Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / Cosmic Comets, Magnetic Pole Puzzles & The Enigma of Time | Q&A

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Cosmic Comets, Magnetic Pole Puzzles & The Enigma of Time | Q&A · Space Nuts: Astronomy Insights & Cosmic Discoveries

• 0:00
  Speaker 1: Hello again, and thank you for joining us on a
• 0:01
  Speaker 1: Q and A edition of Space Nuts. Andrew Duncley here,
• 0:05
  Speaker 1: thanks for your company today. We've got four questions to answer.
• 0:09
  Speaker 1: Actually that usually ends up being ten because people ask
• 0:12
  Speaker 1: multiple questions. I suppose you've got to use your time wisely.
• 0:16
  Speaker 1: But we've got a question about the journey of comets.
• 0:20
  Speaker 1: We've got a question about magnetic pole reversal. We've had
• 0:25
  Speaker 1: that one before, but it was quite a while back.
• 0:28
  Speaker 1: It's worth revisiting. The origin of time has been brought up,
• 0:32
  Speaker 1: and the age of the universe versus galaxies far far away.
• 0:37
  Speaker 1: We'll tackle all of that on this episode of Space.
• 0:40
  Speaker 2: Nuts fifteen in Channel ten nine ignition sequence Space Nuts
• 0:49
  Speaker 2: or three two Space Nurts as the Nights reported Bill's
• 0:56
  Speaker 2: goods and.
• 0:58
  Speaker 1: Joining us to unpack all all of that is Professor
• 1:01
  Speaker 1: Fred What's an astronomer at Large?
• 1:03
  Speaker 3: Hello Fred, Hello Andrew, Nice to see you again.
• 1:07
  Speaker 1: Good to see you too. Haven't changed much since our
• 1:10
  Speaker 1: last laid eyes on you.
• 1:12
  Speaker 3: It's fully funny you should say that look looking good,
• 1:15
  Speaker 3: looking good.
• 1:17
  Speaker 1: Let's do some questions, shall we?
• 1:20
  Speaker 3: Why not more ross blow here so we might as well?
• 1:23
  Speaker 1: Yes, and nice to get a couple of new voices
• 1:27
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• 1:30
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• 1:32
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• 1:35
  Speaker 1: button ama up the top or it's more of a link.
• 1:38
  Speaker 1: And if you've got a device with a microphone you
• 1:41
  Speaker 1: should be able to record a lot. A few people
• 1:42
  Speaker 1: have had issues with it lately, so maybe that's the
• 1:45
  Speaker 1: reason why we're sort of questions. But anyway, we've got
• 1:49
  Speaker 1: a couple. This first one comes from Andrea.
• 1:53
  Speaker 4: Hi, Andrew and Fred. This is Andrea from Wanneroo in Perth,
• 1:57
  Speaker 4: Western Australia. Question is around comets again and how do
• 2:04
  Speaker 4: they How is their you know, pass created and tracked
• 2:11
  Speaker 4: like their elliptical path? Do they all follow us.
• 2:15
  Speaker 1: As similar.
• 2:18
  Speaker 5: Journey or do they create their own as they come through?
• 2:24
  Speaker 5: Thanks has appreciate it and love to show thanks Andrew.
• 2:28
  Speaker 1: Lovely to hear from you, and nice to get a
• 2:32
  Speaker 1: new voice into the into the program. And want a
• 2:36
  Speaker 1: roo I think that's an Aboriginal word for wanting a
• 2:40
  Speaker 1: pat kangaroo. No, I wouldn't have got there. I couldn't
• 2:49
  Speaker 1: it myself. So Andrea's question is all about the journey
• 2:53
  Speaker 1: of comets. Do they kind of all do the same thing,
• 2:55
  Speaker 1: or do they figure it out for themselves or are
• 2:57
  Speaker 1: they you know, they're real loaners and don't want to
• 3:00
  Speaker 1: do what everyone else is doing.
• 3:03
  Speaker 3: So it is a great question, Andrea, and it's actually
• 3:06
  Speaker 3: got a little bit more to it than perhaps people
• 3:08
  Speaker 3: might think, because comets, as you know, they make their
• 3:14
  Speaker 3: appearance from time to time, and individual comets, some of
• 3:18
  Speaker 3: them fairly regularly. But the story starts much much further
• 3:24
  Speaker 3: away from the Sun than any of the planets, way
• 3:28
  Speaker 3: way beyond the trans Neptunian objects. Those are icy asteroids
• 3:33
  Speaker 3: out there where. We've got this hypothesized, never yet observed,
• 3:39
  Speaker 3: but well established, I think, is the best way to
• 3:41
  Speaker 3: call it, shell of cometary debris, And by that I
• 3:47
  Speaker 3: mean chunks of ice basically, which are the leftovers from
• 3:52
  Speaker 3: the gas cloud from which the Solar system formed. So
• 3:56
  Speaker 3: these are ancient blocks of dusty ice.
• 4:01
  Speaker 1: Let's be realistic. It's where the trade's left their junk
• 4:05
  Speaker 1: after they finished building the solar sits.
• 4:09
  Speaker 3: That's what it is, all right, Yeah, Well, the hypothesized
• 4:12
  Speaker 3: celestial trade is it's the debris. It's the leftover stuff
• 4:20
  Speaker 3: frozen at very low temperatures with the dusty you know,
• 4:25
  Speaker 3: dusty contents as well. So the thinking is that shell
• 4:30
  Speaker 3: of comets when when our sun as it chundles its
• 4:34
  Speaker 3: way around the galaxy, it passes nearby other stars and
• 4:38
  Speaker 3: other objects which gravitationally disturb the cloud. And so from
• 4:43
  Speaker 3: time to time you might get quite large numbers of
• 4:47
  Speaker 3: these cometary bodies being disturbed from where they lie and
• 4:52
  Speaker 3: plunging down into the Fini Solar System. So there's probably
• 4:56
  Speaker 3: a steady flux of these things coming in, but once
• 4:59
  Speaker 3: in a while, because of gravitational disturbances, you'll get a
• 5:02
  Speaker 3: lot more. And that was actually the subject of a
• 5:04
  Speaker 3: book written by two colleagues of mine in Edinburgh called
• 5:07
  Speaker 3: The Cosmic Serpent, when it worked out that maybe comets
• 5:11
  Speaker 3: had actually had a lot to do with shaping the Earth,
• 5:15
  Speaker 3: but impacts from comets when the Sun passed into the
• 5:19
  Speaker 3: start anyway, here we have comets. So here's a mister
• 5:23
  Speaker 3: comet sitting out there in the big Departner's comet sitting
• 5:27
  Speaker 3: out there in the in the oak cloud and falls
• 5:31
  Speaker 3: in towards the inner Solar System in a path that
• 5:34
  Speaker 3: is almost a straight line, but it's not because it
• 5:37
  Speaker 3: is actually an eclip, sorry, an ellipse. Anything that follows
• 5:42
  Speaker 3: the gravity of an object follows in an elliptical path.
• 5:45
  Speaker 3: It's in an orbit that often takes it round the Sun,
• 5:48
  Speaker 3: and so you get that's when the Sun's radiation starts
• 5:52
  Speaker 3: acting on the ice and you start to see it.
• 5:55
  Speaker 3: So that path is determined just by gravity and the
• 6:00
  Speaker 3: gravitation mechanics and sort of determined, well, what the starting
• 6:03
  Speaker 3: point of that comet is in the Oort Cloud. Often, though,
• 6:11
  Speaker 3: there might be an interaction with the gravity of some
• 6:15
  Speaker 3: of the planets in the Inner Solar System, most especially Jupiter,
• 6:19
  Speaker 3: and we think that many comets have their orbits modified
• 6:23
  Speaker 3: by the planet Jupiter, so they become much much shorter,
• 6:26
  Speaker 3: because in an orbit to take you out to the
• 6:29
  Speaker 3: Oak Cloud, you're talking about tens, maybe even hundreds of
• 6:32
  Speaker 3: thousands of years. But we find comets with periods much
• 6:36
  Speaker 3: shorter than that, some even as small as four or
• 6:38
  Speaker 3: five years. Anything with a period of revolution around the
• 6:42
  Speaker 3: Sun of less than two hundred years is called a
• 6:45
  Speaker 3: short period comet, and that includes comet Halley seventy six years.
• 6:50
  Speaker 3: So that came down from the Oak Cloud a long
• 6:52
  Speaker 3: long time ago, interacted with Jupiter that pushed it into
• 6:57
  Speaker 3: a short period orbit. So their paths being modified all
• 7:01
  Speaker 3: the time by you know, interactions with the planets, and
• 7:05
  Speaker 3: sometimes they're modified in a in a really quite serious way.
• 7:08
  Speaker 3: There's a great question, Andrea, and quite nice to think
• 7:11
  Speaker 3: of it in the terms that you put it. What
• 7:13
  Speaker 3: determines the pass that these objects take. It's all about
• 7:17
  Speaker 3: gravity and where they started off from and whether they've
• 7:20
  Speaker 3: you know, whether they've interacted with planets on the way down.
• 7:24
  Speaker 1: You did mention the Oord Claud. They also come from
• 7:27
  Speaker 1: the Kuiper Belt, don't they.
• 7:29
  Speaker 3: The Kuiper Belts are much nearer than the York Cloud,
• 7:34
  Speaker 3: and that there are one or two objects because the
• 7:37
  Speaker 3: Caiper Belt they're pretty icy out there as well, you
• 7:41
  Speaker 3: know that. But there might be rocky objects with a
• 7:44
  Speaker 3: coating of ice, a bit like we think Plutoy's rocky core,
• 7:49
  Speaker 3: slushy ocean over the top ice icy crust, whereas the
• 7:54
  Speaker 3: comets don't have crusts, they're just chunks of ice. And
• 7:58
  Speaker 3: I might mention the Ork Cloud was postulated by a
• 8:01
  Speaker 3: very well known Dutch astronomer, Jan Ort I think in
• 8:06
  Speaker 3: the nineteen fifties was when he said comets must come
• 8:09
  Speaker 3: from a sort of reservoir somewhere, a cloud of comets.
• 8:12
  Speaker 3: And the reason why he postulated that it was spherical
• 8:15
  Speaker 3: aspherical shell is that comets when they come in from
• 8:18
  Speaker 3: the Oak Cloud come in at all different angles. They
• 8:20
  Speaker 3: don't just sit in the plane of the Solar System.
• 8:24
  Speaker 1: Yeah. Well, we haven't seen it though, have we the
• 8:26
  Speaker 1: Ork Cloud? Oh no, it doesn't, so it's still theoretical
• 8:30
  Speaker 1: or we've got enough evidence to know. I think it's
• 8:33
  Speaker 1: the plane at nine.
• 8:36
  Speaker 3: I think there's more evidence for comets for Oak Cloud
• 8:39
  Speaker 3: than for planet nine. You're right, though, I mean the
• 8:42
  Speaker 3: problem is these objects are small. They are typically a
• 8:45
  Speaker 3: few kilometers across, and they're you know, they're light Almost
• 8:49
  Speaker 3: a light year away. Is the distance of the Oak Cloud.
• 8:52
  Speaker 3: It's a long, long way out. It's way way beyond
• 8:55
  Speaker 3: where Voyager one is now at twenty light at twenty
• 8:59
  Speaker 3: three light hours away. It's much much further than that.
• 9:03
  Speaker 3: And so you're not ever going to be able to
• 9:05
  Speaker 3: see individual objects in the York Cloud with our telescopes.
• 9:10
  Speaker 3: But the inferences and all the evidence supports the existence
• 9:14
  Speaker 3: of this cloud.
• 9:15
  Speaker 1: Okay, thank you, Andrew. Fabulous question, and we learn a
• 9:20
  Speaker 1: little bit more about commets. O next question comes from
• 9:23
  Speaker 1: Michael in Canada. Apologies Fred and Andrew. I do not
• 9:26
  Speaker 1: have a dark matter or black hole question at this time,
• 9:29
  Speaker 1: but perhaps this question still might be acceptable. I understand
• 9:33
  Speaker 1: that Earth is somewhat overdue for a magnetic pole reversal,
• 9:37
  Speaker 1: and that this is also not something immediate when it
• 9:41
  Speaker 1: does occur. How likely is it that there might be
• 9:45
  Speaker 1: some extraordinary negative effects on satellites in low Earth orbit?
• 9:50
  Speaker 1: Thank you Fred and Andrew, and thank you Hugh in
• 9:52
  Speaker 1: the studio for keeping these two in line every show. Yes, yes,
• 9:56
  Speaker 1: he's conspicuous by his absence, is Hugh very busy man? Though,
• 10:02
  Speaker 1: let's see, all right, negative effect on satellites in lower
• 10:07
  Speaker 1: Earth or But if we start seeing that magnetic pole reversal,
• 10:12
  Speaker 1: I suppose we should address the fact that it doesn't
• 10:14
  Speaker 1: just happen like a light switch.
• 10:16
  Speaker 3: That's certainly true. Yes, so the evidence for rehear not
• 10:21
  Speaker 3: rehearsals reversals. They probably have to rehearse it as well.
• 10:25
  Speaker 3: But the evidence for magnetic poor reversal comes from what
• 10:31
  Speaker 3: we know from principally rocks deep under the ocean. Ocean
• 10:36
  Speaker 3: bed rocks which have the grains of silicates. They're aligned
• 10:44
  Speaker 3: in a way that you can trace the aarth magnetic history.
• 10:47
  Speaker 3: And so the thinking is, I think this is still
• 10:51
  Speaker 3: the sort of number that people talk about, something like
• 10:54
  Speaker 3: three reversals of the magnetic the arth magnetism every million years. Now,
• 11:03
  Speaker 3: that's fairly fairly slow compared with an object like the sum,
• 11:10
  Speaker 3: which we think reverses its magnetic poles every twenty two years.
• 11:15
  Speaker 3: So that's you know, that poot polary reversal, which we
• 11:20
  Speaker 3: can sense from looking at sunspots, is much faster. So
• 11:27
  Speaker 3: the process seems to be on Earth that you've got
• 11:31
  Speaker 3: a gradual weakening of the magnetic field, which when it
• 11:35
  Speaker 3: reappears is the other way around. And we think it's
• 11:39
  Speaker 3: due to the interaction between the Earth's two cores. We've
• 11:43
  Speaker 3: got a solid metallic core with a liquid metallic core
• 11:47
  Speaker 3: on the outside, and the two are rotating with respect
• 11:50
  Speaker 3: to one another. So it's a dynamo effect which generates
• 11:53
  Speaker 3: a magnetic field. So we're talking about time scales for
• 11:58
  Speaker 3: the reversal of thousands of years. It's not something as
• 12:03
  Speaker 3: you said, it doesn't switch on overnight. The process takes
• 12:06
  Speaker 3: a long long time, and it's i mean, there will
• 12:10
  Speaker 3: be some spacecraft that will last for thousands of years
• 12:13
  Speaker 3: because they're high enough that their orbits are not threatened
• 12:17
  Speaker 3: by decay. However, I think the effects of the reversal
• 12:23
  Speaker 3: of magnetic polarity are going to be negligible compared with
• 12:27
  Speaker 3: the magnetic effects that you get from the Sun's the
• 12:32
  Speaker 3: solar wind and the stream of seb atomic particles that
• 12:35
  Speaker 3: comes from the Sun. I think that's the dominant magnetic
• 12:38
  Speaker 3: force for satellites. They're beyond the protective magnetosphere that the
• 12:47
  Speaker 3: Earth provides. That reversal will produce a reduction in the magnetosphere,
• 12:53
  Speaker 3: and that itself might allow spacecraft to be bombarded more
• 12:59
  Speaker 3: by solar wind particles. So there could be an effect
• 13:02
  Speaker 3: caused by the weakening of the ospognetic field as reversal
• 13:06
  Speaker 3: takes place.
• 13:07
  Speaker 1: Okay, so there is something to that. Yeah, I issueably right,
• 13:11
  Speaker 1: because one of the big dangers we face these days
• 13:14
  Speaker 1: is a direct hit from a coronal mass ejection that
• 13:20
  Speaker 1: could affect our electronics, electro fries, the electronics, and I
• 13:26
  Speaker 1: know emergency services in this country and probably in other
• 13:30
  Speaker 1: parts of the world are building that scenario into their
• 13:35
  Speaker 1: emergency response systems. It's unpredictable. I mean it's it could happen.
• 13:46
  Speaker 1: It may never happen, but it has happened in the past.
• 13:49
  Speaker 1: In the early years of the telegraph, there was one
• 13:52
  Speaker 1: particular case where the system was suffering and suffered a
• 13:56
  Speaker 1: direct hit and no one knew what was going on.
• 14:00
  Speaker 1: It was just a real shock.
• 14:03
  Speaker 3: One person did, and that was an astronomer called Carrington.
• 14:06
  Speaker 1: I can't remember. He's the Carrington event.
• 14:08
  Speaker 3: Yeah, I can't remember his first name. His picture is
• 14:10
  Speaker 3: actually on the current issue of Astronomy and Geophysics, which
• 14:13
  Speaker 3: is the the Royal Astronomical Society's journal, and there's a
• 14:20
  Speaker 3: picture on the front of it. I haven't read it yet,
• 14:22
  Speaker 3: but it's me. Mister Carrington is the title of the article.
• 14:28
  Speaker 3: I'm just trying to look up his name, Richard Richard
• 14:32
  Speaker 3: Carrington Tugton. Yes, so he observed, sorry, I was going
• 14:37
  Speaker 3: to say, he observed a very bright flare on the
• 14:41
  Speaker 3: sun and then that was followed by all these magnetic
• 14:44
  Speaker 3: effects that you've spoken about. So he recorded that flair.
• 14:48
  Speaker 1: Yeah, September the first, eighteen fifty nine was the Carrington event.
• 14:54
  Speaker 1: So yes, Michael, definitely something to your concerns hopefully never,
• 14:59
  Speaker 1: but they can't write off the possibility. Thanks for your question.
• 15:03
  Speaker 1: This is Space Nuts Andrew Dunkley here with Professor Fred
• 15:07
  Speaker 1: what's an Let's take a little break from the show
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  Speaker 6: I believe that this nation should commit itself we achieving
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• 17:15
  Speaker 1: Next question, Fred comes from a local Indubo, New South Wales.
• 17:19
  Speaker 1: Hello George, I'm not sure if we've met. I hope
• 17:22
  Speaker 1: we do someday if we have it already, If that
• 17:25
  Speaker 1: makes any sense at all, I have a question about
• 17:28
  Speaker 1: the origin of time. Years ago, I read that time
• 17:31
  Speaker 1: emanates from the ceaseless and never ending motion of energy
• 17:36
  Speaker 1: that pervades the entire universe. It's beautifully written, George. If
• 17:40
  Speaker 1: this universal energy were to freeze or even disappear, would
• 17:44
  Speaker 1: time as we know it still exist or would it
• 17:48
  Speaker 1: be in a state of quintessence or maybe even disappear
• 17:51
  Speaker 1: as well. It seems to me that without the motion
• 17:54
  Speaker 1: of energy to bring forth time, there would be no time.
• 17:59
  Speaker 1: The most interesting conundrum, don't you think. Thank you for
• 18:03
  Speaker 1: the interesting podcasts. Thank you, George. Great to hear from
• 18:06
  Speaker 1: a local. This is something we've talked about time and
• 18:12
  Speaker 1: time again for it.
• 18:15
  Speaker 3: Look, it's a very deep thinking local as well, because
• 18:19
  Speaker 3: George is pretty well on the money. I think what
• 18:22
  Speaker 3: you read about a long time ago might not be
• 18:24
  Speaker 3: current thoughts in this field. But time is one of
• 18:29
  Speaker 3: the biggest mysteries that we have, and we really don't
• 18:35
  Speaker 3: understand it how it arises. We know it's a dimension.
• 18:40
  Speaker 3: We know that in the in the relativity world, time
• 18:45
  Speaker 3: is flexible, we know it bends, but when you look
• 18:49
  Speaker 3: at quantum mechanics, it apparently doesn't exist. So it's a
• 18:57
  Speaker 3: very very peculiar thing. And these two that's one of
• 18:59
  Speaker 3: the reasons why the two theories. The theory of relativity
• 19:03
  Speaker 3: and quantum mechanics while they're at loggerheads because they've got
• 19:06
  Speaker 3: fundamental inconsistencies between them. Now I've tried to follow this
• 19:14
  Speaker 3: argument and debate is taking place at the level of
• 19:20
  Speaker 3: quantum mathematics that is far deeper than my capabilities.
• 19:25
  Speaker 1: From my.
• 19:28
  Speaker 3: Fairly what's the word tawdry degree in mathematics that I have,
• 19:34
  Speaker 3: which I only just scraped.
• 19:36
  Speaker 1: It's a better degree in mathematics than mine.
• 19:39
  Speaker 3: Well anyway, yes, it nearly wasn't a degree at all,
• 19:43
  Speaker 3: only the generosity of the Scottish education system let me
• 19:46
  Speaker 3: fail in exam five times and pass it on the
• 19:48
  Speaker 3: sixth attempt.
• 19:50
  Speaker 1: Yes, it sounds like my driver's license.
• 19:53
  Speaker 3: All right, okay, don't remind me never to come driving
• 19:56
  Speaker 3: with you anyway, I hang have it eventually. Yeah, so
• 20:00
  Speaker 3: that the mathematics that you know, the quantum, particularly quantum mechanics,
• 20:06
  Speaker 3: are quantum theory people theoreticians, that's the word I'm looking for.
• 20:13
  Speaker 3: The mathematics that they use are very very abstruse and
• 20:18
  Speaker 3: obscure to the likes of me. I could probably use
• 20:21
  Speaker 3: the words like Hilbert's pace and things like that, but
• 20:24
  Speaker 3: that's all. Now what I read though, is really interesting
• 20:30
  Speaker 3: that you know it was actually Einstein who said times
• 20:34
  Speaker 3: and illusion. In fact, the quote comes from a letter
• 20:41
  Speaker 3: he wrote to the widow of a friend, a close
• 20:45
  Speaker 3: friend of his, who died, And what he said in
• 20:48
  Speaker 3: that letter was to those of us who believe in physics,
• 20:54
  Speaker 3: we know that the concepts of past, present, and future
• 20:59
  Speaker 3: are only a stubbornly persistent illusion. And he said that
• 21:04
  Speaker 3: because relativity suggests that all of time exists, you know
• 21:09
  Speaker 3: that it's that it's all there, and we see it
• 21:12
  Speaker 3: as an illusion, We see it stepping from one moment
• 21:15
  Speaker 3: to the next. But actually what we're doing is we're
• 21:19
  Speaker 3: just plowing through something that exists in its entirety, which
• 21:23
  Speaker 3: sort of casts all sorts of interesting questions about free
• 21:26
  Speaker 3: will and things of that sort. If if if what's
• 21:30
  Speaker 3: going to happen is already predetermined, what happened to free will?
• 21:36
  Speaker 3: But quantum physics, so I think the quantum theoreticians they
• 21:43
  Speaker 3: don't need time at all in their deliberations. And so
• 21:47
  Speaker 3: what's I think emerging from this is that you've got
• 21:53
  Speaker 3: these two different theories that suggest, and this is the
• 21:58
  Speaker 3: language that they're using, that time actually doesn't exist, that
• 22:01
  Speaker 3: time simply does not exist, and what we see as
• 22:04
  Speaker 3: time actually emerges from quantum entanglement. Now, you and I
• 22:10
  Speaker 3: have talked about quantum entanglement a lot, because it's something
• 22:13
  Speaker 3: that space nuts listeners like talking about and I do too,
• 22:17
  Speaker 3: even though it's not that straightforward to understand. But it's
• 22:22
  Speaker 3: basically how you can if you've got two quantum particles
• 22:26
  Speaker 3: in a state of superposition, which means that you you know,
• 22:30
  Speaker 3: things like their position and their state are not determined
• 22:36
  Speaker 3: until you observe them. If you've got two particles that
• 22:40
  Speaker 3: come together in this entangled means, then they retain this
• 22:47
  Speaker 3: what Einstein called spooky connection at a distance. They retain
• 22:51
  Speaker 3: that in some weird way. How time might emerge from that,
• 22:55
  Speaker 3: or the illusion of time might emerge from that, I
• 22:57
  Speaker 3: have no idea, but it is something that is very
• 23:02
  Speaker 3: much ongoing basically new physics ideas. Now, how do you
• 23:07
  Speaker 3: probe that? How do you find out if these ideas
• 23:09
  Speaker 3: are anything like the truth. Well, it's by looking for
• 23:14
  Speaker 3: holes in relativity. For example, we test relativity all the time.
• 23:18
  Speaker 3: It's good to I think the last time I read
• 23:20
  Speaker 3: about it was something like one party in ten to
• 23:22
  Speaker 3: the power eighteen is how accurate it is. So it's
• 23:26
  Speaker 3: a very very robust theory.
• 23:28
  Speaker 1: If you could if somebody keep trying to break it
• 23:30
  Speaker 1: but they can't.
• 23:32
  Speaker 3: Yeah, find if you could break it, then you might
• 23:36
  Speaker 3: see a chink into the new physics that might underlie
• 23:39
  Speaker 3: what we're talking about now. And likewise, with you know,
• 23:44
  Speaker 3: the subatomic particle world, where we're seeing in the Large
• 23:47
  Speaker 3: Hadron Collider, we're seeing we are seeing new particles. A
• 23:51
  Speaker 3: new one was discovered not that long ago, but it's
• 23:54
  Speaker 3: one that is not sort of revealing any cracks in
• 23:57
  Speaker 3: our understanding of the particle world. Supersymmetry was the buzzword
• 24:04
  Speaker 3: ten years ago where people were hoping that the upgraded
• 24:06
  Speaker 3: Large hundred Collider would reveal evidence of what's called supersymmetry,
• 24:11
  Speaker 3: which might talk about new dimensions and things of that sort.
• 24:14
  Speaker 3: But there's absolutely no sign of it at the moment.
• 24:17
  Speaker 3: So all of that's ongoing. Maybe there will be some
• 24:19
  Speaker 3: chinks that appear.
• 24:21
  Speaker 1: When they do.
• 24:21
  Speaker 3: You and I'll talk about it, Andrew.
• 24:23
  Speaker 1: Wouldn't it be cool?
• 24:24
  Speaker 3: Yeah?
• 24:25
  Speaker 1: I suppose you could. Quite often when we talk about
• 24:29
  Speaker 1: this sort of thing. People get together on the Space
• 24:32
  Speaker 1: podcast group on Facebook and talk about time and some
• 24:36
  Speaker 1: of just say, look, time's a construct, it's not real.
• 24:41
  Speaker 1: And I suppose to a certain degree that's true. We
• 24:43
  Speaker 1: did invent time to suit ourselves on this planet, the
• 24:47
  Speaker 1: construction of various forms of calendar and clocks, but we
• 24:52
  Speaker 1: worked it in with what the planet's doing. That's our
• 24:55
  Speaker 1: version of time. But we're talking about time at a
• 24:58
  Speaker 1: universal level, the progression of existence, I suppose for one
• 25:06
  Speaker 1: of a bitter description.
• 25:08
  Speaker 3: I mean, yeah, to an astrophysicist, time seems to be
• 25:12
  Speaker 3: a fundamental part of the universe because we see things evolving.
• 25:16
  Speaker 3: It's one of the reasons why the Big Bang theory
• 25:20
  Speaker 3: really rose to prominence, the fact that when you look
• 25:22
  Speaker 3: further out into space, you're looking further back in time,
• 25:26
  Speaker 3: and you see galaxies that are clearly different from what
• 25:30
  Speaker 3: they are now you've seen them in the early universe.
• 25:33
  Speaker 3: And of course that is ongoing with the web, telescope
• 25:36
  Speaker 3: and all the weird and wonderful things we're discovering with that.
• 25:39
  Speaker 3: So time is sort of real in that sense, but
• 25:42
  Speaker 3: in a fundamental physics sense, maybe there's a deeper reality
• 25:46
  Speaker 3: that hides underneath quantum theory and relativity, and it's down
• 25:51
  Speaker 3: there where time is made.
• 25:54
  Speaker 1: Wow. Yeah, it's pretty deep stuff. I find it fascinating
• 25:59
  Speaker 1: even though I don't understand, and you know, at an
• 26:03
  Speaker 1: internetellectual level, I just know that when I look at
• 26:07
  Speaker 1: my JPS on the golf course, that tells me I'm
• 26:09
  Speaker 1: behind time because I'm bland too slow. That's a bad
• 26:12
  Speaker 1: as deep as it gets for me. Thank you, George Gee.
• 26:16
  Speaker 1: I love that question.
• 26:18
  Speaker 3: Yeah.
• 26:18
  Speaker 1: I hope we hear from you again, and I hope
• 26:21
  Speaker 1: I run into you somewhere in Dubai place say hello.
• 26:24
  Speaker 1: Final question comes from Tom.
• 26:27
  Speaker 7: Hi, this is Tom from Ireland. Love your show. Something
• 26:31
  Speaker 7: I can't get my head around. I hope you can help.
• 26:34
  Speaker 7: If I stand on the Earth and I have a
• 26:35
  Speaker 7: powerfulm of telescope and I can see, say, a galaxy
• 26:39
  Speaker 7: that's thirteen billion late years away. Now if I turn
• 26:42
  Speaker 7: my head and look at one hundred and eighty degrees
• 26:45
  Speaker 7: in the opposite direction with the same telescope, and I
• 26:47
  Speaker 7: pick out a galaxy that's also thirteen billion light years away.
• 26:52
  Speaker 7: How can those two galaxies be twenty six billion late
• 26:56
  Speaker 7: years apart when the universe is only thirteen point eight
• 27:00
  Speaker 7: billion years old. I asked this question because if I
• 27:04
  Speaker 7: get it right, if I'm assuming right when I see
• 27:07
  Speaker 7: the galaxy just thirteen point eight thirteen billion light years
• 27:10
  Speaker 7: where I'm seeing it as it was in that position
• 27:13
  Speaker 7: thirteen billion years ago, and likewise, the one in the
• 27:16
  Speaker 7: opposite direction, I'm seeing it as it was thirteen billion
• 27:20
  Speaker 7: years ago. So how could both of them be that
• 27:24
  Speaker 7: far apart with the universe only thirteen point eight billion
• 27:28
  Speaker 7: years old? I know I'm missing something, something I just
• 27:30
  Speaker 7: can't get my head around.
• 27:32
  Speaker 1: Thank you, love the show, Thank you Tom. This old chestnut, Fred,
• 27:37
  Speaker 1: this old chestnut come up once or twice over the years,
• 27:42
  Speaker 1: but did put it very, very beautifully though he has
• 27:45
  Speaker 1: test something. Yeah, so well yeah, now what's the solution? Well, so.
• 27:54
  Speaker 3: I think the first thing to understand is that the
• 28:02
  Speaker 3: universe is so we think it's thirteen point eight billion
• 28:07
  Speaker 3: years old. So that's right, that's exactly as Tom says,
• 28:10
  Speaker 3: since the Big Bang. But immediately after the Big Bang,
• 28:14
  Speaker 3: we hypothesize, and there's good evidence for this, that the
• 28:18
  Speaker 3: universe went through a period of what we call inflation,
• 28:22
  Speaker 3: where it expanded from the size of a football to
• 28:25
  Speaker 3: the size of a galaxy in something like a gazillion
• 28:29
  Speaker 3: to a second.
• 28:30
  Speaker 1: Yeah, it was.
• 28:31
  Speaker 3: Something you can't get your head around, isn't it. Yes,
• 28:35
  Speaker 3: so expanding much faster than the speed of light. But
• 28:38
  Speaker 3: as we've said before, the universe can actually do anything.
• 28:41
  Speaker 3: It's not limited by the speed limit which we are
• 28:45
  Speaker 3: when we travel through the universe. When we travel through space,
• 28:47
  Speaker 3: we're limited to the speed of light. But space itself
• 28:51
  Speaker 3: can and indeed did expand at a very very rapid rate.
• 28:55
  Speaker 3: So what we have is a universe that is much
• 29:00
  Speaker 3: much bigger than what we can see. And that sort
• 29:06
  Speaker 3: of explains, I think the issue. Because we from our
• 29:10
  Speaker 3: vantage point here on Earth, when we look out into space,
• 29:16
  Speaker 3: we can only see so far back, and that is
• 29:20
  Speaker 3: because we eventually, at great distance, we run into the
• 29:23
  Speaker 3: flash of the Big Bang. You're looking so far back
• 29:26
  Speaker 3: in time that you're still seeing that the universe when
• 29:29
  Speaker 3: it was a bright fog which was not transparent, So
• 29:33
  Speaker 3: it was this fog of radiation, and we see that
• 29:36
  Speaker 3: as a cosmic microwave background radiation, which we've talked about
• 29:39
  Speaker 3: many times. It's all over the sky's got slight variations
• 29:42
  Speaker 3: in it which correspond to temperature variations because of acoustic
• 29:46
  Speaker 3: oscillations in the Big Bang. In other words, the noise
• 29:50
  Speaker 3: of the Big Bang so that's a horizon. Now we
• 29:54
  Speaker 3: can't see beyond that, Tom, But the universe self goes on.
• 30:03
  Speaker 3: It's almost as though we're in a bubble in a
• 30:05
  Speaker 3: huge universe, and all we can see is limited by
• 30:10
  Speaker 3: that time of thirteen point eight billion years, because eventually
• 30:13
  Speaker 3: we're on into the flash of the Big Bang looking
• 30:15
  Speaker 3: back in time, but because of that inflationary period, the
• 30:21
  Speaker 3: you know, the hypervelocity expansion that the universe went through
• 30:24
  Speaker 3: early in its history, then it's it is much much bigger.
• 30:31
  Speaker 3: So if you all, right, so you see a galaxy
• 30:34
  Speaker 3: that's thirteen point eight billion years ago away, and then
• 30:38
  Speaker 3: imagine yourself standing on that galaxy, you wouldn't see the
• 30:43
  Speaker 3: galaxy that was twenty six billion years like years away,
• 30:48
  Speaker 3: because you're limited by the horizon at the same horizon.
• 30:53
  Speaker 3: From any point in the universe, you can only see
• 30:55
  Speaker 3: back thirteen point eight billion years to the flash of
• 30:57
  Speaker 3: the Big Bang. But the universe itself is much bigger.
• 31:00
  Speaker 3: It's it's a difficult thing to get your head around,
• 31:04
  Speaker 3: and to Tom's conundrum, is absolutely understandable. But that's the answer.
• 31:09
  Speaker 3: The universe is a lot bigger than what we can
• 31:11
  Speaker 3: actually see.
• 31:13
  Speaker 1: Yes, and if you did look in both directions and
• 31:15
  Speaker 1: could see something thirteen billion light years away that way
• 31:19
  Speaker 1: and that way. It stands to reason that from where
• 31:22
  Speaker 1: you are, you're looking across twenty six billion light years.
• 31:25
  Speaker 1: Would that be correct?
• 31:28
  Speaker 3: Yes, but if we own yeah, I mean that's right,
• 31:34
  Speaker 3: and that's you know, the separation between them. In fact,
• 31:41
  Speaker 3: we're talking a little bit enigmatically anyway, because the proper
• 31:48
  Speaker 3: distance to it. So if we have a look back
• 31:52
  Speaker 3: time of thirteen point eight billion years to an earlier
• 31:54
  Speaker 3: baby galaxy, that is the distance that we see presented
• 32:01
  Speaker 3: to our telescopes. But in reality, because the universe has
• 32:04
  Speaker 3: been expanding since the light left it, that is probably
• 32:08
  Speaker 3: more like forty billion light years away. But that's something
• 32:12
  Speaker 3: we call the proper distance. But there's no point in
• 32:14
  Speaker 3: imagining the proper distance or thinking about it, because all
• 32:17
  Speaker 3: the information comes at the speed of light. So, yes,
• 32:20
  Speaker 3: the universe is much bigger than even than we can see,
• 32:24
  Speaker 3: but you know, the distance is I think it's always
• 32:28
  Speaker 3: better to talk in terms of look back time rather
• 32:30
  Speaker 3: than distances when you're looking towards the limits of look
• 32:35
  Speaker 3: back time, which is the flash of the Big bang.
• 32:37
  Speaker 1: Yeah, I'm going to ask, oh, how big the universe is.
• 32:42
  Speaker 3: See what it says? Yeah, how big is the universe? Oh,
• 32:47
  Speaker 3: it's quite a big thing.
• 32:48
  Speaker 1: Square. Well, they say the observable universe is approximately ninety
• 32:54
  Speaker 1: three billion light years in diameter.
• 32:57
  Speaker 3: Yes, okay, so that's exactly what I said. It's forty
• 33:00
  Speaker 3: odd light years to the proper distance of the of
• 33:03
  Speaker 3: the of the of the horizon. But the proper distance
• 33:09
  Speaker 3: takes into account the expansion. That doesn't matter to us
• 33:13
  Speaker 3: because all we can see is what we can measure
• 33:15
  Speaker 3: in light years look back time.
• 33:17
  Speaker 1: Yeah, it's fascinating and confusing all at the same time,
• 33:21
  Speaker 1: really really interesting.
• 33:22
  Speaker 3: But the main comment, the main word there in that
• 33:26
  Speaker 3: AI answer is observable. That's the observable universe. That's all
• 33:30
  Speaker 3: we can see.
• 33:30
  Speaker 1: There's much what we can't see is much much bigger.
• 33:34
  Speaker 1: We can't even put a number on that, can we. No,
• 33:37
  Speaker 1: it could be infinite, no idea. All right, Tom, love
• 33:43
  Speaker 1: your question. Thanks so much for bringing that up. It's
• 33:45
  Speaker 1: always a good discussion point. And yeah, it just keeps
• 33:49
  Speaker 1: you thinking, it does. So thanks to everyone who sent
• 33:53
  Speaker 1: questions in Andrew and Michael, George and Tom and if
• 33:56
  Speaker 1: you've got questions for us, please send them via our website,
• 34:00
  Speaker 1: and you can do that through they Ask Me Anything
• 34:02
  Speaker 1: button at the top ama where you can leave text
• 34:06
  Speaker 1: and audio questions. Don't forget to tell us who you
• 34:08
  Speaker 1: are and where you're from. And Fred's about to find
• 34:11
  Speaker 1: out who that is and where they're from, probably from
• 34:16
  Speaker 1: the other end of the universe. Could be you wouldn't
• 34:19
  Speaker 1: that be a coup indeed? But thanks to your questions
• 34:22
  Speaker 1: and keep them coming. And while you're on our website,
• 34:24
  Speaker 1: have a look around, maybe click on the support our
• 34:27
  Speaker 1: podcast button and see if you can help us out.
• 34:30
  Speaker 1: It's totally optional, and plenty of other things to see
• 34:34
  Speaker 1: and do, including visit the Space Nuts shop and leave
• 34:38
  Speaker 1: some reviews while you're at it. Fred, thanks so much.
• 34:41
  Speaker 1: It's been a great pleasure, lots of fun.
• 34:43
  Speaker 3: Thank you Andrew, some excellent questions.
• 34:46
  Speaker 1: Takes to all hones, Professor Brett Watson, Astronomer at Large.
• 34:50
  Speaker 1: And thanks to Hugh in the studio who couldn't be
• 34:53
  Speaker 1: with us today because time stopped for him, and from
• 34:56
  Speaker 1: me Andrew Dunkley, thanks for your company. We'll see you
• 34:58
  Speaker 1: on the next episode of Space Nuts. Bye bye. You'll
• 35:02
  Speaker 1: be listening to the Space Nuts podcast, available at Apple Podcasts. Spotify, iHeartRadio,
• 35:11
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• 35:14
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• 35:16
  Speaker 7: This has been another quality podcast production from sites dot com.