Name: The planet in our solar system that’s hiding a weird secret | Sara Seager
Uploaded: 2026-03-10T18:03:53.000Z
Duration: 7 min 52 s
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The search for another Earth, the planet B.

We want to find a true Earth twin with continents, oceans and sunlight, and

A place where we humans could potentially live.

The reason we're doing it primarily is not to find a new home for humans, but

it's to understand our Earth, our origin of life.

It's today's way of answering, where did we come from?

A very astronomical, scientific way to answer that question.

I'm Professor Sarah Seager, an astrophysicist and planetary scientist.

I work on the search for signs of life beyond Earth.

When I first saw the dark sky, it was completely by accident.

We went camping and I don't know why, but

I stepped out of the tent in the middle of the night.

I saw the stars and I just couldn't believe it.

And at that moment, I understood at a deep level that there just has to be something else out there.

And if our sun has planets, Mercury, Venus, Earth, Mars, et cetera, it makes sense that other stars, you know, other suns should have planets also.

An exoplanet is a planet orbiting a star outside of our solar system.

Thirty years ago, we didn't know about any exoplanets.

But when I was in graduate school in the mid-1990s, the first exoplanet around a sun like star was reported.

And it presented the possibility of life on another planet.

The line between mainstream research and research that's considered completely crazy.

Back in the early days of exoplanets, it was all considered crazy.

No one thought the field would go anywhere.

People thought it was silly to spend time on it.

But a while back, a journalist called me the Indiana Jones of astrophysics.

Because in research I was willing to take risks, try out new ideas, explore in a way that makes most people a bit uncomfortable.

And we astronomers have found thousands of planets.

And there's several thousand planet candidates out there just waiting to be confirmed as planets.

The search for Planet B or Earth 2.0 is like a forensic crime scene.

We have real data, but we have to interpret.

We have to make a lot of interpretation to make the picture whole.

For example, Venus is sometimes called our sister planet because Venus is about the same size and the same mass as Earth.

But the surface of Venus is so hot, it's way too hot for life of any kind.

But Just like on Earth, if you hike up a mountain or go on an airplane, it gets colder and colder above the surface.

And so way above the surface, at 50 km above, the temperature is just right for the.

In fact, the temperature and pressure in the clouds is just like here on Earth's surface.

So over half a century ago, Carl Sagan first proposed that perhaps there's life in the clouds of Venus.

But people didn't know at the time what we know now, that the clouds are made of concentrated sulfuric acid.

It will burn a hole in your clothes and your skin instantly.

So this idea of life in the clouds of Venus, even tiny primitive bacteria, it sounds ridiculous, but

Just like if you're exploring in the wilderness or you're driving somewhere, do you keep going straight or do you make a right?

Well, I came to one of these pivot points because of phosphine on Venus.

Astronomers discovered a gas on the planet that could suggest.

In the fall of 2020, we made an announcement.

We reported the discovery of tiny amounts of phosphine gas in the atmosphere of Venus.

Phosphine on Earth occurs naturally in decaying organic matter, like in dead fish or swamps.

How in the world did phosphine get on Venus?

And we presented 100 pages of chemistry, and

we explained that all the known chemistry on Venus couldn't produce the amount of phosphine that we reported to detect in the atmosphere of Venus.

So it definitely points us to opening our minds to what is out there.

What other types of planets might be out there, what other type of archetypes.

There could be way more planet types out there that we just haven't yet conceived of.

My goal is to find a true Earth twin and to search for signs of life on it.

But so far, it's hard to find, and we haven't found any.

And when we are ready to find them, whether they be just like Earth, it's more or less unlikely.

The other problem is stars and exoplanets are so far away, we can think of science fiction we can hibernate.

Perhaps we'd send our DNA and, you know, get ourselves printed out there on the new planet in the future.

So although we love exoplanets, we're trying to find signs of life.

So definitely our search for another Earth informs us just how wonderful our planet is.

All the pieces evolve together and sit in an amazing way.

And we really need to spend what resources we can taking care of our planet.

Honestly, I'd love to find signs of life anywhere in our solar system or beyond.

My memoir is titled the Smallest Lights in the Universe.

It means to find the other Earths, we have to really aim to find, literally, the smallest, smallest lights out there.

And it also means something here on Earth.

It means when times are tough, whether that's the world around us or, like a personal tragedy, it means that we have to find those little lights, the smallest lights in our own internal universe, and

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The planet in our solar system that’s hiding a weird secret | Sara Seager

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