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  • [♪ INTRO]

  • From meteorite samples to atmosphere simulations, this week has been a banner week

  • for finding out what space is made of!

  • And not to spoil it or anything, but it's some pretty cool stuff.

  • First up: meteorites!

  • Last week at a meeting of the American Physical Society, a team of scientists announced that

  • they'd found the first confirmed superconductors in meteorites.

  • Besides being a first, their discovery could someday help us

  • make super-efficient technology here on Earth.

  • Normally, when electricity flows through a conductor, like a copper wire,

  • the conductor resists that flow, and some of the energy is lost to heat.

  • This means most machines that use conductors aren't totally efficient.

  • Superconductors can get around this problem.

  • They're materials with virtually no resistance to electrical flow,

  • although they have to be really cold to do it.

  • Like, anywhere from -140 to -270°C!

  • At these temperatures, the atoms' electrons start pairing up, which allows them to flow

  • extra smoothly with basically no energy loss.

  • As a bonus, superconductors also have a property called the Meissner effect:

  • They repel weak magnetic fields around them.

  • This is one reason why, if you put a superconductor in a magnetic field, it'll float!

  • Scientists are interested in these materials

  • because we could use them in all kinds of applications.

  • They'd be great for building machines that have very little energy loss.

  • Researchers are also on the hunt for ones that work at room temperature, since those

  • would be way easier to use than ones that have to be cold.

  • Right now, they can make some superconducting materials in the lab, but meteorites are a

  • great place to search for new ones, too.

  • These space rocks sometimes form under really extreme pressures and temperatures that can't

  • be replicated in a lab, so they might have all kinds of weird, neat stuff in them!

  • People had been looking for superconductors in meteorites for a while, but no one had

  • found any yet, partly because the available techniques led to pretty imprecise measurements.

  • But this team picked them out.

  • And they did it by creating a new technique based on the Meissner effect.

  • It's called magnetic field modulated microwave spectroscopy, or MFMMS.

  • It uses superconductors' magnetic properties to locate them in impure samples.

  • In this new method, a couple of magnetic fields are applied to the meteorites.

  • And ultimately, these fields force any superconducting materials in the rocks

  • in and out of superconducting mode.

  • That creates a signal that the team can use to pinpoint the metals.

  • And it works really well!

  • These scientists were able to identify mixtures of indium and tin in the rocks, along with

  • indium-tin mixes that had something else in them, maybe lead.

  • All of these are confirmed superconductors, though they only work at about -270°C. So

  • they aren't the room-temperature holy grail we've been looking for.

  • But these results are still important, because they show us that superconductors are probably

  • widespread in rocks throughout the universe!

  • They also show us how this new technique can be used to find all kinds of materials,

  • even ones we've never seen.

  • So let the discoveries commence.

  • Now, you can't simulate how all meteorites form in a lab, but one thing you can simulate

  • are the atmospheres of other planets.

  • You just pump some gases into containers and see what happens!

  • It sounds pretty simple, but these experiments are especially important when it comes to

  • studying exoplanets, and figuring out which ones could support life.

  • Last week in the journal Nature Astronomy, a team of scientists based at

  • Johns Hopkins University published a paper about their new atmosphere simulations.

  • And they're going to really help out our telescope game.

  • Specifically, this team wanted to see which kinds of atmospheres develop photochemical hazes.

  • These are those sort of smoky fogs created when sunlight reacts with chemicals in the air.

  • Hazes can affect a planet's temperature

  • and how much ultraviolet radiation reaches its surface.

  • And these are both things that shape whether or not something could live there.

  • We've studied hazes in atmospheres like Earth's and also Pluto's, but we didn't

  • know a lot about what they could look like in other solar systems.

  • That's what this team wanted to find out.

  • They mixed up nine different possible atmospheres in the lab, varying concentrations of nitrogen,

  • water vapor, organic materials, and other good gassy stuff.

  • Then, they heated them up with plasma to simulate stellar radiation and drive the reactions.

  • They found that every single atmosphere they tested produced some haze,

  • but more importantly, they saw that water vapor can play a huge role in haze production.

  • We used to think that most of these fogs were made through interactions with hydrocarbons

  • and nitrogen, because that's what we see around here.

  • But the two haziest atmospheres the researchers simulated

  • had high amounts of water and low amounts of nitrogen.

  • So it seems like nitrogen isn't always that important

  • and that water vapor can be a good substitute.

  • Knowing all of this will be important when NASA launches the James Webb Space Telescope,

  • which should happen next year.

  • I can't believe it's finally happening!

  • Webb will study tons of faraway exoplanets and should give us great observations.

  • But hazes can sometimes make it hard for

  • telescopes to determine which kinds of gases are in a planet's atmosphere.

  • So if we know right from the start what mixes tend to produce haze, we'll be able to better

  • interpret and fill any holes in the data Webb provides.

  • These experiments are kind of like doing prep work before you walk into your lab class.

  • So thanks to these recent studies, we now know a lot more about meteorites and potentially

  • habitable exoplanets, but somehow, we still have a lot more to learn.

  • Maybe thankfully, there's a long way to go, and a lot more science to tell you about.

  • It would be kind of a shame, yeah?

  • If we just were like 'Uh, science is done!

  • Thanks for participating in Scishow, we're done.

  • All the science got finished, see ya!'

  • But that's not happening.

  • So thank you for watching this episode of SciShow Space,

  • brought to you by all of our patrons on Patreon!

  • We couldn't keep talking about space news without you, so thanks for all that you do.

  • If you would like to learn how to support the show, you can go to patreon.com/scishow.

  • [♪ OUTRO]

[♪ INTRO]

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B1 中級

隕石の中に超伝導体を発見! (We Found Superconductors in Meteorites!)

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    林宜悉 に公開 2021 年 01 月 14 日
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