Cosmic Queries: White Holes, Dark Matter & the Universe's Mysteries

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Heidi Campo: Welcome back to another fun and exciting

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Q and A episode of space nuts.

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Voice Over Guy: 15 seconds. Guidance is internal.

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10, 9. Ignition

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sequence start. Space nuts. 5, 4, 3,

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2, 1. 3, 3, 4, 5, 5, 4,

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3, 2', 1. Space nuts. Astronauts

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report it feels good.

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Heidi Campo: I am your temporary host, Heidi,

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joining you today with Professor Fred Watson,

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astronomer at large, while our

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usual host, Andrew Dunkley, is off on his world

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cruise, having a grand old time.

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Ah, Fred, how are you doing today?

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Professor Fred Watson: I'm very well, thank you. Um, ah, still

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inundated with people interested in the end of the

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universe, which we talked about a few episodes

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ago. Uh, so that's good to know that,

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um, uh, people are taking some notice of the fact that

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20 billion years might be the, uh,

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closing down ceremony for the universe. We'll

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cover that in Space Nuts.

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Heidi Campo: Obviously we'll talk about the end

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of the universe.

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Well, today, um, we've got more great

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questions. I always say that our questions are what makes

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up half the show? And our very first question

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of our episode today comes from

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Casey. From my side of the world, from

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Colorado, which is a beautiful

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state. And I always tell people if you see beautiful

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pictures of the mountains, they're definitely from Colorado, not

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from Utah. Utah's full. Don't go.

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So Casey from Colorado says,

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hi, guys. I know that white holes are basically

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the opposite of black in the way that nothing can

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enter them. I understand that at this point

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they are completely theoretical and we haven't actually

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found any. If we did find one,

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what would be inside of it? Would it have mass?

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How does gravity work in and around it? Love

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the show and hope you're both well. Thanks.

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Professor Fred Watson: That's great. Thanks. Thanks. Thanks very much, Casey.

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And, uh, it's a good question. Um,

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uh, it's probably about 30 years ago that white holes

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were all the rage. People were talking about them

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endlessly. Uh, and, uh,

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I guess what that did was set up people

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looking for them. And we've never found any, any evidence of

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one. Uh, but the reason why people think that

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they might exist is that there's

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nothing in the equations

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of relativity, which is what govern the

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behavior of black holes and space. And

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generally. It's Einstein's theory of gravity.

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Uh, there's nothing in that that says that you can't

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have, uh, a sort of opposite object

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to a black hole. And what you have to

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do in the equations is reverse the direction that

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time works in. Uh, and if you switch

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that round and yes, that's hard to get your head around

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at all. But if you do that, put negative time

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in instead of a black hole, you get a white hole. Uh,

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and so the theoretical

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physicists said there's nothing that we can

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find that would rule out the existence

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of these objects, that they, they may

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exist. And then there was the connection

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that perhaps two black holes or two

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white holes, or a black hole and a white hole could, could

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connect with each other to make a wormhole, which might give us

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a way of getting from one side of the universe to the other very

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quickly. Um, I think you'd risk all kinds of

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horrible things happening if you did that. But anyway, uh, that's

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the idea. So, uh, the quest was on, uh,

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for uh, you know, looking for

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evidence of white holes, which

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you would think, unlike a black hole, would be

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very bright. Uh, and um,

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so far we found nothing, no evidence of

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anything that would correlate with

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the, you know, the um, observations

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that physicists, um, suggest might be made of a,

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uh, of a, of a white hole. Um, if we

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did find one, as, as Casey asks, uh,

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what would be inside it? Well, yeah, it's

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hard to know, uh, because, you know, black

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holes, it's a one way process for stuff going

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in. Uh, with a white hole, as you say,

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Casey, it's a one way process with stuff coming out.

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Uh, so where's that stuff come from? What's inside it?

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Where has the material

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that might be escaping from it? If it was,

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uh, where did that, where did

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that come from? Maybe from a wormhole, maybe just

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from sucking it in from the fabric of space.

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Um, I'm not qualified enough in

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relativistic theory to be able to give you an answer to that.

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Um, would it have mass? Yes, I think it would. Um,

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I think the mass is one of the

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constants in the equations of the

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white hole. So I think the answer is it would have mass

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and so gravity would probably work around

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it in the same way as a black hole does.

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I'm sort of speculating here, Casey. Uh,

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these are not authoritative answers because I have,

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have not had a look at the white hole theory for a long

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time. But I think you can draw all

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kinds of comparisons. It's a, there's an analog,

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you know, from, from a black hole to a white hole.

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Uh, the fact that we've never found anything that has

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symptomatic, uh, or is symptomatic of the

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existence of a white hole probably means that in

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reality they don't exist. Um, but

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we're always open to suggestions.

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Heidi Campo: We could just be in the wrong universe for them.

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Professor Fred Watson: That's true. Uh, in a different universe, maybe white Holes

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are everywhere. Yes, quite so.

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Heidi Campo: And they can't find any black holes. There's some

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podcast where there's a Fred

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interviewing a Fred's interviewing Heidi and they're

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wondering, well, why can't we find these theoretical black holes?

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Professor Fred Watson: Yeah, that's right. And time's running backwards for us.

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Heidi Campo: Yeah, uh, we're getting younger.

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Professor Fred Watson: That'd be good.

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Heidi Campo: Our next question, um, you must have listened to a few

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episodes ago where we were talking about name history.

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Um, this is from Martin.

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Martin says hi Adelheid and

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Frederick. I just listened to your latest

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episode Stellar Questions and um, the

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very first one puzzled me. This is about time

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dilation. The formula Fred used for

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calculations takes into account only

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velocity. Isn't it only for

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observation dilation. The reason it

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puzzles me is that the scenario was

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traveler returns back to Earth. Isn't that

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more like twin paradox? And the

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differences should be explained by acceleration

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because without acceleration and given the

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velocity is relative, we couldn't tell

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if it was the astronaut who traveled or the Earth who went

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for a trip and returned to a, uh, stationary

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protagonist. I hope I'm not completely off.

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Great work with the podcast, I love it.

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Professor Fred Watson: And Martin, great work on the question because everything

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you've said is absolutely correct. Um, I just didn't

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say all that because didn't seem as though there was time to do

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it. But yeah, um, you're right. Um, um,

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you've got to have for the twins paradox to work. And

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that's where one twin goes off on a long journey

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into space very quickly at what was it,

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99.99995% of the speed of

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light. If you want to have a 100 year ratio

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or 100 to 1 ratio, uh,

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um, the astronaut goes off,

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uh, uh, visits a distant star,

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takes their photographs and with their

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smartphone and all the rest of it comes back to Earth.

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Uh, the Earth has aged by 100 years

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and the astronaut has only aged by a year.

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Um, that's called the twins paradox because you imagine that

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it's would be two twins who were being separated like

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that. Uh, and

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it only works because of

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the accelerative component. So uh, the

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answer I gave was purely special

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relativity. That's simply, um,

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you know, relativity, uh, with

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motion at a constant speed.

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Uh, so clearly you're not going at a constant speed. If you turn

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around and come back again, uh, you've got a deceleration and

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then an acceleration. And those are the terms

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that allow the twins paradox to work. It's

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the fact that you're actually switching acceleration because

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that introduces, uh, geometrical,

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uh, elements which are more related

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to general relativity. And in

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fact, um, what I also didn't mention, um,

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so just to, um, fill you in,

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Martin, that, uh, there is more to the story. Exactly as

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you've said, uh, in general relativity,

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that's Einstein's second theory of relativity,

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the one that accounts for gravity and that lets black

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holes exist and white holes and all the rest of it.

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Um, that theory also has time dilation in

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it. In other words, uh, what it says is

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that if you get in a strong gravitational

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field, your clocks run more slowly as observed

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from outside than they would

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if you were just outside, uh, the gravitational

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field. So, for example, our clocks are running slightly

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more slowly than clocks on board spacecraft, uh,

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orbiting the Earth. And that has been measured,

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that time dilation has been measured. And I think

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it is taken into account in the

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GPS in your phones as well. I think you have to

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have those relativistic corrections in there for it to work.

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So. Yes. Good pickup. Thank you very much, uh,

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Martin. Uh, and, um, thanks also for

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giving my Sunday Best name as well. Uh, very few people

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call me Frederic. It's usually people in banks

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or in medical reception areas

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because that's my full name. Is your full name Adelheid?

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Heidi?

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Heidi Campo: My full name is Heidi, but the, uh, name comes from

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Adelheid, um, which I believe

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means noble is the kind of

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the history of the name. Um,

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but I know it's a German name. I know my

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mother read the book Heidi when she was young and she

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loved the character. So that's how I got the name

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Heidi. Despite. I'm actually, um, my, my family

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heritage is Italian. I'm, I'm

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second generation Sicilian. So I still have family in

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Sicily, but I have a German first name, an

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Italian last name and an Irish husband. So

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I'm a, uh, classic American, you can say.

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Professor Fred Watson: Yeah, that's good.

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Heidi Campo: Space nuts.

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Our next question is, uh, from

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Ash from Bris Brisbane. And

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Ash says, hi, Heidi and Fred. I hope this

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message finds you well. I recently came across

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a statement by Professor Brian Greene regarding

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the observable universe

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being 93 billion light years across.

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He mentioned that if we were to condense the known

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mass of the observable universe into

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theoretical black hole, the

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calculations suggest that the event horizon would

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align with the distance of the cosmic

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microwave background. This leads me

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to wonder, is Roger Penrose correct in his

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theories? Could the cmb, the

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cosmic microwave background, actually represent the

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inside of an event horizon? And that's

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why we cannot penetrate it? Is this

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just One big universe sized

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coincidence. I'm looking forward to hearing your

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thoughts on this intriguing topic.

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Professor Fred Watson: That's great. Thanks for that, Ash. Uh, um, we

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did talk about the idea, uh, of the universe

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being a black hole or inside a black hole, I,

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uh, think in the last Q and A episode. But

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I was talking last night to some of my colleagues at the conference

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that I'm at at the moment, Astronomical Society of Australia's

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annual science meeting about this,

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um, and um, I think

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the general

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opinion was

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basically what you've said, Ash, at the end

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of your question there. Is this just

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one big universe sized coincidence?

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I think, uh, everybody thinks that,

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um, it's drawing a long bow

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to assume that we might be inside a

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black hole, uh,

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only by the fact that the universe,

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effectively what we call the proper distance to the event,

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sorry, the cosmic microwave background radiation

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would be about the size of the event horizon,

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uh, if the mass of the observable universe

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was in a black hole. So, uh, that's

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one strand to this, but you've highlighted another one

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as well. As with Roger Penrose, his ideas are

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very much concerned with, um, big

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bangs coming from black holes

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detonating in a universe that just keeps

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on going. So we've got this multiple multi

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universe idea again, the multiverse with

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supermassive, uh, black holes or hyper massive black holes popping

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off everywhere. And each one forms its own

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universe, uh, inside it, and we're

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inside one of those. It's a nice theory. Again,

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very, uh, speculative. There's no

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evidence to, in fact, it's hard to

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imagine what the evidence might be to prove that.

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We have people working on the idea of multiverses

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and indeed the Penrose theories

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as well. Um, but it's very hard to think

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what evidence you might bring to bear on that that

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says yes or no, uh, about living in a black

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hole. Um, it's a nice coincidence though, this,

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uh, you know, the radius of the universe being approximately

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the radius of the event horizon of a black hole.

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I think that's all it is, though.

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Heidi Campo: We may never know.

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Professor Fred Watson: We may never know. That's right.

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0G. And I feel fine.

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Heidi Campo: Space nuts.

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Well, what I do know is that our last question

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of the day is from one of our regular listener

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listeners. I can still talk. I

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haven't gotten fatigued. I usually get a couple audio questions

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mixed in. That's all these written questions. I'm doing more

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talking, but I can still say that our last question is

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from Rennie Trabb from Sunny Hills West,

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California. Sunny West

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Hills, California. Maybe I losing my Ability to talk. But it's

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good because this is a short question and Rennie

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says it seems that there is a purpose for why the

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universe is the way it is. What are your thoughts on

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why dark matter functions the way it does and

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the need for it to not react with the light,

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but, but yet it reacts to our matter in the

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universe?

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Professor Fred Watson: Yeah, uh, I mean, this is a really deep,

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deep question, uh, which is sort

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of concealed in some, you know,

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very innocent language. I think it's a beautiful

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question, Rennie, as yours always are. Um,

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so that, that first sentence, it seems there is a

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purpose for why the universe is the way it is. Um, I

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think the way I would look at that,

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uh, is the other way around.

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That, uh,

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it's something called the, uh, strong anthropic

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principle that says that,

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uh, we can observe the universe

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because we are here. It's a, you know,

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it's almost like a non sequitur, something that

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just doesn't follow. Uh, but what it's saying is

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that we are here because

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the universe has certain physical

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properties. And it's the laws of physics that

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let stars form, galaxies form, planets

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form. You know, humans form

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all the rest of it. Uh, that is,

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um, to say that it looks as though

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we live in a universe that is fine tuned for life.

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That if these physical, uh,

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constants were different, particularly if the speed of light was

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different or the charge on the electron was different or whatever,

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uh, the universe might never have been able to

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form planets. It might have either been so short that it

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collapsed on itself almost immediately, uh,

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or it may have been so

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rarefied that atoms never came together to react and

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form molecules and make up the ingredients for life.

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So it's this fine tuning, as I said, it's

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the anthropic principle. Um, and so

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in a way you can interpret that is

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as the universe having. Let me just read your

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sentence again. A purpose for why the universe is

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the way it is. Uh, its

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purpose is perhaps a strong word, but,

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um, it's saying the universe is the way it is.

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It allows us to be in it. If there was a

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different universe that we're in, we wouldn't be here, so we

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wouldn't be able to observe it. Uh, so

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I think that's a fascinating question. It's one that's been written about

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a lot. Uh, the anthropic principle.

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Um, what are my thoughts on why dark matter

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functions the way it does and the need for it not to react with light,

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but yet it reacts to our matter in the universe? Look,

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that's just a huge mystery, um,

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that um, we have this,

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these observations that suggest that there is something in the universe

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that has gravitational, uh,

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attraction. It attracts things.

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It's got enough gravity that it

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stops galaxies from flying apart because their rotation's

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too high. Uh, and yet

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it does not interact in any way

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in any of the other properties. So it doesn't,

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uh, have any reaction, as you say, with light,

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electromagnetic radiation. So for example, it

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doesn't block out the light. Light coming behind it would

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be very handy if it did. Then we could actually see it

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and measure its properties. Um, what we have to

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do is look at the way,

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uh, it does interact with light, which is through

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gravity. Uh, that means, uh,

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it can act as a lens. If you've got a large blob of dark matter,

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it can act as a gravitational lens, which means it will focus

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light and let us see magnified images of very

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distant galaxies if you've got a large blob of

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dark matter around a cluster of galaxies in the

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foreground. Because we do know that dark matter

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is where normal matter is. Wherever there's

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normal matter, there is dark matter, except in a

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very few cases. So, uh, yeah,

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it's still a mystery and it is still possible,

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um, uh, that we've got it

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wrong, that there is something

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else going on, uh, that that

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negates the need to have dark matter

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as a property of the universe. And one of those

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things is something studied by a friend and

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colleague of mine, Peter Verwein. He's uh,

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still, I think, writing his PhD thesis on a theory called

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MON Modified, um, Newtonian

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dynamics, uh, which suggests

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that, uh, at very low accelerations,

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uh, which are the kind that are experienced by

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stars going in orbit around the center of

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a galaxy, for example, at very low accelerations,

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our, uh, normal understanding of Newtonian physics

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breaks down. So MOND is Modified Newtonian

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Dynamics, uh, and it was introduced

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back in the 1980s when dark energy was first

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postulated by a scientist,

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uh, whose name was Mordechai Milgrom. Uh, he

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introduced the idea and it's been floating around ever since.

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M why isn't it accepted generally as the main

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reason why the galaxy behaves like it does and why

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the universe as a whole behaves like it does? Uh,

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that's because, um, if you tinker around with

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Newtonian dynamics, a lot of other things don't make sense.

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Uh, the early universe doesn't make sense. Globular clusters don't

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make sense. And so that's why it's not popular.

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Uh, but it's still possible that we might be missing something.

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Maybe there is something out there that

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makes us think we're surrounded by dark matter and we're not.

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So, uh, scientists have to be open minded about that.

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Uh, not so open minded that your brains fall out, as somebody

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once said. Uh, but open minded enough that you can

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recognize any possibility. And I think that's really what,

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what my thoughts would be in the

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questions that you've asked Rennie. And thanks again for

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very profound and thought provoking questions.

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Heidi Campo: You guys did a great job with your questions this week

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and Fred did a great job as always answering

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them and I am just so grateful to be a part

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of this journey.

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Fred, um, do you have any, um, we got,

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you know, maybe we can give another minute. Do you have anything

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that you really have enjoyed from this conference

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that's been like some of your highlights?

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Professor Fred Watson: Yeah. So, uh, the session that um,

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I was really keen to be at was

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yesterday. And it's about the

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things that I lose sleep over. Uh,

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how is Australia going to, uh,

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be involved with the next generation of large telescopes,

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large visible light telescopes? These are things

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that um, might seem a bit pedestrian when you

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compare it with the other stuff that's going on at a conference.

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Uh, there's a lot of really interesting new

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science coming out. And one of

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them that I sort of seem to pick up a lot

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on is the idea of how, how galaxies

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work, how the um, the

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outflows of gas from their black holes at the

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center. This is particularly in the early universe, how that

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uh, can interact with the gases that are forming

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stars. Uh, there's a process called quenching,

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which is where these winds that are blown out by black

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holes actually blow out the star

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formation process. So, uh, you get the

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star formation process quenched. And that's something that

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still has a lot of research going on with it. That was

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certainly one of the hot topics yesterday. Uh, but

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um, my fascination is always with,

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uh, because basically I'm a telescope man. Uh,

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it's what I did all my life. I ran telescopes,

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uh, for a lot of my life. Uh, and I'm always

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interested in where our country is going in regard

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to the facilities that it needs so our astronomers can

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make these discoveries of the kind that we've been talking about

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today. Um, so that was, I

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think, the highlight of the conference for me.

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Um, some of the news is good, some of it's not so good.

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Uh, of course all facilities for astronomy

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rely on funding and it tends to be governments that do

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that funding because many of the arrangements are bound

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by international treaties, which have to be signed by governments and not

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private individuals. So we

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will see where this all goes. And, um, certainly

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on Space Nuts, uh, we will keep everybody

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well aware of what's happening in the world of telescopes and the world of

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astronomy generally.

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Heidi Campo: Thank you so much, Fred. Uh, it's been a

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pleasure chatting with you today, and thank you again to all

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of our listeners. And with that, we are going to

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wrap it up and say good night till the next

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time.

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Professor Fred Watson: Good night and good morning.

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Voice Over Guy: You've been listening to the Space Nuts podcast,

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available at Apple Podcasts, Spotify,

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00:23:19.300 --> 00:23:21.020
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