Chapter 1: What fascinating topics are covered in this episode?
This is a Triple J podcast.
Hello, welcome to another episode of Science with Dr. Carl. My name is Lucy Smith and this week it's one of those episodes that kind of blew my mind. In fact, I want to go back and listen to this week's episode just to get all of this information in my brain. But it's brought to you by people who can explain it so well.
This week's episode, we delve into the world of physics, astrophysics, dark matter, neuroscience, and so much more with friend of the show, Professor Geraint Lewis, and you're going to meet Caitlin Thurn. It is her first time on the show. She's someone who is still studying and yet has put together some really amazing initiatives for paying it forward for the next generation of scientists.
You'll learn more about that in this episode. I'm Lucy Smith.
Chapter 2: What recent discoveries are being explored in astrophysics?
Let's do it. We've got Dr Karl across from me in the studio right now, but Dr Karl, we are having a full-blown party in the studio this morning.
I do love working in the School of Physics because they're just searchers for the truth, and so let's introduce them, take it away.
So we've got Geraint Lewis joining us. Now, Geraint, you've been on the show many times, friend of the show. You are someone who is specialising, I guess, in the worlds of physics, astrophysics, dark matter, astronomy. What is one thing you've been working on recently?
Oh, I've been working on this new sort of experiment we're trying to do to find out if the universe is broken. Yeah, it is. A minor question. It's a big question everyone's looking at at the moment. It might be that the universe has a preferred direction, which is something that's quite unexpected. So we're really trying to look at is it broken or not.
Okay. Is it broken or not?
Because if it had a spin, we might be in a black hole. That was another story. Yeah, yeah, yeah. Okay, okay. Next person, Caitlin.
Next person, Caitlin Thurn, making your Science with Dr. Carl debut. Caitlin, welcome to the show.
Oh, thanks so much for having me.
There's a few different avenues that we can go down with you, Caitlin. So let's start with the fact that you are specialising in physics and mathematics. You're still studying. You've previously studied neuroscience at the University of Melbourne and you founded a really special project, which we're going to get to a little bit later on. Mm-hmm.
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Chapter 3: How does Caitlin Thurn contribute to science and education?
But it's really wonderful to just start exploring the magic of how physics works and how the universe works.
uh doing quantum at the end of last term was beautiful because it was the first little taste of the real mathematics that underpins that understanding yeah and getting to understand how much of it is feels like absolute magic and just a statistical basis for how we understand the universe to work rather than being the classical world one would expect
to live in where if you throw a tennis ball, it's going to do exactly what you told it to.
Yeah.
And it was really fascinating and good fun to start dipping my toe into exploring that world.
Totally. And this is something that you're also applying. You are a serving member of the Australian Army Reserve as a combat engineer. Tell us about that work. What does that look like?
Yeah, I will admit it's one of my absolute joys. There's such a strong community and connection there. And it's the kind of place where you're just never alone, no matter what you need to do, no matter if it's digging holes in the rain or running up and down in circles in the bush, you're just never alone, which is really, really beautiful to see.
For that role I've been in the reserves for about six or seven years now and combat engineering boils down to three main things. It's find it, build it or blow it up.
Wow.
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Chapter 4: What is the significance of dark matter in the universe?
Look it up on Wikipedia. And I still have difficulty understanding it, but thank you for taking me part of the way down.
Let's talk about that a little bit later on as well. But we'll jump into a question here. To kick us off, Caleb on the Central Coast. Caleb, what do you want to know this morning? You've got three big brains to get into it.
I've just always wondered what would happen if we let a nuclear bomb off on the moon, if it would affect Earth's gravity and tides.
Really, if you explode a nuclear bomb on the moon, it would have essentially no effect on the Earth whatsoever. We think nuclear bombs are very, very powerful. Of course, they are for humans. They can destroy cities and decimate large areas. Astronomically speaking, they're actually a small amount of energy. So if you wanted to really affect the tides on the Earth, you need a lot more energy.
You would need to move the Moon or break the Moon up, and nuclear weapons just aren't powerful enough. Sorry about that. Did you have a plan? No, no, but maybe I can come up with one.
Okay, cool. Kayla, we've got to watch out for it.
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Chapter 5: How does time dilation affect our perception of time?
Dr. Carl, anything to add there?
The Americans had a plan to explode nuclear weapons on the moon, but the amount of energy is relatively small compared to the big things that we have happening. So, for example, when the two black holes that we first saw running into each other back in 2015, a century after Einstein predicted it,
When they collided in that one tenth of a second, apparently they put out 50 times more power than every star in the entire universe to add up, but only for a tenth of a second. Wow. That is serious power. But nuke, small time.
Thanks, Caleb.
Okay, thank you.
All right, we've got Connor in Ngunnawal country. Connor, this is a kind of, you've asked this in a really good way because I think it's a very, a common sensation we don't think about. Talk us through it.
howdy howdy doctors uh I was with my housemates last night and we were I don't know who brought it up but someone mentioned uh if you look at a surface or an object you can imagine what it's like to lick it or have it on your tongue respectfully um and I'm just wondering why why is that why are we able to you know feel tech well imagine textures on our tongue better than say our hands
Totally, Connor. I'm looking down at this desk and I know exactly what it would be like. I'm looking at this mic sock. I know exactly what it would feel like. Caitlin, can you speak to this at all from a neuroscience perspective? Dr. Carl?
Well, I can do a little bit of a start. So it takes three-tenths of a second from when light lands on your retina to end up giving you that full 3D colour thing. And then it has to be further processed. Roughly 4% of us cannot have a visual memory. It's called aphantasia.
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Chapter 6: What are the implications of rogue planets in our galaxy?
So when you're thinking about licking something, there's just not that many different ways that you would be able to experience a surface. So there's not that many patterns to need to remember. Or there's not that many patterns that you need to become familiar with to be able to then understand and identify, oh, if I licked the surface of the table, it's going to feel smooth.
If I lick something that's
like a carpet other than finding dog hair on my tongue it's going to be fairly fluffy feeling so the brain building process of identifying those variety of patterns to then be able to apply that to this with how it would feel if I licked this thing it's just not that complex and just one thing I suddenly realized from working with grandchildren and little nieces if they're under the age of one everything goes in their mouth yes everything
Bridget in Newcastle, what's your question? Hi, I was just wondering what is dark matter and why does it matter so much? I like that. What is dark matter and why does it matter? Who wants to start, Geraint?
I'll take that because I work on dark matter, so I know this topic. So for the last hundred years or so, astronomers have been measuring gravity in the universe. And what we keep finding is that there's a lot more gravity than we can account for from the stars that we can see. So basically, we've had to hypothesize that there's extra mass out there that we can't see, but we can feel its gravity.
Why is it important? Well, it turns out there's a lot more of it than there is of the atoms of stuff that we're made of. There's a lot more of this dark matter than there is normal matter. So is it important? Well, in your day-to-day, it might not be very, very important. But for the Sun, it's very important because it's what holds the Sun in its orbit in the Milky Way galaxy is the dark matter.
So dark matter is very important for holding the universe together. But the problem is we don't really know what it is. We have got lots of ideas, but we've never found any in our laboratory. So we're still looking for what is dark matter. And that might unlock some new secrets to just the way the universe works.
Interesting. Does that help, Bridget? Yeah, that helps a lot. Thank you so much. Fabulous.
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Chapter 7: Why do people experience brain fog during pregnancy?
Thank you. We're going to Sydney now with Stephen. Dr. Stephen, you're going to take us into the sci-fi movie world. Talk to us.
Absolutely. I love my sci-fi movies. And there's stuff like Interstellar that do a really good job at explaining time dilation. You know, spend an hour around a black hole and it's like seven years on Earth. But I don't understand length dilation. I watched Project Hail Mary and the faster they got to the speed of light, the closer the planet was. I don't get it.
This is gonna warp my brain, isn't it, Garion?
It is, it is. Unfortunately, it's just a weird way that the universe works. So as you mentioned, if I start flying off to the nearest star, it might take 100 years for me to get there for people here on Earth, but to myself, it might only be a couple of days for that particular journey. So you get that time dilation, as it's called.
But to me, on board that ship, it means that the distance to that star, as contracted, it feels a lot closer. Mm-hmm. And in fact, the faster and faster I go in the universe, the closer and closer everything feels. I can get to things quicker than if I could imagine the clocks ticking back at home. So I actually had a student work on this a few years ago.
If you fly off in a rocket and keep accelerating, in about 99 years to your own time, you would reach the edge of the universe as we can see it now. Billions of years would pass on Earth, but to you it would be a long lifetime. So, yeah, we do get this contraction. Everything feels closer the faster and faster we get to the speed of light. That makes me sick.
In fact, we've now got clocks that are so accurate that if you have an atomic clock and lift or drop it by a fraction of a millimetre, we can measure it speeding up and slowing down. I don't know what the equivalent is for length.
Caitlin, anything to add here? I mean, I will say that as to the actual experience of that, it may be 99 years to reach the end of the universe, which is strange that it feels a vaguely achievable human timeframe there.
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Chapter 8: How close are we to achieving time travel as a species?
That's a really cool number to know of. But you personally in the rocket ship going that fast, you wouldn't experience the contraction because you're contracting yourself. So that whole idea that what you experience in that moment is just... kind of your normal.
And is, you know, leads to a very devastating scene in Interstellar. No spoilers, Stephen. Thank you so much for your question.
Thanks, guys. Warps my brain. Love it.
Warps the brain. Continuing that, Francis in Epping, tell us about The Expanse. It's a TV show. What have you seen in it?
Yes. In it, the hero ship, the Rocinante, comes under fire by multiple missiles, about 15, I think, and they do a manoeuvre called a death blossom where it's a sort of wobbly roll to bring all the guns on the ship to bear on the missiles to try and defend against them. Would that actually work in real life?
All right, Caitlin, do you want to try and break this down for us as best you can?
Yeah, certainly. So I think, I will, and I'm thinking from a little bit of a more military-minded perspective here, I mean, it depends how those missiles were targeting you. If they were straight, just plug the coordinates in or tell you your angle of elevation and your velocity at launch, then absolutely, if you move out of the way, well, then you're not going to be there.
So it would work to defend. If it were something more in the lines of if it was locking onto a heat signature of some kind, then doing that death blossom move, as you described, might fire the engine such that it moves the heat signature of the vessel enough that those missiles might get confused by what they're locking onto, and that would save them.
The third kind of thing I can think of would be that if... the cannons were facing the wrong way. If somebody's coming up behind you and you have to turn around, well, doing a little flip to really be, have that element of surprise and maintain that element of surprise would definitely be an option.
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