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SN350: Questions Time · Space Nuts: Astronomy Insights & Cosmic Discoveries

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Hello, thanks for joining us. This is Space Nuts. I'm Andrew Dunkle,
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your host, and it's so good to have your company once again.
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And coming up on this episode, it is all questions because it's episode three
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hundred and fifty, and that's when we dedicate our show to the audience to
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nail down such questions as those of stellar mass, black holes, our place
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in the universe, and where that place might be in the future because it's
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moving. Is there a size limit to rocky planets. We're going to look
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at expansion limits, expansion effects, asteroids, space time, and photons.
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All questions coming from our vast audience of nine here on Space Nuts. Hope
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you can hang around a while. Dan Sack and Rad in Ternel ten nine
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Magnian sequenced Space Nuts three two two one Space Nuts and actually report a bill
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good and joining me to discuss all of that and much much more is Professor
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Fred Watson, a storm Er at Large. Hello Fred, Hello Andrew,
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very good to be at large again. If I haven't caught you yet,
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not at all. We've got a smashing program. It's there's so much to
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talk about today, so I think we'll just hose straight in and get stuck
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into it. And our very first question comes from none other than Hallo Space
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Nuts, Margin Burman Gorvyn here, writer extraordinaire in many genres, and today
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we're crossing my strength in science fiction with horror as we ask how close could
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a spacecraft with human beings aboard realistically get to a stour mass black hole before
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all the inside our fried and or linguinified, which I think sounds better than
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spaghettified, don't You can't wait to hear the answer? Margin Burming Gorvine in
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Potomac, Maryland here over and act linguinified. Yeah, yeah, with that
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or with that? Yeah that's not bad? Um? Yeah, how close
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is too close? So I suppose the answer is it depends? Uh,
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it does, doesn't it? Yeah? I am um so somewhere and here
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we go. This is the the usual um tribute to one of my books,
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but I can't remember which one, which Chat's five episodes? Sorry,
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I'm not naming any at least I don't think I'm going to um. I
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did write about the event. Horizon divers are a stellamass black hole, and
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I can't remember what it is, but it's it's relatively compact, measured in
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kilometers if I remember rightly, But the event horizons not really what would sort
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you out in you know, in the answer to Martin's question, because yes,
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you'd be linguinified spaghettified. You probably would even be result of fired as
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well, because you might end up in bids when you got within a much
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closer distance. Um, So here is a something I'm pulling out of my
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memory from only about four weeks ago. There is a there's a gas cloud
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which is currently orbiting the it's not orbiting, it's passing by the supermassive black
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hole in the center of our galaxy. Now that's not a tellomass black hole,
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which is what Martin's asking about. This is a three point six million
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stellar mass black hole. This, this gas cloud is passing within a few
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trillion kilometers if I remember rightly, of the black hole, and it is
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being spaghettified. It's been watched, it's been observed to do that over quite
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a long period. Notwithstanding that a few more million trillion kilometers there are stars
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happily in orbit around the supermassive black hole. So I don't haven't done the
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calculation, Martin. It's probably conjecture as to you know what, at what
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level do the tidal forces separating your head and your feet start to become significant
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enough that they overcome the the you know, the stomic forces which are holding
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your atomies together. And that's a calculation that I haven't done. But it's
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even for a stellar mass black hole, it's probably not very far away.
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I think the title forces that you would experience would would really start to make
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things uncomfortable, Okay, And which one is the stella mass black hole?
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Again, in terms of the size of black holes, it's the massive one
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star. Stella mass is one star, right, Okay, gotcha, hen's
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the name. Yes, sorry, sorry, I'm I'm being lived there,
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But that's right. It's an object of the order of the massive one star,
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which sometimes includes things up to twenty or thirty times the mass of the
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song. But it's still not a super massive black hole. And it's not
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the other thing that we've talked about from Touch to Town. The intermediate mass
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black calls things of order a thousand times the mass of the song, which
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which quite rare, we believe, and very much unlike the ultra massive black
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hole that we talked about four weeks ago, that's bigger than big. Just
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wait for the hypermassive black hole. That's the next one to come up.
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Well, it could happen, couldn't it? And did it? Could?
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You just never know these things, these like we when we started the podcast
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and write through several episodes or several years of episodes, we could only confirm
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there were two yes, moall and large. Now we've got yeah, yeah,
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loads different, including that ultra massive black hole that we talked about.
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That's sort of pushing the limits of which we thought black holes could exist.
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We thought that couldn't exist. I can't remember what it was. Was it
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thirty billion or thereabout? It was some astronomical numbs a huge number. Yeah,
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yeah, yeah, it was amazing. Um. So the answer to
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Martin's question is, in real terms, you could get reasonably close, but
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not but not that close. Sorry Martin, we haven't given you another for
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at all. We've just talked about. But reasonably close is what I think.
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Yeah, I don't think you'd want to get you know, if it
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was at the center of the solar system. I don't think you want to
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get much nearer than such an r neptune. Sorry, your readers, so
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well, no one wants to get hear that now. Okay, so Martin,
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that's a very loose answer to your question, but it's a good question
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because you know, one day we might be able to get out there and
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get close to one of these things, and you just really, you really
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didn't need to do your mathematics before you lined yourself up. Bring it.
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Who came out of your space warp ups? I mentioned the name and got
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too close. Yeah, all right, thanks Martin. Great to hear from
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you. Let's go to a text question. This actually came in via email
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from Andrew. He says, I love the show. I have a science
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question. Does our Sun move its position as the planet's orbit? If so,
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by how much? Thanks? Andrew? Hit reply to respond. Now
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we'll just talk about that. Yeah, it's a great question, and the
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answer is yes, it does. And so basically the bottom line here is
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that the Sun in a sense, is not the center of the Solar system.
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The point at the center of the Solar system is something called the Barry
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center, which is the sort of it's like the center of gravity of the
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Solar System. So it includes not just the Sun but also the planets,
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of which really only one counts in this argument, and that's the planet Jupiter,
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which is, you know, the most massive of the Solar System's planets.
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So, but the Barry center, that's to say, this center of
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gravity does actually move around with respect to the Sun, or should I say
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the Sun moves around with respect to the Barrier center. And it's that process
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that actually allows us to detect the planets of other stars. Because if you've
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got if you've got a object in deep space, a star, you know,
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one hundred light years away, all you can observe is its light and
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its spectrum. But what you can see is it's velocity changing slightly as the
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planets pullets, you know, slightly one way or the other. And you
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can actually disentangle how many planets there are around at the star without being able
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to see any of them, just by knowing how the star moves with respect
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to the barri center. It's that movement that you can see reflected in the
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star's velocity. And in fact, we can now detect motions of stars with
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an accuracy measured believe it or not, in centimeters per second. Rather than
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well the work I did, you were doing well if you got down to
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a kilometer per second accuracy, but meter per second accuracy has been attainable for
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a long time, but now people are talking about sentimeter per second accuracy in
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the speed of a star that you can detect if I remember rightly, the
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planet Jupiter changes the Sun's velocity by around eleven meters per seconds, right to
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detect. Yeah, if to detect a Jupiter sized planet in the same orbit
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as Jupiteres, but around another star rather than the Sun, you would see
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motions of that star of eleven meters per second as it moves with respect to
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the Barrit Center. Now, Andrew's other part of his question was how much
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does it move? How much does the Sun move with respect to the center
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of gravity of the Solar system, And it's basically not much, but that
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Barry center does actually from time to time it is outside the Sun rather than
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being within it. So you're talking about the Sun moving by, you know,
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some fraction of its diameter. It might be quite a large fraction.
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It's not millions of kilometers. It's well, actually the Sun is one point
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formula kilometers in diameter, so it might be millions of kilometers, but but
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you know, more likely to be tens of hundreds of thousands. That's which
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means that the Barris center is for the most part inside the Sun, but
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it does occasionally go outside when you reckon. When you include the effect of
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all the planets that include Saturn as well, it's one of the Jupiter.
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I suppose the other way to describe the movement would be that that wobble we
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talk about when they're trying to detect planets around other stars, that that's one
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of the mythos, isn't it. Yeah, exactly what that wobble is the
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eleven kilometers per second in the place of Jupiter el the song Dopler wobbles technique.
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It's called yeah, yeah, very good. Thanks Andrew, hope you're
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doing well. Let's go on to our next question. This comes from Tom
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in Ireland. He said, Hi, my brain hurts, please help.
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Paracetamol or iberprofen is very good. For that time, thirteen point eight billion
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years ago, the universe began and has been expanding ever since. How is
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it that we can see objects up to twelve billion light years away in one
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direction and also in the opposite direction. If we are seeing these objects where
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they were twelve billion years ago, which means they were twenty four billion years
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apart. How could they have originated at the same point thirteen point eight billion
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years ago? Please help love the show Tom in Ireland. I think he's
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getting his light years and his universal age years mixed up. Possibly, No,
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it's it is. It's a confusing thing because yeah, and your age
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years is a good point, because we talk in terms of lookback times.
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That's the kind of usual phrase, and so it's misleading to say Gallex is
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twelve billion light years away and unless you qualify it by adding in the in
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the co moving coordinate system, and not many people do, I know,
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I don't know. There you go, So the bottom it's better to talk
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in terms of look back times, because that's the sort of fundamental thing.
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When you see an object in very the very distant universe, it's seeing it
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as it was, maybe when the universe was one point eight billion years old.
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If it's if it's got a twelve billion year lookback time, but it's
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actual distance is much more than twelve billion light years, because the universe has
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expanded by a huge amount since their light left that object. So the the
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what you might call in fact, it's got a name, it's called the
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proper distance would be something like thirty maybe thirty five billion light years away because
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of the expansion of the universe. But that's something that you can't actually measure
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in any way, that distance, because all we see is the light that's
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reached us after it's twelve billion year journey. And so it's more accurate to
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talk about look back time of four billion years than to say a distance of
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a look back time of twelve billion years, rather than a distance of twelve
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billion light years, unless you say it's a co moving distance, which is
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the distance which doesn't account for the expansion of the universe. Good grief kind
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of equates to the question we often get about where is the center of the
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universe and where we are? Where are we in it? Well, we
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are in it, that's rightly speaking. Yeah, so sorry, and Tom,
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I didn't really answer probably the address your question about things being separated by
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twenty eight and sorry, twenty four billion light years. And that's all that
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is saying, Yes, we see things receding from us in different directions.
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And the Hubble law seems to work everywhere whatever direction you're looking, and the
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Hubble law is the one that relates. It's this velocity of the velocity away
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from us of an object to its distance. It's how we know that redshift
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equals distance in the you know, standard cosmological model of the universe. So
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what what that is telling you is that the universe, first of all,
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is extremely big. And we think that when it kicked off within the first
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gazillions to the second, in fact, about tenth of minus thirty three of
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us and if I remember the number rightly, it expanded very violently in this
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period we call the Age of inflation, which only lasted a few quintillions of
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a second, but blew up the universe from the size of a p to
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the size of a galaxy. And then the expansion sort of settled down.
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But that's how we think. That's why we think the universe looks the same
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in all directions, even though it's very very large and the distances separating objects
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is very very extreme. We think at one time everything was very close together,
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and then it wasn't. And that's why we she what was she today?
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Okay, Tom's headache is throbbing now, Yes, probably, Yeah.
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I go for asprints, actually you know you do? Yeah, yeah,
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I just go around trying to find willow trees and lick the bark. Okay,
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all right, I wondered what you were doing. That's that's a natural
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pankiller. I didn't know that. Hell, that's that's I think that's how
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aspurin was invented. Not sure something like that. Yeah, willow is a
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natural has a natural painkilling property in it. It does. Thank you,
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Tom. Great to hear from you. This is space Nuts with Andrew Duntley
17:15
and Professor Fred. What's a space nuts? Now? Fred to a regular
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contributor to our question answer session, and it's Duncan from Weymouth. I think
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I'm pretty sure he'll tell me that's where he's from. Hello, Duncan.
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Hear from Weymouth in the UK. Another quick question. I know that Andrew
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likes hypothetical one, so here's one that's been bugging me for a while.
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If you could get a huge mass of rock together, say, well,
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I don't know, a hundred times Jupiter's mass of solid rock in one place
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and put it in either they wore a bit around a star. Would it
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form a really massive rocky planet? Or is there an upper limits to how
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big or how massive a rocky planet can be? Just interested to know and
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if it couldn't form a massive, massive rocky planet, what would actually happen
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to that rock to prevent it becoming a rocky planet. Would it somehow not
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be able to be bound together, or would it melt or boil and form
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a gas or what would prevent that? Okay, keep up the good work
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and thanks for your efforts. Bye bye, thank you. Duncan m I
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kind of become a type of belt or an asteroid belt or something like that
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if it couldn't form a planet would have to sort of break up like that?
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But how big is the limit? That's they So, yeah, it's
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a really interesting question. And I think the limit is imposed is imposed not
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by the physics of how big something can be. It's more about how things
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evolve when planetary systems are formed. So we think that rocky planets do evolved
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by the sort of silicon material in the original dust and gas cloud that formed
19:34
the Solar System. We think that stuff all stuck together became solidified turned into
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rock. These bits are rock bashed into one another, some stuck together,
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some didn't. But in the end you got planets building into a sort of
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rocks building into planetismals and then to protoplanets and eventually two planets. But this
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is all taking place within an environment that is very very gasy. And if
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you form rocky cause that start getting very big, you will also a mass
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gas you want just you don't want just to create rock, you'll acret gas
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as well. And that's why we think the gas giants are gas giants,
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because they grew big enough that they not only collected more bits of rock,
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they actually collected very significant envelopes of gas around them. And it sort of
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helped as well by them what we call the frost line or the ice line
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in the Solar system, that region which is between the orbits of Miles and
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Jupiter, where where ice actually forms because the temperatures low enough. Yeah,
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and so that the you know, the limits are more about the way you
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form planets rather than what could exist. Um, whether a hundred jupiter mass
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I mean a hundred jupiter mass solid, a hundred jupiter mass object is is
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actually a star because I think the the mass linits for brown dwarfs, is
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is it thirteen jupiter mass is up to about eighty I think in something in
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that range will produce deuterium burning and become what's called a brown dwarf star.
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But if you get above that, then you've got a dwarf star. Um
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So, but that's assuming it is made of gas. I think that the
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physics present prevent you from forming a rocky planet with anything like that kind of
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mass, because it would have created gas rather than create just more rock.
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Okay, that's that's pretty good though. I think we are discovering rocky planets
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that are much much bigger than Earth. Yeah, that's sort of up to
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neptune mass. But they're called super earths, so that yes, So what
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that's saying is that we we perhaps haven't achieved that limit within the Solar System.
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Yeah. Well, in the scheme of things, our rocky little world
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is actually one of the smaller ones, isn't it in real terms? Yeah,
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although it's hard to you know, the bottom line is that we're not
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really yet able to detect all the smaller planets that around stars because it's harder
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to detect them. You can do and there are programs that that you do
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that. Gravitational lensings. Want transit method lets you do it as well.
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But the and perhaps you know, the Kepler and tests spacecraft have both contributed
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many objects which are small compared with you know what we used to be finding,
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which were always the Jupiter of us. Things are bigger, so we
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are finding rocky planets. But there's still I think, gaps in our knowledge
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because when I've got the technology yet to define the smallest ones, so when
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we get that perfected, we might find a whole bunch thinks that a smaller
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than the Earth as well. Yeah, okay, thanks Duncan. Always good
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to hear from you. Jim is next. He's from something I can't pronounce,
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New Orleans. Yeah, New Orleans, it's Jim dear, Professor Watson,
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and mister Dunkley. I've been traveling by car a lot in the past
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year and was able to catch up on all your podcasts thus far, Blimy,
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I truly enjoy the show and look forward to the next episode. Onto
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my question. Because the bodies in the universe are accelerating at an ever increasing
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rate, eventually there will come a time when space time will become impracticable or
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space travel will become impracticable, if not impossible. What I mean is that,
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eventually, as a result of increasing excel leration, the velocity at which
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galaxies and their component parts move through the universe will attain a substantial percentage of
24:06
the speed of light. If we cannot build spacecraft that attain speeds greater than
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that substantial percentage of the speed of light, then it seems that when a
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spaceship leaves the Earth's gravity, well, the Earth will become unreachable by the
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spaceship because the spaceship cannot catch up. Can this be right? There must
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be something that I'm missing. Thanks for your thoughts. Have a great day,
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Jim. Yeah, that's I can see where he's coming from. It
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is a quandary, And yes, we have talked about the fact that as
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things expand, we're eventually just going to be totally isolated in the universe.
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We won't be able to see anything else, which is due to happen in
24:45
a couple of days. But what yeah, yeah, indeed, what's the
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what's the answer to Jim's quandity? I think on the body actually, because
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yes, if we look into the distant future, when the expansion has accelerated
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so that you know, you're talking about a hugely greater expansion of space time
25:12
than we have at the moment, things will disappear beyond the horizon because the
25:19
light that's leaving them now will never catch up with the expansion of the universe,
25:23
so we won't see them. And that's the point that you were just
25:26
making, Andrew, that we will have a very lonely existence when you look
25:32
a few trillion years perhaps down the track, because there won't be anything other
25:40
than the local group of galaxies visible. Maybe the local group will disappear as
25:45
well. And I suppose what Jim's question about the spacecraft really means is that
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if the spacecraft could get far enough from the Earth so that it was being
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carried away from the Earth due to the expansion of the universe by a velocity
26:07
higher than the velocity of the spaceship could have achieved, then yes, you're
26:11
right, you will abs get back. You'd never never make it back.
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So yeah, it's an interesting conjecture, and the universe very different from the
26:22
one we live in today than It's a horrifying thought, though, isn't it.
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Let's go visit that rock. Oh it's gone, yeah, and we
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can't get back. Not good, thank you, Jim. On a similar
26:36
kind of playing field, Paul in Melbourne says there has been talked recently about
26:41
the energy that causes the universe to expand coming from black holes. If this
26:45
is so, then wouldn't we see the space time around or near a black
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hole expanding at a faster rate than that further away from black holes, for
26:55
example, between galaxies or that in the spaces between the filaments of the cosmic
27:00
web. Wouldn't the filaments of the cosmic web be expanding faster? And it's
27:06
pretat data. Yeah, I'm just trying to remember what the mechanism wants that
27:11
linked and quite get my head to it that linked black holes with the dark
27:21
energy, which is what, you know, what is the thing that we
27:27
think drives the expansion of the universe. Dark energy seems to be very much
27:33
a property of space itself, a uniform property that that's the same wherever you
27:38
look. So Paul's question is is an interesting one. So and I can't
27:45
remember the exact link between the mechanisms within black holes and the dark energy,
27:55
because yes, you know, it's an intuitive thought if if dark energy coming
28:00
from black holes, then the region around black holes should be expanding more than
28:06
the region elsewhere. But we already observe the fact that that doesn't happen.
28:11
We do see space time distorted around black holes. But that's due to their
28:15
gravitational attraction. That's the standard general relativity distortion of space time that we see,
28:25
you know, whenever we find gravitational lenses, for example. So,
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as I said, the point about dark energy is, say it is a
28:36
phenomenon that is a property of space. I would have to I'd have to
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look back at what I was reading up on the mechanism that feeds the energy
28:48
of black holes into the space around them to be able to give an answer
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to pulse question. So I'm a bit embarrassed that I can't do that.
28:56
I mean, it was about well, it must have been at least two
29:00
months ago when we talked about this. Yeah, I guess, so I
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don't remember the conversation. I just yeah, I just can't recall it.
29:07
Is it is that paper I don't think has been refuted, the one that
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suggests that maybe black holes could provide the origin of dark energy. And I
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wish I could there is a there's a there's a point about it which I'm
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just not not able to recover at the moment from the memory bikes. Yeah,
29:27
I could have a quick look and see if I can find the article,
29:30
but gosh, I don't know. There's yeah, there's there's plenty of
29:36
articles about it, So which one do you pick? But yeah, it's
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certainly got a lot of interest at the time. Will continue. So we're
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talking, we're talking mid February when that first came. Yeah, so you
29:47
know it's fair enough that at our age we've forgotten. I felt we remember
29:52
the was there? Yes, yes, indeed, So Paul, I might
29:56
try and look at that again and we might get back to if we don't
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forget. Thanks entire conversation. I'll put an asterisk next to his question.
30:07
Follow up. All right, thank you, Paul, Thanks for sending in
30:10
the question. This is Space Nuts Andrew Duncley here with Professor Fred Watson.
30:18
Great Space Nuts. Okay Fred, a few more questions before we wrap it
30:26
up. And this one comes from Western Australia and our good friend Rusty,
30:30
actually, to be more specific, Rusty's wife. Hello, Space Nuts.
30:34
It's Rusty and Donnybrook. My lovely wife Ally came up with a question about
30:40
asteroids and she's seen a few movies with asteroid fields in them and wonders if
30:48
they're realistic, how close do they get and how often do they collide,
30:55
and I think I'm sure she'd love your answer. Cheers, Thanks, Rusty,
31:00
we are Yeah, asteroids are not an uncommon topic of questions either,
31:06
mainly the ones that are going to hit us or near nar hit us.
31:10
But yeah, a different spin on it, so to speaking, and a
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good one too, great question, because we you know, when you look
31:18
at depictions of the Solar System, the main asteroid belt, which sits between
31:22
the orbits of Males and Jupiter, is always portrayed as being full of asteroids,
31:29
asteroids everywhere in every direction. Whereas the bottom line here is, you
31:36
know Douglas Adam's famous quotation, space is big. You will believe how big
31:41
it is. Anyway, it's big. What was it? You might think
31:45
it's a long way. You might stret a long way down the street to
31:47
the chemist. That's right. Anyway, there is a lot of space between
31:52
them. So, as witnessed by the fact that I can't remember how many
32:00
is it must be this five. About eight or nine spacecraft have gone through
32:06
the asteroid belt, including Galileo Cassini, two Voyagers to two Pioneers New Horizons.
32:15
They've all gone through the asteroid belt and of course been completely unscathed.
32:21
On having said that, the second part of rust wife's question, I'm sorry
32:29
I didn't catch your name, But the second part is do they collide?
32:34
And the answer is yes. From time to time they do, which we
32:37
see usually as a plume of material coming from an asteroid that's being accidentally observed,
32:45
usually because since part of the field of view of something else, so
32:50
some nondescript asteroid will suddenly start looking like a comet. It will get a
32:53
tale of material, a bit like Demorphus did after it was clouted by the
33:00
Dart spacecraft. So you get this usually reasonably straight lined cloud of material which
33:07
is interpreted as having been a collision between two asteroids. We think we've even
33:14
observed one in the planetary system of another star. The star is Famulo.
33:20
It's a bright star in our southern skies, and over a number of years
33:25
that's been observed to have an object going around it. We covered this,
33:30
I think a year or so ago Andrew, which was thought to be a
33:34
planet. They gradually got fainter and eventually disappeared, And the thinking is that
33:40
what we actually were looking at was the debris cloud from two large asteroids that
33:45
it collided. That collided because that thing's vanished altogether now as the debris cloud
33:52
disperses, so they do collide relatively rarely because the space between them is so
33:59
it's big. Yeah, I mean, going back a few billion years,
34:02
it was probably a lot more collisions. There's a lot more stuff out there
34:06
to hit each other in close proximity. In fact, that we give that
34:08
period a name, it's called the Late Heavy bombardment about three point eight billion
34:13
years ago, when the place was full of debris charging around and bashing into
34:17
other things, including Earth. Yeah, including Earth. That's right. Indeed,
34:23
Thanks Rusty and spouse. Let's get let's go onto annex. Question from
34:30
Renny all right, this is ready from West Hills, California, with another
34:37
question. I'm trying to understand what space time is made out and why it
34:44
bends when it interacts with matter. I envisioned space climb as an invisible energy
34:50
force pushing against some object of matter, which is another form of energy,
34:55
where they to find a balance, which is gravity. Am I correct?
35:01
Yes? And the answer to your question is it's made up of space end
35:07
time. Yeah, that's the trouble. Nobody really knows what space time is,
35:14
but I can qualify that a little bit further because whatever it is,
35:20
yeah, you know, we glibly talk about the fabric of spacetime bending under
35:24
the action of mass. Renny is quite right. It's really hard to get
35:29
your head around that because back in the eighteen eighties we got rid of the
35:35
idea that there was an ether something that actually permeated space and allowed light to
35:40
pass through a medium that would transmit light that got thrown out, and the
35:45
consequence of that was actually the special theory of relativity, which says that you
35:51
know you're in the speed of light is the same everywhere because the experiments,
35:54
the Mikolson Morley experiment as it was called, to measure the ether relied on
36:00
the fact that you should see the speed of light changing depending on what direction
36:05
you're moving through the ether. And we're not moving through the ether, so
36:08
the speed of light doesn't change. And that then brings up special theory of
36:13
relativity. So we really don't know what it is. But I think you
36:22
have to look at the big picture here, because the big picture says,
36:27
well, there are two sort of pivotal theories on which we base our view
36:35
of reality. General relativity, which works incredibly well for things on a large
36:42
scale and quantum mechanics, which works incredibly well for things on a small scale.
36:47
But the two are incompatible. They don't sort of sit together, and
36:52
that sparks back in Einstein's day. Actually the quest for a theory of quantum
36:59
gravity that would allow us to unite these two theories, which we're still looking
37:04
for. But one of the themes that I think is addressed by quantum gravitists,
37:12
if I can put them that way, people theoretical physicists who work on
37:16
this. One of the themes is that we're missing something, and what we're
37:21
missing is a more fundamental theory of space and time that underpins what we see
37:29
as space and time. In other words, there might be something else that
37:32
from which space and time emerge and hence space time. Many quantum theorists in
37:38
the last twenty years have proposed that, and most of the theories I mean
37:43
string theories one of those. It's that sort of idea that there's something there
37:49
that underpins what we observe in relativity and in quantum mechanics, and a kind
37:53
of deeper version of reality which may include additional dimensions. There is some recent
38:01
work that's being done on this, which we might talk about in coming weeks.
38:05
Andrew, that once again highlights that there might be this hidden reality beneath
38:13
space and time, which how do we probe it? That's the problem and
38:19
the suggestions that are being put forward by how we might deal with that in
38:22
a real situation, how we might actually try and peer underneath the gossom avail.
38:30
It's not gossom avail, it's a curse relativity. And on the other
38:36
side, quantum mechanics, also known as the banking industry. The banking industry
38:40
has got that as well as different realities. In fact, yes, I
38:44
think there are many places in the world where you can put to different realities.
38:50
Yeah, indeed, thank you, Renny, and hope that helped somewhat
38:53
now adequately. Now, finally we'll go to David, who is from Huntsville,
39:00
Alabama. First of all, I'm a huge fan of the show and
39:04
appreciate what you guys do to put new wrinkles in my brain. I look
39:08
forward to each Thursday for my space nuts fixed. My question is if a
39:13
photon does not experience time after it's been emitted, and the universe is expanding
39:20
greater than the speed of light, assuming the photon has an unimpeded line straight
39:24
towards the edge of the universe. Is the photon essentially trapped in time at
39:29
that point? Thanks keep up the great work kind of relates to a question
39:32
we had earlier. It does yet, and it presupposes the universe as an
39:37
edge, which we don't think it has. We don't know what it's got
39:45
will beget us an edge. It's got a banking industry surrounding it, a
39:51
pique veil. So if but if the photon, you know, to the
39:59
photons always traveling through the universe at the speed of light. Now, the
40:02
fact that it's the source of the photon and its destination are separating, are
40:12
being separated by the expansion of the universe greater than the speed of light,
40:16
doesn't matter to the photon. It just keeps ongoing. The fact that its
40:21
target is moving away from it faster than it's ever going to get there is
40:25
not a concern to the photon. It will still not experience the passage of
40:30
time, which is exactly what David said. That's what we think is the
40:35
case. We'll just keep going forever. I suppose, in a sense it's
40:42
the scenario that he he mentioned that it will just keep on passing through space
40:47
and infinitem because it's destination is not good. He is always going to be
40:52
further away that it will reach until the big rip an escape, yeah maybe,
41:00
or if there's a big rip, there'll be tidal forces beyond imagination that
41:05
would probably disturb everything as it. Yes, that's the big rip. There's
41:10
got consequences that we can't really envisage it at the moment, but it's definitely
41:15
not nice and it reminds me of that famous song I'm a Photon and I'm
41:20
okay, I Glow all day and I Glow all night and I Glow all
41:22
day stealing from Monty Python. Yeah, not quite, but nearly works as
41:30
well as the original Lumberjack song. Thank you, David. It's so great
41:37
to hear from you, and thanks to everyone who's sending questions. It's nice
41:40
to fill an episode with audience questions. And we've got a whole fresh batch
41:45
like one minute before we started, so that was that was good, and
41:47
that's why some of them sort of caught us out of left field because we
41:52
did what we usually do and went in totally unprepared. Sometimes works, So
41:59
if you do have a question for us, of course, send it to
42:01
us, because that's what it's all about. We love to interact with you
42:05
and we love to hear your voices. So where you can record through our
42:08
website, space nuts podcast dot com or space nuts dot io. Click on
42:13
the AMA link and you can record a question there, or send us a
42:15
text question, or you can just hit the tab on the right hand side
42:19
at the home page send us your voice message. And as long as you've
42:22
got a smart device or a computer or something dumber than that that's got a
42:27
microphone, you can send us a question. But we're taking text and audio
42:30
questions all the time. The more the merrier. And yes, don't forget
42:35
the hypotheticals. I love those hypotheticals. Fred, we're wrapping it up for
42:38
you yet another. It's a milestone. It is actually three hundred and fifty.
42:45
Kind of let that slip through to keep it. I'll believe it.
42:47
Yeah, fifty three hundred and fifty. Oh my gosh, it seems like
42:52
only six months ago we did episode. Probably a year ago we did episode
42:57
three hundred. That's a bit, wouldn't it, Yes, that will be
43:00
I have to be near a year would yes? That's a calculation there the
43:07
words we should get a life really come to by. Maybe we should thank
43:15
you Fred as always good good to tell Andrew take care all right, We'll
43:19
catch you soon. Fred Watson, astronomer at large part of the team here
43:22
adds Space Nuts and back at Space Nuts HQ, we say thanks to Hugh
43:29
for reasons we cannot comprehend, but anyway, thank you anyway, and from
43:34
me Andrew Dunkley, thanks for joining us each and every weekend for this latest
43:37
episode. We'll catch you on the very next one on Space Nuts. Bye
43:42
bye. You'll be listening to the Space Nuts podcast, available at Apple Podcasts,
43:50
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You can also stream on demand at bides dot com. This is been another
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