Celestial Wonders: Unveiling Solar Flares, Atmospheric Flight, and Mars' Chunky Core

0:00 Avery: Welcome to Astronomy Daily, the podcast that

0:03 brings the cosmos down to Earth. I'm Avery.

0:05 Anna: And I'm Anna. It's great to be with you

0:08 today. We've got a fantastic lineup. We're

0:11 starting with our own sun, which just put on

0:14 a spectacular and slightly terrifying

0:17 show for our most powerful solar telescope.

0:19 Avery: Then we're heading into our own atmosphere,

0:22 to a mysterious layer we can barely reach.

0:25 And the brilliant new technology that might

0:27 finally unlock its secrets. After that, we'll

0:30 dig deep into Mars to find out why its

0:33 insides are as chunky as a cookie.

0:35 Anna: And finally, we'll tackle the big one, time

0:38 travel. A new study suggests it might be

0:41 possible, but it comes with a catch that

0:44 changes everything. So let's get started.

0:46 Avery: Alright, Anna, let's talk about the sun. We

0:49 know it can be violent, but this is something

0:51 else. The NSF Inouye Solar

0:54 telescope just got its first look at an X

0:56 class flare. And the images are mind

0:59 blowing.

1:00 Anna: They really are. For our listeners, an X

1:02 class flare is the most powerful category of

1:05 solar flare there is. These are massive

1:08 explosions of energy and catching one with

1:10 this level of detail is a huge deal. The

1:13 telescope managed to capture it at a

1:15 resolution where the smallest details are

1:18 just four Earths across.

1:19 Avery: That's incredible. It's like having a super

1:22 powered magnifying glass on, um, the most

1:24 energetic event in our solar system.

1:27 So what did they actually see with this new

1:29 level of clarity?

1:30 Anna: They saw something called coronal loops, but

1:33 on a scale we've never seen before. These are

1:36 thin filaments of plasma that arch over the

1:38 sun's surface following magnetic field lines.

1:41 We've seen bundles of them before. But

1:43 Inoue's power allowed scientists to see

1:46 individual loops for the first time. Some

1:49 of these loops were as small as 21 kilometres

1:52 wide, which is right at the telescope's

1:55 resolution limit. It's these magnetic field

1:57 lines twisting, snapping and reconnecting

2:00 that powers the solar flares in the first

2:02 place.

2:03 Avery: So saying the fundamental building blocks of

2:05 these events is a game changer. I know these

2:08 flares can be dangerous, knocking out radio

2:10 communications and power grids here on Earth.

2:13 Does this help us prepare for that?

2:15 Anna: That's the goal. According to the

2:17 researchers, peering into these smaller

2:19 scales where the magnetic reconnection

2:21 actually happens, opens the door to

2:24 understanding the engine behind the flares.

2:26 Better understanding leads to better

2:28 prediction models, which gives us a better

2:31 chance to protect our technology. When the

2:33 sun decides to act, it's a huge step

2:36 forward in forecasting space weather.

2:38 Avery: From the very big to the very,

2:41 very small.

2:42 Our next Story is about exploring a part of

2:44 our own atmosphere that's been stubbornly out

2:47 of reach. The mesosphere. It's too high for

2:50 balloons, but too low for satellites.

2:52 Anna: Exactly. It's a huge blind spot for

2:55 climate and weather data. But researchers at

2:58 Harvard and the University of Chicago may

3:00 have found a way to reach it. And it sounds

3:02 like something out of science fiction.

3:04 They've designed ultralight flying structures

3:07 that float by harnessing sunlight itself.

3:10 No engines, no fuel, powered by

3:12 sunlight.

3:13 Avery: How does that work?

3:14 Anna: It uses a phenomenon called photoforces.

3:17 It's a gentle force that pushes on an object

3:20 when light heats one side more than the

3:22 other. Down here on the ground, the force is

3:25 so weak, we never notice it. But in the

3:27 extremely thin air of the mesosphere, that

3:30 tiny push is enough to overcome the weight of

3:32 these new structures.

3:33 Avery: So, so what are these things made of? They

3:36 must be unbelievably light.

3:37 Anna: They are. They're built from ultra thin

3:40 ceramic alumina with a special coating on the

3:43 bottom to absorb sunlight. The researchers

3:45 actually tested them in a lab in a low

3:47 pressure chamber that mimics the mesosphere.

3:50 And they levitated perfectly with just a bit

3:52 of light.

3:53 Avery: That's amazing. The applications seem

3:55 endless. You could attach sensors for climate

3:57 data or create floating communication arrays

4:00 like a, uh, low orbit starlink. One of the

4:03 researchers even said they could eventually

4:04 fly on Mars.

4:06 Anna: That's the long term vision. Mars has a thin

4:08 atmosphere that's very similar to our

4:11 mesosphere, making it a perfect target.

4:14 One of the lead authors called it the Wild

4:17 west in terms of applied physics, because

4:19 nothing has ever been able to fly sustainably

4:22 up there before. This opens up an

4:25 entirely new way to explore our upper

4:28 atmosphere and potentially other

4:30 worlds too.

4:32 Speaking of Mars, our next story takes

4:35 us deep inside the red planet. A

4:37 new analysis has revealed that the

4:40 interior of Mars is, and this is

4:43 a direct quote, as chunky as a

4:46 delicious macadamia cookie.

4:48 Avery: I love it when scientists get creative with

4:50 their analogies. So what does that mean

4:52 exactly? It's not actually made of cookies, I

4:55 assume.

4:56 Anna: No. Unfortunately, what they found

4:59 using data from the Insight lander is

5:02 that huge chunks of Mars

5:04 ancient early crust are preserved

5:07 deep within its mantle. These are

5:10 geological fossils from when the planet was

5:13 first forming four and a half billion years

5:15 ago.

5:16 Avery: Insight was the mission that listened for

5:18 Marsquakes. Right. So they used seismic waves

5:21 to map the interior. Like an ultrasound.

5:24 Anna: That's right. By studying how the waves from

5:26 these quakes travelled and bounced, they

5:29 couldn't map out the Composition. And they

5:31 found these massive fragments, some up

5:34 to four kilometres across, just drifting in

5:37 the mantle. The theory is that during the

5:39 chaotic early days of the solar system,

5:42 giant impacts shattered the young planet's

5:45 crust and those pieces sank into the

5:48 molten mantle before a new crust formed.

5:51 Avery: And they've just been sitting there ever

5:52 since?

5:53 Anna: Pretty much. Unlike Earth, Mars doesn't

5:56 have active plate tectonics. Our crust and

5:59 mantle are constantly churning and recycling

6:02 each other. Mars has a single

6:05 solid crust, a stagnant lid.

6:07 So its interior evolution is much slower.

6:11 It's acted like a, uh, time capsule,

6:13 preserving this evidence of its violent

6:15 birth. This gives us an incredible

6:18 window into what rocky planets look like

6:21 before tectonics get started.

6:23 Avery: Okay, for our final story, we're going from

6:25 planetary history to rewriting it. Or

6:29 maybe not.

6:30 Anna, uh, let's talk time travel.

6:32 Anna: This is a really fascinating one. A new

6:35 study looked at what would happen inside a

6:37 spaceship travelling on a closed time

6:40 like curve, which is basically a loop through

6:43 space time that brings you back to the exact

6:46 moment you left.

6:47 Avery: The classic sci fi setup. So do we get to go

6:50 back and fix our mistakes or accidentally

6:53 erase ourselves from existence by bumping

6:55 into our grandfather?

6:56 Anna: Well, according to this research, neither.

6:59 The study uses standard quantum mechanics

7:02 and thermodynamics, not some exotic new

7:05 theory. And the conclusion is

7:08 the laws of physics themselves demand

7:11 self consistency. After one full

7:14 loop, everything inside the ship clocks

7:16 computers, and even you must return

7:19 to its original state.

7:21 Avery: So time travel would be like pressing a

7:23 cosmic reset button.

7:25 Anna: Precisely. And it gets weirder.

7:28 To maintain that consistency, the second law

7:31 of thermodynamics, the one that says

7:33 disorder or entropy always increases,

7:36 has to be temporarily reversed. At a

7:39 certain point in the loop, entropy hits a

7:42 maximum and then it starts decreasing.

7:45 Processes run backwards. Coffee would get

7:47 warmer, broken eggs would reassemble.

7:50 Avery: And what does that do to a person? What about

7:53 our memories?

7:54 Anna: This is the biggest catch. The formation of

7:57 memory is a thermodynamic process,

8:00 as entropy reverses to bring the system back

8:03 to its starting state. Any memories you

8:05 formed during the trip would have to be

8:08 erased completely.

8:10 Avery: So you could live through this incredible

8:12 journey. But from your point of view, it

8:15 would feel like nothing happened at all.

8:17 You'd get in the ship, complete the loop, and

8:19 arrive back in the same instant. With no

8:21 memory of the trip.

8:23 Anna: Exactly. It's the ultimate form of what

8:26 happens in the loop stays in the loop because

8:29 it gets completely wiped clean. So instead

8:32 of rewriting history, you just reset

8:34 it and forget it. A very different and

8:37 much less adventurous picture of time travel

8:40 than the movies suggest.

8:42 Avery: And that's all the time we have for today,

8:43 from the fiery heart of the sun to the

8:45 delicate flyers in our atmosphere, the chunky

8:48 interior of Mars, and the strange,

8:50 forgettable physics of time travel.

8:53 Anna: Thanks for joining us on Astronomy Daily. If

8:56 you'd like to stay on top of the latest space

8:58 and astronomy news, simply visit our website

9:00 at astronomydaily IO and

9:03 check out our constantly updating newsfeed.

9:06 You can also find all our back episodes

9:08 there. If you'd like to do some binge

9:10 listening, I'm Anna.

9:12 Avery: And I'm Avery. We'll see you next time for

9:14 another look at our amazing universe. Until

9:17 then, keep looking up.