Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / #448: Galactic Life Cycles, Black Hole Growth & Space Junk Rings

Transcript

#448: Galactic Life Cycles, Black Hole Growth & Space Junk Rings · Space Nuts: Astronomy Insights & Cosmic Discoveries

• 0:00
  Speaker 1: Hello again, thanks for joining us on Space Nuts. Andrew
• 0:03
  Speaker 1: Dunkley here, and it's a Q and A edition. That
• 0:06
  Speaker 1: means that we're going to answer questions, or we're going
• 0:09
  Speaker 1: to pretend to, or we're going to refer them to
• 0:13
  Speaker 1: a future episode for possible answering or not, or maybe
• 0:18
  Speaker 1: we'll just put them in a bin. I don't know
• 0:20
  Speaker 1: what have we got today. We're looking at life and
• 0:22
  Speaker 1: death within the universe, not the life or death of
• 0:26
  Speaker 1: people or other entities for that matter, but maybe the
• 0:31
  Speaker 1: life and death of planets and galaxies and maybe the
• 0:35
  Speaker 1: universe itself. What's that all about? Will tell you. We're
• 0:39
  Speaker 1: also going to look at how black holes grow. That
• 0:44
  Speaker 1: question has been asked. Another question about space junk and
• 0:47
  Speaker 1: seeing the Milky Way in the UK. How do you
• 0:50
  Speaker 1: do it? Ah, You get a very tall ladder to
• 0:53
  Speaker 1: get above all the smog and the clouds. That's what
• 0:55
  Speaker 1: I reckon. That's all coming up on this edition of
• 0:58
  Speaker 1: Space Nuts.
• 1:00
  Speaker 2: Second guidance is in Channel ten nine ignition Space Nuts
• 1:07
  Speaker 2: or three two one spaces.
• 1:13
  Speaker 1: As when I reported, Bill's good and it's good to
• 1:16
  Speaker 1: have Professor Fred Watson here to answer all of those
• 1:19
  Speaker 1: because I haven't got a clue. Hello, Fred, Oh yeah, true,
• 1:24
  Speaker 1: another of I really, Oh well, we'll do our best.
• 1:31
  Speaker 1: We have a homework segment that we occasionally do where
• 1:34
  Speaker 1: a question gets too hard. Might take us three or
• 1:37
  Speaker 1: four months to get back to you, but we do it.
• 1:40
  Speaker 1: We do it.
• 1:40
  Speaker 3: What's the rush? Shall we begin? Why not?
• 1:45
  Speaker 4: Okay?
• 1:46
  Speaker 1: This first question comes from Trevor. Trevor's in Port Macquarie,
• 1:50
  Speaker 1: which is up on the mid north coast of New
• 1:52
  Speaker 1: South Wales, Australia. Horrible part of the world. Nobody wants
• 1:55
  Speaker 1: to live there. I mean, they've got beautiful green trees
• 1:59
  Speaker 1: and subtropical forests and white beaches and fishing and why
• 2:04
  Speaker 1: would you want to live there? Okay Trevor, Nice to
• 2:10
  Speaker 1: get your question. Hi, Andrew and Fred. Everything in the
• 2:13
  Speaker 1: universe is born at some point and has a lifespan
• 2:17
  Speaker 1: on Earth at the end of their life. At the
• 2:21
  Speaker 1: end of their life, plants and animals return to the
• 2:24
  Speaker 1: soil from where they came In space, suns and planets
• 2:27
  Speaker 1: live and die and eventually become part of the space
• 2:30
  Speaker 1: around them once more. So could this be true for
• 2:33
  Speaker 1: the entire universe? We think we know that the universe
• 2:37
  Speaker 1: was born in the Big Bang, and that it will
• 2:40
  Speaker 1: probably die at some point in the future. So I'm
• 2:43
  Speaker 1: wondering if, over the eons of time, could the black
• 2:47
  Speaker 1: holes that seem to be at the middle of every
• 2:49
  Speaker 1: galaxy eventually pull everything currently in the universe back into
• 2:54
  Speaker 1: one singularity, at which point we would have another Big
• 2:57
  Speaker 1: Bang and a new universe. Would he bought many thanks
• 3:01
  Speaker 1: for your program. I listened in bed every night and
• 3:03
  Speaker 1: it helps me go off to sleep at least twice
• 3:06
  Speaker 1: a week. I'm glad we can do that for you. Drever.
• 3:12
  Speaker 3: We put him to sleep for it, that's right, and
• 3:15
  Speaker 3: that's something I'm really good at. Boy, I'm sure he
• 3:21
  Speaker 3: didn't mean it that way. I'm sure he didn't know. Look, Trevor,
• 3:27
  Speaker 3: great to talk to you. You have, as you might know,
• 3:30
  Speaker 3: in Port mcquarie a brand new, marvelous science center in
• 3:34
  Speaker 3: the middle of town which is being opened a little
• 3:37
  Speaker 3: bit later in the year. It's on the site of
• 3:40
  Speaker 3: the old observatory there, which I was always very fond
• 3:43
  Speaker 3: of and indeed was its patron, and I think I
• 3:46
  Speaker 3: might be the patron of the new science center as well. Wonderful, brilliant,
• 3:49
  Speaker 3: and so that opens in a couple of months. So
• 3:53
  Speaker 3: make sure you go along and check it out, Trevor,
• 3:55
  Speaker 3: because you're in pop position to do that up there
• 3:59
  Speaker 3: in Port McQuary. And the answer is, well, yes, it's true.
• 4:04
  Speaker 3: Everything seems to have a life cycle. And the theory
• 4:09
  Speaker 3: that you've mentioned that the gravitational pull of everything in
• 4:12
  Speaker 3: the galaxy in the universe might eventually cause the universe
• 4:17
  Speaker 3: to collapse back on itself into another singularity, the gibb.
• 4:23
  Speaker 3: They're gonnab gibb, that's right, the opposite of the Big Bang.
• 4:27
  Speaker 3: That's the name coined by Brian Schmidt before he did
• 4:31
  Speaker 3: his nobelp Ice spinning work. We used to we usually
• 4:35
  Speaker 3: called it the Big Crunch. The idea was that everything
• 4:38
  Speaker 3: would eventually collapse back on itself and would be a
• 4:42
  Speaker 3: big Crunch which may have spawned another Big Bang, and
• 4:46
  Speaker 3: that would be a you know, a new universe being
• 4:49
  Speaker 3: rebuilt born exactly as you've said, Trevor. What basically through
• 4:54
  Speaker 3: that or through cold water onto that argument was Brian
• 4:58
  Speaker 3: himself and the colleagues in the United States so together
• 5:02
  Speaker 3: in nineteen ninety eight discovered that actually the universe, its
• 5:06
  Speaker 3: expansion is not slowing down as you would have had
• 5:09
  Speaker 3: to have if you're going to get a good nab
• 5:11
  Speaker 3: GiB or a big crunch. It's accelerating. So the accelerated
• 5:17
  Speaker 3: expansion of the universe really knocks that on the head.
• 5:21
  Speaker 3: And it also tells us that there is something in
• 5:24
  Speaker 3: the universe that is causing space to accelerate, not just expand,
• 5:30
  Speaker 3: but to expand ever more rapidly. And we call that
• 5:33
  Speaker 3: dark energy. And if you thought dark matter was a mystery,
• 5:37
  Speaker 3: wait till you get to dark energy. We really have
• 5:40
  Speaker 3: very little idea of what it is. It's some sort
• 5:42
  Speaker 3: of vacuum energy. It's some kind of energy of space itself.
• 5:46
  Speaker 3: The more space you get, the more energy you get,
• 5:49
  Speaker 3: and it's causing the universe to expand ever more rapidly.
• 5:53
  Speaker 3: So it looks as though the universe may never have
• 5:57
  Speaker 3: an ending if it just keeps on going and expanding,
• 6:02
  Speaker 3: unless the thing that some other people have hypothesized that
• 6:07
  Speaker 3: one day space itself might just get so stretched by
• 6:13
  Speaker 3: the accelerating expansion that it fractures and you get something
• 6:17
  Speaker 3: called the big rip. And the big Rip is another
• 6:19
  Speaker 3: possible end to the universe when space itself just gets
• 6:23
  Speaker 3: ripped apart.
• 6:24
  Speaker 1: Well, yeah, that seems to be the popular opinion at
• 6:29
  Speaker 1: the moment, doesn't.
• 6:29
  Speaker 3: It It is. Yeah, well, the big rip is a
• 6:33
  Speaker 3: little bit hypothesized, but certainly the accelerated expansion is taken
• 6:38
  Speaker 3: as fat. Now since that discovery was made, it's not
• 6:41
  Speaker 3: just the observations of supernova exploding stars that were what
• 6:45
  Speaker 3: allowed that discovery to be made, but many other observations
• 6:49
  Speaker 3: of the state of the universe. If I can put
• 6:51
  Speaker 3: it that way, imply that the big that the dark
• 6:55
  Speaker 3: energy is there.
• 6:57
  Speaker 1: Okay, there you are. So in regard to his question
• 7:02
  Speaker 1: about life cycles in the universe, we are seeing that
• 7:07
  Speaker 1: and we I mean, eventually everything's going to finish in
• 7:13
  Speaker 1: terms of the physical forms, the stars, the galaxies, the
• 7:17
  Speaker 1: black holes themselves may well billions upon billions of years
• 7:22
  Speaker 1: evaporate because they are burning their energy. They're getting weaker
• 7:27
  Speaker 1: over time. It's just a very slow process. But the
• 7:31
  Speaker 1: universe as a whole, that's a different question.
• 7:33
  Speaker 3: I suppose, Yes, that's right. You know, so you're right
• 7:40
  Speaker 3: in that the kind of life and death processes that
• 7:44
  Speaker 3: involve stars and stars are the you know, the main
• 7:48
  Speaker 3: kind of matter in the universe apart from dark matter.
• 7:51
  Speaker 3: They're the way we detect matter in the universe. Anyway,
• 7:54
  Speaker 3: that life and death cycle is well known. And when
• 7:58
  Speaker 3: you look forward some hundred billion years or so, all
• 8:02
  Speaker 3: you've got is dark remnants, remnants black dwarfs with them,
• 8:06
  Speaker 3: remnants of stars, and probably a lot of black holes
• 8:09
  Speaker 3: as well. So everything's kind of dead and dormant. There's
• 8:12
  Speaker 3: no black holes are not feeding because there's nothing for
• 8:15
  Speaker 3: them to feed on, and so it becomes a very
• 8:17
  Speaker 3: boring universe. Indeed, and maybe a big rip would be
• 8:21
  Speaker 3: the fitting end for a universe like that.
• 8:23
  Speaker 1: And once everything's expanded beyond our capacity to see them,
• 8:28
  Speaker 1: no astronomers, Fred, damn, Yeah, you'll have to retire then.
• 8:37
  Speaker 3: Yeah, I'm just a dying greed. That's terrible.
• 8:41
  Speaker 1: How many gazillion years away is that?
• 8:43
  Speaker 3: Yes? Anyway, yeah quite a few.
• 8:46
  Speaker 1: We're in no rush. Thank you, Trevor. I hope you're
• 8:49
  Speaker 1: enjoying Port McQuary. Lovely, lovely place it is. Let's go
• 8:54
  Speaker 1: to our next question. This one comes from David.
• 8:58
  Speaker 5: Hey Fred and Andrews. David from Singing Texas, just sitting
• 9:04
  Speaker 5: here in bed thinking about black holes and questioning how
• 9:09
  Speaker 5: is it that black holes grow like want? A black
• 9:14
  Speaker 5: hole over time becomes a super massive black hole that
• 9:20
  Speaker 5: was it that they grow? Because if they're gravity can
• 9:22
  Speaker 5: sucking even late and they're supposed to be infinitely dense,
• 9:27
  Speaker 5: why don't they just stay the same size and just
• 9:29
  Speaker 5: continue eating? Why do they Why do they grow as
• 9:33
  Speaker 5: they eat? Like? What is it that's growing? Thank you guys,
• 9:37
  Speaker 5: love the podcast.
• 9:39
  Speaker 1: Thank you David. It's it's it's a tough nut to crack,
• 9:42
  Speaker 1: isn't it the old black hole? What? What's it eating?
• 9:45
  Speaker 1: How is it getting bigger? They eat each other or
• 9:48
  Speaker 1: they merge and we know that, but yeah, it's a
• 9:52
  Speaker 1: good question. Why don't they just stay the same size?
• 9:54
  Speaker 1: Why do they keep growing?
• 9:55
  Speaker 5: What?
• 9:55
  Speaker 1: What is causing that? What? What are they actually eating?
• 9:59
  Speaker 3: Well, yes, I think that the issue is not so
• 10:02
  Speaker 3: much what they're eating, because we do know that the
• 10:05
  Speaker 3: gobble of anything that's well basically yes, that's right, Not
• 10:10
  Speaker 3: that they go chasing around the universe to find them.
• 10:14
  Speaker 1: Now they need a trapdoor spider, aren't they.
• 10:16
  Speaker 3: It's yes, yes, or indeed a huntsman spider which also yes,
• 10:20
  Speaker 3: and just grabs things. But so that all goes into
• 10:25
  Speaker 3: the black hole, All that debris, stars, gas, dust, other
• 10:29
  Speaker 3: black holes occasionally all goes into the black hole apart
• 10:33
  Speaker 3: from what's shot out, by the way, by the magnetic
• 10:36
  Speaker 3: fields that give you the jets from an active black hole.
• 10:40
  Speaker 3: But the questions really about why doesn't it grow? Now,
• 10:46
  Speaker 3: it doesn't grow in physical dimensions because by definition, a
• 10:50
  Speaker 3: black hole has zero dimensions. It's a singularity, and so
• 10:56
  Speaker 3: its volume is zero. And we know, I think the
• 11:02
  Speaker 3: way we define a black hole is a point in
• 11:04
  Speaker 3: space of infinite density. So it's density is infinite. Now
• 11:09
  Speaker 3: density is mass over volume. Density is infinite because volume
• 11:14
  Speaker 3: is zero and you're dividing something by zero, which produces infinity.
• 11:20
  Speaker 3: That's the density. But that says nothing at all about
• 11:23
  Speaker 3: its mass. And the mass is what changes. So it's
• 11:27
  Speaker 3: not the size of the black hole, but it's mass
• 11:29
  Speaker 3: that changes. They do grow, but they grow in mass,
• 11:33
  Speaker 3: and that's how we get the super massive black holes
• 11:35
  Speaker 3: because they've been at it for a long time and
• 11:38
  Speaker 3: creating this material. So yeah, so they do grow. They
• 11:42
  Speaker 3: don't get physically bigger, their mass gets bigger, and in turn,
• 11:46
  Speaker 3: the event horizon gets bigger. So that's the bit that
• 11:50
  Speaker 3: delineates where you can't penetrate. Nothing can penetrate out of it.
• 11:55
  Speaker 3: Not even light is the event horizon, and so as
• 11:59
  Speaker 3: a black hole gets big, it's event horizon grows and
• 12:01
  Speaker 3: grows and grows, even though it's still a singularity, but
• 12:05
  Speaker 3: its mass is going up and that causes the event
• 12:08
  Speaker 3: horizon to swell. Okay, yep.
• 12:11
  Speaker 1: And if you can do this experiment at home by
• 12:13
  Speaker 1: eating one hundred doughnuts exactly, the same thing increases.
• 12:20
  Speaker 3: It does, but usually your volume does as well. You
• 12:23
  Speaker 3: do that, Yes, I will do that any further.
• 12:29
  Speaker 1: Okay, fair enough. So what was the answer to the question.
• 12:33
  Speaker 1: The mass increases, but the black hole don't. The dimensions don't.
• 12:40
  Speaker 1: The dimensions of the event horizon do because they're linked
• 12:43
  Speaker 1: to the mass. So it's the mass that increases.
• 12:46
  Speaker 3: Okay, there you go, David.
• 12:48
  Speaker 1: You can go to sleep now sitting in bed trying
• 12:52
  Speaker 1: to figure out black holes. That's that's self inflicted torture.
• 12:55
  Speaker 1: That is that this at least somebody's trying to figure
• 12:59
  Speaker 1: it out. A lot of people trying to figure out. David,
• 13:02
  Speaker 1: Thanks for the thanks for the question. Lovely to hear
• 13:05
  Speaker 1: from you, and Hopaul as well.
• 13:08
  Speaker 3: In Texas.
• 13:08
  Speaker 1: This is Space Nuts Andrew Dunkley here with Professor Fred Watson.
• 13:16
  Speaker 5: Three Space Nuts.
• 13:21
  Speaker 1: Now, Fred, we've got another audio question. This one a
• 13:24
  Speaker 1: little closer to home from Mokey.
• 13:26
  Speaker 4: Hey, Brad, Hey, Andrew, This is Nike from Illinois. Again.
• 13:29
  Speaker 4: I was wondering about space junk. There's a lot of
• 13:33
  Speaker 4: it around Earth right now, and there's only going to
• 13:36
  Speaker 4: be more, you know, come the future and if nothing
• 13:39
  Speaker 4: ever gets done of it. I was wondering I's somewhere
• 13:42
  Speaker 4: and maybe the distant future, all of this space junk
• 13:46
  Speaker 4: would kind of coalesce and the Earth would maybe have
• 13:49
  Speaker 4: its own artificial ring system, kind of like Saturn, but
• 13:53
  Speaker 4: just instead of ice, rock and dust, it's junk. Yeah,
• 13:58
  Speaker 4: just something that kind of cross my main I wonder
• 14:00
  Speaker 4: what you go to think about it?
• 14:02
  Speaker 3: Thanks, guys.
• 14:02
  Speaker 1: Yeah, that's a really interesting sort And I mean, it's
• 14:06
  Speaker 1: out there. Some of it re enters, some of it
• 14:08
  Speaker 1: burns up, some of it's just floating around out there,
• 14:12
  Speaker 1: and it can be as small as a fleck of paint,
• 14:16
  Speaker 1: but it's moving at a rapid speed, and it has
• 14:18
  Speaker 1: had a few close calls and caused a few problems
• 14:21
  Speaker 1: from time to time in terms of dealing with it.
• 14:24
  Speaker 1: It's every nation's responsibility to look after their own stuff,
• 14:29
  Speaker 1: isn't it, or every entities responsibility although that's only a
• 14:34
  Speaker 1: recent law and we're still you know, grappling with it.
• 14:38
  Speaker 1: We've been experimenting with ways to collect this stuff. But
• 14:41
  Speaker 1: I think there's just too much stuff.
• 14:44
  Speaker 3: Well it's not that there's too much, it's that it's
• 14:47
  Speaker 3: kind of spread all over the place. Yeah, and space
• 14:50
  Speaker 3: is big, as Douglas Atoms puts it. But you know,
• 14:56
  Speaker 3: just thinking about this his point, and in a way,
• 14:59
  Speaker 3: there are already has a ring of debris because it's
• 15:04
  Speaker 3: around it's the geostationary satellite ring. That's where there are
• 15:09
  Speaker 3: very large numbers of satellites. I don't know the total
• 15:11
  Speaker 3: number that's in geostationary orbit, but it's quite large. And
• 15:15
  Speaker 3: beyond that there is what they call the graveyard orbit,
• 15:18
  Speaker 3: where GET stationary satellites have to be pushed out into
• 15:22
  Speaker 3: a graveyard orbit once their useful life is over. And
• 15:28
  Speaker 3: it's a fairly stable orbit, one that's not you know,
• 15:32
  Speaker 3: being perturbed so that it will so that a satellite
• 15:36
  Speaker 3: will collide you with another satellite. So so we've already
• 15:40
  Speaker 3: got a ring, the GET stationary satellite ring. Most of
• 15:44
  Speaker 3: them are in one piece because we use them every
• 15:47
  Speaker 3: day for communications. In terms of the lower orbit and
• 15:54
  Speaker 3: mid Earth orbits spacecraft. Yes, there is a lot of
• 16:00
  Speaker 3: debris around because these spacecraft collide with one another from
• 16:04
  Speaker 3: time to time. It's, as you said, flex of paint,
• 16:08
  Speaker 3: everything upwards from flex of paint. And it just begs
• 16:13
  Speaker 3: the question whether at some time in the future they
• 16:18
  Speaker 3: would actually coalesce into a ring, that the orbits of
• 16:22
  Speaker 3: these things would flatten out, so that rather than having
• 16:26
  Speaker 3: orbits that all inclinations are going all around the Earth,
• 16:28
  Speaker 3: so the Earth is like inside a shell of space.
• 16:32
  Speaker 3: Debry whether it would flatten out into a ring, and
• 16:36
  Speaker 3: I suspect it would in the very long term that
• 16:38
  Speaker 3: you would have with a ring of space junk. However,
• 16:42
  Speaker 3: we're a long way from that. I think the thing
• 16:43
  Speaker 3: about the lower orbit stuff is that that will burn
• 16:47
  Speaker 3: up before it before we ever get to that stage.
• 16:51
  Speaker 3: So it did you know they'll re enter and burn
• 16:54
  Speaker 3: up and cause pollution in the upper atmosphere, which we
• 16:57
  Speaker 3: now know is happening, detecting aliminium and other stuff like
• 17:01
  Speaker 3: that in the upper atmosphere that comes from re entering spacecraft,
• 17:05
  Speaker 3: But that's a vapor rather than a solid entity like
• 17:09
  Speaker 3: a ring. So I think the answer to your question,
• 17:12
  Speaker 3: Mike he is. We've got a ring already, and most
• 17:14
  Speaker 3: of it it's useful, but some of it's not.
• 17:17
  Speaker 1: No, and long term, maybe some of the stuff that
• 17:20
  Speaker 1: is orbiting by default and won't return to Earth may
• 17:23
  Speaker 1: well become a ring. Yes, that's right, assuming we don't
• 17:29
  Speaker 1: find a good way to clean it up in the meantime.
• 17:31
  Speaker 3: Yeah, I mean we could. You know, there's many projects
• 17:34
  Speaker 3: that have been launched to and some have actually been
• 17:36
  Speaker 3: launched into space, but they're you know, ways that you
• 17:39
  Speaker 3: can either throw a grappling island or a net or
• 17:42
  Speaker 3: something at a piece of space debris and slowly down
• 17:44
  Speaker 3: so it does re enter the atmosphere. That's becoming or
• 17:50
  Speaker 3: maybe it's too early to say it's becoming, but it
• 17:54
  Speaker 3: will become a standard procedure. I think, especially for large
• 17:57
  Speaker 3: pieces of debris that if they re entered in a
• 18:00
  Speaker 3: noncontrolled fashion, they could do damage. I think that's going
• 18:05
  Speaker 3: to be the norm. It's also the norm, as you
• 18:07
  Speaker 3: hinted at, that any any nation that launches anything into space,
• 18:14
  Speaker 3: or any organization that launches anything to space, has to
• 18:17
  Speaker 3: demonstrate that they've built in a way of deorbiting it.
• 18:22
  Speaker 3: In other words, they can get rid of it and
• 18:24
  Speaker 3: that I think has been in place for quite a
• 18:25
  Speaker 3: few years now, so in the long term we're in
• 18:29
  Speaker 3: better shape than we are at the moment. Hopefully the
• 18:32
  Speaker 3: space junk situation will improve.
• 18:36
  Speaker 5: Indeed.
• 18:36
  Speaker 1: All right, great question, Mikey, Thank you very much. One
• 18:40
  Speaker 1: more question, possibly two. I don't know how we'll go
• 18:43
  Speaker 1: for time, but we've got a question without notice from
• 18:46
  Speaker 1: YouTube I assume, or something to that effect. But this
• 18:50
  Speaker 1: one coming from Ian who is in Cambridge. Hi, Andrew
• 18:54
  Speaker 1: and Fred. I asked a question last year about not
• 18:56
  Speaker 1: being able to see the Milky Way. I still haven't
• 19:00
  Speaker 1: seen the Milky Way here in the UK. However, there
• 19:02
  Speaker 1: are some photos on social media showing the Milky Way
• 19:06
  Speaker 1: high in the sky above Stonehenge. Are these genuine? I
• 19:11
  Speaker 1: would have thought from the UK perspective the Milky Way
• 19:14
  Speaker 1: would be low in the southern sky. Thanks for the
• 19:17
  Speaker 1: great podcast.
• 19:18
  Speaker 3: Ian.
• 19:20
  Speaker 1: Well you're from the UK, Fred, so you know the
• 19:23
  Speaker 1: lie of the land and the lie of the stars,
• 19:27
  Speaker 1: or the lie of the stars in perspective to the
• 19:31
  Speaker 1: positioning of the northern hemisphere. Can you see the Milky
• 19:35
  Speaker 1: Way from the UK even on a clear.
• 19:37
  Speaker 3: Night you can, and the Milky Way it goes all
• 19:44
  Speaker 3: the way around the sky, so everywhere on Earth we'll
• 19:47
  Speaker 3: see it at some point. The best time to look
• 19:53
  Speaker 3: from those two kind of good times, I suppose from
• 19:56
  Speaker 3: the northern hemisphere is the midd of winter, because the
• 20:01
  Speaker 3: Milky Way stretches right up, goes past to Ryan, goes
• 20:04
  Speaker 3: through Cassiopia, all those constellations. It goes right basically from
• 20:07
  Speaker 3: north to south across the sky. It's in the middle
• 20:14
  Speaker 3: of the year as well. You can see it quite well.
• 20:17
  Speaker 3: I think what Ian is really meaning though, is the
• 20:22
  Speaker 3: center of our Milky Way galaxy, which is the brightest
• 20:25
  Speaker 3: part of the Milky Way, which goes directly overhead here
• 20:28
  Speaker 3: in Australia, but it only skirts the southern horizon in
• 20:35
  Speaker 3: the northern Hemisphere, certainly at the latitude of the UK,
• 20:38
  Speaker 3: so you can see it. I've observed Sagittarius, which is
• 20:41
  Speaker 3: where the galactic center is. I've observed it from Scotland actually,
• 20:46
  Speaker 3: but it's been very very low down in the sky.
• 20:49
  Speaker 3: Good to see because there's pollution and light pollution and
• 20:52
  Speaker 3: everything there. But the problem but the Milky Way itself
• 20:55
  Speaker 3: goes all the way around the sky and is visible,
• 20:57
  Speaker 3: as I said, best in midwinter in fact, in the
• 21:00
  Speaker 3: middle of summer, it's to date, there's too much daylight,
• 21:04
  Speaker 3: the nights last too long or the days last too long.
• 21:07
  Speaker 3: So but the main thing is to be away from
• 21:11
  Speaker 3: light pollution. And that's because the Milky Way, has seen
• 21:15
  Speaker 3: from the northern hemisphere, is fainter than it is in
• 21:17
  Speaker 3: the south. Because we've got the galactic center where it
• 21:20
  Speaker 3: is richest milky ways, it is pricest. So you are
• 21:24
  Speaker 3: right in that the Milky Way is fainter in the
• 21:26
  Speaker 3: northern hemisphere, but it's still visible and on a dark
• 21:29
  Speaker 3: night away from city lights, is pretty impressive. So that
• 21:33
  Speaker 3: picture of the other Stonehenge would not necessarily be a fake.
• 21:37
  Speaker 1: Okay, I've looked at a few here, and one of
• 21:41
  Speaker 1: them referring to a photograph on a summer night at
• 21:44
  Speaker 1: Stonehenge and it's showing the Milky Way vertical. How does
• 21:49
  Speaker 1: that say under you?
• 21:50
  Speaker 3: That will be right. It will be vertical as it
• 21:53
  Speaker 3: is in winter as well and midwinter night.
• 21:56
  Speaker 1: Okay, you have it ian, so it's probably genuine. There'd
• 22:00
  Speaker 1: be a lot of others out there that have been
• 22:02
  Speaker 1: constructed from superimposed photographs, but yes, it is a possibility,
• 22:09
  Speaker 1: and yeah, thanks for the question one quick one without
• 22:11
  Speaker 1: notice fread comes from I think TDJ has a message
• 22:17
  Speaker 1: just before it's just got home from work. Do have
• 22:19
  Speaker 1: a question? Does the early spring effect viewing of the
• 22:22
  Speaker 1: skies in any way?
• 22:25
  Speaker 3: Yeah? Only weather wise. You know, we've got probably warmer
• 22:30
  Speaker 3: weather that should produced drier atmospheres and give you a
• 22:37
  Speaker 3: better view. I noticed, I've just I've got a bit
• 22:40
  Speaker 3: of a weather station on the wall. I noticed the
• 22:43
  Speaker 3: pressures low. Actually at the moment it's much warmer than
• 22:46
  Speaker 3: it should be in winter. Yeah. The air though, is
• 22:50
  Speaker 3: very dry compared with what it normally is like, and
• 22:52
  Speaker 3: that normally gives you better viewing, less twinkling in the
• 22:57
  Speaker 3: sky because the amount of turbul it's in the atmosphere
• 23:00
  Speaker 3: settles down when the when the air is dry.
• 23:03
  Speaker 1: How about that? There you go to DJ thanks for
• 23:06
  Speaker 1: the question at the last minute, and he's in Sydney
• 23:08
  Speaker 1: as well for it probably probably cross the road from you,
• 23:13
  Speaker 1: indeed wrestling goannas.
• 23:16
  Speaker 3: Yes, that's right.
• 23:18
  Speaker 1: And a reminder to anybody who wants to send in
• 23:21
  Speaker 1: a question to us to go to our website because
• 23:23
  Speaker 1: that's where you send them and you can do text questions.
• 23:27
  Speaker 1: Just click on the a m a tab or link
• 23:30
  Speaker 1: at the top. You can also send audio questions that
• 23:33
  Speaker 1: way or on the right hand side where you would
• 23:36
  Speaker 1: usually be send us your voice message, and it's not
• 23:40
  Speaker 1: there today. I don't know what happened to that. Probably
• 23:43
  Speaker 1: my computer doing silly bugger things like it tends to.
• 23:46
  Speaker 1: But yes, we welcome your questions for our Q and
• 23:49
  Speaker 1: A episodes of Space Nuts. Keep them coming. Thanks for it.
• 23:53
  Speaker 1: As always, it's a great pleasure.
• 23:55
  Speaker 3: Two or two Andrew, we struggled through and we've got
• 23:59
  Speaker 3: some good answers there.
• 24:00
  Speaker 1: Think yeah, I think so. And we made them all
• 24:02
  Speaker 1: up as we went along. We didn't even have to
• 24:05
  Speaker 1: sit down before the show and work out fake answers.
• 24:08
  Speaker 1: We made them up as we went along. It was brilliant.
• 24:12
  Speaker 1: We're getting better at this.
• 24:13
  Speaker 3: Thanks for Red.
• 24:14
  Speaker 1: We'll see a zooon. Fred Wat's an astronomer at large.
• 24:19
  Speaker 1: Thanks to here in the studio who sent us one question. Yeah,
• 24:23
  Speaker 1: we can't tell you anything about that at all, Fred,
• 24:26
  Speaker 1: for here, we don't know the answer. Talk to your
• 24:30
  Speaker 1: electricity provider and from me from me Andrew Dunkley. Thanks
• 24:34
  Speaker 1: for your company. We'll see you again soon on another
• 24:36
  Speaker 1: episode of Space Nuts.
• 24:38
  Speaker 6: Bye bye, you'll be listening to the Space Nuts podcast,
• 24:44
  Speaker 6: available at Apple Podcasts, Spotify, iHeartRadio, or your favorite podcast player.
• 24:50
  Speaker 6: You can also stream on demand at bides dot com.
• 24:54
  Speaker 4: This has been another quality podcast production from nights dot com.