March 9, 2023

Moon Time - What? | Space Nuts #342

Hi there, thanks for joining us. This is Space Nuts. I'm your host, Andrew Dunkley. Hope you can stick around. We've got a lot to talk about today. What time is it on the moon? It's moon time.
It could be daytime, could be night-time. It depends where...

Hi there, thanks for joining us. This is Space Nuts. I'm your host, Andrew Dunkley. Hope you can stick around. We've got a lot to talk about today. What time is it on the moon? It's moon time.
It could be daytime, could be night-time. It depends where you are, but we're talking about real time.
We'll elaborate in this episode and offer up some solutions. There might be a new way to find Planet Nine. We're going to look at some sunrays on Mars and the dark Big Bang Theory. We'll also be answering some audience questions and much, much more on this episode of Space Nuts. "Throughout human history, exploration has actually been a key driver of improved timekeeping and geodetic reference models." The idea is how do you define time on the Moon. Do you have lots of different time zones, like we have on Earth? Or do you have a single lunar time zone? A joint international effort is now being launched towards achieving this. In this episode, you will learn the following: 1. How is time being defined on the Moon? 2. What is Planet Nine and can we find it? 3. Have Crepuscular Rays been seen on Mars for the first time? For more Space Nuts simply visit our website at where you can find our entire back catalogue, plus learn how you can join our crew and become a supporter and access the rewards that go with that. Come join our elite family. Connect with mus: Facebook: spacenutspodcast YouTube: @spacenutspodcast Twitter: spacenutspodcst Website: Loved this episode? Leave us a review and rating here on either Apple Podcasts or Spotify. It would be enormously helpful. Thank you.
#space #science #astronomy #news #podcast #spacenuts




[0:00] Hi there, thanks for joining us. This is Space Nuts. I'm your host, Andrew Dunkley. Hope you can stick around. We've got a lot to talk about today. What time is it on the moon? It's moon time.
It could be daytime, could be nighttime. It depends where you are, but we're talking about real time.
We'll elaborate shortly. There might be a new way to find Planet Nine. We're going to look at some sunrays on Mars and the dark Big Bang Theory. We'll also be answering some audience questions and much, much more on this episode of Space Nuts.
15 seconds, guidance is internal.
10, 9, ignition sequence start. Space Nuts. 5, 4, 3, 2. 1, 2, 3, 4, 5, 5, 4, 3, 2, 1.
Space Nuts. Astronauts report it feels good.

[0:55] And joining me to hash all of that out with a hash brown in hand is Professor Fred Watson, Stronger road large. Hello, Greg.
Yeah, Hush Brown are good and really well, actually. Thank you.
Thank you for mentioning it.
I have to say too.
I know they're a hard attack for breakfast. Yeah, quite so.
Welcome back to the real world in the same time zone as me. Are you still suffering from jet lag after yours sojourned to Europe?
It's not been too bad. Thanks, Andrew. I did hit the wall at nine o'clock for a couple of nights after the nine PM, I have to say, not nine AM, which would have been difficult.
But yeah, it's, it's pretty good. Thank you.
So far, so good. Excellent. Good.
Oh, and there's Muscat just we've never heard from Muscat.
Well, he just, he's kind of looking for somebody.
Yeah. Probably not you. Not me.
Ah, well, it's nice to hear from Muscat. Now we've got a lot to talk about.
What time is it on the moon, Fred?
It's probably hash brown time.

[2:06] Yeah. So this is what's prompted this piece of research or investigation that's actually going on.
I think it's being led from Europe, but includes pretty well all the world's space agencies. And so I think...

[2:26] The idea is how do you define time on the moon do you have lots of different time zones like we have on earth or do you have a single lunar time zone.
How does it all work and how do you deal with nuances like the fact that the moon is a much less.
Massive body than the earth it only has one eightieth of the mass of the earth and so the gravitational time the relative is the gravitational time dilation on the moon is different from what it was what it is on earth.

[2:58] So there's a very very tiny difference amounting to microseconds between the way clock stick on the moon and the way they tick on earth.
But the story kind of starts really with the fact that over the history of our exploration of the moon, every space mission that's gone to the moon has basically set up its own time system.
Usually they use the time back, you know, mission headquarters, wherever that might be.
That's clearly not going to work if you've got many, many experiments going on on the moon, perhaps many simultaneous missions on the moon, where you might have a permanent permanent base on the moon.
And so, I can imagine that the Americans have set up a base and the Russians set up a base that will have a meeting at seven o'clock using different times.
So you've got to, they've got a history of not keeping up with the world on time.
They stuck with the Julian calendar a lot longer than everybody else. Oh, that's true.
We switched to the Gregorian calendar. We were pretty slow at that in the, in the, in Pricknell.
Yes. 1752.

[4:13] Is that the famous case of where there were like 11 days lost and all those people got upset because they thought they were going to die or something?
Give us back our 11 days. That's exactly what happened. Yes.
I can't remember the, excuse me, can't remember the dates when the change was made.
I should do it because I've given talks about this stuff in the past.
That was a long time ago.
But yeah, 1752, there was a general election about the same time.
And that became a hot topic in the election, you know, the election material.
We're talking about a time where people still sort of didn't understand the whys and wherefores of things. And they thought that taking those days away would cause- Would have shown their life.
Yeah. It wasn't their life by 11 days or what it would turn out to be.
And the government had stolen it. Yeah, it's a good story.
Same as having your spirit stolen when your photograph is taken.
That was, yes, along the same lines. Yeah.
That's a fascinating story. If you want to look it up, it's on Wikipedia and a bunch of other websites.
It's a really fascinating story about those catch-up days.

[5:23] Back in the day. Back in the day. That's right.
And of course that same time system spread to Australia by nefarious means, I'm sure.
Coming back to the moon. Where we were.
Yeah, there is a, so there's essentially a set of discussions going on to basically to nut out an architecture that will oversee communications on the moon, navigation surfaces on the moon and part and parcel of that is time.
It's been called Lunanet, L-U-N-A-N-E-T, all one word, a bit like space nuts is all one word.
Lunanet is the architecture that is trying to be agreed. And a comment from Xavier Ventura Travesse, who is the European Space Agency's Moonlight Navigation Manager, who's coordinating the European Space Agency's contribution to Lunar Net.
Xavier says, Lunar Net is a framework of mutually agreed upon standards, protocols, and interface requirements allowing future lunar missions to work together, conceptually similar to to what we did on earth for joint use of GPS and Galileo.

[6:43] Now in the lunar context, we have the opportunity to agree on our interoperability approach from the very beginning before systems are actually implemented.
Hello, Marnie. Marnie's dropped in with you. Is that your coffee?
Thank you, Marnie. Told you you might get a coffee. Yeah.
That's great. Thank you.

[7:04] So that's basically what's happening. And, you know, in fact, there's another comment from an ESA navigation systems engineer, Pietro Giordano, who says, timing is the crucial element.
During this meeting, we agreed on the importance and urgency of defining a common lunar reference time, which is internationally accepted and towards which all lunar systems and users may refer to a joint international effort is now being launched towards achieving this.
And that's really what this story is all about. It's about people talking about how we set up time on the moon.
I'm just going to ask what may be a dumb question, but why can't they just go with Zulu time or international time?
Well, my guess is that that's what will happen.

[7:55] I've solved it. You solved the problem. UT1 is the universal time system that is agreed upon on Earth.
It comes from the International Bureau of Weights and Measures in Paris.
That's, I think, the organization that coordinates it all.
But the issue, though, is that if you've got lunar GPS systems and things of that sort, which by the way, some radio astronomers take a pretty deep view of because they want to put a radio telescope on the far side of the moon where you're immune from radio contamination from Earth.
If you put GPS satellites in orbit around the moon, well, you've kind of ruined that to start with.
Anyway, the issue is that if you're looking at really precise lunar timing, you have got this issue of the gravitational time dilation on the moon.

[8:57] There is a figure which, I haven't checked this, check this, but it may well be about right. Because the gravitational potential on the surface of the Moon is less than the gravitational potential on the surface of the Earth, the clock on the Moon is going to run faster than one on the Earth by about 56 microseconds per day. That is significant. That is really significant because GPS systems rely on nanoseconds.
Know, they're, they've got to be accurate to far better precision than that.
So you can't, so that's really the answer. The, the, the counter answer to your suggestion.
You can't just import terrestrial time. You've got to tweak it in some way.
You could, if you could just make a clock that runs 0.56 microseconds faster.
Couldn't you just change the speed of.

[9:57] Yes, that's right. So you've got, but then you've immediately got something different from UT1.
You can't just import it.
You've got, you can use it as the basis, but you've got to tweak it to allow for the, you know, to allow for the lower gravitational field.
So all of this sort of thing is clearly what these people are talking about.
Now why do we call it committee?
Yes, that's right.
If in doubt, form a committee is what you do. They even did that when Hans Lippehei turned up with the first telescope in the Hague.

[10:32] Yes, indeed in 1608, they formed a committee. That's what everybody does.
Anyway, there is a nice final comment from Xavier who I mentioned earlier.
Throughout human history, exploration has actually been a key driver of improved time and geodetic reference models, which is a really good point because exploration is what drove the invention of the chronometer, you know, the Harrison chronometer and all of that stuff so that you can find your way properly.
Yeah. And he goes on to say, it's certainly an exciting time to do that now for the moon, working towards defining an internationally agreed time scale and a common selenocentric reference, which will not only ensure interoperability between the different lunar navigation systems, systems, but which will also foster a large number of research opportunities and applications in Cislunar space. There you go. That's the words from the top.
Who would have thought it was so complicated to tell time on the moon?
Although it gives me an opportunity to razz my brother who, when growing up, couldn't understand how he was older than our sister because she was born in April and he was born in July. So how could he be older? He didn't get the concept of years.
That's interesting. Yeah. Yeah. It's always funny just hearing you try to figure it out.

[11:55] Well, yes. All right. So, moon time is yet to be established. Something that they may establish is a new way to find Planet Nine. What's that? Well, I like this story. We're going to look with our eyes. Yeah, that's the problem. That's what we've been doing so far. It doesn't work.
It's, um, it is a.
Add an issue that goes back you and I talked about this several times before but not recently which is why it was a nice story to cover the idea of course that there are several and it's quite a large number of the objects the icy asteroids.
Out there in the Coica Belt beyond the orbit of Neptune, whose highly elongated orbit seemed to align.
It's a particular cluster of those objects, and so their orbits are all aligned in one direction.

[12:58] Now, that's been disputed in more recent papers. What has been suggested is that that's just a selection effect.
Seeing that because we're only looking at the brighter objects.
And if you look at everything or you look at the whole cloud of Coelpheobel objects in orbit around the sun, beyond Neptune, you're going to find that that thing disappears.
However, the proponents for PlanetMine9 are confident that they are correct, that this curious alignment of the orbits is being caused by something that has not yet been discovered. And the suggestion is it's an object five to 10 times, the Earth's mass. And I think if I remember rightly, something like four times the diameter of the Earth was suggested, but that depends on its density, of course. So five to 10 times the mass of the Earth is the critical bit. And that's led to it being called Planet Nine, which has upset some other people who think Planet Nine is Pluto, but the international astronomical community doesn't think that is the case. Anyway, how do you...

[14:12] How do you discover Planet Nine? Well, looking for it doesn't seem to have worked.
No. And part of the reason is that the position where it's most likely to be is slap bang in the middle of the Milky Way.
And so it's really, it's hidden among gazillions of other stars.
You're looking for something whose distance is, if I remember right, it's thousands of of times the distance of the Earth from the sun.
So way, way out there in the depths of the solar system, you have to look for its motion to identify that it's not a star.
And things at that distance move very, very slowly through space.
So this suggestion though comes from Man Ho Chan, who is an associate professor in the Department of Science and Environmental Studies at the Education University von Kohn has written a paper called, What If Planet Nine Has Satellites?

[15:16] And follows through some of the tricks that that might bring for would-be discoverers of Planet Nine.
So if you, so the theory goes, if you have satellites of a planet like Planet Nine, As they orbit it, if they're in orbits that are anything but perfect circles, they will be heated by tidal interactions.
This is kind of what happens to the, well, particularly EO in orbits around Jupiter, that's squeezed and squashed by the gravity of Jupiter as it orbits.
That is why its temperature is high enough to make it the most volcanically active body in the solar system, it's erupting all the time. So this same idea, if you apply it to Planet 9, what you've got is a, essentially heating that is variable as the satellite goes around its planet.
That heating changes, or the temperature of the satellite changes throughout the orbit around its parent body, which in this case is the hypothetical planet nine.
That change is something that could be detected.

[16:39] And so rather than looking for desperately slowly moving objects in the Milky Way, what you look for is objects which are changing relatively rapidly, a heat signature, you could put it that way, that's changing more rapidly than what you would expect from any other object in the background.
It would be a variable object. And moreover, the author of this paper has pointed out that there is one telescope on Earth which would be eminently capable of detecting that at this enormous distance from Earth, and that is ALVA, the Atacama Large Millimeter, 7mm array, up there in the heights above San Pedro de Atacama at 5,000 meters and operated by actually a.

[17:34] I sort of it's in these three different organizations that operate Alma but one of which is the European Southern Observatory, which of course is very close to our hearts here in Australia because of our strategic partnership.
So this author is suggesting we should get Alma onto looking for satellites for Planet Nine, which is an extraordinary idea.
So, yeah.
Fascinating thought, except what if it's not a planet? What if it's a body of smaller objects, which is another theory as to what might be causing those gravitational effects?
That's right. There are a number of, you know.

[18:12] Planet-sized black hole is another one that's been suggested.

[18:17] But even such a weird and wonderful object as that might have satellites. That's the idea.
If the Planet Nine or the Planet Nine proxy, whatever it is, is compact enough and has satellites around it, then the tidal effects will still exist.
All right. So it's just an idea as to how we should look that's not actually happening as yet.
Sadly no, but it might go on the wish list for Planet Nine pundits and you never know, it might happen.
That, I mean, somebody might apply for time on Alma to do this.
And that could do the trick.
The other reason it's called Planet Nine is because when you ask the question, have they found it? The answer is nine.
I think it would be in Munich where it was last week. Two weeks in a row we've had the...

[19:09] Yes, we have. We're getting messages about it as well. Yeah, in tweets.
Yes, that's right. I do. All right. This is Space Nuts with Andrew Dunkley and Professor Fred Watson.

[19:25] Space nuts. Now we're going to talk about sun rays on Mars. This has been a rather amazing photograph that's been sent back by the Curiosity rover.
It also dovetails well with a photo that was sent to me by Rusty and Donnybrook of a similar situation looking out from his place in Western Australia.
Was asking why the Sun sort of split up into rays. And the answer on Earth is dust and sort of only letting through the rays of red light because the dust had scattered all the other colors in the spectrum, something to that effect if I'm remembering it correctly. But it doesn't look the same on Mars. It's a different effect. Maybe for the same reason, but a different effect.
Yeah, so you're right about the sunlight being red when it's really down on the horizon.
Sometimes it's dust, but actually the molecules of the atmosphere also scatter light.
So the blue light scattered out and we see this predominantly red light.
Now, I'm not sure what Rusty was sending you, but when we get this phenomenon, and everybody's seen it, the phenomenon of sunlight being sort of separated into.

[20:51] Individual raise by clouds blocking our view of the sun and you combine that with a dusty atmosphere then you get these rays of light shafts of light that are so obvious at sunset.
I've got a technical term that called a possible raise the school is a french roll reading evening twilight and so that that that you know they're very common and i find them fascinating.
Sometimes I've only seen this once and it was not very far from you where I used to live in Terry Hills in Northern Sydney.

[21:28] I saw those rays going right across the sky all the way from the setting sun on one side to the opposite what's called the anti solar point on the other side.
And occasionally you will see that and occasionally you'll see what looked like rays.
If you've got your back to the sun, you can see rays sort of coming out from the point exactly opposite the sun and they're called anti-solar crepuscular rays.
And actually there's a picture of them taken by Marnie some years ago in my book Cosmic Chronicles or what's he called in America, Exploding Planets and Invisible Stars.
That's right. There's a nice color picture of those anti-solar crepuscular rays.
So the chase, we now have a lovely image from Curiosity, the other rover on Mars that's still going strong of creposcular rays on Mars.
It's a phenomenon that has been expected but has never been seen before.

[22:30] This is after sunset. And so what you've got is these rays of light and they're blocked into rays by clouds that are blocking the sunlight below the horizon.
So it turns the light, instead of being a fan of light, it turns it into these individual streaks of light, but they too are lighting up thin clouds in the sky above Curiosity.
And that's why they show up, the crepuscular rays.
I think it's something that we might expect down the track from somewhere over on Mars to see the anti-solar crepuscular rays that I've just been talking about as these shuts of light meet on the other side of the sky, an effect of perspective.
Of course the whole thing is due to perspective because these shafts of light are actually parallel.
It's the sun's lightest.

[23:22] Power parallel rays because the sun is so far away is it blocks the clouds block block bits of it so you get just individual shaft of light they look as though that.
There's streaming from the sun itself a very evocative image but they're actually parallel.
Yes and yes being after sunset on mars it's it's not the kind of red you see on earth it's it's a very different term yes.
Sunset some of the blue in what that's because i'm well the sky the daytime sky on mars is pink and the sunset sky is blue and it's the opposite way round from what we expect on the.
Yeah that's because the dust particles such a large amount of suspended dust.

[24:06] In the martian atmosphere the dust particles are bigger than the molecules of air that scatter scatter some light on earth and so there's a different.
Scuttering process takes place and that's why you've got a pink sky.
Yeah, looks amazing. If you want to look at that image, it's on the website.
It's quite pretty. I'll say pretty. And yeah, sun rays on Mars.
If you do a search for that, you should be able to find it.
Now to another story. We're jamming it in today, aren't we? Chumming's the word.
Yeah. And it goes back to something that we get a lot of questions about, and I think we got a couple of questions about it last week, and that is the Big Bang. Now they're saying our universe may have been started by a dark Big Bang. What's a dark Big Bang?
Well, it's the suggestion. Anyway, wasn't it at the beginning? Well, we don't know. But biblically it was.
So the Big Bang itself was not dark and we know that because we still see it.
In the cosmic microwave background radiation, that's the Big Bang, the light of the Big Bang red shifted to be a thousand or fifteen hundred times longer wavelength than it was when the light left.
This is really trying to understand.

[25:34] How dark matter came into being because the current theory suggests that the big bang created.

[25:50] Space time and matter and at first it was just pure energy but that pure energy i think when the universe was something like fifteen to twenty minutes old.
It's kind of condensed into protons and neutrons in a period which has the technical term of the Big Bang nucleosynthesis.
And it's one of the reasons why we believe the Big Bang because when you do the theory of how this Big Bang nucleosynthesis would work, you get exactly the amount of hydrogen, helium, and some lighter elements.

[26:31] I can't remember what they are actually. It's lithium one, I think there is a lithium issue.
Anyway, those lighter elements basically are exactly what we find in the universe is what's predicted by Big Bang nuclear synthesis, which is one reason why the Big Bang theory is so well established.
However, what we can't understand is where the dark matter came from.
I mean, we don't know what dark matter is.
Know, it's some form of subatomic particle and there's a very good reason for believing that, but it makes up the majority of mass in the universe.
And so most theories of the Big Bang assume that whatever the process was that generated the particles themselves, the particles that we can see or detect, also created dark matter.

[27:30] After and the dark matter then really didn't do much. It was just there, not interacting with anything else.
But this new idea, I'm not actually sure, it's Katherine Frese is the lead author on this paper.
Not quite sure where Katherine's based. But that new idea that's due to Katherine and her colleagues, it I'll use that the wizard different formation.

[28:01] Of dark matter particles. So the dark matter...
Didn't condense into particles at the same time as the visible matter.
It was left as a sort of radiation field within the early universe that took longer to, basically flop out into dark matter particles than the protons and neutrons did.
They did it within the first 20 minutes or so. But the suggestion is that this radiation field that eventually became dark matter took longer to turn from a radiation field into subatomic particles, even though they're invisible to us.
The reason why that is useful in trying to work out what happened was that it essentially separates the evolution of normal matter from the evolution of dark matter.

[29:13] That kind of lets you concentrate on the way normal matter came into being, which we think we understand very well, but perhaps opens up new ways that we could look at the models of dark matter, if it had a completely separate evolution from the normal matter. I'm not sure I'm explaining this very well, but it is actually a really nice idea. The team that's doing this research is giving us, coined the term, a dark big bang. They have put a limit on it, a time limit. That That dark big bang had to happen before the universe reached the age of one month.
So sometime within the first month, You got the dark big bang.

[30:03] Okay, now I did look up Katherine, she's got her own website.
Good. And it says here on her website that she is the George E. Uhlenbeck Professor of Physics at the University of Michigan.
There you go. Thank you for that.
Thank you. There's one other consequence of this that we might just mention before we turn it to pumpkins, that suggests that that dark big bang would actually generate very strong gravitational waves that might be detected in today's universe. And so they are concentrating on gravitational wave detection as being perhaps one way of investigating this further. That's unerring. Lovely stuff, isn't it? It's great. Yeah, it is. Well, as I keep saying, we will crack it one day.
We will figure it out. Indeed we will. Hopefully tomorrow. Probably will be you and me, but we'll do it. Maybe not. All right. This is Space Nuts with Andrew Dunkley and Professor Fred Watson.
Okay, we checked all four systems and Keen was a gov. All right, Fred, we turn it over to the audience or we turn our attention to the audience as.

[31:24] They come up with some questions for us.
And our first one today is from Peter and it's a subject we've never talked about before except for last week and maybe the week before.
Hello, Fred and Andrew. This is Peter from Belgium.
I was just listening into the last episode and just thinking of a thought experiment.

[31:48] If traveling faster than the speed of light allows you to travel backwards in time from an outside point of view, imagine that you have an observer from Earth.
You need to be traveling twice the speed of light to actually travel backwards in time just at the same rate but then in reverse on how we currently perceive time on Earth.

[32:21] And so to travel faster back in time, you would just have to travel like three times the speed of light.
Is this like a linear equation or are we talking about exponential or another form of relation?
Thank you very much and love the show. Looking forward to the new episode every time.
Thank you, Peter. A faster than light question yet again, we get a few of those. So if you you travel faster than the speed of light, which you can't do, but if you could, the.

[32:51] Theory is that time would go backwards.
But if you traveled faster and faster, like one, two, three, four, five, ten times the speed of light, would you travel back in time faster?
So this is kind of a tachyon theory, is this? T-A-C-H-Y-O-N rather than T-A-C-K-Y-O-N.
Why your head it's not that tacky it's uh it's uh tachyons are hypothetical particles uh able to travel at faster than the speed of light now as far as we know they don't exist because.

[33:27] Relativity is quite firm on the view that to accelerate anything to the speed of light except light itself uh you have to provide infinite energy and that tends to be a showstopper infinite energy is not something we have even today where energy is a lot easier to come by than it used to be unless you're in Europe. So the idea of tachyons, exactly as Peter says, is that you will get the phenomenon that from the tachyons point of view, time is traveling backwards.
Now, I think actually what Peter's hypothesized is probably right, that the faster you travel, the quicker you go backwards in time. It would definitely not be a linear relationship because nothing in relativity is linear. Everything's usually multiplied or divided by a factor of the square root of one minus V squared over C squared. That's the bit that always comes into to relativity equations, at least special relativity equations.
That's for example why if you, just to put it back to something that really does happen, if you are on an object moving at close to the speed of light, if you're on a spacecraft.

[34:51] And you point a torch out ahead of you and shine the torch beam ahead of you, your velocity and the speed of light from the torch don't just add, because if they did, they would give you a, they'd exceed the speed of light.
There's something called relativistic addition of velocities.
You can look it up on the web and it, once again, it's got that.
What is the square the sea squared thrown in that that actually means that you never achieve the speed of light so the velocity addition has it's not like.
No more arithmetic and the same will be true in terms of tacky and never really looked at a theory that should probably should do should i since we get.

[35:35] Talk about it quite a lot. I'll look at the equations and see what they look like, but I can imagine already what they look like just because all relativistic equations have got that.
So great question, Peter, and thank you for thinking along those lines.
So the answer was yes.
Could have done that. Yes-ish. Yes-ish. Yes, maybe. So they're not linear. That's the one thing I can say for definite. It's not a linear addition.

[36:03] Okay. Thank you, Peter. Now I'm going to swipe this question over and put it on your face because I need to read it in front of me. This one comes from Gavin in Iass in New South Wales, which is near our national capital of Canberra. He's got two questions, so we'll do them one at a time. I have a question for Dr. Fred regarding a topic seldom mentioned here, space. It appears from photos, et cetera, that all matter has an angular momentum, which appears to be anti-clockwise except Venus. As all matter was formed from the Big Bang, I assume that the Big Bang also has angular momentum. If space was also formed in the Big Bang, it seems logical that space also has angular momentum. If you think of a bicycle, wheel, the hub rotates at a slower speed than the rim. This means that further out you look from the hub, the faster the wheel is turning. If the Big Bang center is everywhere, we are The Hub, Same applies to distant galaxies. I what do you think of that idea? Great.

[37:10] So we don't know if the universe has angular momentum. What we do know and Gavin's correct.
Certainly in the solar system, most things revolve anti-clockwise as seen from above the Earth's north pole.
That's because the cloud of gas and dust that formed the planets and the sun actually was rotating.
The sort of theory is that these giant gas clouds that form solar systems, they collapse.
In them, you get little worlds and eddies being formed.

[37:49] It's those eddies that gradually build up to give you a preferred rotational direction.
That's what imparts as it collapses, the energy of the collapse goes into imparting rotation to the planets.
So, well, first of all, the protoplanetary disk, and then in turn the planets which are formed within that disk.
So that's how solar systems work in terms of their rotation.
Galaxies are probably somewhat similar.
You start off with gigantic clouds in the early universe that collapse under their own gravity and begin rotating.
And so, you know, the point I'm trying to make is that the angular momentum of objects within the universe comes from processes separate from the Big Bang.
They are physical processes that take place in the normal course of events of the universe.
So in terms of the universe itself...

[38:44] We don't have any way of detecting whether it's rotation or whether it's rotating and if it was what frame of reference would it be rotating in because.
By the definition of the universe is everything we can see or detect and that doesn't allow for multiverses which is a different idea but in the normal definition of the universe you wouldn't you be able to tell.
Only if there are multiverses would you perhaps be able to work out that there is some higher order reference frame against which you could measure the rotation of the universe.
Okay. Have we found any galaxies that are rotating in the opposite direction to what we would consider normal?
Yes, only in the sense that, for example, spiral galaxies are almost always rotating with the spiral arms trailing.

[39:42] So that would be what you call the normal rotation direction.
There is at least one that is completely counterintuitive. It's rotating in the opposite direction from the spiral arm trailing model.
I can't remember what it's called. But generally, galaxies behave well.
I should explain though that you don't really know the difference between clockwise and anti-clockwise when it comes to galaxies because they're all completely random angles.
There are some indications of alignments along the filaments of the cosmic web, which is that sort of background scaffolding structure that we think is what gave rise to the large-scale structure in the universe. I think there are some ideas of alignments of rotation for galaxies along those filaments of the cosmic web. But yeah, we looked at that recently. But in general terms, Galaxy rotations are pretty random.

[40:41] Okay now Peter has a second question and he said recently either the James Webber Hubble telescopes found a gravitational lens the lens had three images of a distant galaxy.
It was observed that a supernova occurred in the galaxy and the scientists were able to watch the supernova at three different times I the images must have traveled various distances through space due to the curvature of space around the lens.
If we have a black hole or neutron star merger which creates a gravitational wave in that distant galaxy, would we detect three gravitational waves, i.e. one from each image, or would we see only the one?
I feel that it would confirm that space bends or light bends one or the other. Yes.
I'm going to quote them from a paper, paper in astronomy and astrophysics, the main European journal for astronomy. I'm going to quote from that. The quote is as follows, when gravitational waves propagate near massive astrophysical objects, their trajectories will curve resulting in gravitational lensing and multiple images. As we observe the waves from each multiple image, their amplitudes will have changed because of the focusing by lensing.
So the bottom line is, yes, gravitational waves behave like lines when it comes to.

[42:10] Gravitational lensing, which means that, yes, you might see multiple, detections of gravitational waves from the same object, if it's lensed by an intervening galaxy or cluster of galaxies, for example. So there you go. Great question.
Yes the answer is three times g w.
Rather than one times G jump dot G W which was Gavin's yes little um yeah that's right.
Okay so it's a great times G W Gavin.
That would occur there alright thanks for your question thanks also to pay that you have questions for us of course we'd love to hear from you you can jump on our website and click on the AMA link.
And send us a text or audio question that way, or you can click on the send us your voice message on the right hand side, which just sits there regardless of which page you're on.
And it's easy. If you've got a device with a microphone, that's as simple as just pushing the button and saying, hi, I'm Fred from Sydney and I have a question about must cats.

[43:16] Or whatever. ever. Yes, that's as easy as it gets. While you're on our website, have a browse around, check out Astronomy Daily, check out the shop, check out ways of supporting us if you so desire through various means. It's all available on our website and pretty easy. Don't forget social media.
Lots of people are very, very active on the Space Nuts podcast group on Facebook and it's a lot of fun too. I shamelessly posted a link to my eBooks being on sale for the next couple of weeks, just in case you want, you know, just in case.
Well, Fred got your plug. Yeah, dude.
Yeah, anyway, it's a good fun site. We're done for another week.
Fred, thank you so much.
It's a pleasure and great to be back in what is a really very special country.
It is, isn't it? We're shrouded in smoke here at the moment.
Oh yes, you will be. Yeah, you've got fires down there.
Big, big, hot, windy, dry day last week. We got a big fire south of the city.
Still burning, but they've got it almost under control.
Yeah. I love the wording they use at the rural fire service around here.
If it's not under control, it's being controlled.
Okay. That's good stuff. Well, yeah. All right. That's right.
Yeah. But yeah, we could say the grandchildren thought it was amazing.
They thought it was a cloud, but it wasn't. It was smoke. Yes.

[44:45] Till next week, Fred, thank you so much. We'll see you soon.
Sounds great. Thanks, Andrew.
Fred Watson, a stroma at large part of the team here at Space Nuts.
And thanks to Hugh back in the studio. It's not a studio, it's actually a smoking room or something that he's converted into, you know, a man cave.
And from me, Andrew Dunkley, thanks for your company. We look forward to joining you again next time on another edition of Space Nuts.
Bye bye. Space Nuts, you'll be listening to the Space Nuts podcast.
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