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Cosmic Questions: Black Holes, Antimatter Stars, and Meteor Photography
In this enlightening Q&A episode of Space Nuts, hosts Andrew Dunkley and Professor Fred Watson tackle a series of fascinating listener queries. From the enigmatic nature of black holes to the potential existence of antimatter stars, and practical tips for capturing meteors on camera, this episode is a treasure trove of cosmic insights and practical advice.
Episode Highlights:
- Collapse of the Universe: Listener Nate raises an intriguing question about the future of the universe and the concept of the Gnab Gib, or the reverse Big Bang. Andrew and Fred Watson discuss how gravity might pull everything back together and what happens to light during this cosmic collapse.
- The Nature of Black Holes: Tad's thought-provoking question leads to a discussion on gravitational time dilation and the observer's perspective of black holes. The hosts explore how black holes form and why it appears as if nothing ever falls into them from our vantage point.
- Antimatter Stars: Mark from London and Canada revisits the idea of antimatter stars, prompting a conversation about their potential existence and how we might detect them through unique gamma ray emissions.
- Astrophotography Tips: Dave from Inverel shares his passion for nighttime photography and seeks advice on capturing meteors. Andrew and Fred Watson provide practical tips on the best times and techniques for successful meteor photography, including the benefits of using specific apps.
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Stay curious, keep looking up, and join us next time for more stellar insights and cosmic wonders. Until then, clear skies and happy stargazing.
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00:00:00 --> 00:00:02 Andrew Dunkley: Hi there. Welcome to a Q and A edition of
00:00:02 --> 00:00:05 Space Nuts. My name is Andrew Dunkley, your
00:00:05 --> 00:00:07 host. Good to have your company again. Uh,
00:00:07 --> 00:00:10 questions coming today from Pete. Uh, he's
00:00:10 --> 00:00:12 looking at the collapse of the universe.
00:00:13 --> 00:00:15 Wants to know where he needs to be when it
00:00:15 --> 00:00:17 happens, so he gets a good view. Actually, I
00:00:17 --> 00:00:19 think it's about something else. Uh, we've
00:00:19 --> 00:00:22 also got a question from Tad, who has
00:00:22 --> 00:00:23 brought up a really interesting point about
00:00:24 --> 00:00:26 falling into a black hole. From an observer's
00:00:27 --> 00:00:29 perspective. If we were to watch someone or
00:00:29 --> 00:00:31 something do, uh, really is a.
00:00:33 --> 00:00:36 A great piece of science to talk about. Uh,
00:00:36 --> 00:00:38 Mark is, uh, bringing up something from an
00:00:38 --> 00:00:41 episode four years ago, I think. Antimatter,
00:00:41 --> 00:00:44 uh, stars. And Dave, um,
00:00:44 --> 00:00:46 wants to know about the best time and place
00:00:46 --> 00:00:49 to aim a camera for low, uh, light
00:00:49 --> 00:00:52 astrophotography. Uh, that
00:00:52 --> 00:00:54 is a great question. Uh, I've had so much
00:00:54 --> 00:00:56 trouble with that myself. We'll get stuck
00:00:56 --> 00:00:59 into it right now on this edition of space
00:00:59 --> 00:00:59 nuts.
00:00:59 --> 00:01:02 Voice Over Guy: 15 seconds. Guidance is internal.
00:01:02 --> 00:01:05 10, 9. Ignition
00:01:05 --> 00:01:08 sequence start. Space nuts. 5, 4, 3.
00:01:08 --> 00:01:11 2. 1. 2, 3, 4, 5, 5, 4,
00:01:11 --> 00:01:14 3, 2, 1. Space nuts. Astronauts
00:01:14 --> 00:01:15 report it feels good.
00:01:18 --> 00:01:19 Andrew Dunkley: And here he is again. Professor Fred Watson
00:01:19 --> 00:01:21 Astronomer at large. Hello, Fred
00:01:22 --> 00:01:24 Professor Fred Watson: Hello, Andrew. Fancy seeing you here.
00:01:24 --> 00:01:27 Andrew Dunkley: Yes, yes. And we're in similar coloured
00:01:27 --> 00:01:27 shirts today.
00:01:27 --> 00:01:29 Professor Fred Watson: That's right. I think we're very chic.
00:01:29 --> 00:01:32 Andrew Dunkley: Judy reckons green's my colour, but I've
00:01:32 --> 00:01:34 never really liked green. But
00:01:34 --> 00:01:37 anyway, she's more of a
00:01:37 --> 00:01:39 fashionista than I am, so I'll take her word
00:01:39 --> 00:01:41 for it. Uh, how you been?
00:01:42 --> 00:01:45 Professor Fred Watson: Very well, thank you. Yes, um, all seems to
00:01:45 --> 00:01:46 be going well so far.
00:01:47 --> 00:01:49 Andrew Dunkley: You look and sound as well as the last time I
00:01:49 --> 00:01:49 saw you.
00:01:49 --> 00:01:52 Professor Fred Watson: Well, that's right. I've, you know, uh,
00:01:53 --> 00:01:55 it's, uh, it's. It seems like only
00:01:55 --> 00:01:57 a few minutes ago. It does, doesn't it?
00:01:58 --> 00:02:00 Andrew Dunkley: Funny that, um. That's because of a black
00:02:00 --> 00:02:00 hole.
00:02:01 --> 00:02:02 Professor Fred Watson: It could be a black bill.
00:02:04 --> 00:02:07 Andrew Dunkley: Although we must point out that this will be
00:02:07 --> 00:02:10 your last show for a short while. You're
00:02:10 --> 00:02:12 taking a bit of a trip which will take, um,
00:02:12 --> 00:02:14 you into time zones that are just not
00:02:14 --> 00:02:16 compatible with life on Earth in Australia.
00:02:16 --> 00:02:19 So, um, uh, we will be, uh,
00:02:19 --> 00:02:22 bringing our, uh, stand in Jaunty Horner in
00:02:22 --> 00:02:23 to look after things while you're away for
00:02:23 --> 00:02:26 about 7ish weeks, something like that.
00:02:27 --> 00:02:30 We, we knew this was going to happen this
00:02:30 --> 00:02:32 year with me away for three months and you
00:02:32 --> 00:02:35 away for, uh, a couple of months. So we knew
00:02:35 --> 00:02:37 this was going to happen and we, we planned
00:02:37 --> 00:02:40 ahead so that the show could go on. So,
00:02:40 --> 00:02:42 um, anyway, we'll um, we'll look forward to
00:02:42 --> 00:02:45 chatting with, with Jonty and wish, uh, you
00:02:45 --> 00:02:46 well on your trip. Um, where.
00:02:49 --> 00:02:51 Professor Fred Watson: We'Ve got about two and a half weeks in
00:02:51 --> 00:02:54 Japan. Uh, then we're back in
00:02:54 --> 00:02:56 Australia very briefly and then we're off up
00:02:56 --> 00:02:59 to Ireland for a Dark sky conference and,
00:02:59 --> 00:03:02 uh, skipping over to the UK to hang out
00:03:02 --> 00:03:04 with my family for a little bit in the uk and
00:03:04 --> 00:03:07 uh, that'll take us to the end of November.
00:03:07 --> 00:03:09 Andrew Dunkley: Why wouldn't you? It's just a short hop,
00:03:09 --> 00:03:09 isn't it, really?
00:03:09 --> 00:03:11 Professor Fred Watson: Yeah, that's right. Yeah. It's stupid. Going
00:03:12 --> 00:03:15 to uk. That's right, yeah. So we'll do
00:03:15 --> 00:03:17 a few, uh, things. We're going to, uh.
00:03:17 --> 00:03:19 Marnie's got a nice itinerary for us. We're
00:03:19 --> 00:03:21 going to go to places that I have wanted to
00:03:21 --> 00:03:24 go ever since I was a child and never made it
00:03:24 --> 00:03:26 in the uk. So that's fantastic. We'll tell
00:03:26 --> 00:03:27 you about it when we get back.
00:03:28 --> 00:03:31 Andrew Dunkley: Love to hear about it. Um, we better get
00:03:31 --> 00:03:32 into, uh, the questions.
00:03:33 --> 00:03:33 Professor Fred Watson: Yes, yes.
00:03:33 --> 00:03:35 Andrew Dunkley: Yeah, I guess so. Yeah. Yeah.
00:03:35 --> 00:03:37 Our first question's an audio question
00:03:38 --> 00:03:40 coming, uh, from Pate Fred Watson and
00:03:40 --> 00:03:41 Andrew.
00:03:41 --> 00:03:43 Pete: Pete from Longpoint got a question.
00:03:43 --> 00:03:46 I know that there's
00:03:46 --> 00:03:49 contested as to what's going to happen in the
00:03:49 --> 00:03:52 future with the universe. The kind of
00:03:52 --> 00:03:55 dang, or however it's pronounced, or
00:03:55 --> 00:03:57 expansion or the Big Rip or whatever. The
00:03:57 --> 00:04:00 question if, if the universe is going to
00:04:00 --> 00:04:03 collapse back in itself. I get the concept
00:04:03 --> 00:04:06 of the gravity
00:04:06 --> 00:04:08 bringing sort of physical matter back
00:04:08 --> 00:04:11 together and I know that's only what, 5% of
00:04:11 --> 00:04:14 the universe, but I don't understand how
00:04:14 --> 00:04:16 that would work with
00:04:17 --> 00:04:19 the. Basically pulling light
00:04:20 --> 00:04:22 backwards. So you have light is
00:04:22 --> 00:04:25 expanding ever increasingly,
00:04:25 --> 00:04:27 obviously at the speed of light. Um,
00:04:28 --> 00:04:31 basically what happens with that in the event
00:04:31 --> 00:04:33 there is a collapse back to another
00:04:33 --> 00:04:36 singularity? Um, yeah, I'm
00:04:36 --> 00:04:38 confused. Thanks guys.
00:04:39 --> 00:04:41 Andrew Dunkley: I think a lot of people are, uh, um, yeah, he
00:04:41 --> 00:04:44 was referring to the Gnab Gib, which is the
00:04:44 --> 00:04:47 reverse Big Bang. Yeah. Uh, but it's
00:04:47 --> 00:04:49 an interesting question because if, if it
00:04:49 --> 00:04:52 does happen, rather than a Big Rip, uh, the,
00:04:52 --> 00:04:55 the universe stops expanding and then starts
00:04:55 --> 00:04:58 receding back in on itself. What does
00:04:58 --> 00:05:01 happen to the light and the dark matter
00:05:01 --> 00:05:03 and all that other stuff that we don't
00:05:03 --> 00:05:04 understand.
00:05:05 --> 00:05:06 Professor Fred Watson: So, um,
00:05:08 --> 00:05:11 uh, this. No, thanks very much,
00:05:11 --> 00:05:11 Pete.
00:05:11 --> 00:05:14 Great question. Uh, which has arisen because
00:05:16 --> 00:05:17 I, um, think it might be. While you were
00:05:17 --> 00:05:20 away, Andrew, we covered the new
00:05:20 --> 00:05:23 observations that have come from the dark
00:05:23 --> 00:05:26 energy, uh, instrument, um,
00:05:27 --> 00:05:30 which is on a, on a, on the
00:05:30 --> 00:05:32 mail telescopes, a telescope very similar to
00:05:32 --> 00:05:35 our Anglo Australian telescope which is uh,
00:05:35 --> 00:05:37 which has been surveying the universe as you
00:05:37 --> 00:05:40 do with such instruments, um, getting the
00:05:40 --> 00:05:42 redshifts, which means the distances of all
00:05:42 --> 00:05:45 the galaxies and building up a map. And that
00:05:45 --> 00:05:47 map um, has just the first hint
00:05:48 --> 00:05:50 that dark, the acceleration of the
00:05:50 --> 00:05:53 universe which we attribute to this dark
00:05:53 --> 00:05:55 energy, whatever it is, uh, that the
00:05:55 --> 00:05:56 acceleration of the universe is actually
00:05:56 --> 00:05:59 slowing down. It's still only a hint, it's
00:05:59 --> 00:06:01 not confirmed yet. But if the acceleration
00:06:01 --> 00:06:04 is slowing down then it does
00:06:05 --> 00:06:07 raise once again the possibility that we
00:06:07 --> 00:06:10 talked about a lot in the 1970s and 80s.
00:06:10 --> 00:06:13 Uh, the idea of an eventual collapse, a
00:06:13 --> 00:06:15 reversal of the expansion of the universe to
00:06:15 --> 00:06:18 a collapse. Uh, and the end product of
00:06:18 --> 00:06:21 that often called the Big Crunch. But we
00:06:21 --> 00:06:23 like the GNAB gib. That was the name that
00:06:23 --> 00:06:25 Brian Schmidt gave to it. It's a great name.
00:06:26 --> 00:06:28 So what happens in the Gnab gib? Well, um,
00:06:30 --> 00:06:33 it is interesting. You've got gravity taking
00:06:33 --> 00:06:35 over and it doesn't just
00:06:36 --> 00:06:37 sort of bring together
00:06:39 --> 00:06:42 the objects in space, it doesn't just
00:06:42 --> 00:06:45 collapse all the galaxies towards one place,
00:06:45 --> 00:06:47 it actually collapses space time with it.
00:06:48 --> 00:06:50 Um, because the, you know, the,
00:06:50 --> 00:06:53 the matter bend space. We know and that
00:06:53 --> 00:06:56 bending is effectively what you, what you
00:06:56 --> 00:06:59 would call the collapse uh, in the run
00:06:59 --> 00:07:01 up to the, or the run down to the Ganab gib.
00:07:02 --> 00:07:05 And so in a sense, uh, the light,
00:07:05 --> 00:07:08 uh, so, so what I'm saying is that
00:07:08 --> 00:07:11 um, the, the distances that, that across
00:07:11 --> 00:07:13 the, the distances that we measure between
00:07:13 --> 00:07:16 galaxies becomes less. But, but
00:07:16 --> 00:07:19 it's because the space time has shrunk
00:07:19 --> 00:07:22 basically. Uh, and so not just that
00:07:22 --> 00:07:24 the galaxies have got closer together.
00:07:25 --> 00:07:27 And that means uh, that yes, light will still
00:07:27 --> 00:07:29 continue to travel through space time at
00:07:30 --> 00:07:32 300 kilometres per second, but that
00:07:32 --> 00:07:34 space time has got less space in it.
00:07:35 --> 00:07:38 Um, and so the light just shrinks with the
00:07:38 --> 00:07:41 universe. It doesn't kind of escape or
00:07:41 --> 00:07:44 anything that many gazillions
00:07:44 --> 00:07:46 of photons that are currently traversing the
00:07:46 --> 00:07:49 universe and will continue to do that, uh, as
00:07:49 --> 00:07:50 long as things are shining and there's energy
00:07:50 --> 00:07:53 to provide that they will have shorter
00:07:53 --> 00:07:56 distances to go. Uh and we will find
00:07:56 --> 00:07:58 that the universe just gets smaller. As it
00:07:58 --> 00:08:01 gets smaller, the light goes with it and we
00:08:01 --> 00:08:04 end up with a bundle of stuff, uh, subatomic
00:08:04 --> 00:08:07 particles, including photons, particles of
00:08:07 --> 00:08:08 light, a whole lot of stuff that is going to
00:08:08 --> 00:08:11 hit an almighty singularity,
00:08:11 --> 00:08:14 uh, uh, which we might call the GNAB
00:08:14 --> 00:08:16 gib. Yeah, wow.
00:08:16 --> 00:08:19 Andrew Dunkley: Um, correct Me if I'm wrong, but didn't
00:08:19 --> 00:08:22 we talk in the past about a time where the
00:08:22 --> 00:08:24 universe will become dark and
00:08:24 --> 00:08:27 cold and there won't be
00:08:27 --> 00:08:28 any light?
00:08:29 --> 00:08:31 Professor Fred Watson: Well, um, that's right. If the universe
00:08:31 --> 00:08:34 continues expanding, then eventually
00:08:34 --> 00:08:36 there will be light there, but it won't be
00:08:36 --> 00:08:38 able to reach you because it'll be beyond
00:08:38 --> 00:08:40 your. Your horizon. Uh,
00:08:40 --> 00:08:43 so, uh, the light will still be going through
00:08:43 --> 00:08:46 the universe, but that light source will
00:08:46 --> 00:08:48 be receding from us, um,
00:08:49 --> 00:08:51 too fast for the light ever to get to us.
00:08:51 --> 00:08:54 So, yes, it becomes dark and dreary. Uh, but,
00:08:54 --> 00:08:55 yeah, light is still there.
00:08:55 --> 00:08:58 Andrew Dunkley: Uh, all right, there you go, Pete. Um,
00:08:58 --> 00:09:00 it will all be cataclysmic and horrible, and,
00:09:01 --> 00:09:02 uh, we'll all be a lot shorter.
00:09:05 --> 00:09:06 Professor Fred Watson: Every dimension.
00:09:06 --> 00:09:09 Andrew Dunkley: Indeed, yes. Although I'm starting to like
00:09:09 --> 00:09:11 the idea of a big rip. Because a big rip
00:09:11 --> 00:09:13 might open us to another universe and we
00:09:13 --> 00:09:14 could all escape.
00:09:15 --> 00:09:17 Professor Fred Watson: Well, yeah, maybe. Well, of course, you with
00:09:17 --> 00:09:19 the big. The gnab gib, you could get the big
00:09:19 --> 00:09:22 bounce. Uh, you know, it could just bounce
00:09:22 --> 00:09:24 back. So you've suddenly got an expanding
00:09:24 --> 00:09:25 universe immediately.
00:09:26 --> 00:09:28 Andrew Dunkley: Yeah, it's hard to get your head around. And
00:09:28 --> 00:09:31 I understand why Pete feels confused, because
00:09:31 --> 00:09:34 it really is beyond our imagination in many
00:09:34 --> 00:09:34 ways, isn't it?
00:09:34 --> 00:09:35 Professor Fred Watson: That's right.
00:09:36 --> 00:09:38 Andrew Dunkley: Thanks, Pete. Great question. Hope you're
00:09:38 --> 00:09:38 well.
00:09:38 --> 00:09:41 Uh, let's go to a question from Tad.
00:09:41 --> 00:09:43 Uh, this one's really interesting. Uh, we
00:09:43 --> 00:09:45 understand that due to extreme gravitational
00:09:45 --> 00:09:48 time dilation, from the perspective of an
00:09:48 --> 00:09:51 outside observer, anyone falling into a black
00:09:51 --> 00:09:54 hole takes an infinite amount of time to
00:09:54 --> 00:09:56 cross the event horizon, even if, from that
00:09:56 --> 00:09:59 person's perspective, they actually do in
00:09:59 --> 00:10:02 real time. Uh, if this is true, how
00:10:02 --> 00:10:04 do black holes and their event horizons even
00:10:04 --> 00:10:07 form in the first place, from an outsider's
00:10:07 --> 00:10:09 perspective? And does this mean that
00:10:09 --> 00:10:11 technically nothing has ever fallen into a
00:10:11 --> 00:10:13 black hole from our perspective here on
00:10:13 --> 00:10:16 Earth? I love this question. Thank you, Tad.
00:10:17 --> 00:10:19 Uh, he's bringing up the point
00:10:19 --> 00:10:21 where if you're watching someone fall into
00:10:21 --> 00:10:24 the. Into a black hole because of
00:10:25 --> 00:10:27 the. The effect, the gravitational effect on
00:10:27 --> 00:10:29 time space, it never happens,
00:10:30 --> 00:10:31 but that person
00:10:32 --> 00:10:35 experiences it in real time until they get
00:10:35 --> 00:10:38 spaghettified. So, um,
00:10:38 --> 00:10:41 yeah. How come we see black holes
00:10:41 --> 00:10:43 when this effect should
00:10:44 --> 00:10:46 suggest we. We should never see it happen?
00:10:47 --> 00:10:49 Is that. Is that what I'm. Is that what he's
00:10:49 --> 00:10:49 saying?
00:10:50 --> 00:10:53 Professor Fred Watson: Yeah, yeah. How do black holes form in the
00:10:53 --> 00:10:53 first place?
00:10:55 --> 00:10:55 Andrew Dunkley: Uh.
00:10:57 --> 00:10:59 Professor Fred Watson: So it, uh, yes. So in that regard,
00:11:00 --> 00:11:03 that time dilation is a kind of optical
00:11:03 --> 00:11:05 illusion because the thing has crossed the
00:11:05 --> 00:11:08 event horizon, whatever it is. Uh, has
00:11:08 --> 00:11:10 contributed to the mass of the black hole.
00:11:10 --> 00:11:13 So, uh, the reality is, yes,
00:11:13 --> 00:11:15 you're, you know, if it's you, you get
00:11:15 --> 00:11:17 spaghettified and then you get absorbed by
00:11:17 --> 00:11:19 the black hole itself a gazillionth of a
00:11:19 --> 00:11:22 second later. Um, it's from the outside
00:11:22 --> 00:11:25 perspective. Uh, I've always struggled with
00:11:25 --> 00:11:26 this actually in trying to envisage it
00:11:26 --> 00:11:29 because, yeah, you imagine some poor person
00:11:29 --> 00:11:31 who's fallen into a black hole. Um,
00:11:32 --> 00:11:34 it's be like the, um, you know those,
00:11:35 --> 00:11:37 uh, chalk things on the road where
00:11:38 --> 00:11:40 somebody's got hit by a car. There'd
00:11:40 --> 00:11:43 be this chalk mark of somebody, uh, on the
00:11:43 --> 00:11:45 surface of the event horizon.
00:11:46 --> 00:11:48 Um, uh, but they'd
00:11:48 --> 00:11:51 also, uh, uh, along with that person, there'd
00:11:51 --> 00:11:52 be everything else that's gone into it. And
00:11:52 --> 00:11:55 black holes are notorious for accreting
00:11:55 --> 00:11:56 material. So all the stuff that's spiralling
00:11:56 --> 00:11:59 into it from an outsider's perspective just
00:11:59 --> 00:12:01 ends up looking as though it's stuck on the
00:12:01 --> 00:12:03 surface of the event horizon, even though
00:12:03 --> 00:12:06 it's actually been absorbed by the
00:12:06 --> 00:12:08 black hole. So it is a kind of optical
00:12:08 --> 00:12:10 illusion. Yes, it's very weird. It, uh, just
00:12:10 --> 00:12:13 means that from, you know, what it highlights
00:12:13 --> 00:12:16 is, uh, it's all about your
00:12:16 --> 00:12:18 reference frame. Uh, our reference frame is
00:12:18 --> 00:12:21 an, um, observer looking out, looking in from
00:12:21 --> 00:12:24 the outside. If you've got the reference
00:12:24 --> 00:12:26 frame of the person who's falling into the
00:12:26 --> 00:12:28 black hole, things are a lot different. We,
00:12:28 --> 00:12:31 uh, can watch, um, you know, from the
00:12:31 --> 00:12:32 sidelines and cheer people on as they fall
00:12:32 --> 00:12:35 through the black hole event horizon. All,
00:12:35 --> 00:12:38 uh, we see is them frozen on the
00:12:38 --> 00:12:41 event horizon. Uh, which must be a very messy
00:12:41 --> 00:12:42 place with all the stuff that's falling into
00:12:42 --> 00:12:43 it.
00:12:43 --> 00:12:43 Andrew Dunkley: Yeah.
00:12:43 --> 00:12:46 Professor Fred Watson: So, um, I, yeah,
00:12:46 --> 00:12:49 I, you know, it to me, that transforms what
00:12:49 --> 00:12:51 the event horizon might look like. It's
00:12:51 --> 00:12:53 probably not that nice sphere of darkness
00:12:53 --> 00:12:56 that we imagine, but it's got splattered with
00:12:56 --> 00:12:58 lots of stuff. And in fact, we know that the
00:12:58 --> 00:13:01 magnetism of a black hole actually plays a
00:13:01 --> 00:13:03 huge role in, um,
00:13:03 --> 00:13:06 directing material so that some of the stuff
00:13:06 --> 00:13:08 is actually accelerated perpendicular to the
00:13:08 --> 00:13:11 accretion disc, uh, backward, up, upwards
00:13:11 --> 00:13:14 and downwards. And that in itself is a
00:13:14 --> 00:13:16 process. It's very hard to get your head
00:13:16 --> 00:13:18 around how stuff that's swirling in towards a
00:13:18 --> 00:13:21 black hole suddenly gets dragged up, uh,
00:13:21 --> 00:13:24 and shot out the poles of the
00:13:24 --> 00:13:27 black hole, top and bottom. Um, so a
00:13:27 --> 00:13:30 lot of hard work to conjecture. I hope that
00:13:30 --> 00:13:32 helps Tad to envisage what's going on.
00:13:33 --> 00:13:35 Uh, um, because it's all about your
00:13:35 --> 00:13:36 perspective, basically.
00:13:37 --> 00:13:40 Andrew Dunkley: Yeah, yeah. Uh, so the black hole,
00:13:40 --> 00:13:41 uh, has happened.
00:13:44 --> 00:13:47 My brain had an idea and it just fell into a
00:13:47 --> 00:13:49 black hole. Now, um, I can't remember, but,
00:13:49 --> 00:13:52 uh, we. We see the black hole
00:13:53 --> 00:13:56 because it's already happened. Is that.
00:13:56 --> 00:13:58 Professor Fred Watson: Well, yeah, the black. The black hole's been
00:13:58 --> 00:14:01 created in. I mean, typically in the collapse
00:14:01 --> 00:14:04 of a. Of a star at the end of
00:14:04 --> 00:14:06 its life. Uh, so that's a
00:14:06 --> 00:14:08 straightforward gravitational collapse. The
00:14:08 --> 00:14:11 material of the star, uh, basically collapses
00:14:11 --> 00:14:14 down so that nothing will hold it out
00:14:14 --> 00:14:16 and it becomes this singularity, a point of
00:14:16 --> 00:14:18 infinite density, which is how we define it.
00:14:19 --> 00:14:21 Um, and that's. It's during that collapse
00:14:21 --> 00:14:24 that the event horizon forms. And you've got
00:14:24 --> 00:14:26 that. As I said, it's an optical illusion.
00:14:26 --> 00:14:29 That's the main point to recognise. It's an
00:14:29 --> 00:14:31 optical illusion as seen from the outside,
00:14:32 --> 00:14:35 um, that nothing reaches a black hole.
00:14:35 --> 00:14:36 M Mm.
00:14:36 --> 00:14:38 Andrew Dunkley: I'm sure we'll get some more questions on
00:14:38 --> 00:14:40 this one, but, uh, you've probably opened a
00:14:40 --> 00:14:42 can of spaghetti there, Tad.
00:14:42 --> 00:14:44 Professor Fred Watson: Yeah, which is great because Jonty can deal
00:14:44 --> 00:14:45 with all of that.
00:14:45 --> 00:14:48 Andrew Dunkley: Yes, he can. Yeah. Yes, that's for
00:14:48 --> 00:14:48 sure.
00:14:48 --> 00:14:51 M All right, Tad. Thank you for the question.
00:14:51 --> 00:14:53 This is Space Nuts, a Q A edition with Andrew
00:14:53 --> 00:14:56 Dunkley and Professor Fred Watson Watson.
00:14:58 --> 00:15:00 Three, two, one.
00:15:01 --> 00:15:03 Space Nuts. Now, uh, our next
00:15:03 --> 00:15:06 question's an audio question. It comes
00:15:06 --> 00:15:07 from Mark.
00:15:08 --> 00:15:10 Mark: Hi, it's Mark in London and Canada.
00:15:11 --> 00:15:13 I just listened to an episode from
00:15:14 --> 00:15:17 March 2021 and Fred Watson mentioned the
00:15:17 --> 00:15:20 possible existence of an antimatter
00:15:20 --> 00:15:23 star and how. Obviously we wouldn't want to
00:15:23 --> 00:15:25 get, uh, anywhere near it,
00:15:25 --> 00:15:28 but I was wondering, is it. Is it possible?
00:15:28 --> 00:15:31 Do they exist? Uh, and how could we tell if
00:15:31 --> 00:15:33 we're looking at a star from Earth, can we
00:15:33 --> 00:15:36 tell if it's regular matter or antimatter
00:15:36 --> 00:15:39 or. What if the entire Andromeda Galaxy
00:15:39 --> 00:15:42 was antimatter, would we have a way of,
00:15:42 --> 00:15:43 uh, figuring that out?
00:15:44 --> 00:15:44 Professor Fred Watson: Thanks.
00:15:44 --> 00:15:45 Mark: Bye.
00:15:46 --> 00:15:48 Andrew Dunkley: M Uh, I would ask my Auntie
00:15:48 --> 00:15:51 Shirley, but she wouldn't know either. Um,
00:15:51 --> 00:15:54 thank you, Mark. Antimatter stars. We did. I
00:15:54 --> 00:15:56 remember us talking about them. Uh, we do
00:15:56 --> 00:15:58 know there is antimatter.
00:15:58 --> 00:16:00 Professor Fred Watson: There's just a hell of a lot.
00:16:00 --> 00:16:03 Andrew Dunkley: Less of it than actual matter, if I recall
00:16:03 --> 00:16:05 correctly. But if you've got, um, a molecule
00:16:05 --> 00:16:08 of matter and a molecule of antimatter and
00:16:08 --> 00:16:11 they collide, they just cease to exist.
00:16:11 --> 00:16:12 Is that how it goes?
00:16:13 --> 00:16:15 Professor Fred Watson: Yes, that's right, yeah. Um, what you get,
00:16:16 --> 00:16:18 um, is so if you. The
00:16:18 --> 00:16:21 difference between a normal matter
00:16:21 --> 00:16:24 particle, like, uh, an electron,
00:16:24 --> 00:16:27 and. And, uh, its antimatter equivalent
00:16:27 --> 00:16:29 is the electrical charge is the opposite.
00:16:30 --> 00:16:32 So the antimatter equivalent of an electron
00:16:32 --> 00:16:35 is a positron. Um, it's got positive
00:16:35 --> 00:16:37 electrical charge. Uh, and
00:16:39 --> 00:16:41 when two
00:16:42 --> 00:16:44 particles like that meet, they
00:16:44 --> 00:16:47 annihilate. And what you get is a
00:16:47 --> 00:16:49 gamma ray. You get a photon of gamma ray
00:16:49 --> 00:16:51 energy which has a uh,
00:16:51 --> 00:16:54 characteristic, a uh,
00:16:54 --> 00:16:56 characteristic frequency, um
00:16:56 --> 00:16:59 distribution. In gamma rays we call it
00:16:59 --> 00:17:01 energy. Uh, in light we think of it as
00:17:01 --> 00:17:03 wavelength, in radio waves we think it as
00:17:03 --> 00:17:05 frequency. Uh, but it's the same thing
00:17:05 --> 00:17:08 basically, uh, different, different levels of
00:17:08 --> 00:17:11 energy. So you get these gamma rays which
00:17:11 --> 00:17:13 will be emitted with a specific and
00:17:13 --> 00:17:16 characteristic frequency and that's the way
00:17:16 --> 00:17:18 that you might be able to detect
00:17:19 --> 00:17:21 an antimatter star.
00:17:22 --> 00:17:22 Andrew Dunkley: Um.
00:17:24 --> 00:17:26 Professor Fred Watson: I think this story actually goes back, it
00:17:26 --> 00:17:28 does go back to 2021. I've just found the
00:17:28 --> 00:17:30 article that we referred to. Stars made of
00:17:30 --> 00:17:32 antimatter might be lurking in the universe.
00:17:32 --> 00:17:34 It's from Scientific American, a very
00:17:34 --> 00:17:37 authoritative source. Um,
00:17:37 --> 00:17:40 but what they were starting the story
00:17:40 --> 00:17:42 with was something that happened in 2018
00:17:43 --> 00:17:46 when uh, one of the
00:17:46 --> 00:17:47 experiments on the outside of the
00:17:47 --> 00:17:49 International Space Station which we talked
00:17:49 --> 00:17:51 about in the last episode with great warmth
00:17:51 --> 00:17:54 and admiration. Um,
00:17:54 --> 00:17:56 it's one of those experiments may have
00:17:56 --> 00:17:58 detected uh, two
00:18:00 --> 00:18:02 basically uh, nuclei of anti helium. Um,
00:18:03 --> 00:18:05 these are anti helium particles.
00:18:06 --> 00:18:09 And so you mix that with normal helium
00:18:09 --> 00:18:10 and you get the gamma rays.
00:18:11 --> 00:18:14 Um, and so the question
00:18:14 --> 00:18:17 is where, where does
00:18:17 --> 00:18:20 that come from? And that was
00:18:20 --> 00:18:22 the um, the outcome of this, the, the
00:18:22 --> 00:18:25 suggestion that the easiest way to produce
00:18:25 --> 00:18:28 anti helium is inside anti stars.
00:18:29 --> 00:18:32 Um, which we don't, still
00:18:32 --> 00:18:34 don't know whether they exist or not. Uh, but
00:18:34 --> 00:18:37 really the, the point of Marx question is a
00:18:37 --> 00:18:39 good one. Um, I don't think we know much more
00:18:39 --> 00:18:41 about this uh,
00:18:42 --> 00:18:45 since that you know that speculation.
00:18:46 --> 00:18:48 Um, but what they're
00:18:48 --> 00:18:51 suggesting, uh, I might actually read
00:18:51 --> 00:18:54 uh, from that Scientific American article
00:18:54 --> 00:18:56 and acknowledge the source there.
00:18:57 --> 00:18:58 It was written by
00:18:59 --> 00:19:02 Leto Supuna who's the author
00:19:02 --> 00:19:05 of that. Um, and I think it
00:19:06 --> 00:19:08 sort of puts it a lot better than I can.
00:19:09 --> 00:19:12 Antistars would shine much as normal ones do,
00:19:12 --> 00:19:14 producing light of the same wavelengths, but
00:19:14 --> 00:19:16 they would exist in a matter dominated
00:19:16 --> 00:19:19 universe. And so as particles and
00:19:19 --> 00:19:22 gases made of regular matter fell into
00:19:22 --> 00:19:24 an antistar's gravitational pull and made
00:19:24 --> 00:19:27 contact with its antimatter, the resulting
00:19:27 --> 00:19:29 annihilations would produce a flash of high
00:19:29 --> 00:19:30 energy light. That's the gamma rays I
00:19:30 --> 00:19:33 mentioned. We can see this light as a, There
00:19:33 --> 00:19:35 you go. We can see this light as a specific
00:19:35 --> 00:19:38 colour of gamma rays. Um, and
00:19:38 --> 00:19:40 so one of the teams that they're Talking
00:19:40 --> 00:19:42 about took 10 years of data, uh,
00:19:43 --> 00:19:45 which amounted to roughly 6 light
00:19:45 --> 00:19:47 emitting objects. They paired the list down
00:19:47 --> 00:19:49 to sources that shone with the right gamma
00:19:49 --> 00:19:51 ray frequency and that were not ascribed to
00:19:51 --> 00:19:53 previously catalogued astronomical objects.
00:19:54 --> 00:19:57 Um, so this left us with
00:19:57 --> 00:20:00 14 candidates. This is one of the authors,
00:20:00 --> 00:20:02 uh, talking, which in my opinion and my co
00:20:02 --> 00:20:04 author's opinion, two are, uh, not antistars.
00:20:05 --> 00:20:08 Um, yeah, but they say
00:20:08 --> 00:20:11 if all those sources were such stars, that
00:20:11 --> 00:20:13 means one anti star would exist for every
00:20:13 --> 00:20:15 400 ordinary ones in our stellar neck of
00:20:15 --> 00:20:18 the woods. So we're still
00:20:18 --> 00:20:20 struggling to get our heads around this and
00:20:20 --> 00:20:23 I'm not sure whether any more of uh,
00:20:23 --> 00:20:26 these characteristic gamma ray flashes,
00:20:27 --> 00:20:29 uh, have been observed or what the latest
00:20:30 --> 00:20:32 is on this topic. But it is a very
00:20:32 --> 00:20:34 interesting one, I think. Um, thank you,
00:20:34 --> 00:20:35 Mark, for raising it again because it's one
00:20:35 --> 00:20:37 we should perhaps look at in a bit more
00:20:37 --> 00:20:40 detail. Might try and dig out some
00:20:40 --> 00:20:42 stories for when I return to space nuts on
00:20:42 --> 00:20:45 um, antistars and see what we've got
00:20:45 --> 00:20:46 in that. Uh.
00:20:47 --> 00:20:48 Andrew Dunkley: Do you think they could exist for him?
00:20:49 --> 00:20:51 Professor Fred Watson: I do think they could exist, yeah. Um, I mean
00:20:52 --> 00:20:53 it's one of the big puzzles of the universe
00:20:53 --> 00:20:56 as to why there's so much matter and so
00:20:56 --> 00:20:59 little antimatter. When our best theories of
00:20:59 --> 00:21:01 the origin of the universe suggest that
00:21:01 --> 00:21:04 antimatter and matter were created in equal,
00:21:04 --> 00:21:07 you know, in equal proportions. So
00:21:07 --> 00:21:10 uh, it's, it's one of these, it is, it's one
00:21:10 --> 00:21:12 of these issues that um, is, keeps on
00:21:12 --> 00:21:15 bubbling up and uh, you know, challenging
00:21:15 --> 00:21:16 our understanding.
00:21:16 --> 00:21:19 Andrew Dunkley: Yeah, uh, well, I'm probably dredging up
00:21:19 --> 00:21:21 the same joke I used four and a half years
00:21:21 --> 00:21:23 ago, but there's a lot of, there's a lot of
00:21:23 --> 00:21:25 doesn't matter in astronomy as well.
00:21:27 --> 00:21:30 Professor Fred Watson: See, I can hear Jordy. You got a lot of Jordy
00:21:30 --> 00:21:31 there. Yeah.
00:21:32 --> 00:21:35 Andrew Dunkley: Um, but yeah, antimatter stars are
00:21:35 --> 00:21:38 right up there with white holes. Uh, we've
00:21:38 --> 00:21:41 never seen one. But there's, you know,
00:21:41 --> 00:21:43 there's certain elements of
00:21:43 --> 00:21:45 science that think these things exist.
00:21:46 --> 00:21:49 Um, but we've just never found the,
00:21:50 --> 00:21:52 the direct evidence or proof, have we?
00:21:52 --> 00:21:54 Professor Fred Watson: No, that's. Excuse me. That's correct.
00:21:54 --> 00:21:57 Um, just along those lines, there's
00:21:58 --> 00:22:00 something, um, that cropped, um, up about a
00:22:00 --> 00:22:03 week ago or two weeks ago. Um, it's a
00:22:03 --> 00:22:06 gravitational wave event which I think
00:22:06 --> 00:22:08 dates back to 2019. And you know,
00:22:08 --> 00:22:11 gravitational waves measured by LIGO and uh,
00:22:12 --> 00:22:14 Kagra and Virgo, the three big gravitational
00:22:14 --> 00:22:17 wave detectors in the world. They um,
00:22:18 --> 00:22:21 uh, this particular, most Most gravitational
00:22:21 --> 00:22:23 waves come from, uh, either neutron stars
00:22:23 --> 00:22:24 colliding or neutron stars colliding with
00:22:24 --> 00:22:27 black holes or black holes colliding. And
00:22:27 --> 00:22:28 they always have characteristic signature.
00:22:28 --> 00:22:31 They spiral together and then when they come
00:22:31 --> 00:22:32 together at the end they produce this
00:22:32 --> 00:22:35 characteristic chirp, um,
00:22:35 --> 00:22:37 which is when they merge. Um,
00:22:38 --> 00:22:41 and, uh, that usually lasts a few seconds
00:22:41 --> 00:22:44 that, um, run up to the chirp. Uh, but
00:22:44 --> 00:22:47 this one in 2019 only lasted, I think
00:22:47 --> 00:22:50 it was a tenth of a second. Uh, and
00:22:51 --> 00:22:54 one interpretation of that is that,
00:22:55 --> 00:22:58 uh, it was two very massive
00:22:58 --> 00:22:59 black holes. I think. I think that's the way
00:22:59 --> 00:23:01 around. It goes. Could be the other way
00:23:01 --> 00:23:04 around. Anyway, a,
00:23:04 --> 00:23:06 um, recent paper from China, and I think this
00:23:06 --> 00:23:09 was two weeks ago, proposed that you could
00:23:09 --> 00:23:12 get nearly the same modelling, which,
00:23:12 --> 00:23:14 because they model these gravitational wave
00:23:14 --> 00:23:17 phenomena if, uh, it turned out
00:23:17 --> 00:23:18 that what you were looking at was not
00:23:18 --> 00:23:21 colliding black holes but a collapsing
00:23:21 --> 00:23:24 wormhole. Um, and that's
00:23:24 --> 00:23:26 the first evidence that I think anybody has
00:23:26 --> 00:23:28 put forward for the existence of wormholes.
00:23:28 --> 00:23:31 But it's still very conjectural because,
00:23:32 --> 00:23:34 um, the likelihood, you know, the model of
00:23:34 --> 00:23:36 just two black holes colliding actually fits
00:23:36 --> 00:23:39 the data slightly better than the model of
00:23:39 --> 00:23:41 the collapsing wormhole. But people are still
00:23:41 --> 00:23:43 looking at these things as they are for white
00:23:43 --> 00:23:45 holes and, um, I hope also for
00:23:45 --> 00:23:46 antimotor stars.
00:23:47 --> 00:23:50 Andrew Dunkley: Yes. Yeah. Well, um, I suppose
00:23:50 --> 00:23:53 there's so much to consider in the
00:23:53 --> 00:23:56 universe that some things just don't get the
00:23:56 --> 00:23:58 amount of time and attention they probably
00:23:58 --> 00:24:01 deserve. But the workforce
00:24:01 --> 00:24:03 is spread so thin in astronomy and space
00:24:03 --> 00:24:05 science, I would imagine so,
00:24:06 --> 00:24:08 um. Yeah, it's hard to deal with everything.
00:24:09 --> 00:24:11 Professor Fred Watson: With everything. That's right. There's
00:24:11 --> 00:24:13 certainly enough questions to keep us busy
00:24:13 --> 00:24:15 for a long time. The world of astronomy.
00:24:15 --> 00:24:16 Absolutely.
00:24:16 --> 00:24:19 Andrew Dunkley: Yeah. All right, Mark, thank you. Hope
00:24:19 --> 00:24:20 all is well in Canada.
00:24:23 --> 00:24:24 Roger, you're live right here.
00:24:24 --> 00:24:26 Professor Fred Watson: Also, space nuts.
00:24:26 --> 00:24:29 Andrew Dunkley: Our final question comes from Dave. And, uh,
00:24:29 --> 00:24:32 Dave is from Inverel in Northern, uh, New
00:24:32 --> 00:24:34 South Wales, Australia. As someone who is
00:24:34 --> 00:24:37 lucky enough to enjoy fairly low light
00:24:37 --> 00:24:39 pollution where I live, I like to
00:24:39 --> 00:24:42 attempt some nighttime photography now and
00:24:42 --> 00:24:45 then. Lately I've been using the nightcap
00:24:45 --> 00:24:47 app on my phone. I've got that one as well.
00:24:47 --> 00:24:50 Uh, with, uh, the meteor setting, he says
00:24:50 --> 00:24:53 to try and capture some meteor photos.
00:24:53 --> 00:24:55 Uh, I find the best time to see a great
00:24:55 --> 00:24:58 falling star is just as I'm getting the phone
00:24:58 --> 00:25:00 set up, ready to start shooting.
00:25:01 --> 00:25:04 Just wondering if you have any advice for
00:25:04 --> 00:25:06 when to try and capture a meteor on camera.
00:25:07 --> 00:25:09 Example, uh, time of night, direction, et
00:25:09 --> 00:25:12 cetera. Or should I just uh, wait until a
00:25:12 --> 00:25:15 good meteor shower turns up. Uh, and how many
00:25:15 --> 00:25:18 meteors would we expect to see collide in
00:25:18 --> 00:25:20 our atmos, uh, collide with our atmosphere on
00:25:20 --> 00:25:23 any given night. Um, also,
00:25:23 --> 00:25:25 uh, great to hear you back Andrew and
00:25:25 --> 00:25:28 hearing. Enjoy, uh, hearing your travels. Uh,
00:25:28 --> 00:25:31 when you talk of Iceland, it makes me very
00:25:31 --> 00:25:32 keen to return.
00:25:32 --> 00:25:34 Can I ask which company you cruised with?
00:25:34 --> 00:25:37 Dave from Inverel. Yes, you can.
00:25:38 --> 00:25:41 Uh, the uh, the answer, uh, is Princess.
00:25:41 --> 00:25:44 It was Princess Cruises. Uh, we made the
00:25:44 --> 00:25:47 news early in the cruise when we got smashed
00:25:47 --> 00:25:50 just um, southwest corner of Australia by
00:25:50 --> 00:25:52 a squall that knocked the ship over, not
00:25:52 --> 00:25:55 completely 7 degree list which
00:25:55 --> 00:25:57 we took three hours to straighten up. I had
00:25:57 --> 00:25:59 to go up to the bridge and help the captain
00:25:59 --> 00:26:02 by, you know, using my weight to stand at
00:26:02 --> 00:26:04 the. No, I didn't. Uh, but uh, it was um,
00:26:05 --> 00:26:07 pretty hair, uh, raising for a while there.
00:26:07 --> 00:26:09 We uh, made the news all over Australia
00:26:09 --> 00:26:11 apparently. But um, yeah, it was the Princess
00:26:11 --> 00:26:14 Cruise Line. Um, and we've been with them
00:26:14 --> 00:26:16 many times on other cruises and they're uh.
00:26:16 --> 00:26:19 I, I really enjoy them. Um, they
00:26:19 --> 00:26:21 probably uh, it's debatable but I
00:26:21 --> 00:26:24 think food wise they're probably the best.
00:26:24 --> 00:26:27 But yes, um, now, and you
00:26:27 --> 00:26:29 mentioned the. Sorry, go on. Br.
00:26:29 --> 00:26:31 Professor Fred Watson: I was just going to say if you want to avoid
00:26:31 --> 00:26:33 uh, the rigours of sea travel, you could come
00:26:33 --> 00:26:36 with Dark Sky Traveller. We go up to Iceland
00:26:36 --> 00:26:37 pretty regularly too. Yes, well, there's a
00:26:37 --> 00:26:38 thought.
00:26:38 --> 00:26:38 Andrew Dunkley: Yeah.
00:26:39 --> 00:26:39 Professor Fred Watson: Yeah.
00:26:39 --> 00:26:42 Andrew Dunkley: So the downside of cruising is it's slow.
00:26:42 --> 00:26:44 Yeah, I mean it's very relaxing. But if you
00:26:44 --> 00:26:47 do want to get somewhere in a hurry, it's
00:26:47 --> 00:26:49 probably not the way to do it. Um,
00:26:50 --> 00:26:53 and uh, Dave also mentioned the nightcap app.
00:26:53 --> 00:26:55 Uh, I do have that one on my phone. I haven't
00:26:55 --> 00:26:58 had an opportunity to really use it because
00:26:58 --> 00:27:01 it's um, there's too much light around
00:27:01 --> 00:27:01 here.
00:27:02 --> 00:27:04 Professor Fred Watson: Uh, what does it do, Andrew? What's the,
00:27:04 --> 00:27:06 what's the purpose of the nightcap?
00:27:06 --> 00:27:09 Andrew Dunkley: I haven't got my phone with me but uh, you
00:27:09 --> 00:27:10 can preset it to
00:27:11 --> 00:27:13 photograph in low light
00:27:14 --> 00:27:17 and, and you can either put it in manual
00:27:17 --> 00:27:19 mode or you can have this series of presets
00:27:19 --> 00:27:22 where you can, if you know what you want to
00:27:22 --> 00:27:24 photograph, it will set up the phone
00:27:25 --> 00:27:27 to create the exact situation you need to
00:27:27 --> 00:27:29 take that particular photograph. Yeah, yeah,
00:27:29 --> 00:27:32 it's really, it's really good software. Um,
00:27:32 --> 00:27:35 but I haven't really had a chance to use
00:27:35 --> 00:27:38 it properly. But it can do time lapse and all
00:27:38 --> 00:27:40 sorts of things. It's really good gear.
00:27:41 --> 00:27:44 Uh, so yeah, when and where
00:27:44 --> 00:27:47 and how to take low light
00:27:47 --> 00:27:49 photographs, Fred Watson, of meteors.
00:27:49 --> 00:27:52 Professor Fred Watson: That was meteors crucial thing. Yeah. From
00:27:52 --> 00:27:55 Dave's question. And yeah, so Dave up
00:27:55 --> 00:27:58 in Verrel will have pretty easy
00:27:58 --> 00:27:59 access to dark skies.
00:28:00 --> 00:28:01 Andrew Dunkley: Uh, yeah, that's, you know why? You know why?
00:28:01 --> 00:28:04 Because they're not putting the electricity
00:28:04 --> 00:28:06 on up there for another 10 years.
00:28:06 --> 00:28:08 Professor Fred Watson: Okay. Uh, sorry.
00:28:08 --> 00:28:11 Andrew Dunkley: Everyone asks, in the 30
00:28:11 --> 00:28:12 odd years I've lived here people have often
00:28:12 --> 00:28:14 asked do you have electricity where you are?
00:28:15 --> 00:28:17 Um, so I couldn't help that joke.
00:28:17 --> 00:28:20 Professor Fred Watson: No. Well you do. We did in Kun Durban as well
00:28:20 --> 00:28:22 but we were at the end of the line and uh, so
00:28:22 --> 00:28:24 if ever there was a thunderstorm we usually
00:28:24 --> 00:28:26 left our electricity, they were gone.
00:28:26 --> 00:28:28 Andrew Dunkley: Ah yeah, we had that problem the first 15
00:28:28 --> 00:28:29 years we lived here.
00:28:31 --> 00:28:33 Professor Fred Watson: Um, but they do have electricity in Varel and
00:28:33 --> 00:28:35 they also have dark skies. Relatively easily
00:28:35 --> 00:28:38 accessible by just driving up a few
00:28:38 --> 00:28:41 few kilometres further up the highway one way
00:28:41 --> 00:28:41 or the other.
00:28:42 --> 00:28:44 Um, so, so meteors. Um,
00:28:45 --> 00:28:46 yeah. Dave's question, how many meteors are
00:28:46 --> 00:28:49 coming in? Uh, quite a large number. We think
00:28:49 --> 00:28:52 it's something like 100 tonnes, 50 to 100
00:28:52 --> 00:28:55 tonnes a day meteoritic material hits the
00:28:55 --> 00:28:58 atmosphere that's worldwide. Uh, but that
00:28:58 --> 00:29:00 means there are billions of meteors streaking
00:29:00 --> 00:29:01 through the atmosphere because most of them
00:29:01 --> 00:29:04 are specks of dust. Um, and they
00:29:04 --> 00:29:07 can, yeah, sporadic meteors as they're
00:29:07 --> 00:29:08 called, they can whiz through the earth's
00:29:08 --> 00:29:11 atmosphere at any time. People talking about
00:29:11 --> 00:29:13 this stargazing I was doing at uh, Sea
00:29:13 --> 00:29:16 Lake uh in rural Victoria last week, um,
00:29:17 --> 00:29:19 quite a few people were spotting meteors as
00:29:19 --> 00:29:21 they flashed through the sky. I was looking
00:29:21 --> 00:29:23 at screens so I missed a, most of them. Um,
00:29:24 --> 00:29:27 but uh, probably the
00:29:27 --> 00:29:29 time to uh,
00:29:30 --> 00:29:33 really concentrate on uh, if you serious and
00:29:33 --> 00:29:35 I think you kind of need an all sky lens
00:29:35 --> 00:29:38 effectively for good meteor photography. Um,
00:29:39 --> 00:29:42 um, uh, the new generation of
00:29:42 --> 00:29:45 phones do have very wide angle lenses
00:29:46 --> 00:29:48 but they're not fisheye in the sense that you
00:29:48 --> 00:29:50 can see the whole sky. Uh, but they're wide
00:29:50 --> 00:29:53 enough probably to use the
00:29:53 --> 00:29:55 snag with them is that they've got a low
00:29:56 --> 00:29:59 uh, uh aperture. So a
00:29:59 --> 00:30:02 high focal ratio, uh, you know
00:30:02 --> 00:30:05 the ratio of the focal length to aperture and
00:30:05 --> 00:30:07 what you need is a low focal ratio to give
00:30:07 --> 00:30:09 you fast imaging, it's what we call a fast
00:30:09 --> 00:30:12 lens. Whereas these wide angle ones tend not
00:30:12 --> 00:30:15 to have that. Uh, and so you're tossing up
00:30:15 --> 00:30:17 you know, the relative merits of a very
00:30:17 --> 00:30:19 wide angle view or
00:30:20 --> 00:30:23 likely to capture more meteors or a narrow
00:30:23 --> 00:30:25 angle of view. But greater sensitivity, so
00:30:25 --> 00:30:27 you'll see fainter meteors. So, um,
00:30:28 --> 00:30:29 that's, you know, taking all that into
00:30:29 --> 00:30:32 consideration. I, um, haven't tried meteor
00:30:32 --> 00:30:33 photography with my phone. I've done a lot of
00:30:33 --> 00:30:36 aurora borealis photography with it and that
00:30:36 --> 00:30:38 works really well because they're sensitive.
00:30:38 --> 00:30:40 But it will be an interesting thing to try.
00:30:40 --> 00:30:43 Uh, it's the fact that you need the shutter
00:30:43 --> 00:30:45 open for a long time. But I guess what you
00:30:45 --> 00:30:47 can do is just keep on taking short
00:30:47 --> 00:30:50 snapshots. Um, the point I was going to
00:30:50 --> 00:30:53 get to is when you think about the Earth, uh,
00:30:54 --> 00:30:56 in its orbit around the sun,
00:30:56 --> 00:30:59 uh, the forward facing side of the orbit
00:30:59 --> 00:31:01 is where you are after midnight.
00:31:02 --> 00:31:05 So after midnight means that you're
00:31:05 --> 00:31:07 on the leading edge of the Earth and that's
00:31:07 --> 00:31:09 where you're going to get the most meteors.
00:31:09 --> 00:31:12 Basically, uh, as the Earth, uh, ploughs
00:31:12 --> 00:31:14 through the various clouds of dust, you've
00:31:14 --> 00:31:17 got meteor showers which come from big clouds
00:31:17 --> 00:31:19 of dust that the Earth goes through. But
00:31:19 --> 00:31:22 these things are always best seen in the
00:31:22 --> 00:31:24 early morning, um, when you're on the side
00:31:24 --> 00:31:27 after midnight. So that's the best advice I
00:31:27 --> 00:31:28 can give. I'd be interested to hear how you
00:31:28 --> 00:31:31 get on Dave and, uh, what sort of results you
00:31:31 --> 00:31:31 might get.
00:31:31 --> 00:31:34 Andrew Dunkley: Yeah, yeah. And if you do get a couple of
00:31:34 --> 00:31:35 good ones, send them in and we'll, we'll, um,
00:31:36 --> 00:31:38 post them on our Facebook page or you can
00:31:38 --> 00:31:39 post them yourself on the Facebook group,
00:31:39 --> 00:31:41 whatever you like. Um, love to see what you
00:31:41 --> 00:31:44 come up with. We do get, um, some great
00:31:44 --> 00:31:46 astronauts of photography from space, uh,
00:31:47 --> 00:31:48 arts listeners on the Facebook group
00:31:48 --> 00:31:51 sometimes. So, yeah, um, more than happy to,
00:31:52 --> 00:31:54 uh, have you, uh, post them
00:31:55 --> 00:31:57 on that page, Dave, and
00:31:57 --> 00:31:59 hopefully that will help. But, uh, yeah, uh,
00:31:59 --> 00:32:01 the idea of having to get up and do it at the
00:32:01 --> 00:32:03 middle of night, not, not appealing. But, uh,
00:32:03 --> 00:32:05 that's life in astronomy, isn't it,
00:32:05 --> 00:32:05 Fred Watson?
00:32:06 --> 00:32:07 Professor Fred Watson: Tis a bit, yeah.
00:32:08 --> 00:32:11 Andrew Dunkley: Yeah. All right, Dave, thanks very much for
00:32:11 --> 00:32:12 your question. Don't forget, if you've got a
00:32:12 --> 00:32:14 question, send it in to us because we'd love
00:32:14 --> 00:32:17 to try, uh, and answer it. No guarantees, of
00:32:17 --> 00:32:19 course, uh, but you go to our website,
00:32:19 --> 00:32:22 spacenutspodcast.com spacenuts
00:32:22 --> 00:32:25 IO Click on the AMA tab and you can send, uh,
00:32:26 --> 00:32:28 uh, questions there, audio or text. Just
00:32:28 --> 00:32:30 remember to tell us who you are and where
00:32:30 --> 00:32:33 you're from and we'll do the rest. Or
00:32:33 --> 00:32:36 Huw in the studio will, if he ever turns up
00:32:36 --> 00:32:38 again. He didn't turn up today.
00:32:39 --> 00:32:41 I don't know what he was doing. Probably
00:32:41 --> 00:32:43 trying astrophotography in the middle of the
00:32:43 --> 00:32:46 day. Just never listens to us.
00:32:46 --> 00:32:49 That's his problem. Uh, Fred Watson, thank
00:32:49 --> 00:32:52 you as always and, uh, bon voyage.
00:32:52 --> 00:32:54 Have a safe journey. Uh, enjoy your time in,
00:32:54 --> 00:32:57 in Japan and Ireland and the, uh, UK
00:32:58 --> 00:33:00 and uh. Yeah, and, and look forward to
00:33:00 --> 00:33:02 hearing about your travels when you get back.
00:33:02 --> 00:33:05 And we will welcome, uh, Jonty Horner from
00:33:05 --> 00:33:08 the University of Southern Queensland, uh,
00:33:08 --> 00:33:11 with, um, Space Nuts for the
00:33:11 --> 00:33:13 foreseeable future. So take care,
00:33:13 --> 00:33:14 Fred Watson, and thank you.
00:33:15 --> 00:33:17 Professor Fred Watson: Thank you, Andrew. Uh, I'll miss you all,
00:33:17 --> 00:33:19 but, um, I'll be glad to come back and, uh,
00:33:19 --> 00:33:21 talk to you sometime before Christmas.
00:33:21 --> 00:33:23 Andrew Dunkley: Okay, catch you then, professor, uh,
00:33:23 --> 00:33:25 Fred Watson Watson, astronomer at large, and
00:33:25 --> 00:33:27 from me, Andrew Dunkley. Thanks again for
00:33:27 --> 00:33:29 your company. We'll see you on the very next
00:33:29 --> 00:33:31 episode of Space Nuts. Until then, bye
00:33:31 --> 00:33:32 bye.
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