Source:
https://www.spreaker.com/episode/navigating-the-cosmos-and-redshift-riddles--62264103
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Space Nuts #458 Q&A Edition
Join Andrew Dunkley and Professor Fred Watson in this engaging Q&A episode of Space Nuts, where they tackle a variety of intriguing questions from listeners. From the mysteries of light and redshift to the enigmatic cores of gas giants, this episode is packed with fascinating insights and cosmic curiosities.
Episode Highlights:
- Light and Redshift: Mario from Melbourne (Australia) queries how light can redshift if it doesn't experience time. Fred Watson Watson delves into relativity and the observer's role in this cosmic phenomenon.
- Gas Giants' Cores: Nigel from Brisbane (Australia) wonders if there's a rocky planet beneath the gas layers of Jupiter and Saturn. Explore the theories about the mysterious cores of these colossal planets.
- Galaxy Collisions: Raul from California asks about the collision of galaxies amidst the universe's expansion. Discover why some galaxies are on a collision course despite the ever-expanding cosmos.
- Future Navigation: David from Tucson questions how we will navigate when exploring beyond our solar system. Learn about the quasars that provide a stable reference point for cosmic navigation.
For more Space Nuts, including our continually updating newsfeed and to listen to all our episodes, visit our https://www.spacenutspodcast.com. Follow us on social media at SpaceNutsPod on facebook, X, YouTube Music, Instagram, and TikTok. We love engaging with our community, so be sure to drop us a message or comment on your favourite platform.
For more Space and Astronomy News Podcasts, visit our HQ at https://www.bitesz.com.
Become a supporter of this podcast: https://www.spreaker.com/podcast/space-nuts/support.
Stay curious, keep looking up, and join us next time for more stellar insights and cosmic wonders. Until then, clear skies and happy stargazing.
00:00:00 --> 00:00:02 hi there uh Andrew Dunley again with
00:00:03 --> 00:00:05 another episode of Space Nuts and it's
00:00:05 --> 00:00:07 good to have your company this is a Q&A
00:00:07 --> 00:00:10 Edition this is where we answer your
00:00:10 --> 00:00:12 questions if we can if we can't we just
00:00:12 --> 00:00:15 pretend to uh we've got questions about
00:00:15 --> 00:00:19 light and red shift today uh we're also
00:00:19 --> 00:00:21 going to talk gas giants expansion of
00:00:21 --> 00:00:24 the Galaxy versus uh or expansion of the
00:00:24 --> 00:00:27 Universe versus Galaxy collisions and
00:00:27 --> 00:00:29 the future of navigation reference
00:00:29 --> 00:00:31 points how are we going to do that when
00:00:31 --> 00:00:34 we start going further and further out
00:00:34 --> 00:00:36 those questions will be answered or
00:00:36 --> 00:00:38 they'll be faked we're not sure yet deep
00:00:38 --> 00:00:42 fake radio coming up soon on this
00:00:42 --> 00:00:45 edition of Space Nuts 15 seconds
00:00:45 --> 00:00:49 guidance is internal 10 9 ignition
00:00:49 --> 00:00:54 sequence start Space Nuts 5 4 3 2 1 2 3
00:00:55 --> 00:00:58 4 5 5 4 3 2 1 Space Nuts as nuts report
00:00:58 --> 00:01:00 it feels good
00:01:00 --> 00:01:03 and he's here again like a fly on a
00:01:03 --> 00:01:06 piece of meat hello
00:01:06 --> 00:01:10 Fred thanks Andrew thanks Professor Fred
00:01:10 --> 00:01:11 what's an astronomer at large nice to
00:01:12 --> 00:01:15 see you um yeah that's right it's nice
00:01:15 --> 00:01:18 to see you too I
00:01:18 --> 00:01:21 think oh I I have enough Digs at Hue I
00:01:22 --> 00:01:23 thought maybe I should just you know
00:01:23 --> 00:01:26 should that's fine yeah land land a left
00:01:26 --> 00:01:28 hook for a change it always comes back
00:01:28 --> 00:01:31 and hits me though eventually so
00:01:31 --> 00:01:34 yeah I can take it I'm tough um let's
00:01:34 --> 00:01:36 let's go straight to our questions our
00:01:36 --> 00:01:38 first question today Fred comes from
00:01:38 --> 00:01:40 Mario in
00:01:40 --> 00:01:42 Melbourne uh he likes to go go-karting
00:01:42 --> 00:01:45 uh hi Fred and Andrew hoping you can
00:01:45 --> 00:01:48 help explain why if life itself doesn't
00:01:48 --> 00:01:51 experience time how can it red shift
00:01:51 --> 00:01:54 doesn't red shifting imply it changes
00:01:54 --> 00:01:57 somehow which implies it must have been
00:01:57 --> 00:02:00 subject to time or is this some sort of
00:02:00 --> 00:02:03 Relativity witchcraft where we as
00:02:03 --> 00:02:05 observers experience time and the red
00:02:05 --> 00:02:08 shift but the photon itself somehow in
00:02:08 --> 00:02:12 all states it can be simultaneously or
00:02:12 --> 00:02:15 something like that um simul yeah
00:02:15 --> 00:02:18 simultaneously or something like that um
00:02:18 --> 00:02:20 appreciate you unscrambling my brain on
00:02:20 --> 00:02:23 this one still listening from the far
00:02:23 --> 00:02:26 start uh keep up the great show Mario
00:02:26 --> 00:02:30 from Melbourne I I think we've kind of
00:02:30 --> 00:02:32 had variations of this question come up
00:02:32 --> 00:02:36 in the past people sort
00:02:36 --> 00:02:39 of have trouble differentiating between
00:02:40 --> 00:02:42 light and time and and what's going on
00:02:42 --> 00:02:46 out there um can you shed some light on
00:02:46 --> 00:02:47 this one
00:02:47 --> 00:02:50 Fred I'm sorry I'm completely in the
00:02:50 --> 00:02:53 dark about this one oh
00:02:53 --> 00:02:57 bu it's um it's a good point though and
00:02:57 --> 00:03:00 um so it's made me you know you know got
00:03:00 --> 00:03:03 the old cogs working to try and work out
00:03:03 --> 00:03:05 what's happening because that's right
00:03:05 --> 00:03:07 because uh light travels at the speed of
00:03:07 --> 00:03:10 light which is the fastest speed
00:03:10 --> 00:03:12 anything could travel through the
00:03:12 --> 00:03:16 Universe um it does not experience time
00:03:16 --> 00:03:18 a photon of light does not experience
00:03:18 --> 00:03:24 time and yet uh they change and you're
00:03:24 --> 00:03:28 you're right Mario is correct that we do
00:03:28 --> 00:03:32 see pH changing because the photons that
00:03:32 --> 00:03:34 we are now receiving from distant Galaxy
00:03:34 --> 00:03:36 for example are highly red shifted
00:03:36 --> 00:03:39 they've they've become red photons now
00:03:39 --> 00:03:42 what that corresponds to is a loss of
00:03:42 --> 00:03:46 energy which results from the expansion
00:03:46 --> 00:03:50 of the universe and so I think I'm right
00:03:50 --> 00:03:55 in saying that the photon doesn't notice
00:03:55 --> 00:03:58 that um it it doesn't know that it's
00:03:58 --> 00:04:00 lost energy
00:04:00 --> 00:04:05 because it doesn't experience time um so
00:04:05 --> 00:04:08 uh I think you know in a sense the loss
00:04:08 --> 00:04:11 of energy which by the way just filters
00:04:11 --> 00:04:14 out into the universe apparently uh
00:04:14 --> 00:04:17 normally that's where it goes it's
00:04:17 --> 00:04:21 um I think uh that is a property of the
00:04:21 --> 00:04:23 of the Observer the the the fact that
00:04:23 --> 00:04:27 we're observing this thing um the photon
00:04:27 --> 00:04:30 as to to the best of mind understanding
00:04:30 --> 00:04:33 doesn't care it it arrives at the same
00:04:33 --> 00:04:36 time as it left um because it doesn't
00:04:36 --> 00:04:38 experience time uh but it might be
00:04:38 --> 00:04:41 surprised that where the place where it
00:04:41 --> 00:04:44 arrived at is very different from the
00:04:44 --> 00:04:46 place where it left at in terms of the
00:04:46 --> 00:04:48 energy balance and what's happening
00:04:48 --> 00:04:49 there I'm not sure whether I'm making
00:04:49 --> 00:04:52 much sense here Mario but uh but that's
00:04:52 --> 00:04:54 my understanding of the situation okay
00:04:54 --> 00:04:56 it is it is a bit complicated it' be
00:04:56 --> 00:04:58 nice to be a photon if you're doing a
00:04:58 --> 00:05:00 long haul flight cuz if you did
00:05:00 --> 00:05:01 experience time you wouldn't have to
00:05:01 --> 00:05:04 worry about a 20-hour flight to Turkey
00:05:04 --> 00:05:05 for
00:05:05 --> 00:05:07 example no you wouldn't that's nothing
00:05:07 --> 00:05:11 or anything like that is weak yeah all
00:05:11 --> 00:05:14 over the place yeah um we hope we
00:05:14 --> 00:05:17 unscrambled your brain uh Mario because
00:05:17 --> 00:05:19 it is a it is a bit of a scrambly issue
00:05:19 --> 00:05:22 but photons don't experience time and
00:05:22 --> 00:05:23 they don't know that they're losing
00:05:23 --> 00:05:31 energy it's sort of like old people
00:05:31 --> 00:05:34 yep yep oh
00:05:34 --> 00:05:36 boy go to hell for that it's funny you
00:05:36 --> 00:05:37 should say that though no you know no
00:05:37 --> 00:05:41 look I um I can vouch for
00:05:41 --> 00:05:44 that I'm starting to experience that
00:05:44 --> 00:05:47 myself yes uh thanks Mario let's move on
00:05:47 --> 00:05:51 to our next one uh this comes from Nigel
00:05:51 --> 00:05:53 hi FR and Andrew this is Nigel from
00:05:53 --> 00:05:56 brisban Australia I have two questions
00:05:56 --> 00:06:00 about our gas giants Jupiter and Saturn
00:06:00 --> 00:06:03 I want to know beneath all that gas is
00:06:03 --> 00:06:06 there a rocky planet and if so how big
00:06:07 --> 00:06:09 are they in relation to the Earth okay
00:06:09 --> 00:06:12 thank you love the show keep up the good
00:06:12 --> 00:06:16 work um thanks Nigel uh yeah I look it's
00:06:16 --> 00:06:18 um it's it's Theory isn't it Fred we
00:06:18 --> 00:06:20 don't know for sure what's down deep in
00:06:21 --> 00:06:25 those gas giants um but there might be
00:06:26 --> 00:06:28 something well you've absolutely
00:06:28 --> 00:06:29 answered the question Andre okay move on
00:06:29 --> 00:06:33 to the next one from R Nigel's question
00:06:33 --> 00:06:35 is uh you know it's one that many
00:06:36 --> 00:06:38 astronomers and planetary scientists ask
00:06:38 --> 00:06:40 because we don't know we don't know the
00:06:40 --> 00:06:44 answer um the the modeling suggests
00:06:44 --> 00:06:48 that uh because of the way we we believe
00:06:48 --> 00:06:50 planets have formed that there should be
00:06:50 --> 00:06:54 a rocky core underneath all that gas
00:06:54 --> 00:06:58 that it should be quite massive um maybe
00:06:58 --> 00:07:01 with a fair degree of of water ice
00:07:01 --> 00:07:04 involved with it as well although some
00:07:04 --> 00:07:07 of the papers that I've read suggests
00:07:07 --> 00:07:08 that there might be something called
00:07:08 --> 00:07:11 metallic hydrogen at the center of these
00:07:11 --> 00:07:15 gas giants I'm not sure what that means
00:07:15 --> 00:07:17 probably means hydrogen in a state where
00:07:17 --> 00:07:19 it can conduct
00:07:19 --> 00:07:23 electricity so um yeah so that's uh it
00:07:23 --> 00:07:24 it's a question that's really at the
00:07:24 --> 00:07:27 Forefront of knowledge so uh you and me
00:07:28 --> 00:07:29 both njel I I wonder what's at the
00:07:29 --> 00:07:31 center of these gas giants and how big
00:07:31 --> 00:07:33 the the central core might be if there
00:07:33 --> 00:07:36 is one which we assume there is yeah I
00:07:36 --> 00:07:41 mean gas giants uh to a certain degree
00:07:41 --> 00:07:43 what could have been Stars had their
00:07:43 --> 00:07:46 formation happened in a bigger better
00:07:46 --> 00:07:50 way at what point do they reach in size
00:07:50 --> 00:07:53 or structure where they wouldn't have a
00:07:53 --> 00:07:57 solid core like would a brown dwarf had
00:07:57 --> 00:08:00 have a solid core perhaps
00:08:00 --> 00:08:03 uh yeah that certainly a brown dwarf
00:08:03 --> 00:08:04 would have a core and it probably
00:08:04 --> 00:08:08 wouldn't be solid either um
00:08:08 --> 00:08:11 uh similar to more similar to what the
00:08:11 --> 00:08:14 sun's core we think is like compared
00:08:14 --> 00:08:16 with what a planets core is like so
00:08:16 --> 00:08:19 brown dwarf has nuclear reactions taking
00:08:19 --> 00:08:21 place but they're lowlevel ones they're
00:08:21 --> 00:08:25 something called dyum Burning uh and um
00:08:25 --> 00:08:26 that doesn't generate anything like the
00:08:26 --> 00:08:29 same amount of heat as as the hydrogen
00:08:29 --> 00:08:31 process that is going on at the center
00:08:31 --> 00:08:34 of of our sun so at the center of the
00:08:34 --> 00:08:37 sun you've got this ball of energy uh
00:08:38 --> 00:08:40 very very hot
00:08:40 --> 00:08:42 radiating gamma ray photons out which
00:08:42 --> 00:08:44 eventually find their way there's
00:08:44 --> 00:08:47 visible light out to the surface um the
00:08:47 --> 00:08:50 brown dwarf you've got low level
00:08:50 --> 00:08:52 radiation which Finds Its way to the
00:08:52 --> 00:08:56 surface with a gas giant though um we
00:08:56 --> 00:08:57 don't know that's the thing we really
00:08:57 --> 00:08:59 don't know what the the core would be
00:08:59 --> 00:09:04 like um it it it the thinking is that
00:09:04 --> 00:09:05 that they are cold enough to have a
00:09:05 --> 00:09:07 solid core you know that you're not
00:09:07 --> 00:09:09 talking about a ball of energy but we do
00:09:09 --> 00:09:11 know again that there are nuclear
00:09:11 --> 00:09:13 actions taking place in for example in
00:09:13 --> 00:09:15 the core of Jupiter Jupiter radiates 1.8
00:09:16 --> 00:09:17 times more heat than it receives from
00:09:17 --> 00:09:21 the salt that's coming from maybe
00:09:21 --> 00:09:23 uranium fish or something like that
00:09:23 --> 00:09:26 happening down there in its interior wow
00:09:26 --> 00:09:28 do they have a theory if it if Jupiter
00:09:28 --> 00:09:31 has a do they have a theory on how big
00:09:31 --> 00:09:33 it is compared to
00:09:33 --> 00:09:35 Earth
00:09:35 --> 00:09:36 um
00:09:36 --> 00:09:38 [Laughter]
00:09:38 --> 00:09:41 probably but uh look I'm gonna take us
00:09:41 --> 00:09:43 take a punt and say yes people probably
00:09:43 --> 00:09:45 do think it is about the size of Earth
00:09:45 --> 00:09:48 I'm sure I've heard that kind of
00:09:48 --> 00:09:50 suggestion before because remember
00:09:50 --> 00:09:52 Jupiter's about 11 times the diamet of
00:09:52 --> 00:09:56 Earth so yeah wow all right um jury's
00:09:56 --> 00:10:00 still out Nigel but um it's maybe could
00:10:00 --> 00:10:03 be doo type of
00:10:03 --> 00:10:06 scenario but thanks for the question
00:10:06 --> 00:10:09 sorry yeah nothing to do with us nothing
00:10:09 --> 00:10:11 nothing nothing to see here uh this is
00:10:11 --> 00:10:14 space nut Sandra Dunley with Fred Watson
00:10:14 --> 00:10:18 Professor astronomer at large great
00:10:18 --> 00:10:20 guy now let's take a little break from
00:10:20 --> 00:10:23 the show to tell you about our sponsor
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00:12:48 --> 00:12:50 and check out the deal today you won't
00:12:50 --> 00:12:53 regret signing up with
00:12:53 --> 00:12:59 nordvpn now back to the show 3 2 1 space
00:12:59 --> 00:13:03 nuts okay our next question Fred comes
00:13:03 --> 00:13:08 from Raul hi guys Raul from California
00:13:08 --> 00:13:10 here and a big Chelsea fan I know you
00:13:10 --> 00:13:13 were talking about American football but
00:13:13 --> 00:13:14 I do like European
00:13:14 --> 00:13:19 football had a question for
00:13:19 --> 00:13:24 you if the universe is ever expanding
00:13:24 --> 00:13:26 from The Big Bang then all the galaxies
00:13:26 --> 00:13:28 would be moving apart from each other
00:13:28 --> 00:13:30 but I recall seeing on a show that
00:13:30 --> 00:13:33 galaxies could One Day Collide does that
00:13:33 --> 00:13:36 mean that the universe is stopping its
00:13:36 --> 00:13:39 expansion or slowing a expansion
00:13:39 --> 00:13:42 allowing the gravity of galaxies to then
00:13:42 --> 00:13:46 Collide and if that is the case will the
00:13:46 --> 00:13:48 universe one day stop expanding and
00:13:48 --> 00:13:51 start to contract upon whatever the
00:13:51 --> 00:13:53 hugest big black hole in the middle of
00:13:53 --> 00:13:56 the universe really is thanks a lot you
00:13:56 --> 00:13:59 guys do great love listening to it
00:13:59 --> 00:14:03 newbie to the show but love what you do
00:14:03 --> 00:14:07 bye thank you David um
00:14:07 --> 00:14:11 Chelsea I'm a was R oh sorry yeah
00:14:11 --> 00:14:14 David's next r r thanks for that uh yes
00:14:14 --> 00:14:17 um Chelsea fan but um yeah we'll forgive
00:14:18 --> 00:14:20 you for that I'm a um a Liverpool fan
00:14:20 --> 00:14:23 myself do you follow English premier
00:14:23 --> 00:14:28 league league slightly yeah only um you
00:14:28 --> 00:14:30 know of the bigger teams I always
00:14:30 --> 00:14:32 interested in what they're doing I've
00:14:32 --> 00:14:35 got um a son-in-law and a grand couple
00:14:35 --> 00:14:37 of grandsons who are absolutely mad
00:14:37 --> 00:14:41 Manchester United Freaks and you know
00:14:41 --> 00:14:45 various various other football teams I
00:14:45 --> 00:14:47 never really got heavily into football I
00:14:47 --> 00:14:48 could never remember which way I was
00:14:48 --> 00:14:50 supposed to be kicking the ball so
00:14:50 --> 00:14:55 wasn't my scene really um uh but I yeah
00:14:55 --> 00:14:58 I that takes an interest yeah I I played
00:14:58 --> 00:15:00 soccer for 10 years never won a thing I
00:15:00 --> 00:15:01 didn't even win the
00:15:01 --> 00:15:06 raffle um anyway uh Raul's asking about
00:15:06 --> 00:15:08 the universe and his expansion versus
00:15:08 --> 00:15:12 Galaxy collisions basically um and you
00:15:12 --> 00:15:15 know is is the expansion slowing or
00:15:15 --> 00:15:17 stopping and is that why galaxies are
00:15:17 --> 00:15:20 going to crash into each other uh is it
00:15:20 --> 00:15:22 all going to sort of fall back into a
00:15:22 --> 00:15:24 giant black hole in the middle uh we've
00:15:24 --> 00:15:26 had variations of questions like this
00:15:26 --> 00:15:29 over the years it's um it's one that
00:15:29 --> 00:15:32 always spawns a lot of
00:15:32 --> 00:15:35 interest it does doesn't it and there
00:15:35 --> 00:15:37 are actually two things going on here I
00:15:37 --> 00:15:39 think in R's question because he quite
00:15:39 --> 00:15:41 right that some galaxies do collide with
00:15:41 --> 00:15:44 each other and in fact we are in poor
00:15:44 --> 00:15:46 position for a collision with Andromeda
00:15:46 --> 00:15:49 that might already be happening in fact
00:15:49 --> 00:15:51 uh yeah in fact yeah we talked about it
00:15:51 --> 00:15:53 the other day they're actually sort of
00:15:53 --> 00:15:55 you know tickling their fingertips at
00:15:55 --> 00:15:56 the moment because of their Giant Gas
00:15:56 --> 00:16:01 balls that's been revealed
00:16:01 --> 00:16:04 indeed so um and and so why are they
00:16:04 --> 00:16:06 colliding if the universe is expanding
00:16:06 --> 00:16:07 because both those statements are true
00:16:08 --> 00:16:10 the universe is expanding and the two
00:16:10 --> 00:16:12 galaxies are colliding and that's
00:16:12 --> 00:16:16 because uh at the on the scale of the
00:16:16 --> 00:16:19 distance between us and Andromeda which
00:16:19 --> 00:16:22 is 2.5 million light years the expansion
00:16:22 --> 00:16:26 of the universe is negligible more or
00:16:26 --> 00:16:28 less uh the universe the universe is EXP
00:16:28 --> 00:16:31 expanding but over a small distance like
00:16:31 --> 00:16:33 that what becomes the dominant force is
00:16:34 --> 00:16:36 gravity and the gravity the
00:16:36 --> 00:16:38 gravitational pull between the Milky Way
00:16:39 --> 00:16:41 and Andromeda easily enough to overcome
00:16:41 --> 00:16:44 the fact that they're being pulled apart
00:16:44 --> 00:16:47 much more gently by the by the expansion
00:16:47 --> 00:16:50 of the universe so and that's we we give
00:16:50 --> 00:16:53 a a term we got a name for the
00:16:53 --> 00:16:55 individual motions of galaxies kind of
00:16:55 --> 00:16:57 superimposed on the expansion of the
00:16:57 --> 00:16:59 universe we call it their peculiar
00:16:59 --> 00:17:01 motions and it's so the peculiar motion
00:17:01 --> 00:17:06 of Milky Way relative to Andromeda is uh
00:17:06 --> 00:17:08 the colliding together and they will
00:17:08 --> 00:17:11 collide um whereas the expansion of the
00:17:11 --> 00:17:13 universe is trying to pull them apart
00:17:13 --> 00:17:15 but at a much much slower rate if I can
00:17:15 --> 00:17:17 put it that way it's only when you look
00:17:17 --> 00:17:19 on the big scales that you see the real
00:17:19 --> 00:17:21 effects of the expansion of the universe
00:17:21 --> 00:17:22 things that are billions of light years
00:17:23 --> 00:17:24 away from us rather than just a couple
00:17:24 --> 00:17:29 of million uh and uh uh basically was
00:17:29 --> 00:17:33 right uh until 1998 we used to think
00:17:33 --> 00:17:36 that eventually the gravitational pull
00:17:36 --> 00:17:38 of everything in the universe would slow
00:17:38 --> 00:17:40 down the expansion uh and the universe
00:17:41 --> 00:17:44 would indeed collapse on itself uh in
00:17:44 --> 00:17:47 what we always call Andrew the ganab
00:17:47 --> 00:17:51 Gibb the ganab Gibb exactly big bang big
00:17:51 --> 00:17:53 bang that's right Brian Branch mates
00:17:53 --> 00:17:56 praise the gab Gib we used to think uh
00:17:56 --> 00:18:00 you often call the Big Crunch as well um
00:18:00 --> 00:18:02 that was that was the thinking and it
00:18:02 --> 00:18:05 was but it was when um Brian schit and
00:18:05 --> 00:18:08 his colleagues and uh other colleagues
00:18:08 --> 00:18:11 in the United States uh when they
00:18:11 --> 00:18:13 discovered the accelerated expansion of
00:18:13 --> 00:18:16 the universe that possible the
00:18:16 --> 00:18:18 possibility of the ganab Gibb was thrown
00:18:18 --> 00:18:21 out the window um because the universe
00:18:21 --> 00:18:23 is as far as we know going to expand
00:18:23 --> 00:18:25 forever uh and there isn't enough stuff
00:18:25 --> 00:18:28 in it for its gravitational pool to Halt
00:18:28 --> 00:18:30 the expansion and part of that is
00:18:30 --> 00:18:32 because we think that space itself has
00:18:32 --> 00:18:35 an energy we call it dark energy uh and
00:18:35 --> 00:18:37 the more space you have the more energy
00:18:37 --> 00:18:40 you've got uh and that energy is trying
00:18:40 --> 00:18:42 to push things apart to push the
00:18:42 --> 00:18:45 universe into ever ex ever faster
00:18:45 --> 00:18:48 expansion so yes it looks as though that
00:18:48 --> 00:18:50 uh big crunch scenario has gone out the
00:18:50 --> 00:18:52 window but it was very popular in the
00:18:52 --> 00:18:55 1970s and 80s so what's the opposite to
00:18:55 --> 00:18:59 a big crunch it's a h Gib
00:18:59 --> 00:19:04 [Laughter]
00:19:04 --> 00:19:08 yes that sounds right yeah yeah
00:19:08 --> 00:19:09 someone's going to ask again because
00:19:09 --> 00:19:11 we've had the question before but you
00:19:11 --> 00:19:13 know if the if the uh Universe keeps
00:19:13 --> 00:19:15 expanding and it's filling with dark
00:19:15 --> 00:19:17 energy where's where's the energy coming
00:19:17 --> 00:19:19 from you know how how's that fueling
00:19:19 --> 00:19:21 itself we don't
00:19:21 --> 00:19:25 know we don't comes out of space yeah it
00:19:25 --> 00:19:28 comes from somewhere yeah uh people say
00:19:28 --> 00:19:30 coming from dark matter but we they're
00:19:30 --> 00:19:32 not related they're just badly
00:19:32 --> 00:19:35 named yes they are that's that's correct
00:19:35 --> 00:19:37 I mean maybe it's coming from outside
00:19:37 --> 00:19:40 you know if there's multiverses oh that
00:19:40 --> 00:19:42 would be something wouldn't it we should
00:19:42 --> 00:19:45 just go and have a look simple that's a
00:19:45 --> 00:19:47 good idea yeah yeah send
00:19:47 --> 00:19:50 Voyager that well it's it's on its way
00:19:50 --> 00:19:52 we just have to sit here and twid our
00:19:52 --> 00:19:55 thumbs and just wait a little while and
00:19:55 --> 00:19:57 then we'll know if the batteries don't
00:19:57 --> 00:20:00 run out uh did we finish with Raul I
00:20:00 --> 00:20:03 think so yeah we did yes all the best
00:20:03 --> 00:20:06 Raul and um I hope Chelsea doesn't win
00:20:06 --> 00:20:09 as much as Liverpool uh let's go to our
00:20:09 --> 00:20:12 final question and this one comes from
00:20:12 --> 00:20:15 this is David wow what a coincidence hi
00:20:15 --> 00:20:18 love your podcast I live in the lovely
00:20:18 --> 00:20:20 dark City of Tucson that'll be the
00:20:20 --> 00:20:24 Arizona variety I imagine my question I
00:20:24 --> 00:20:26 uh my question I assume astronomers use
00:20:26 --> 00:20:29 the Sun as a center of reference but
00:20:29 --> 00:20:31 what about the future when we want to
00:20:31 --> 00:20:34 travel somewhere else uh everything is
00:20:34 --> 00:20:39 moving and it's a nobody system it's
00:20:39 --> 00:20:41 hard to know exactly where anything is
00:20:41 --> 00:20:44 going to be if you wait long enough how
00:20:44 --> 00:20:47 will you tell our Colony on proximus
00:20:48 --> 00:20:51 centor where to go or where to look when
00:20:51 --> 00:20:54 it takes 4.2 years for them to get the
00:20:54 --> 00:20:56 message that's from David I I like this
00:20:57 --> 00:20:59 question it's uh it's a it's a long-term
00:20:59 --> 00:21:02 future problem when we're living in
00:21:02 --> 00:21:05 other parts of the U of the galaxy
00:21:05 --> 00:21:07 outside our own solar system we've we've
00:21:07 --> 00:21:10 made the giant leap and ended up on one
00:21:10 --> 00:21:14 of those perfectly normal planets around
00:21:14 --> 00:21:19 um the alpha centor system and we want
00:21:19 --> 00:21:22 to come back how do we how do we find
00:21:22 --> 00:21:24 our way back I mean we we can find our
00:21:24 --> 00:21:26 way there so I ass assume we can find
00:21:26 --> 00:21:31 our way back
00:21:31 --> 00:21:33 mathematics would be my answer to this
00:21:33 --> 00:21:36 one well it is it's um it's a it's a
00:21:36 --> 00:21:39 good question actually and it has a real
00:21:39 --> 00:21:41 uh significance to it
00:21:41 --> 00:21:47 because we uh we need we already need uh
00:21:47 --> 00:21:50 reference points like that for things
00:21:50 --> 00:21:52 like
00:21:52 --> 00:21:55 GPS uh you know satellite navigation
00:21:55 --> 00:22:00 systems um space space uh
00:22:00 --> 00:22:03 navigation even in the small distances
00:22:03 --> 00:22:05 within our solar system you need you
00:22:05 --> 00:22:08 need fixed reference points and what we
00:22:08 --> 00:22:13 use are the things on the sky that move
00:22:13 --> 00:22:16 least and the bright uh and they are
00:22:16 --> 00:22:20 quazar so quazar are very bright sources
00:22:20 --> 00:22:22 but they're at very great distances so
00:22:22 --> 00:22:25 distant that nothing we could ever do in
00:22:25 --> 00:22:27 terms of our movement would change their
00:22:27 --> 00:22:29 positions on the sky
00:22:29 --> 00:22:31 and so quazar have formed the
00:22:31 --> 00:22:34 fundamental reference system that's used
00:22:34 --> 00:22:36 uh in astronomy actually as well as for
00:22:36 --> 00:22:40 navigation we use them uh to set up uh
00:22:40 --> 00:22:42 basically reference systems for
00:22:42 --> 00:22:44 measuring Galaxy positions star
00:22:44 --> 00:22:46 positions things of that sort you use
00:22:47 --> 00:22:48 something that's not going to move and
00:22:48 --> 00:22:50 the qual don't move because they're so
00:22:50 --> 00:22:53 far away so it's already there uh David
00:22:53 --> 00:22:56 and um hopefully when you leave Tucson
00:22:56 --> 00:22:59 and head out towards Alpha Center story
00:22:59 --> 00:23:01 you won't need to have any worries that
00:23:01 --> 00:23:03 you'll lose your way home you'll find
00:23:03 --> 00:23:06 your way back yes and and don't ignore
00:23:06 --> 00:23:09 the sign that says next fuel stop 2
00:23:09 --> 00:23:10 billion
00:23:10 --> 00:23:13 kilometers you really don't want to skip
00:23:13 --> 00:23:15 that one because it's a long way to the
00:23:15 --> 00:23:17 toilet let's face
00:23:17 --> 00:23:21 it yeah um yeah all right I I didn't
00:23:21 --> 00:23:23 realize it'd be that easy Fred it's good
00:23:23 --> 00:23:26 to know yep we just got to we just got
00:23:26 --> 00:23:28 to perfect the engines that are aable us
00:23:28 --> 00:23:31 to travel far distances in a in a bit of
00:23:31 --> 00:23:33 a hurry that's that's probably the
00:23:33 --> 00:23:35 bigger challenge than the
00:23:35 --> 00:23:37 navigation thanks David great question
00:23:37 --> 00:23:39 uh and if you have a question please
00:23:39 --> 00:23:41 send it into to us via our website SPAC
00:23:41 --> 00:23:44 nats.io you thought I was going to say
00:23:44 --> 00:23:47 sputs podcast.com didn't you yes well
00:23:47 --> 00:23:49 that counts too you can use both they
00:23:49 --> 00:23:51 all end up in the same place and uh you
00:23:51 --> 00:23:53 can send us a text or audio question
00:23:53 --> 00:23:56 just by clicking on the AMA Tab and if
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00:24:00 --> 00:24:02 don't forget to leave your reviews on
00:24:02 --> 00:24:04 whatever platform you use to listen to
00:24:04 --> 00:24:08 us and social media follow us like us
00:24:08 --> 00:24:10 subscribe wherever you are we'd uh we'd
00:24:10 --> 00:24:12 love you to make our little family a
00:24:12 --> 00:24:13 little bit bigger and don't forget about
00:24:13 --> 00:24:16 the space NS podcast group on Facebook
00:24:16 --> 00:24:18 it's uh it's always growing it's it's
00:24:18 --> 00:24:21 it's growing like a um like a blob of
00:24:21 --> 00:24:25 gas in a nebula or whatever it is uh and
00:24:25 --> 00:24:28 um we'll um yeah it's where you can sort
00:24:28 --> 00:24:31 of chat with like-minded people who
00:24:31 --> 00:24:33 follow Space Nuts um talk to each other
00:24:33 --> 00:24:35 ask each other questions share your
00:24:35 --> 00:24:38 astronomical photographs and stories
00:24:38 --> 00:24:40 it's uh growing at a rate of knots it is
00:24:41 --> 00:24:43 Fred and thank you for your company
00:24:43 --> 00:24:45 today Fred and thanks for um tolerating
00:24:45 --> 00:24:49 my stupidity and answering All Those
00:24:49 --> 00:24:51 Questions that's all right I I can live
00:24:51 --> 00:24:53 with that Andrew
00:24:53 --> 00:24:57 um no doubt we'll continue to do so uh
00:24:57 --> 00:24:58 keep up the good work it's always great
00:24:58 --> 00:25:00 to talk thanks a lot we'll see you soon
00:25:00 --> 00:25:02 Professor Fred Watson astronomer at
00:25:02 --> 00:25:05 large and the not Professor Hugh uh
00:25:05 --> 00:25:07 thank you to him for helping out um not
00:25:07 --> 00:25:11 today and we'll see you very soon Andrew
00:25:11 --> 00:25:12 Dunley signing off we'll catch you on
00:25:12 --> 00:25:15 the very next episode of Space Nuts
00:25:15 --> 00:25:18 bye-bye nuts you'll be listening to the
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