Speaker 1: Hi there, Welcome to a Q and A episode of
Speaker 1: Space Nuts. I'm Andrew Dunkley and it's good to have
Speaker 1: your company. As always, We've got a lot of questions today,
Speaker 1: but we're three. We might squeeze in an extra one
Speaker 1: time permitting. We'll just leave that one hanging in the
Speaker 1: ether for the moment. But what would be the effect
Speaker 1: on dark matter if something big exploded, like I don't
Speaker 1: know a star. That's a question that has come into us.
Speaker 1: Ryan wants to talk about the Sun's ecliptic. What does
Speaker 1: that mean? I have no idea, but we will will
Speaker 1: answer the question anyway by making something up. And we've
Speaker 1: got a question from James about planetary rings. That's all
Speaker 1: coming up on this Q and a episode of Space
Speaker 1: Nuts fifteen in.
Speaker 2: Channel ten nine ignition.
Speaker 1: Space Nuts or three two Space Nurtes.
Speaker 3: What it feels good? Yes?
Speaker 1: I feel good?
Speaker 3: He feels good. We all feel good?
Speaker 1: How do you feel freend.
Speaker 3: I feel terrible? Feel good to It's a feel good show?
Speaker 3: Is space so you can't do anything else?
Speaker 2: Well?
Speaker 1: The Q and A edition tends to go that way.
Speaker 3: We get all sorts.
Speaker 1: We even get genuine questions sometimes, which is always nice.
Speaker 1: Shall we just go straight for it.
Speaker 3: I think we should. I think that's a really good idea.
Speaker 1: And a big hesitation. I was a bit worried there
Speaker 1: for a minute. We'll we'll go to our first question.
Speaker 1: This comes from Damien on the Gold Coast. We're not
Speaker 1: talking about West Africa. We're talking about Southeast Queensland, because
Speaker 1: there's a Gold coast in both places. In regard to
Speaker 1: dark matter, if there's five times the amount of it
Speaker 1: to ordinary matter when Beetlejuice explodes, will the explosion blow
Speaker 1: will blow away the dark matter as well? Would this
Speaker 1: now make the neutron star one fifth of the mass
Speaker 1: until the dark matter returned. That's from Damien on the
Speaker 1: Gold Coast. Interesting question. We don't know much about dark matter,
Speaker 1: but could or would it be affected by something as
Speaker 1: dramatic as Beetlejuice or some other star exploding super novastyle.
Speaker 1: No Ah, that's interesting because I thought the answer would
Speaker 1: be yes.
Speaker 3: I thought you might think that yeah, and it's no.
Speaker 3: That's because dark matter does not interact with normal matter
Speaker 3: at all, except by gravitation, So an explosion blowing things
Speaker 3: away needs a physical push. It's usually a shock wave
Speaker 3: that passes through a medium, and yes, if dark matter
Speaker 3: responded that shock wave would compress the dark matter, you'd
Speaker 3: have all kinds of phenomena. But dark matter doesn't interact
Speaker 3: with normal matter, and so it ignores the explosion completely.
Speaker 3: We know this because of observations that have been made,
Speaker 3: and I think there's at least two examples of this, Andrew,
Speaker 3: where you've got clusters of galaxies which are colliding. Now,
Speaker 3: you can use clusters of galaxies to basically reveal where
Speaker 3: dark matter is in them, because you can look at
Speaker 3: the way the space around them is distorted by gravity
Speaker 3: and the dark matter contributes to that. And the way
Speaker 3: you investigate that distortion of space is by looking at
Speaker 3: distant galaxies beyond. You can look at their shapes and
Speaker 3: you know the extent to which they're twisted or their
Speaker 3: images are twisted, and figure out how much the space
Speaker 3: in front of them is being distorted. And that distortion
Speaker 3: comes from the matter of the galaxy clusters. So to
Speaker 3: come back to the point, as I said, there's at
Speaker 3: least a couple of examples of this where you've got
Speaker 3: two galaxy clusters that have collided and basically ground to
Speaker 3: a halt. Their hydrogen gas that the company's galaxy clusters
Speaker 3: has sort of compressed itself and is excited enough to
Speaker 3: emit radiation in the X rays. But you can sense
Speaker 3: where the dark matter clouds that originally accompanied these galaxy
Speaker 3: clusters have gone, and it turns out that they just
Speaker 3: carry on going without batting an eyelid. So what you've
Speaker 3: got is basically a cluster which is formed of two
Speaker 3: clusters coming into collision. On either side of it, you've
Speaker 3: got the dark matter cloud answer that were associated with
Speaker 3: the original galaxy clusters, which have just carried on going
Speaker 3: as though nothing had happened. And so that's an extraordinary
Speaker 3: example that illustrates very cogently that we don't see any
Speaker 3: interaction between normal matter and dark matter.
Speaker 1: Ah Okay, I'm surprised. I thought I thought the two
Speaker 1: potential answers were yes or we don't know.
Speaker 3: There's no.
Speaker 1: No.
Speaker 3: Yeah, yeah, it's pretty well known, and it's because you know,
Speaker 3: that's if there was a reaction. If something did happen,
Speaker 3: that will be great because we're able to detect the
Speaker 3: dark matter and have a much better idea of what
Speaker 3: it is than we have now. So, Damien, your question
Speaker 3: is a good one, but has perhaps a surprising answer.
Speaker 1: HM, okay, very interesting. All right, thanks Damien. Let's move
Speaker 1: on to a next question, which comes from Ryan.
Speaker 2: Hey guys, it's Ryan here from town in Delaware, voted
Speaker 2: Delaware's third most okay as town.
Speaker 3: I had a quick question for you.
Speaker 2: I was thinking about how the Sun revolves or orbits
Speaker 2: around our galaxy and granted takes, you know, millions, hundreds
Speaker 2: of millions of years to make it make a trip around,
Speaker 2: but I was wondering about our ecliptic in regards to
Speaker 2: how the Sun is moving around the galaxy. Are we
Speaker 2: orbiting the Sun like a you know, hoop around a
Speaker 2: dancer as they go around. Are we orbiting more like
Speaker 2: a halo around the Sun as we move around? What
Speaker 2: is our orientation of the ecliptic as it pertains to
Speaker 2: the Sun's orbit around our galaxy? Thanks a lot, guys,
Speaker 2: keep up the great work.
Speaker 1: Thank you, Rian, and I hope you're enjoying being number
Speaker 1: three most Okay town. I can tell you with absolutely
Speaker 1: certainly THEO wouldn't write in the top three of anything
Speaker 1: in this country. We cop a lot of stick from
Speaker 1: the media, probably because of the name of our town.
Speaker 1: It's very unfair and they're all wrong. But it's good
Speaker 1: to be number three. Now I might get here or
Speaker 1: explained for it, just to we sort of get our
Speaker 1: heads around it. Does How does the Sun's orbit work
Speaker 1: on a galactic level?
Speaker 3: Yeah, it's a great question and it's got a great
Speaker 3: answer as well, which is sixty two degrees thirty six minutes.
Speaker 3: Oh okay, yeah, So that's the angle that the Sun's
Speaker 3: path around the around the galaxy, around the center of
Speaker 3: the galaxy. That's the angle it makes with the equator,
Speaker 3: the equator of the Earth. So let me just step
Speaker 3: back a bit because that, you know, the end of
Speaker 3: Ryan's question was what's the orientation, and that's the answer,
Speaker 3: sixty two degrees thirty six minutes. But we don't call
Speaker 3: it the ecliptic for the galaxy. So remembering that the
Speaker 3: ecliptic as seen from the Earth, is the path of
Speaker 3: the Sun through the sky. It's tilted with respect to
Speaker 3: the equator, and that means that the Earth, you know,
Speaker 3: the Earth's axis of rotation is not perpendicular to the
Speaker 3: plane of its orbit. It's not standing upright in its
Speaker 3: orbit at twenty three and a half degrees. So that's
Speaker 3: the ecliptic, as we call it, and it's the apparent
Speaker 3: path of the Sun through the sky. Of course, it's
Speaker 3: the Earth actually moving around the Sun, but that's what
Speaker 3: we see now. In a similar fashion, we can think
Speaker 3: about the path of the galactic center through the sky
Speaker 3: as the Solar system moves around the center of our galaxy.
Speaker 3: The difficulty with this is that it takes two hundred
Speaker 3: million years to go around once, and so you don't
Speaker 3: see it every year like you do with the eclipsic,
Speaker 3: see the Sun going around every year. But we do
Speaker 3: know that the Sun's path is fairly near what we
Speaker 3: call the plane of the Milky Way galaxy, basically the disc,
Speaker 3: the plane in which the disc of the galaxy lies.
Speaker 3: The Sun's path is fairly close to that. It may
Speaker 3: wabble a little bit up and down as it goes
Speaker 3: around the galactic center. There may be disturbances caused by
Speaker 3: giant molecular clouds and things like that as it passes,
Speaker 3: but we know from the observations of the stars around
Speaker 3: us that those are not particularly high level disturbances. The
Speaker 3: thing is really going around mostly along the galactic plane,
Speaker 3: and so what that means is that you can define
Speaker 3: the angle that that makes with the equator of the Earth.
Speaker 3: And it's what I said, sixty two degrees thirty six minutes.
Speaker 3: So the Milky Way is tilted over at quite a
Speaker 3: high angle compared with the Ecliptic, which is tilted over
Speaker 3: at quite a small angle twenty three and a half degrees.
Speaker 3: And in a way, you know, if you imagine the
Speaker 3: way the Earth is the or sorry some and its
Speaker 3: family of planets as they progress around their path around
Speaker 3: the center of the galaxy, they're not lying in the
Speaker 3: same plane as that path. They're sort of tilted upwards
Speaker 3: to it at you know, quite quite a steep angle.
Speaker 3: And so that's how the Sun and its planets move
Speaker 3: around the center of the galaxy. It's not, as Ryan conjectured,
Speaker 3: is not sort of moving around the halo of the
Speaker 3: galaxy or anything like that. It is sitting firmly in
Speaker 3: the plane. It's just an ordinary star in the main
Speaker 3: part of the Milky.
Speaker 1: Way, and it's doing what billions of other stars are doing,
Speaker 1: and our planets are doing what billions upon billions of
Speaker 1: planets are doing throughout galaxy. And it's just going around
Speaker 1: and around. It's a slow motion dance that's happening fast
Speaker 1: more or less frost motion dance that's happening slowly, which
Speaker 1: could be both. It's all relative. Okay, thank you, Ryan.
Speaker 1: This is Space Nuts Andrew Dunkley here with Professor Fred Watson.
Speaker 1: Space Nuts. Now we've got a question from James Shalom Gents.
Speaker 1: He says, I've got a question regarding planets with rings.
Speaker 1: Could there be a planet with multiple sets of rings
Speaker 1: that are different to each other. I'm envisioning something like
Speaker 1: rings wrapping around an equator from gravity as per usual,
Speaker 1: but some other materials possibly being caught in the north
Speaker 1: to south magnetic field at a larger smaller diameter than
Speaker 1: the equatorial rings. Thanks for entertaining my nonsense, James Greenfield,
Speaker 1: It's not nonsense. It's a question and it deserves and answer. James.
Speaker 1: We're going to tackle that one right now. Most rings,
Speaker 1: like the ones around Saturn, which are the most prominent
Speaker 1: in our Solar system, are made up of dust and
Speaker 1: rocks and ice and bits and bobs. So what else
Speaker 1: could they be made off? For him?
Speaker 3: Well, yes, so it would be debris of some sort
Speaker 3: or other gas dust. I think James's question.
Speaker 1: I know the rings around Earth which are made of metal.
Speaker 3: Yeah, that's right, they are, and they go around the
Speaker 3: equator as well, like the rings of Saturn, like the
Speaker 3: rings of Uranus and Jupiter and Neptune. So I think
Speaker 3: James's question is, you know, could could there be rings
Speaker 3: that go at a different angle from the equator of
Speaker 3: other planet? And the answer is probably no, because this
Speaker 3: debris tends to be squashed down into a disc. In
Speaker 3: the case of Saturn, it is mostly ice, icy debris.
Speaker 3: A bit of rock in it as well, but mostly ice,
Speaker 3: and it's squashed down just by gravitational forces in connection
Speaker 3: with the rotation of the planet, So it tends to
Speaker 3: be forced into the equator of the planet. So a
Speaker 3: ring that's tilted at some jaunty angle a little bit
Speaker 3: like what we've just been talking about with the disc
Speaker 3: of the galaxy, that is I think highly unlikely to happen.
Speaker 3: Even if you envisiit ship being entrapped with magnetic fields
Speaker 3: and things of that sort. I think we'd be struggling
Speaker 3: to make a ring that would not be at the
Speaker 3: equator of a planetry body.
Speaker 1: Okay, so no one both counts. It's probably not going
Speaker 1: to ever be made of anything else. And it's probably
Speaker 1: not going to move beyond the.
Speaker 3: Equatorial Yeah, that's right, rotation an equatorial plane.
Speaker 1: Plane, that's the word I want to that's when you
Speaker 1: think of it. So yeah, sorry, James, good good idea,
Speaker 1: but not likely. Now have we got time for one more?
Speaker 1: I reckon we could squeeze one more in.
Speaker 3: Fred, Yes, yes, we can be quick on this one.
Speaker 1: Yeah, all right, let's be quick on this one. Hello,
Speaker 1: and best wishes to you both. A couple of questions
Speaker 1: about solar activity? One? What are the differences between solar
Speaker 1: flares and coronal mass ejections?
Speaker 3: Two?
Speaker 1: What predisposes red dwarf stars to the outbursts of solar
Speaker 1: activity that would seem to challenge development of life on
Speaker 1: planets in their solar systems. Thank you for the answers,
Speaker 1: and thanks for very much for a terrific podcast. You
Speaker 1: guys are stars. Bob Mark from Bloomington, Indie.
Speaker 3: And a.
Speaker 1: Question one, what's the difference between solar flares and coronal
Speaker 1: mass ejections?
Speaker 3: Thread, So it's mostly a much of degree, I think
Speaker 3: the you know, the physical processes are different. A solar
Speaker 3: flare is something that is generated by magnetic activity, tends
Speaker 3: to come from sun spot regions when you know there's
Speaker 3: a high level of magnetic activity there. And we think
Speaker 3: of the magnetic field lines stretching between sun spots which
Speaker 3: come in pairs, and one has a northern polarity and
Speaker 3: one has a southern magnetic polarity. So when they are
Speaker 3: particularly energetic, then you get solar flares. I think I'm
Speaker 3: right in saying that coronal mass ejections start off the
Speaker 3: same way. But if you get these magnetic field lines
Speaker 3: breaking so that there is a kind of magnetic twang,
Speaker 3: what you get is matter mass actually being expelled outwards
Speaker 3: at a great velocity. It's almost like an elastic and
Speaker 3: breaking on the gigantic scale, and that gives you a
Speaker 3: significant ejection of material. That's a significant rejection of the
Speaker 3: sub atomic particles which are there all the time in
Speaker 3: this in the excuse me, in the solar wind. But
Speaker 3: with a mass ejection, you're getting a very much enhanced
Speaker 3: level of this subatomic particle is being ejected from the Sun.
Speaker 1: And that's the thing that worries people around the world
Speaker 1: in terms of the interference with electronics, and of course
Speaker 1: the beautiful auror ray that we see in the north
Speaker 1: and south of the of the planet. There's pros and
Speaker 1: cons to coronal mass ejections, but with reliance on electronics,
Speaker 1: that's becoming an area of concern. Well, it's not becoming.
Speaker 1: It is an area of concern if we get hit
Speaker 1: directly by something super nasty like that for it.
Speaker 3: Yes, that's correct. So the second part of Mark's question
Speaker 3: is a good one, and it's right that red dwarfs
Speaker 3: are much more active on this sort of scale. We
Speaker 3: know that they are more you know, the outbursts of
Speaker 3: sub atomic particles are much more prevalent, and I think,
Speaker 3: thinking back to my studies of stellar evolution and things
Speaker 3: of that sort, these stars have star spots on them
Speaker 3: which are huge. They are very large compared with the
Speaker 3: star itself, and I think that might be the one
Speaker 3: of the reasons why you've got much more activity, because
Speaker 3: they have enormous star spots on them. And in fact,
Speaker 3: I was just talking only today to a couple of
Speaker 3: my colleagues who are the experts on exactly that in
Speaker 3: this country at the University of Southern Queensland, Brad Carter
Speaker 3: and Stephen Marsden. They did research on this and I've
Speaker 3: worked with him in the past on it. They can
Speaker 3: actually map where these star spots are on stars. They
Speaker 3: do it with a technique called ZAM and Doppler imaging,
Speaker 3: which is a fairly esoteric technique but allows you to
Speaker 3: make maps of the surface of stars, and their Red
Speaker 3: dwarfs have got very big star spots, which I'm sure
Speaker 3: is why you get big, big solar flares. Now, Mark's
Speaker 3: next question, if he was able to talk to us,
Speaker 3: will be why do they have such big star spots.
Speaker 3: The answer to that is, well, I'll go and ask
Speaker 3: my colleagues because I don't know the answer to that,
Speaker 3: but it's totally something in the evil.
Speaker 1: That bloke you were talking about, Samon Doppler, he might know.
Speaker 3: That's two blocks actually hair Doppler, And yeah, it would
Speaker 3: be hair as well as Emma was Dutch, So there
Speaker 3: you go.
Speaker 1: It was probably the big spot that are causing red
Speaker 1: doors to be so nasty, so their planets where it's
Speaker 1: very difficult to establish life. By the sound of it,
Speaker 1: We've talked about that before. That's probably what prompted the
Speaker 1: question from Mars. I'm sure a good question too. Thank you,
Speaker 1: Yes it is, Thank you Mark. Thank you to everyone
Speaker 1: who contributed. Don't forget to send your questions into us
Speaker 1: via our website, Space nuts podcast dot com, Space nuts
Speaker 1: dot io. Click on the AMA link at the top.
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Speaker 1: thank you, Fred, we are done again.
Speaker 3: It sounds great and great to talk to you as always,
Speaker 3: Andrew look forward to the next time.
Speaker 1: Indeed, catch you soon, Fred, what's an astronomer at large?
Speaker 1: And thanks to Hugh in the studio who wasn't in
Speaker 1: the studio today. Thanks anyway, and from me Andrew Dunkley.
Speaker 1: Thanks for your company. We'll catch you next time on
Speaker 1: another edition of Space Nuts.
Speaker 4: By bye you best to the Space Nuts podcast, available
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