Name: NASAの科学者だけど「宇宙人」について質問ある？| Tech Support | WIRED Japan
Uploaded: 2025-08-07T18:25:45.000Z
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Well, I could tell you, but then I'd have to kill you.

I'm astrobiologist David Grinspoon from NASA.

Let's answer your questions from the internet.

This is Alien Support. ["Alien Support"] Disgruntled Hermit asks, what's the most interesting exoplanet you've read about?

If I had to pick a favorite that we've found so far, it would be the planets in the TRAPPIST-1 system.

There are seven planets in the system that we've identified so far, and probably about three of them are potentially habitable.

And by the way, the TRAPPIST system is only 40 light years away, which if you consider that our galaxy is 100,000 light years across, that's relatively close.

I have a sort of chart here, and you can see the habitable zone of the TRAPPIST system with several potential planets in it, compared to the habitable zone of our solar system on the bottom, which has Earth and then, you know, possibly Venus and Mars on the edges of habitability.

And by the way, the TRAPPIST system here, it's a cooler star than our sun.

It's a red dwarf, and so the planets are clustered very close.

But imagine what it would be like for life evolving on a system with multiple habitable planets nearby one another.

Meteorites occasionally get blasted off of one planet and land on another.

So if you have a habitable planet with life and another planet that could be habitable, you could imagine life spreading easily.

Well, my thought is that aliens are real.

There are probably something like 30 billion habitable planets in our own galaxy.

And so even if a small fraction of those have an origin of life, there's lots of life in our galaxy.

And the more we study Earth and its origins, we haven't found anything that's sort of magical or so special about Earth that those things shouldn't be happening elsewhere.

So if you're asking me, do I think aliens are real?

If you're asking me, do I know scientifically?

I'll say not yet, but we're on the road to find out.

I'm watching this scene here with this astrobiologist lost in wonder and awe and a little bit of terror encountering this alien.

We talk about convergent evolution, that evolution on other worlds would find some of the same solutions.

So the idea that they have something that's like fingers for grasping, that makes sense.

The idea that they would have this kind of symmetry, just like we have bilateral symmetry.

They look vaguely squid-like, vaguely octopi-like.

I wouldn't be surprised if we saw complex aliens, if they looked somewhat familiar, but not exactly like any organism we had seen before, because again, they'll be responding to the same overall kinds of evolutionary forces.

And then you have the other factor where she's trying to communicate, and this alien is doing this weird kind of circular writing, and it turns out that they are trying to communicate with us, and they're as equally puzzled by us.

That makes sense, because I think there's this whole idea, something called incommensurability, that it might really be hard to communicate, because they might have very different kinds of cognition, very different notions of reality and time.

Utopia Circle asks, how exoplanets are discovered?

You can't directly observe the planet, because they're too dim and too far away, but you can notice what the planet is doing to the star.

So as a planet orbits a star, because of the gravitational pull of that planet, the star actually wobbles a little bit.

So that star is wobbling, because there's a planet around it, even though you can't see the planet.

So some of the time, the star is coming towards your telescope, and some of the time, the star is coming away from your telescope.

When it's coming towards you, the frequency shifts to a higher frequency.

Blue, when it's coming away from you, it shifts to a lower frequency.

Red, and so our instruments got good enough to detect that slight change, that rhythmic change from blue to red to blue to red.

It's a very, very tiny shift in wavelength.

And then later on, there was a new technique.

When a planet passes directly in between you and the star, you can notice that little bit of dimming of starlight.

It's very tiny, because planets are small compared to the star.

But if you have a very sensitive measurement of the light of that star over time, when a planet passes just in front of it, the star will dim a little bit.

And so if you watch the light curve over time of that star, it'll wobble up and down and up and down and up and down.

So you're not so much seeing the planet as noticing that the planet is blocking the star a little bit, causing it to periodically dim.

If it's a little bit above or a little bit below the direct line between your telescope and that star, you'll miss it.

So only about 5% of stars have planets oriented in the right plane, the right direction, to use that transit method.

But when things are lined up right, it's very sensitive.

So that has allowed us now, especially with space telescopes, like there was an instrument called Kepler that was designed to use the transit method to find lots of exoplanets.

And that was really what revealed to us that most stars in the universe have planets.

Sohat Virgo asks, where do astrobiologists work?

How hard is it to get a job in astrobiology?

So astrobiologists work a lot at universities.

Some of us build spacecraft and send them out to observe other planets.

Some of us do field work and study exotic locations, go on expeditions where there's extreme life to understand the limits of life and look for some of the earliest signs of life.

This one comes from Western Australia and is about 2.7 billion years old.

And if you look in close, you see this rock is made up of layers.

And what we've learned is that those layers are from ancient microbial mats, some of the earliest life on Earth that formed these layers on what was then the seafloor, microbes, single-celled organisms using the energy of sunlight, using different kinds of nutrients flowing in the seawater and organizing themselves into these layers.

I'm at your mom's house asks, what is taking NASA so long to find them aliens?

Well, it's a big universe out there, but we're working on it.

Obviously, we have rovers on Mars searching for the signs of ancient life.

So we have a mission now on its way to Europa, a moon of Jupiter that is home to a vast ocean of liquid water.

So we have a mission called Europa Clipper orbiting the Jupiter system and making close passes by Europa in the early 2030s, helping us to understand if that ocean is habitable.

What are the flows of nutrients and so forth?

Is that ocean a place that could support life?

And if it is, that would motivate us to send missions in the future that would land on the surface and maybe even tunnel under the ice in submarines to look directly for life on Europa.

We also have a mission called Dragonfly that's going to launch in a few years and go to Titan.

It has a thick nitrogen atmosphere like Earth's and it's loaded with organic molecules, the same kinds of molecules that led to the origin of life on Earth.

Dragonfly is going to be basically a nuclear-powered drone that lands on Titan and samples the surface, examines those organic molecules to see if they're the kinds of molecules that may have led to life on Earth.

And then it's going to take off and fly to different locations and repeat its experiment.

So it's gonna be the first time we've actually been able to explore a planet with an aerial craft that lands multiple places and does these kinds of experiments.

We had a mission recently that went to an asteroid called Bennu.

It collected over 100 grams of material from the surface of Bennu and brought it back to Earth.

So we have in our labs now pieces of asteroid dirt.

And what we found is that Bennu is full of the stuff of life, amino acids.

Amino acids are the things, the building blocks that make up proteins.

And nucleotides, which are the components that make up DNA and RNA.

It suggests that not just Earth, but all the planets were being sprinkled with the stuff that basically leads to an origin of life.

So again, we haven't found life elsewhere, but we've been finding results that suggest that life should be common.

At slash x slash text asks, who came up with the flying saucer design and why did it stick?

It turns out that flying saucers go back to a pilot named Ken Arnold, who was flying in the Pacific Northwest in 1947 and he reported something weird that he saw.

What's interesting is that he never even said it was saucer shaped.

He didn't understand and he described its motion as skipping like a saucer.

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NASAの科学者だけど「宇宙人」について質問ある？| Tech Support | WIRED Japan

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