We've always been a bit obsessed with them.

Just think about all the films they starred.

E.T., phone home.

Our home⏤Earth⏤is filled with life so far unmatched by anything we've found in space, but we're only a tiny part of the universe.

There has to be life out there somewhere else, right?

Scientists have been trying to answer that question for decades, but today, research is skyrocketing.

The next decade is probably gonna be packed with the most insights and the most data and the most knowledge in all of human history.

Could we really be about to discover whether life exists out in space?

Ancient Greek philosophers theorized about it.

18th-century academics like Voltaire wrote about it.

But the scientific search for life beyond Earth really kicked off in the 1950s with the dawn of the Space Age.

By October 1957, the first artificial Earth satellite was pronounced ready.

When the Russians sent the world's first satellite into space, the race was on.

They've got the flag up now, and you're gonna see the stars and stripes.

By the 70s, everyone wanted to know the answer to one question:

♪Is there life on Mars? ♪

By 1976, America had landed a probe on our neighbor planet.

The world held its breath to see what or who might be up there.

Who... who are you?

We're from Mars; don't be afraid.

But the reality was a bit disappointing.

Sorry, Bowie.

As soon as people sent satellites into orbit and beyond, they immediately discovered that these places didn't actually have life.

The search for life was very prevalent in science fiction, but in science, it was seen as a little bit of a laughing stock.

There's no way of actually doing it; we didn't have enough technology to do it.

But, in the last two or three decades, astrobiology as a discipline has become this incredibly exciting frontier.

Not only for these big questions that many of us are interested in because of popular culture, [but] because scientifically, we can [also] start to answer them properly.

But in the search for life beyond our own planet, what are we actually looking for?

Scientists hope to detect three things that can signify life.

The first is water.

Water is the solvent for life on Earth⏤that means that life works.

So, water is the first thing that everyone has been looking for.

For liquid water to exist on a planet's surface, it has to be a very specific distance from the star it's orbiting.

Not too far away so that all the water on its surface will freeze,

but the planet is also not too close to the sun so that it's not so hot all the liquid water on the surface would become vapor.

This perfect distance is nicknamed the "Goldilocks Zone".

Not too hot, not too cold.

In the past 10 years, scientists have found 59 worlds outside our Solar System that are just right.

The planet with the most potential is called "Teegarden B".

12 light years away, it is roughly the same size as Earth and receives a similar amount of light from its host star.

But it's one thing to think a planet might be able to sustain life.

It's another thing entirely to know it actually has it.

What you then need is individual biosignatures.

And biosignatures is a very loose term⏤what it basically means is specific molecules are only associated with life.

Elements like oxygen, which life on earth produces and replenishes, or methane, a compound life on earth creates.

Astrobiologist Sara Seager has identified at least 3,500 molecules that could be biosignatures.

So, there are plenty to look for.

But finding biosignatures does not necessarily mean intelligent life.

For decades, scientists have also been looking for something called "techno signatures".

If life evolves on the planet and gets to the point where it's... it communicate and build things and build technology like humans have on earth, then you can detect signs of that, too.

Techno signatures aren't that tricky to pick up on.

All you have to do is watch for telltale signs of technology like radio signals or the bright flash of a laser.

Despite looking, scientists have failed to find a convincing techno signature.

But, in 1977, astronomers saw something that stopped them in their tracks.

A strange signal coming from space.

A handwritten note alongside says it all.

"Wow", which became the signal's name.

Where this apparent signal came from, no one knows.

Some might claim it is proof of life beyond Earth, but it hasn't been verified.

And finding genuine signs of alien technology relies on getting extremely lucky with timing.

You're looking at a planet that's maybe 200 lightyears away, let's say.

So, that means you're seeing that planet 200 years ago, and vice versa.

That planet, if life exists and is technological, is looking at us, and it looked, at let's say London,

they'd... they'd see Victorians walking on the streets right now.

because that's... that's how long it'll take... take for the light to get there.

Now, bear in mind, also, that these civilizations might be hundreds, millions of lightyears away.

So, the communication is not exactly quick, and we're talking many hundreds of generations of people on Earth before you get responses.

So, detecting alien intelligence is... is really tantalizing, but it's also tragic 'cause we'll probably never be able to communicate with them if we did discover it.

That's why today's technology focuses more on looking for the bio than the tech note.

So, how are we looking for biological life?

One way is to scour the skies.

That means telescopes.

But not like those...

... more like these.

So, for several decades now, there have been telescopes in space⏤and on Earth⏤that have been able to detect the presence of planets around other stars.

Now, the next generation of telescopes will be able to take pictures of those planets in much more detail.

In December 2021, the largest and most powerful space telescope ever made was launched into orbit.

The James Webb Space Telescope.

James Webb begins a voyage back to the birth of the universe.

It's equipped with a 6.5-meter mirror, giving it a light collecting area more than six times greater than the world-renowned Hubble Telescope.

If we crave some cosmic purpose, then let us find ourselves a worthy goal.

It's also able to detect molecules of life like oxygen, a handy tool when looking for a habitable environment.

Towards the end of the decade, there are gonna be enormous ground-based telescopes with 40-meter wide lenses,

and these will be able to actually take pictures of things like clouds and atmospheres on these exoplanets.

So, you'll be able to do things like understand the climate of a different planet, you'll be able to understand what a day looks like on all these planets, which is incredible.

In the 2020s, three ground-based telescopes with mirrors 25 to 40 meters wide are expected to become operational.

In the late 2030s, they could be joined by two proposed NASA spacecraft.

One being specifically designed to take photographs of habitable planets.

An even better way of looking for signs of life is to visit places to scoop up bits of air or soil, [and] do scientific experiments with them using sophisticated instruments to really understand what's there.

And there are many, many missions planned for the next decade.

Probes are being sent to collect data from so far untouched parts of our Solar System, like Europa, one of Jupiter's moons, which seems to have canyons of ice.

Ice means that precious, life-giving element, water.

In 2023, Europe's Jupiter Icy Moons Explorer will embark on a 12-year journey to see if it has the potential to support life.

If life on Earth started with warm water sitting on rocks and interacting chemically, then perhaps, it could happen on... on one of those sorts of moons, too.

When it comes to general space exploration⏤these are quite cool missions, anyway⏤but they're all pretty much geared towards looking for life in ways that we've never been able to do before.

These missions cost hundreds of millions of dollars.

Luckily, there seems to be a growing appetite to answer the fundamental question of whether life exists beyond Earth.

NASA's 2022 budget is the largest it's been since the 60s.

Astrobiology has really come of age; the 2020s is when it's gonna take flight.

If life exists within our corner of the galaxy, most scientists in this field are confident that we'll discover some sign of it in the next decade.

If, however, we discover nothing in the next decade, that also tells us something profound.

It tells us that life is much, much, much more rare than we thought it was.

I'm Alok Jha, science correspondent at "The Economist".

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