets there a perverse analogy here
00:04:32 --> 00:04:34 that we're looking at light from stars
00:04:34 --> 00:04:35 and to get a really good idea of what
00:04:35 --> 00:04:37 the planet's like you've got to
00:04:37 --> 00:04:39 understand the star first because that
00:04:39 --> 00:04:41 is overlaid on the DAT and you've got to
00:04:41 --> 00:04:44 disentangle them so to get a real handle
00:04:44 --> 00:04:46 on the fine details of what's going in
00:04:46 --> 00:04:48 in terms of the earth your ideal
00:04:48 --> 00:04:49 situation would be to have every
00:04:49 --> 00:04:52 earthquake be identical to the last so
00:04:52 --> 00:04:54 that all the earthquakes were the same
00:04:54 --> 00:04:55 and you could take that out of your
00:04:55 --> 00:04:57 analysis you could essentially account
00:04:57 --> 00:04:59 for that and that was the first thing I
00:04:59 --> 00:05:00 this article that I thought was really
00:05:01 --> 00:05:02 interesting I mean obviously the results
00:05:02 --> 00:05:03 are cool but it's the where they got
00:05:03 --> 00:05:07 them they looked at this sample of what
00:05:07 --> 00:05:10 a described as um repeating earthquakes
00:05:10 --> 00:05:12 they got data from these earthquakes
00:05:12 --> 00:05:15 near the South Sandwich Islands 121 of
00:05:15 --> 00:05:18 these that occurred between 1991 and
00:05:18 --> 00:05:21 2023 and it says repeating earthquakes
00:05:21 --> 00:05:22 are seismic events that occur at the
00:05:22 --> 00:05:25 same location and produce identical
00:05:25 --> 00:05:28 seismograms so rather than using all the
00:05:28 --> 00:05:30 earthquakes from all around the world
00:05:30 --> 00:05:32 they used this one subset that gave them
00:05:32 --> 00:05:34 very controlled data and that lets you
00:05:34 --> 00:05:36 get very fine resolution on the things
00:05:36 --> 00:05:38 you're looking at because you're not
00:05:38 --> 00:05:41 adding extra noise essentially and by
00:05:41 --> 00:05:42 doing all this they learned a couple of
00:05:42 --> 00:05:44 new things about the Earth's inner core
00:05:44 --> 00:05:46 so we've known for a while that while
00:05:46 --> 00:05:47 the Earth has a core the core actually
00:05:47 --> 00:05:49 has two layers it's got a molten outer
00:05:49 --> 00:05:52 core which the iron and the nickel are
00:05:52 --> 00:05:54 essentially liquid they're moving well
00:05:54 --> 00:05:56 they're molten so they're a fluid they
00:05:56 --> 00:05:58 move around and that movement is tied to
00:05:58 --> 00:06:00 the formation of the magnetic field you
00:06:00 --> 00:06:03 get the induced magnetism that gives us
00:06:03 --> 00:06:05 the magnetic field interior to that
00:06:05 --> 00:06:07 where the pressure is high even though
00:06:07 --> 00:06:09 the temperature is so high the pressure
00:06:09 --> 00:06:10 is such that the inner core has been
00:06:10 --> 00:06:12 thought to be
00:06:12 --> 00:06:14 solid and so you've got a solid with a
00:06:14 --> 00:06:16 liquid layer outside and then the molten
00:06:16 --> 00:06:17 layer of the mantle then the solid layer
00:06:17 --> 00:06:20 of the crust as a rough kind of
00:06:20 --> 00:06:22 structure what these new results have
00:06:22 --> 00:06:24 shown is the headline Act is that that
00:06:24 --> 00:06:26 inner core doesn't spin perfectly
00:06:26 --> 00:06:29 constantly it had apparently for a long
00:06:29 --> 00:06:31 period of time which I wasn't aware of
00:06:31 --> 00:06:33 people were aware that the spin speed of
00:06:33 --> 00:06:35 that inner cor was gradually increasing
00:06:35 --> 00:06:37 it was speeding up a little bit almost
00:06:37 --> 00:06:39 in perceptibly but what this research
00:06:39 --> 00:06:42 has shown is that more recently it has
00:06:42 --> 00:06:44 now started to slow down again so that's
00:06:44 --> 00:06:46 a headline act the inner cor has slowed
00:06:46 --> 00:06:48 down a little bit and they're talking
00:06:48 --> 00:06:49 about here at a scale of about a
00:06:49 --> 00:06:51 thousandth of a second for the rotation
00:06:51 --> 00:06:54 period so it's a tiny effect but they
00:06:54 --> 00:06:56 can measure it thanks to these repeating
00:06:56 --> 00:06:59 earthquakes that have the same signature
00:06:59 --> 00:07:00 that allows them to get a much better
00:07:00 --> 00:07:03 resolution on the data the other thing
00:07:03 --> 00:07:05 which I think is very interesting that
00:07:05 --> 00:07:06 isn't in the main press release but is
00:07:07 --> 00:07:08 in a couple of the other articles is
00:07:08 --> 00:07:10 that these same data suggests that the
00:07:10 --> 00:07:12 inner core is not totally solid but
00:07:12 --> 00:07:15 actually has molten areas within it so
00:07:15 --> 00:07:17 this is a bit of a change to the
00:07:17 --> 00:07:19 Paradigm we had of this very simple
00:07:19 --> 00:07:21 model of a solid inner core then a
00:07:21 --> 00:07:24 molten outer core that there's actually
00:07:24 --> 00:07:26 a bit of molten to the inner core as
00:07:26 --> 00:07:28 well which probably makes a bit of sense
00:07:28 --> 00:07:30 in the context of this thing's rotation
00:07:30 --> 00:07:32 changing over time if you've got bits
00:07:32 --> 00:07:34 that are melting bits that are moving
00:07:34 --> 00:07:36 around a little bit you're moving
00:07:36 --> 00:07:38 angular momentum around so therefore
00:07:38 --> 00:07:40 you'll change the rotation period in
00:07:40 --> 00:07:42 just the same way that the rotation
00:07:42 --> 00:07:44 period of the Earth as a whole will
00:07:44 --> 00:07:46 change if the ice caps melt will change
00:07:46 --> 00:07:47 in a measurable way because you're
00:07:47 --> 00:07:49 moving Mass from the poles to the
00:07:49 --> 00:07:51 equator redistributing that mass will
00:07:51 --> 00:07:53 mean that the earth spin will slow a
00:07:53 --> 00:07:56 little bit to conserve angular momenta
00:07:56 --> 00:07:59 so it's a fascinating story and I think
00:07:59 --> 00:08:01 yes the headline side of it the inner
00:08:01 --> 00:08:04 core has slow down that's interesting
00:08:04 --> 00:08:05 that's a headline story but to me the
00:08:05 --> 00:08:07 really interesting stuff was to how of
00:08:07 --> 00:08:10 how they figure that out and the
00:08:10 --> 00:08:12 subtleties of the choice of earthquakes
00:08:12 --> 00:08:14 to use and the additional things they
00:08:14 --> 00:08:15 can figure out is really shows the
00:08:15 --> 00:08:18 benefit of continuing to get longer data
00:08:18 --> 00:08:20 sets and reanalyzing what you thought
00:08:20 --> 00:08:22 you knew when you've got better data and
00:08:22 --> 00:08:24 better instruments so it's a very cool
00:08:24 --> 00:08:26 story and do encourage people to have a
00:08:26 --> 00:08:27 look around there's a few different
00:08:27 --> 00:08:29 versions of the story out there on the
00:08:29 --> 00:08:32 web um even CNN covered it at one point
00:08:32 --> 00:08:34 so it's got interest and by reading a
00:08:34 --> 00:08:37 variety of stories you can get some of
00:08:37 --> 00:08:38 the different cool facts that maybe the
00:08:38 --> 00:08:41 M press release didn't pick up on yeah
00:08:41 --> 00:08:45 they figured this out by studying what
00:08:45 --> 00:08:49 is21 earthquakes between 1991 and 2024
00:08:49 --> 00:08:53 yes uh how accurate do you perceive
00:08:53 --> 00:08:57 their data to be well I I trust at the
00:08:57 --> 00:08:58 end of the day it's peer reviewed and
00:08:58 --> 00:09:00 published so there's a certain
00:09:00 --> 00:09:03 confidence of fidelity there that's good
00:09:03 --> 00:09:05 and I find their data selection really
00:09:05 --> 00:09:07 interesting there the fact that you've
00:09:07 --> 00:09:09 got thousands of earthquakes happening
00:09:09 --> 00:09:10 all the time you know we see what's
00:09:10 --> 00:09:12 happening in Santeria at the minute with
00:09:12 --> 00:09:14 what is probably a very large motion of
00:09:14 --> 00:09:18 magma underneath that ancient volcano
00:09:18 --> 00:09:19 that suggests it may well erupt again at
00:09:19 --> 00:09:22 some point similarly under Naples so
00:09:22 --> 00:09:24 earthquakes are happening all the time
00:09:24 --> 00:09:26 all around the world and what I loved
00:09:26 --> 00:09:27 about this was finding this subset of
00:09:28 --> 00:09:30 earthquakes that happening recurrently
00:09:30 --> 00:09:32 at the same place that are giving them
00:09:32 --> 00:09:34 the same signal which makes a data
00:09:34 --> 00:09:37 analysis much much much better I just
00:09:37 --> 00:09:40 really like that and it's why in exactly
00:09:40 --> 00:09:42 the same way that we can find planets
00:09:42 --> 00:09:44 using our radial velocity the wobble
00:09:44 --> 00:09:46 method much more easily around quiet
00:09:47 --> 00:09:50 Stars than active STS because active
00:09:50 --> 00:09:51 stars are roiling and bubbling and
00:09:51 --> 00:09:55 boiling so the lines of the spectrum of
00:09:55 --> 00:09:56 the star are moving around because of
00:09:57 --> 00:09:58 the properties of the star that
00:09:58 --> 00:10:01 introduces a lot of nights when you've
00:10:01 --> 00:10:03 got a quiet sour of s that isn't very
00:10:03 --> 00:10:05 active a bit like the sun is that noise
00:10:05 --> 00:10:07 is much less which means that you can
00:10:07 --> 00:10:09 resolve much smaller motions facts to
00:10:09 --> 00:10:12 the planets and so you can detect
00:10:12 --> 00:10:13 smaller planets around stars that are
00:10:14 --> 00:10:17 less active and and it's a direct
00:10:17 --> 00:10:19 parallel here by getting a much simpler
00:10:19 --> 00:10:20 set of earthquakes that all behave the
00:10:20 --> 00:10:22 same way you reduce the nois and
00:10:23 --> 00:10:24 therefore you can get a much more
00:10:24 --> 00:10:25 accurate impression of what's going on
00:10:25 --> 00:10:27 in the interior so I guess if you want
00:10:28 --> 00:10:30 to look at time scale changes in the
00:10:30 --> 00:10:32 mantle and stuff like that you can use
00:10:32 --> 00:10:34 all the data set and map it that way but
00:10:34 --> 00:10:35 for something like this way you need
00:10:35 --> 00:10:37 that really fine tooth comb it's a
00:10:37 --> 00:10:39 beautiful way of doing it yeah yeah it's
00:10:40 --> 00:10:41 fascinating story it's uh yeah we're so
00:10:41 --> 00:10:43 close to it compared to everything else
00:10:43 --> 00:10:47 we study oh yeah in Moss but it's um
00:10:47 --> 00:10:50 yeah it's invisible to us we have to
00:10:50 --> 00:10:51 yeah we have to dig deep boom boom
00:10:51 --> 00:10:54 techniques that are getting developed
00:10:54 --> 00:10:56 from this then apply in astronomy and in
00:10:56 --> 00:10:58 planetary science you know we talked
00:10:58 --> 00:11:00 previously about in it which sat on Mars
00:11:00 --> 00:11:02 and recorded Mars Quakes and that was
00:11:02 --> 00:11:04 just single station I would love at some
00:11:04 --> 00:11:06 point in the future perhaps when um
00:11:06 --> 00:11:08 seron decides that he's finally going to
00:11:08 --> 00:11:10 move to Mars if he could take some
00:11:10 --> 00:11:12 seismometers with him and drop them in a
00:11:12 --> 00:11:15 variety of positions that'll give us a
00:11:15 --> 00:11:17 lot more information on Mar's interior
00:11:17 --> 00:11:19 similarly these kind of techniques are
00:11:19 --> 00:11:20 very similar to what my colleagues at
00:11:20 --> 00:11:21 the University of Southern Queensland
00:11:21 --> 00:11:24 and elsewhere around the sphere of
00:11:24 --> 00:11:26 Academia used to study the Interiors of
00:11:26 --> 00:11:28 starss you've got the same problem you
00:11:28 --> 00:11:29 look at the Sun
00:11:29 --> 00:11:31 and it's our nearest star but all we see
00:11:31 --> 00:11:33 is the surface you can't see inside it
00:11:33 --> 00:11:35 because the surface is in the way yeah
00:11:35 --> 00:11:36 how do we know about the structure in
00:11:36 --> 00:11:38 the interior it's exactly the same kind
00:11:38 --> 00:11:40 of thing they're doing here but using
00:11:40 --> 00:11:43 star Quakes and star wobbles rather than
00:11:43 --> 00:11:45 earthquakes yeah really interesting
00:11:45 --> 00:11:47 stuff and if you'd like to read more
00:11:47 --> 00:11:50 about the inner core of our own Planet
00:11:50 --> 00:11:53 slowing down just do a search for that
00:11:53 --> 00:11:55 there it's everywhere you can find it on
00:11:55 --> 00:12:00 Discover magazine and a few other sites
00:12:00 --> 00:12:01 let's take a little break from the show
00:12:01 --> 00:12:04 to tell you about our sponsor
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00:13:39 --> 00:13:46 today now back to the show 3 2 1 Space
00:13:46 --> 00:13:49 Nuts uh now let's go to this uh story
00:13:49 --> 00:13:52 that is talking about a star that's been
00:13:52 --> 00:13:55 described as hyperactive this this is a
00:13:55 --> 00:13:57 star that's moving well it's probably
00:13:57 --> 00:14:00 one of the fastest if not the fastest
00:14:00 --> 00:14:03 ever discovered this this story is quite
00:14:03 --> 00:14:06 amazing yeah so this is what's called a
00:14:06 --> 00:14:08 hyper velocity star and we do know a few
00:14:08 --> 00:14:10 of these in the Milky Way these are
00:14:10 --> 00:14:12 stars that are traveling at such a high
00:14:12 --> 00:14:15 speed that they're traveling faster than
00:14:15 --> 00:14:17 the local escape velocity for the Galaxy
00:14:17 --> 00:14:19 at their location so we're on the
00:14:19 --> 00:14:20 surface of the Earth and if I throw a
00:14:20 --> 00:14:22 tennis ball up in the air it will fall
00:14:22 --> 00:14:24 back down I'll catch it or I'll fail to
00:14:24 --> 00:14:26 catch it because I'm English and the
00:14:26 --> 00:14:27 English Cricket team's doing terribly at
00:14:27 --> 00:14:29 the minutes I'll probably fail to catch
00:14:29 --> 00:14:31 it because that's where I'm from
00:14:31 --> 00:14:34 originally if I threw it hard enough the
00:14:34 --> 00:14:36 Earth's gravity wouldn't be able to hold
00:14:36 --> 00:14:38 on to it and it would escape and for the
00:14:38 --> 00:14:41 Earth that's about 11 kilm a second the
00:14:41 --> 00:14:43 more massive you are the higher that
00:14:43 --> 00:14:45 velocity is but the further you are from
00:14:45 --> 00:14:47 the mass the lower that velocity is I
00:14:47 --> 00:14:49 it's the kind of thing we teach in first
00:14:49 --> 00:14:51 year astrophysics as an equation for the
00:14:51 --> 00:14:53 escape Velocity um where you can work it
00:14:53 --> 00:14:55 out and I think it's a square root of 2
00:14:55 --> 00:14:58 GM over R um
00:14:58 --> 00:15:00 now sounds about right so that's
00:15:00 --> 00:15:02 basically it's related to the mass of
00:15:02 --> 00:15:04 the thing you're going around and the
00:15:04 --> 00:15:06 and it's inversely proportional to the
00:15:06 --> 00:15:08 distance you are away from that thing
00:15:08 --> 00:15:10 with a square root
00:15:10 --> 00:15:13 there what that means is that anything
00:15:13 --> 00:15:16 that has mass has an escape velocity so
00:15:16 --> 00:15:17 technically I have an escape velocity if
00:15:18 --> 00:15:20 you put me in the vacuum of space far
00:15:20 --> 00:15:22 away from any Star and give me that
00:15:22 --> 00:15:25 tennis ball I could in theory nudge it
00:15:25 --> 00:15:26 gently and make it orbit me but if I
00:15:26 --> 00:15:29 nudge too hard it would Escape but even
00:15:29 --> 00:15:31 though I'm far too heavy my
00:15:31 --> 00:15:33 gravitational pull is incredibly weak
00:15:33 --> 00:15:36 because I'm only 130 kilos not the mass
00:15:36 --> 00:15:37 of the
00:15:37 --> 00:15:39 Earth what that means from the point of
00:15:39 --> 00:15:41 view of our galaxy is that our galaxy
00:15:41 --> 00:15:43 has an escape velocity that varies
00:15:43 --> 00:15:45 depending on where you are in the
00:15:45 --> 00:15:47 galaxy nearer you are to the middle the
00:15:47 --> 00:15:48 higher the speed you need to be
00:15:48 --> 00:15:50 traveling is to escap just as in the
00:15:50 --> 00:15:53 solar system it's harder to escap from
00:15:53 --> 00:15:55 the sun when you know Mercury's orbit
00:15:55 --> 00:15:58 than it is when you know ne's orbit so
00:15:58 --> 00:15:59 that
00:15:59 --> 00:16:01 how stars move and a small fraction of
00:16:01 --> 00:16:03 the stars in our galaxy because they're
00:16:03 --> 00:16:05 constantly moving around all the other
00:16:05 --> 00:16:07 stars because there things going on a
00:16:07 --> 00:16:08 small number of those Stars will
00:16:08 --> 00:16:11 eventually get ejected from the Galaxy
00:16:11 --> 00:16:13 entirely now quite a few of these
00:16:13 --> 00:16:15 actually that are previously known are
00:16:15 --> 00:16:17 linked to stars that were in a binary
00:16:17 --> 00:16:20 star system that was quite close and
00:16:20 --> 00:16:21 then one of the components went
00:16:21 --> 00:16:24 supernova and suddenly there it's like
00:16:24 --> 00:16:25 the lead was cut so suddenly they're
00:16:25 --> 00:16:27 rejected at very high speed right but
00:16:27 --> 00:16:28 that's not the only way you can
00:16:28 --> 00:16:31 conformed that hypervelocity stars and
00:16:31 --> 00:16:34 are these Stars whose speed is so high
00:16:34 --> 00:16:36 that they will probably escape and never
00:16:36 --> 00:16:37 return that will wonder the void between
00:16:37 --> 00:16:39 the galaxies in a very lonely life
00:16:39 --> 00:16:41 forever
00:16:41 --> 00:16:44 more the other side of this story is
00:16:44 --> 00:16:46 planet detection we've talked before
00:16:46 --> 00:16:48 about how the two most successful
00:16:48 --> 00:16:50 methods for finding planets are the
00:16:50 --> 00:16:51 transit method and the radio velocity
00:16:51 --> 00:16:53 method essentially seeing Stars wobble
00:16:53 --> 00:16:56 and wink there is a method a technique
00:16:56 --> 00:16:58 called gravitational micr lensing that
00:16:58 --> 00:17:00 if you went back to the late '90s people
00:17:00 --> 00:17:02 were really hoping it would find
00:17:02 --> 00:17:04 gazillions of planets that it would be
00:17:04 --> 00:17:06 really successful and it's never quite
00:17:06 --> 00:17:09 found as many as people expected because
00:17:09 --> 00:17:11 it's fundamentally hard to do it's not
00:17:11 --> 00:17:12 that these events aren't happening it's
00:17:12 --> 00:17:15 just that they're very hard to observe
00:17:15 --> 00:17:17 but going back to 2011 a team of
00:17:17 --> 00:17:18 scientists that were looking towards the
00:17:18 --> 00:17:21 galactic core where you've got the most
00:17:21 --> 00:17:23 stars on the sky in the smallest area
00:17:23 --> 00:17:25 observed a gravitational microlensing
00:17:25 --> 00:17:27 event they saw a background star
00:17:27 --> 00:17:30 brightened and then fed away again but
00:17:30 --> 00:17:32 it had a double peak in the brightness
00:17:32 --> 00:17:34 so there were two peaks as it went up
00:17:34 --> 00:17:35 and then it went up further and then it
00:17:36 --> 00:17:38 fell away again and that was indicating
00:17:38 --> 00:17:40 that in the foreground between us and
00:17:40 --> 00:17:42 that star something had passed in front
00:17:42 --> 00:17:45 that had mass that mass curving
00:17:45 --> 00:17:47 SpaceTime acted as a lens bent a little
00:17:48 --> 00:17:49 bit more of the light from the
00:17:49 --> 00:17:50 background star towards us and that's
00:17:50 --> 00:17:52 why we saw the star brighten and then as
00:17:52 --> 00:17:54 the thing in the foreground moved away
00:17:54 --> 00:17:56 again the lens went away and it faded
00:17:56 --> 00:17:59 away again and when these events happen
00:17:59 --> 00:18:01 you could infer quite a lot from
00:18:01 --> 00:18:02 studying the degree to which the thing
00:18:02 --> 00:18:05 brightened and faded and also the time
00:18:05 --> 00:18:06 scale over which it
00:18:06 --> 00:18:08 happened and the team at the time
00:18:08 --> 00:18:10 announce their results this is really
00:18:10 --> 00:18:12 exciting but there's a little bit of
00:18:12 --> 00:18:14 what we call a degeneracy there are two
00:18:14 --> 00:18:17 different models that can equally well
00:18:17 --> 00:18:20 explain what we've observed the first is
00:18:20 --> 00:18:21 that you've got a star that's about a
00:18:21 --> 00:18:23 fifth of the mass of the sun with a
00:18:23 --> 00:18:26 planet that is about 29 times the mass
00:18:26 --> 00:18:29 of the Earth that's scenario 1 so you've
00:18:29 --> 00:18:31 got a star with a planet the other
00:18:31 --> 00:18:34 scenario is that you had a planet the
00:18:34 --> 00:18:37 mass of Jupiter with a tiny little Moon
00:18:37 --> 00:18:39 and in either case the ratio of the mass
00:18:39 --> 00:18:40 between the big thing and the little
00:18:40 --> 00:18:43 thing is about 2300 times either of
00:18:43 --> 00:18:46 these scenarios could explain perfectly
00:18:46 --> 00:18:48 well what was seen so how do we
00:18:48 --> 00:18:50 differentiate between them well one
00:18:50 --> 00:18:51 thing we can do now that we've got
00:18:51 --> 00:18:54 better telescope some better technology
00:18:54 --> 00:18:56 is to use theek telescopes which are
00:18:56 --> 00:18:58 among the biggest in the world they're
00:18:58 --> 00:19:01 incred instruments in South America and
00:19:01 --> 00:19:03 also the Gia spacecraft which has been
00:19:03 --> 00:19:04 it's just finished its Mission but it
00:19:04 --> 00:19:07 spent 12 years in orbit mapping the
00:19:07 --> 00:19:10 positions of em motions of up to two
00:19:10 --> 00:19:12 billion stars with unprecedented
00:19:12 --> 00:19:15 mindboggling accuracy so the team that
00:19:15 --> 00:19:17 found this object in 2011 saw this
00:19:17 --> 00:19:19 signal in the gravitational micr lensing
00:19:19 --> 00:19:22 said one way that we could distinguish
00:19:22 --> 00:19:25 between those two different models is to
00:19:25 --> 00:19:27 look for the thing that caused the
00:19:27 --> 00:19:29 lensing
00:19:29 --> 00:19:31 if it's a star in theory there'll be a
00:19:31 --> 00:19:32 point of light there that's moving that
00:19:32 --> 00:19:34 we can see that we can track back and
00:19:34 --> 00:19:35 say it was in the right place at the
00:19:35 --> 00:19:38 right time we'll be able to see it and
00:19:38 --> 00:19:39 that shows that the thing that did the
00:19:39 --> 00:19:41 lensing was a star so it's a star and a
00:19:41 --> 00:19:44 planet if we see nothing then the star
00:19:44 --> 00:19:46 doesn't work because if there was a star
00:19:46 --> 00:19:47 there we'd see it so it must be the
00:19:47 --> 00:19:49 other scenario so they went away and dug
00:19:50 --> 00:19:51 through that data and it took them a bit
00:19:51 --> 00:19:53 longer than expected but they finally
00:19:53 --> 00:19:56 found a star that is moving ridiculously
00:19:56 --> 00:19:58 quickly but was in exactly the right
00:19:58 --> 00:20:00 place at the right time to cause the
00:20:00 --> 00:20:02 micro lensing event and that star is
00:20:02 --> 00:20:04 also quite near the middle of the Galaxy
00:20:04 --> 00:20:06 so it's quite it was quite far from us
00:20:06 --> 00:20:08 quite near the thing it was lensing at
00:20:08 --> 00:20:10 the time they've tracked it back and it
00:20:10 --> 00:20:12 turns out that the movement of this star
00:20:12 --> 00:20:14 just at right angle through our line of
00:20:14 --> 00:20:17 sight so the movement across the sky
00:20:17 --> 00:20:19 gives it a speed that is almost two
00:20:19 --> 00:20:23 million kilometers per hour 540
00:20:23 --> 00:20:26 kilometers per second glimy that is
00:20:26 --> 00:20:28 ridiculous you know
00:20:29 --> 00:20:30 Stars nearby near the Sun that moving
00:20:30 --> 00:20:32 around we typically talk of speeds of
00:20:32 --> 00:20:34 tens of kilometers a second maybe a bit
00:20:34 --> 00:20:37 more than 100 so 540 is ridiculously
00:20:37 --> 00:20:39 extreme and is already almost the escape
00:20:39 --> 00:20:42 velocity of the Galaxy at that point now
00:20:42 --> 00:20:44 the unknown here is that there could be
00:20:44 --> 00:20:45 some movement towards our away fromers
00:20:45 --> 00:20:48 as well so we only see the movement on
00:20:48 --> 00:20:51 the sky and essentially any movement
00:20:51 --> 00:20:54 that is radial toward us or away from us
00:20:54 --> 00:20:56 will be enough to mean that this thing
00:20:56 --> 00:20:58 is Unbound by the Galaxy that it will
00:20:58 --> 00:20:59 eventually
00:20:59 --> 00:21:01 escar it is therefore a hypervelocity
00:21:01 --> 00:21:04 star and this is the very first time a
00:21:04 --> 00:21:05 planet has been confirmed around the
00:21:05 --> 00:21:08 hypervelocity star now planets will form
00:21:08 --> 00:21:10 around these stats that's fine but to
00:21:10 --> 00:21:11 get the very first one that's kind of
00:21:11 --> 00:21:14 cool and that's a planet that is
00:21:14 --> 00:21:16 significantly more massive than the
00:21:16 --> 00:21:18 earth that star probably has other
00:21:18 --> 00:21:20 planets where you find one planet there
00:21:20 --> 00:21:22 will be more so this is a planetary
00:21:22 --> 00:21:25 system that is on a oneway ticket out of
00:21:25 --> 00:21:28 our galaxy never to return wow yeah
00:21:28 --> 00:21:31 that's quite a find isn't it and such an
00:21:31 --> 00:21:34 incredible speed have they worked out
00:21:34 --> 00:21:36 how long it will take to exit the Galaxy
00:21:36 --> 00:21:38 probably a long time even at that speed
00:21:38 --> 00:21:40 very very long time even at that speed
00:21:40 --> 00:21:43 so we can probably try and back of the
00:21:43 --> 00:21:45 envelope mental arithmetic list so I
00:21:45 --> 00:21:47 I'll for get everybody on line to
00:21:47 --> 00:21:50 forgive me but speed of light is 300
00:21:50 --> 00:21:52 kmers a second y I'm going to say that
00:21:52 --> 00:21:55 this is 600 km a second that just keeps
00:21:55 --> 00:21:58 the maths easier right yeah um 600 over
00:21:58 --> 00:22:02 300 th000 is 6 over 300 which is 2%
00:22:02 --> 00:22:04 thereabouts so this thing's traveling at
00:22:04 --> 00:22:06 2% of the speed of
00:22:06 --> 00:22:08 light that's fairly significant now the
00:22:08 --> 00:22:10 Galax is going to be pulling it back and
00:22:10 --> 00:22:12 SL it down as it goes but if you think
00:22:12 --> 00:22:14 about the diameter of the Milky Way is
00:22:14 --> 00:22:16 about a 100 light years so that
00:22:16 --> 00:22:18 means the radius of the Milky Way is
00:22:18 --> 00:22:20 about 50 light years if you're
00:22:21 --> 00:22:23 traveling at 2% of the speed of light
00:22:23 --> 00:22:25 that means it will take you 50 years to
00:22:25 --> 00:22:29 travel one light year right right so 50
00:22:29 --> 00:22:31 years per Lightyear for 50 light
00:22:32 --> 00:22:36 years is 2.5 million years okay now that
00:22:36 --> 00:22:39 is a long time for us but we compare it
00:22:39 --> 00:22:42 to the fact that it takes us some 250
00:22:42 --> 00:22:43 million years also to go around the
00:22:43 --> 00:22:45 middle of the Galaxy that gives you a
00:22:45 --> 00:22:48 sense of how quickness is actually
00:22:48 --> 00:22:51 moving fascinating all right uh yeah so
00:22:51 --> 00:22:54 far the fastest found but there may be
00:22:54 --> 00:22:56 others will probably find another one
00:22:56 --> 00:22:59 that's faster at some stage yes uh you
00:22:59 --> 00:23:00 can read about that at space.com or if
00:23:00 --> 00:23:03 you want to read the actual paper uh it
00:23:03 --> 00:23:04 was published this month in the
00:23:04 --> 00:23:07 astronomical Journal this is Space Nuts
00:23:07 --> 00:23:12 with Andrew Dunley and Professor jonty
00:23:12 --> 00:23:14 Horner okay we checked all four
00:23:14 --> 00:23:18 systems Space Nuts now johy let's move
00:23:18 --> 00:23:22 on to this problem with um dandruff in
00:23:22 --> 00:23:24 space that's what it's described as it's
00:23:24 --> 00:23:26 not really dandruff it's just uh
00:23:27 --> 00:23:29 neighboring uh systems dumping their
00:23:30 --> 00:23:32 stuff on us absolutely I I didn't know
00:23:32 --> 00:23:35 that was a thing Amber doing exactly the
00:23:35 --> 00:23:37 same back of Li should have said no ask
00:23:37 --> 00:23:39 one of those things that I talk about a
00:23:39 --> 00:23:41 lot in the context of our solar system
00:23:41 --> 00:23:44 we have comets and asteroids and the
00:23:44 --> 00:23:46 main way that comets get removed from
00:23:46 --> 00:23:47 the solar system to no longer pose a
00:23:47 --> 00:23:50 threat to the Earth is that many of them
00:23:50 --> 00:23:52 escate the solar system never to return
00:23:52 --> 00:23:53 usually flung out by one of the giant
00:23:54 --> 00:23:56 planets or by subtle gravitational
00:23:56 --> 00:23:58 perturbations like that so you can look
00:23:58 --> 00:24:00 back over the edge of the solar system
00:24:00 --> 00:24:01 and it has continually been shedding
00:24:01 --> 00:24:03 comets and asteroids into the void of
00:24:03 --> 00:24:06 space creating these Interstellar
00:24:06 --> 00:24:08 wonders essentially and that would have
00:24:08 --> 00:24:10 been particularly strongly the case
00:24:10 --> 00:24:12 incidentally when the solar system was
00:24:12 --> 00:24:13 still forming because big part of the
00:24:13 --> 00:24:15 formation of the planets in the cleanup
00:24:15 --> 00:24:17 afterwards was getting rid of most of
00:24:17 --> 00:24:19 the stuff that was left over so the
00:24:19 --> 00:24:21 solar system over it time will have shed
00:24:21 --> 00:24:24 uncounted objects into space and it
00:24:24 --> 00:24:27 continues to do so today and I've often
00:24:27 --> 00:24:29 said in those thoughts it's almost
00:24:29 --> 00:24:30 certain that every other star will be
00:24:30 --> 00:24:32 doing the same thing but any star that
00:24:32 --> 00:24:34 has a planet syst those planets will be
00:24:34 --> 00:24:36 stirring things up and throwing things
00:24:36 --> 00:24:38 out so it's one of those things I've
00:24:38 --> 00:24:40 just taken for granted but it's only
00:24:40 --> 00:24:43 recently that we've actually been able
00:24:43 --> 00:24:45 to detect the products of this from
00:24:45 --> 00:24:47 other stars like I said for decades
00:24:47 --> 00:24:49 people have talked about the possibility
00:24:49 --> 00:24:51 of us finding Interstellar objects in
00:24:51 --> 00:24:53 the solar system so I've seen comets or
00:24:53 --> 00:24:56 astroids coming through that could be
00:24:56 --> 00:24:59 absolutely and definitively not to have
00:24:59 --> 00:25:01 an origin in our solar system how do we
00:25:01 --> 00:25:02 do that well we look at how quick
00:25:02 --> 00:25:04 they're moving it's just like what we
00:25:04 --> 00:25:05 were talking about a minute ago with the
00:25:05 --> 00:25:08 escape Velocity objects moving around
00:25:08 --> 00:25:11 the Sun are gravitationally bound if
00:25:11 --> 00:25:12 they get a nudge and they're going to
00:25:12 --> 00:25:14 escape they will be traveling a bit too
00:25:14 --> 00:25:16 quick to be gravitationally bound but
00:25:16 --> 00:25:20 only just by a tiny amount so when we
00:25:20 --> 00:25:22 find an object that comes in we can work
00:25:22 --> 00:25:25 out what speed it would travel at if it
00:25:25 --> 00:25:28 was infinitely far from the Sun call
00:25:28 --> 00:25:29 this the velocity of infinity so once
00:25:29 --> 00:25:31 the sun has slowed it down as much as it
00:25:31 --> 00:25:35 can how much speed has it got left and
00:25:35 --> 00:25:37 two objects that were found in the last
00:25:37 --> 00:25:39 decade met this criteria of being
00:25:39 --> 00:25:42 Interstellar they were umu which came
00:25:42 --> 00:25:44 through in 2017 and despite what a
00:25:44 --> 00:25:47 certain eminent um person at Harvard and
00:25:47 --> 00:25:48 I'm trying to choose my words carefully
00:25:48 --> 00:25:50 here because I have a certain opinion um
00:25:50 --> 00:25:52 despite what he keeps trying to tell you
00:25:52 --> 00:25:54 to sell his books and make a lot of
00:25:54 --> 00:25:56 money that was not an alien spaceship it
00:25:56 --> 00:25:58 never would be an alien spaceship it
00:25:58 --> 00:26:00 absolutely was not aliens that was just
00:26:00 --> 00:26:04 a lump of rock and debris we then had
00:26:04 --> 00:26:06 comic borisov back in 2019 which was our
00:26:06 --> 00:26:09 second Interstellar object yeah we found
00:26:09 --> 00:26:10 two of them now the odds are that in the
00:26:10 --> 00:26:12 coming decade we will find hundreds
00:26:12 --> 00:26:14 because the Vera Rubin observatories are
00:26:14 --> 00:26:17 going to come online ver ruin
00:26:17 --> 00:26:18 Observatory of course named for one of
00:26:18 --> 00:26:21 the great astronomers of 20th century
00:26:21 --> 00:26:24 who was a woman in astronomy and that's
00:26:24 --> 00:26:25 a challenging thing to discuss at the
00:26:25 --> 00:26:27 moment with what's going on in the US I
00:26:27 --> 00:26:29 will just mention in passing that that
00:26:29 --> 00:26:31 is itself a controversy this week
00:26:31 --> 00:26:33 because with the new government in the
00:26:33 --> 00:26:35 US they've been forced to change the
00:26:35 --> 00:26:39 biography of Vera Rubin on the website
00:26:39 --> 00:26:40 because one of the things that she was
00:26:40 --> 00:26:42 very active on was advocating for women
00:26:42 --> 00:26:44 in science and you know setting up
00:26:44 --> 00:26:45 schemes to try and help women get more
00:26:45 --> 00:26:47 involved in astronomy and now you can't
00:26:47 --> 00:26:49 talk about that anyway that that's an
00:26:49 --> 00:26:51 aside but it's a bit of a frustration of
00:26:51 --> 00:26:53 the human element of this yeah but ver
00:26:53 --> 00:26:55 Rubin Observatory named after this
00:26:55 --> 00:26:57 incredible astronomer is going to come
00:26:57 --> 00:26:59 online in the next year or two and is
00:26:59 --> 00:27:01 forast to find tens or hundreds of these
00:27:01 --> 00:27:03 objects because we'll just be much
00:27:03 --> 00:27:06 better at spotting them what the new
00:27:06 --> 00:27:08 research is is some computer modeling a
00:27:08 --> 00:27:10 group has had this same idea that we're
00:27:10 --> 00:27:12 just talking about and said let's model
00:27:12 --> 00:27:14 this let's try and get a handle on just
00:27:14 --> 00:27:17 how much stuff May by star systems are
00:27:17 --> 00:27:19 throwing our way to fill the space
00:27:19 --> 00:27:23 around us and they looked at our nearest
00:27:23 --> 00:27:25 companions the alpha centor system which
00:27:25 --> 00:27:27 is the binary SAR of alpha centor a andb
00:27:27 --> 00:27:29 and then the Red Dwarf Proxima which is
00:27:29 --> 00:27:31 currently a bit closer towards of the
00:27:31 --> 00:27:32 two bigger
00:27:32 --> 00:27:34 stars there run some simulations very
00:27:34 --> 00:27:36 much of the ilk that I do in my D job
00:27:36 --> 00:27:39 running on the superc Computing cluster
00:27:39 --> 00:27:43 here saying if this star system has the
00:27:43 --> 00:27:44 kind of objects in it we'd expect for
00:27:44 --> 00:27:47 system of that age how many are getting
00:27:47 --> 00:27:49 ejected in our general direction and
00:27:49 --> 00:27:51 what they have found is that their
00:27:51 --> 00:27:53 simulation suggests there could be as
00:27:53 --> 00:27:55 many as a million objects bigger than
00:27:55 --> 00:27:58 100 meters across passing through our
00:27:58 --> 00:28:01 solar system at the current time that
00:28:02 --> 00:28:03 departed from the alpha centor system
00:28:03 --> 00:28:06 now the cirley here is a lot of the time
00:28:06 --> 00:28:08 when we talk about passing through the
00:28:08 --> 00:28:10 solar system we think of our local part
00:28:10 --> 00:28:11 of the solar system the orbits of the
00:28:11 --> 00:28:13 planets but in reality the volume of
00:28:14 --> 00:28:15 space we're considering to be the solar
00:28:15 --> 00:28:17 system here is the entirety of the out
00:28:17 --> 00:28:20 Cloud so this is a volume of space
00:28:20 --> 00:28:22 something like two light years in every
00:28:22 --> 00:28:24 direction from it so it's an
00:28:24 --> 00:28:27 unimaginably vast sphere of space that
00:28:27 --> 00:28:30 has these objects passing through it so
00:28:30 --> 00:28:31 the likelihood of one getting closer to
00:28:31 --> 00:28:33 first to detect in the near future is
00:28:33 --> 00:28:35 pretty low but it's not be on the
00:28:35 --> 00:28:37 balance of possibility and again when
00:28:37 --> 00:28:41 Vera Rubin comes online if any of these
00:28:41 --> 00:28:43 are in you know the domain of the
00:28:43 --> 00:28:44 planets they're coming close enough to
00:28:44 --> 00:28:47 the Sun that they are detectable ver
00:28:47 --> 00:28:51 Rubin will find them now a million
00:28:51 --> 00:28:53 objects spread over the out Cloud to be
00:28:53 --> 00:28:55 honest means that it's very unlikely one
00:28:55 --> 00:28:57 of them will be close enough to see but
00:28:57 --> 00:28:58 these things are going to be TR faster
00:28:58 --> 00:29:01 than the escape velocity of the Sun so
00:29:01 --> 00:29:03 they'll come through fairly quickly and
00:29:03 --> 00:29:04 that means if they're moving through
00:29:04 --> 00:29:06 just because we don't see them M doesn't
00:29:06 --> 00:29:07 mean if we look again in 5 years time
00:29:07 --> 00:29:09 there wouldn't be one that's appeared
00:29:09 --> 00:29:11 the other thing that came out of this is
00:29:11 --> 00:29:13 that they talked about the smaller
00:29:13 --> 00:29:15 particles are more common and it's quite
00:29:15 --> 00:29:17 likely that there may be as many as 10
00:29:17 --> 00:29:20 meteors per year on the earth that are
00:29:20 --> 00:29:21 bits of dust from the alpha centor
00:29:21 --> 00:29:24 system hitting our planet now 10 per
00:29:24 --> 00:29:26 year across the entire surface of the
00:29:26 --> 00:29:27 Earth means you're very unlikely to find
00:29:27 --> 00:29:28 them
00:29:28 --> 00:29:30 but it reminded me of stories that go
00:29:30 --> 00:29:32 back much further because we have these
00:29:32 --> 00:29:34 wonderful networks of cameras across the
00:29:34 --> 00:29:37 Earth that look up at shooting s and try
00:29:37 --> 00:29:39 and get multi-session observations so
00:29:39 --> 00:29:41 you can do trigonometry and figure out
00:29:41 --> 00:29:42 what their orbit was how they were
00:29:43 --> 00:29:45 moving and they've detected over the
00:29:45 --> 00:29:46 years a very small number of
00:29:46 --> 00:29:49 definitively interstellar meteors so
00:29:49 --> 00:29:51 meteors coming into the Earth atmosphere
00:29:51 --> 00:29:52 with a speed significantly higher than
00:29:52 --> 00:29:55 72 km a second which means that they
00:29:55 --> 00:29:57 can't have been bound to the solar
00:29:57 --> 00:29:58 system
00:29:58 --> 00:30:00 one of the things that those papers
00:30:00 --> 00:30:02 discussed for a long time is that there
00:30:02 --> 00:30:04 is one dominant source of dust through
00:30:04 --> 00:30:06 our solar system that gives us more than
00:30:06 --> 00:30:09 all of sources combined it's famous star
00:30:10 --> 00:30:11 called beta
00:30:11 --> 00:30:14 pictoris which back in 1983 was one of
00:30:14 --> 00:30:16 three stars the infrared astronomical
00:30:16 --> 00:30:18 satellite was confused about because it
00:30:18 --> 00:30:20 found an infrared excess around that
00:30:20 --> 00:30:22 star soory light years away it's more
00:30:22 --> 00:30:24 massive than the Sun and hotton but it's
00:30:24 --> 00:30:26 very young and it's still got a disc of
00:30:26 --> 00:30:28 debris around it forming planets it's
00:30:28 --> 00:30:30 got planets in that disc that we've
00:30:30 --> 00:30:32 discovered but that incredibly active
00:30:32 --> 00:30:34 Stellar Wind that that massive star has
00:30:34 --> 00:30:36 is blowing lots of the Dust into Space
00:30:36 --> 00:30:38 streaming off in all
00:30:38 --> 00:30:41 directions and enough of that dust is
00:30:41 --> 00:30:44 traveling to reach us 63 light years
00:30:44 --> 00:30:47 away that we can detect that as a
00:30:47 --> 00:30:50 distinct source of debris crashing into
00:30:50 --> 00:30:52 the Earth atmosphere that really boggles
00:30:52 --> 00:30:55 my mind that a star that far away can be
00:30:55 --> 00:30:57 putting dust into our atmosphere at a
00:30:57 --> 00:30:59 sufficient level that people have
00:30:59 --> 00:31:02 detected that dust stre yeah it is it's
00:31:02 --> 00:31:05 amazing and this must be happening just
00:31:05 --> 00:31:07 about everywhere we we we've probably
00:31:07 --> 00:31:11 got systems exchanging junk constantly
00:31:11 --> 00:31:13 yeah absolutely and it it ties into the
00:31:13 --> 00:31:15 panspermia idea that we've talked about
00:31:15 --> 00:31:17 before as well yeah if you are
00:31:17 --> 00:31:19 constantly ejecting dust and debris from
00:31:19 --> 00:31:22 every planetary system if you have
00:31:22 --> 00:31:24 somewhere with life in that system
00:31:24 --> 00:31:27 eventually that life has the potential
00:31:27 --> 00:31:28 to travel
00:31:28 --> 00:31:31 and you know yeah most of it will most
00:31:31 --> 00:31:32 of the debris ejected from the earth
00:31:32 --> 00:31:34 Will Never Land on any other world it'll
00:31:34 --> 00:31:36 just float in space for forever more but
00:31:36 --> 00:31:40 enough has been ejected that eventually
00:31:40 --> 00:31:41 something ejected from the earth will
00:31:41 --> 00:31:44 land on a planet around another s or
00:31:44 --> 00:31:46 will be incorporated in a planet forming
00:31:46 --> 00:31:47 region around the S that's just being
00:31:48 --> 00:31:50 bought you put enough material out there
00:31:50 --> 00:31:53 with enough bacteria buried in it it's
00:31:53 --> 00:31:54 very reasonable to imagine that you
00:31:55 --> 00:31:57 could get a situation where some point
00:31:57 --> 00:31:59 in the distant future there is a planet
00:31:59 --> 00:32:01 that has life on it and that life is
00:32:01 --> 00:32:02 having the discussion of how did life
00:32:02 --> 00:32:04 get started and someone suggest well
00:32:04 --> 00:32:06 maybe life came from the stars and
00:32:06 --> 00:32:07 everybody says well that's a lot of
00:32:07 --> 00:32:09 rubbish stop watching Star Trek and
00:32:09 --> 00:32:12 after was URS because it's Earth life
00:32:12 --> 00:32:14 yes indeed and this story also proves
00:32:14 --> 00:32:16 that you shouldn't get upset with your
00:32:16 --> 00:32:17 neighbors for throwing the grass
00:32:17 --> 00:32:20 clippings over your fence because it
00:32:20 --> 00:32:23 happens right through the cosmos
00:32:23 --> 00:32:24 absolutely I mean ties into the other
00:32:24 --> 00:32:27 space andruff thing actually so this is
00:32:27 --> 00:32:28 the the whole connection here of course
00:32:28 --> 00:32:30 is the Stars shaking their head and
00:32:30 --> 00:32:32 comets flying through space essentially
00:32:32 --> 00:32:34 the beautiful analogy there but anytime
00:32:34 --> 00:32:36 you're walking around outside or anytime
00:32:36 --> 00:32:38 you're doing the dusting in your house a
00:32:38 --> 00:32:39 certain amount of the dust that is
00:32:39 --> 00:32:41 falling on your shoulders or there is a
00:32:41 --> 00:32:44 crewing in your house is dust from
00:32:44 --> 00:32:46 outter space we have these tiny little
00:32:46 --> 00:32:48 particles of dust which are sometimes
00:32:48 --> 00:32:50 called brownly particles they are small
00:32:50 --> 00:32:52 enough that they are slowed down by the
00:32:52 --> 00:32:54 very tenous outer atmosphere before they
00:32:54 --> 00:32:56 get into a thick enough layer of
00:32:56 --> 00:32:58 atmosphere that they get a bled before
00:32:58 --> 00:33:00 they burn up so there's this steady
00:33:00 --> 00:33:03 little SLE of micro micro microscopic
00:33:03 --> 00:33:05 dust particles from space running down
00:33:05 --> 00:33:07 on the Earth all the time so when you do
00:33:07 --> 00:33:09 the dusting or when you go outside on a
00:33:10 --> 00:33:12 on a day and you're getting dust on you
00:33:12 --> 00:33:14 a tiny fraction of that is space so
00:33:14 --> 00:33:15 you've got space and refraining down on
00:33:15 --> 00:33:18 you at all times yeah it is fascinating
00:33:18 --> 00:33:21 to think about uh I think we have
00:33:21 --> 00:33:22 touched on that story once before a
00:33:22 --> 00:33:25 while ago but uh yeah
00:33:25 --> 00:33:27 fascinating um I think if we're quick we
00:33:27 --> 00:33:30 can squeeze in one more little story if
00:33:30 --> 00:33:32 you want to chase up the Space dandr
00:33:32 --> 00:33:35 story livescience.com uh carries that
00:33:35 --> 00:33:39 one uh one last yarn and this one is
00:33:40 --> 00:33:42 something we um I think we touched on in
00:33:42 --> 00:33:43 the last couple of weeks about you know
00:33:43 --> 00:33:45 where does a planet store start and a
00:33:45 --> 00:33:49 brown dwarf begin and we talked about 13
00:33:49 --> 00:33:52 um Jupiter masses uh well now a new
00:33:52 --> 00:33:56 planet has popped up in a study that has
00:33:56 --> 00:33:59 sparked debate on that issue yes so what
00:33:59 --> 00:34:01 we tend to do as humans in all walks of
00:34:01 --> 00:34:04 life is try and understand the universe
00:34:04 --> 00:34:06 that's just very fundamentally human
00:34:06 --> 00:34:08 thing to do and to do that we break
00:34:08 --> 00:34:10 things that are continual up into
00:34:10 --> 00:34:13 discrete packets into discrete fractions
00:34:13 --> 00:34:15 and we do this with a human lifetime you
00:34:15 --> 00:34:17 know you grow up and then suddenly one
00:34:17 --> 00:34:18 magical morning you wake up and you're
00:34:18 --> 00:34:20 legally able to drive or you're legally
00:34:20 --> 00:34:22 able to drink so long as you're not
00:34:22 --> 00:34:24 driving you know you have these magical
00:34:24 --> 00:34:26 thresholds where we've said one day
00:34:26 --> 00:34:28 you're an adult the day before you were
00:34:28 --> 00:34:30 a child you're not fundamentally any
00:34:30 --> 00:34:32 different across that barrier but we're
00:34:32 --> 00:34:33 grouping like with like and keeping
00:34:33 --> 00:34:35 different things
00:34:35 --> 00:34:37 separated that's what's happened with
00:34:37 --> 00:34:38 definitions of planets you know this was
00:34:38 --> 00:34:41 all the rage all the controversy two
00:34:41 --> 00:34:43 decades ago with the demotion of Pluto
00:34:43 --> 00:34:45 it was a same thing it was trying to
00:34:45 --> 00:34:46 group objects that are similar with each
00:34:47 --> 00:34:49 other in groups so that you can study
00:34:49 --> 00:34:52 that and one of the great areas where
00:34:52 --> 00:34:54 this has happened is you've got planets
00:34:54 --> 00:34:56 you've got stars and in between them
00:34:56 --> 00:34:58 you've got these curious objects that
00:34:58 --> 00:35:00 people call Brown dwarfs which are
00:35:00 --> 00:35:02 things that they viewed as being too big
00:35:02 --> 00:35:03 and too massive to be considered a
00:35:03 --> 00:35:05 typical Planet but they're not massive
00:35:05 --> 00:35:07 enough to have hydrogen fusion and to
00:35:07 --> 00:35:10 shine and become a sar so the boundary
00:35:10 --> 00:35:11 to be a sar is fairly clear upup if you
00:35:11 --> 00:35:14 get hydrogen Fusion going you're a sar
00:35:14 --> 00:35:16 which leads to the slightly quirky thing
00:35:16 --> 00:35:19 that white dwarfs and neutron stars are
00:35:19 --> 00:35:21 not Stars they're cell remnants so
00:35:21 --> 00:35:24 they're dead stars which is a turle
00:35:24 --> 00:35:28 asite but between a planet and a star
00:35:28 --> 00:35:29 there's this domain where you are not
00:35:29 --> 00:35:31 massive enough to burn hydrogen but the
00:35:31 --> 00:35:33 temperature in your core will get high
00:35:33 --> 00:35:34 enough that you will temporarily be able
00:35:34 --> 00:35:37 to burn deuterium which is heavy
00:35:37 --> 00:35:39 hydrogen there's not much of that so
00:35:39 --> 00:35:40 you'll get a very short period of dyum
00:35:40 --> 00:35:42 burning and then you'll just fizzle out
00:35:42 --> 00:35:44 and be a little glowing
00:35:44 --> 00:35:47 Ember now where that boundary is with
00:35:47 --> 00:35:49 the star is very clearcut it's a
00:35:49 --> 00:35:50 hydrogen fusion and it's a very
00:35:50 --> 00:35:53 observable thing but the boundary at the
00:35:53 --> 00:35:55 lower end where you no longer have
00:35:55 --> 00:35:57 enough Mass to burn the uteran is much
00:35:57 --> 00:36:00 woer and if people do modeling it
00:36:00 --> 00:36:02 depends on the composition of the object
00:36:02 --> 00:36:04 and how much solid material it's got and
00:36:04 --> 00:36:06 how much uterum it's got and all sorts
00:36:06 --> 00:36:09 of things going on so what's happened
00:36:09 --> 00:36:10 historically because we didn't really
00:36:10 --> 00:36:11 have the capacity to find low mass
00:36:12 --> 00:36:13 objects is people just put this
00:36:13 --> 00:36:15 arbitrary boundary of 13 Jupiter masses
00:36:15 --> 00:36:18 there to say anything more massive than
00:36:18 --> 00:36:20 that is a brown wolf anything less
00:36:20 --> 00:36:23 massive is a planet so that is setting
00:36:23 --> 00:36:25 this boundary purely on the physical
00:36:25 --> 00:36:27 Mass it's taking no account of the
00:36:27 --> 00:36:29 composition of the object or how it
00:36:29 --> 00:36:31 formed and as we finally got the ability
00:36:31 --> 00:36:32 to find objects in this Mass people have
00:36:32 --> 00:36:36 started to question that because the
00:36:36 --> 00:36:37 formation mechanism the composition
00:36:37 --> 00:36:39 matters a planet like Jupiter has about
00:36:39 --> 00:36:41 30 Earth masses of solid material as a
00:36:41 --> 00:36:45 core because of the way it formed a star
00:36:45 --> 00:36:48 doesn't have that same kind of structure
00:36:48 --> 00:36:50 so there's a growing argument that maybe
00:36:50 --> 00:36:53 we should divide it by formation
00:36:53 --> 00:36:55 mechanism and something that formed like
00:36:55 --> 00:36:57 a planet is a planet even if it's more
00:36:57 --> 00:36:59 massive than risk limit and it probably
00:36:59 --> 00:37:00 wouldn't undergo utaran fusion because a
00:37:00 --> 00:37:03 lot of the mass is solid material so
00:37:03 --> 00:37:06 it's got less utaran alternatively if it
00:37:06 --> 00:37:08 Formed like a star even if it's less
00:37:08 --> 00:37:10 massive than 13 juk to masses maybe it
00:37:10 --> 00:37:12 should be considered a brand W rather
00:37:12 --> 00:37:14 than a planet because of the formation
00:37:14 --> 00:37:16 mechanism and it's a debate that's only
00:37:16 --> 00:37:17 just starting to kick off because we're
00:37:17 --> 00:37:19 only really able to find these objects
00:37:19 --> 00:37:22 now it's being fired up here by the
00:37:22 --> 00:37:24 discovery of what's known as Gia 4B so
00:37:24 --> 00:37:26 the guy spacecraft we talked about
00:37:26 --> 00:37:28 earlier is this incredible miss that was
00:37:28 --> 00:37:29 measuring the positions and the Motions
00:37:29 --> 00:37:32 of a billion stars with Incredible
00:37:32 --> 00:37:35 Precision two billion stars absolutely
00:37:35 --> 00:37:37 ridiculous and what guia has promised
00:37:37 --> 00:37:39 for a long time is that it would find
00:37:39 --> 00:37:42 100 to a million planets under the
00:37:42 --> 00:37:45 stars that was part of the marketing so
00:37:45 --> 00:37:48 far it has found four or five um more
00:37:48 --> 00:37:49 will come because they're still doing
00:37:49 --> 00:37:51 their big de list so it will give us a
00:37:51 --> 00:37:53 deluge of planets at some point but the
00:37:53 --> 00:37:55 reason it can do this is that it
00:37:55 --> 00:37:57 measures the positions of the Stars the
00:37:57 --> 00:38:00 sky so accurately that it can see them
00:38:00 --> 00:38:02 wobbling as they move as a result of the
00:38:02 --> 00:38:05 planets pulling them around so this is a
00:38:05 --> 00:38:07 counterpart to our radial velocity
00:38:07 --> 00:38:09 method radial velocity sees a movement
00:38:09 --> 00:38:12 back and forth on a line of sight Gia
00:38:12 --> 00:38:14 sees the movement at right angles to
00:38:14 --> 00:38:17 that so it's been looking at this star
00:38:17 --> 00:38:19 this star is less massive than the sun
00:38:19 --> 00:38:21 about 2third of the mass of the Sun and
00:38:21 --> 00:38:23 this star is moving across the night sky
00:38:23 --> 00:38:24 because it's moving through the Galaxy
00:38:24 --> 00:38:26 separately to us it's what what we call
00:38:26 --> 00:38:28 proper motion and guy has identified
00:38:28 --> 00:38:29 that instead of that proper motion
00:38:29 --> 00:38:31 ministra line it's following a Corp
00:38:31 --> 00:38:34 group path across the sky zigzagging and
00:38:34 --> 00:38:36 that's a Telltale sign it's got a planet
00:38:36 --> 00:38:39 going around it now because this Stars a
00:38:39 --> 00:38:41 bit like the sun it's a bit cooler you
00:38:41 --> 00:38:43 can do radio velocity observations which
00:38:43 --> 00:38:45 means you can measure the line of sight
00:38:45 --> 00:38:47 wobble as well which means you can
00:38:47 --> 00:38:49 perfectly constrain what's going around
00:38:49 --> 00:38:51 it and the evidence here is that this is
00:38:51 --> 00:38:55 an object 11.8 times the mass of Jupiter
00:38:55 --> 00:38:57 so it's just underneath that threshold
00:38:57 --> 00:38:58 to be a brown dwarf we would
00:38:58 --> 00:39:00 traditionally call it a planet yeah and
00:39:00 --> 00:39:03 job on the complexity comes out that
00:39:03 --> 00:39:05 this SAR is less massive than the Sun
00:39:05 --> 00:39:07 and it's got a roughly similar
00:39:07 --> 00:39:10 composition to the Sun what that means
00:39:10 --> 00:39:12 is the pl material the planets around it
00:39:12 --> 00:39:14 would have formed from would have been
00:39:14 --> 00:39:17 similar to that around the sun it's not
00:39:17 --> 00:39:18 particularly metal Rich so it wouldn't
00:39:18 --> 00:39:20 have had far more solid material around
00:39:20 --> 00:39:22 it than the sun did which means there's
00:39:22 --> 00:39:24 a really difficult question to answer
00:39:24 --> 00:39:26 which is how can a sty less massive than
00:39:26 --> 00:39:28 the Sun which presumably forms from a
00:39:28 --> 00:39:30 less massive cloud of material than the
00:39:30 --> 00:39:33 sun how can it form a planet 12 times
00:39:33 --> 00:39:34 more massive than the biggest planet we
00:39:35 --> 00:39:37 have in our system that just doesn't
00:39:37 --> 00:39:40 make much sense it's really counter to
00:39:40 --> 00:39:41 our planet formation models which is
00:39:41 --> 00:39:43 more massive stars form more massive
00:39:43 --> 00:39:45 planets so that then brings up the
00:39:45 --> 00:39:47 suggestion that maybe this thing didn't
00:39:47 --> 00:39:49 form as a planet at all maybe instead
00:39:50 --> 00:39:51 what we're seeing is a failed binary
00:39:51 --> 00:39:55 star system and this 11.8 Jupiter Mass
00:39:55 --> 00:39:57 object formed in the same way that
00:39:57 --> 00:40:00 binary Stars would form that it wasn't
00:40:00 --> 00:40:02 cor Recreation you didn't get a load of
00:40:02 --> 00:40:04 solid material grow to 30 times the mass
00:40:04 --> 00:40:05 of the Earth or 10 times the mass of the
00:40:06 --> 00:40:08 Earth and then start Gathering gas
00:40:08 --> 00:40:10 because of the gravitational pole that
00:40:10 --> 00:40:11 instead it formed through gravitational
00:40:11 --> 00:40:13 instability in the cloud like another
00:40:13 --> 00:40:15 star would fall right and therefore this
00:40:15 --> 00:40:18 could be considered a failed star in
00:40:18 --> 00:40:20 which case it should be called a brown
00:40:20 --> 00:40:22 dwarf even though it's not massive
00:40:22 --> 00:40:24 enough because it didn't form as a
00:40:24 --> 00:40:26 planet it may even be because it's so
00:40:26 --> 00:40:28 close to the threshold that it could
00:40:28 --> 00:40:29 have almost got to the detarium burning
00:40:29 --> 00:40:32 limit it could have had that happen now
00:40:32 --> 00:40:35 we don't really know if we could go
00:40:35 --> 00:40:37 there if we could borrow Captain Kirk's
00:40:37 --> 00:40:39 spaceship and engage what RAV and go
00:40:39 --> 00:40:41 there we'd be able to answer this after
00:40:41 --> 00:40:42 a little while we'd put a mission up
00:40:42 --> 00:40:45 like Juno that's going around Jupiter
00:40:45 --> 00:40:46 that would allow you to map the interior
00:40:46 --> 00:40:48 of the object a bit like the earthquakes
00:40:48 --> 00:40:50 we were talking about in the first topic
00:40:50 --> 00:40:52 and figure out if it had a car or not
00:40:52 --> 00:40:53 and that would tell you about its
00:40:53 --> 00:40:55 formation but we can't do that we just
00:40:55 --> 00:40:57 can't get there so at the minute it's
00:40:57 --> 00:40:59 purely in the domain of speculation but
00:40:59 --> 00:41:02 it's a sufficiently odd discovery that
00:41:02 --> 00:41:04 it is just restarting that old
00:41:04 --> 00:41:06 discussion about at what point do we
00:41:06 --> 00:41:08 need to look at this again I guess at
00:41:08 --> 00:41:11 what point do we need to discuss whether
00:41:11 --> 00:41:13 we get a more physically motivated
00:41:13 --> 00:41:15 difference between brand woles and
00:41:15 --> 00:41:17 planets or whether we're happy to
00:41:17 --> 00:41:19 sticking with this arbitrary Mass limit
00:41:19 --> 00:41:21 and as the years go on gu is going to
00:41:21 --> 00:41:24 discover far more objects we continue to
00:41:24 --> 00:41:27 find planets using all the other methods
00:41:27 --> 00:41:29 there will be more objects that straddle
00:41:29 --> 00:41:30 that boundary because nature forms
00:41:30 --> 00:41:32 things of all sizes it doesn't say I'm
00:41:32 --> 00:41:34 going to leave a gap here to make it
00:41:34 --> 00:41:35 nice and easy for you there'll be things
00:41:35 --> 00:41:38 of all masses and there will be things
00:41:38 --> 00:41:39 of identical masses that formed in
00:41:39 --> 00:41:42 different ways and so it's going to be
00:41:42 --> 00:41:43 an ongoing question I'm sure we could
00:41:43 --> 00:41:44 have a chat in a couple of years time
00:41:44 --> 00:41:46 and they'd still be having the same
00:41:46 --> 00:41:48 debates but it's great when you get to
00:41:48 --> 00:41:51 the point where our ability to find
00:41:51 --> 00:41:53 things is such that it pushes the
00:41:53 --> 00:41:54 boundaries of how we Define things and
00:41:54 --> 00:41:56 we have to revisit them that's how
00:41:56 --> 00:41:58 science works and I really love it even
00:41:58 --> 00:42:00 if it means you get cranky people waving
00:42:00 --> 00:42:01 flags and going Pluto should still be a
00:42:01 --> 00:42:03 planet yes yes and that's still
00:42:03 --> 00:42:06 happening two years oh
00:42:06 --> 00:42:08 indeed yeah all right uh if you would
00:42:08 --> 00:42:13 like to um look U look into guia 4B and
00:42:13 --> 00:42:16 5B they've posted a report in the
00:42:16 --> 00:42:18 astronomical Journal uh it's a
00:42:18 --> 00:42:20 fascinating Discovery and I imagine the
00:42:20 --> 00:42:22 more we look the more unusual things
00:42:22 --> 00:42:24 we'll find and yes we probably will have
00:42:24 --> 00:42:25 to
00:42:25 --> 00:42:27 redefine where a brown War starts and a
00:42:27 --> 00:42:29 planet finishes in the future it might
00:42:29 --> 00:42:32 come down to that but uh at the moment
00:42:32 --> 00:42:35 we just go with what we know until proof
00:42:35 --> 00:42:38 sends us in a different direction uh we
00:42:38 --> 00:42:41 are just about done JY thank you so much
00:42:41 --> 00:42:42 that's absolute pleasure thank you for
00:42:42 --> 00:42:44 having me always a pleasure and we'll
00:42:44 --> 00:42:47 see you real soon uh Professor jonty
00:42:47 --> 00:42:49 horer from the University of Southern
00:42:49 --> 00:42:51 Queensland and thanks to Hugh in the
00:42:51 --> 00:42:53 studio who couldn't be with us today
00:42:53 --> 00:42:55 he's very embarrassed he's got a severe
00:42:55 --> 00:42:57 case of space dandr
00:42:57 --> 00:42:59 uh don't forget to visit us online as
00:42:59 --> 00:43:02 well at SPAC nuts podcast.com or SPAC
00:43:02 --> 00:43:04 nuts. and from me Andrew Dunley thanks
00:43:04 --> 00:43:06 for joining us we'll see you on the very
00:43:06 --> 00:43:09 next episode of space uh Space Nuts
00:43:09 --> 00:43:12 coming soon until then
00:43:12 --> 00:43:15 bye-bye you'll be listening to the Space
00:43:15 --> 00:43:17 Nuts
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