Name: We Might Find Alien Life In 2089 Days
Uploaded: 2025-07-10T05:18:24.000Z
Duration: 17 min 55 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Clarke had a sequel to 2001 A Space Odyssey.

It's called 2010 Odyssey 2, and at the end of it, an alien intelligence converts Jupiter into a star.

As a group of astronauts narrowly escape the implosion, they receive the following message from the aliens.

All these worlds are yours, except Europa.

No, but it suggests that already in 1982, we suspected that Europa might offer our best chance of finding alien life in our solar system.

Forty-two years later, in October 2024, NASA is actually launching the most advanced mission to hunt for signs of alien life, and it's going to Jupiter's moon, Europa.

And how do you make a probe that can withstand the perilous conditions?

Deep inside Jupiter, there is so much pressure that hydrogen is believed to take the form of a metallic liquid.

And this metallic liquid hydrogen generates an incredibly powerful magnetic field, almost 20,000 times stronger than Earth, if you measure at the same distance away.

So if you could see this magnetic field from Earth, it would appear twice as big as the full moon.

On its own, that magnetic field is harmless, but right in the middle of it is the most volcanically active world in the solar system, Jupiter's moon, Io.

The volcanoes on Io's surface shoot out tons of sulfur dioxide, and every second, one ton of this material gets ionized and trapped inside Jupiter's magnetic field.

And the field accelerates these particles to rotate incredibly fast with Jupiter, so they whiz around at over 300 kilometers per second.

Their inertia actually pulls back on the field, stretching it out, and this trapped material slams into other moons, ejecting even more particles from their surfaces.

This cycle forms massive radiation belts which span past Europa and the other moons of Jupiter.

Now for electronics, this intense radiation is kryptonite.

In the 1970s, the Pioneer 10 and Voyager missions only briefly passed by Jupiter.

But the radiation caused glitches, gave the instruments false commands, and corrupted some of their data.

Even with modern shielding, a spacecraft within the radiation belts would only survive for around three months.

So how will NASA's new mission, the Europa Clipper, orbit Europa for over four years without getting fried?

It'll orbit Jupiter from afar and then swoop in every few weeks to quickly fly by Europa and then leave again.

And since the mission is going to collect a lot of data, it can use the downtime while it's way out here to transmit it all back to Earth before going in for another swoop.

In all, it'll do 49 flybys, mapping almost the entire surface.

That's actually how the Clipper got its name, after the fast and nimble 19th century clipper ships quickly dipping in and out of ports.

But of all the places in the solar system to look for life, why Europa?

If you stood on Europa's surface, you'd be hit with 5,400 millisieverts of radiation in a single day.

That's 1,800 times more than the annual dose here on Earth.

If you stay here for a couple hours, you would eventually die from radiation sickness.

When Voyager 1 passed by Jupiter in 1979, it took this photo of Europa.

If you compare that to most of the other moons in the solar system, you'll notice something is missing.

Every planet and moon has been bombarded by asteroids over billions of years, and most planetary surfaces show it.

Well, something recent, say over the past 60 million years or so, must have been happening on Europa to erase most of these craters from the surface.

Sixteen years after Voyager, Galileo arrived to Jupiter.

It spent eight years studying both the gas giant and its moons.

And Galileo's magnetometer picked up something interesting on Europa.

Jupiter's magnetic poles, like Earth's, aren't aligned with its geographic poles.

So as the planet rotates every 10 hours, the whole magnetic field wobbles.

This changing field from Jupiter induces a magnetic field on Europa, and a relatively strong one at that.

That means there must be an electrically conductive layer within Europa that reacts to Jupiter's  And readings from Galileo indicate that it must be somewhere close to the surface, only tens of kilometers deep.

Well, Europa's white surface is almost entirely covered in a thick crust of water ice.

These reddish-brown regions, when observed through a spectrometer, fit the description of a lot of things, like hydrated salts, sulfuric acid, or even bacteria.

We need more data to be sure, but recent experiments at JPL found that sea salt, when bombarded with intense radiation, turns from white to this same brownish color found on Europa.

So scientists suspect that there's a whole saltwater ocean inside Europa that could be 100 kilometers deep, meaning Europa would contain twice as much water as the whole of the Earth.

And it must be driving geological activity that constantly smooths out and renews the surface of the moon.

But the Jupiter system only gets about 4% of the sunlight we get here on Earth.

So Europa's surface is constantly below negative 160 degrees Celsius, so you'd expect the whole ocean to be frozen solid.

But there's a way to generate heat that doesn't rely on the sun.

And I've got a little demo here to prove it.

Europa's orbit around Jupiter isn't a perfect circle.

This is because Io, Europa, and Ganymede are all in orbital resonance.

Each time Ganymede completes one orbit, Europa completes two, and Io four.

Because of that, Io tugs Europa inward on one side of the orbit, while Ganymede pulls it out on the other, making its orbit more eccentric.

Now Jupiter's pull is stronger on the closer side of the orbit than on the farther side.

So Europa is constantly being stretched and squeezed, stretched and squeezed.

You can see how this rubber ball gets warmer as I squeeze it.

Scientists believe that the friction caused by the tidal flexing of the entire moon can generate enough heat to keep the ocean liquid.

This effect gets stronger the closer you get to Jupiter, which is why Io is so volcanically active.

So you can see this ball is significantly hotter now.

I held on to this ball at the same time to make sure it wasn't just the heat coming in from my hand.

What sort of temperature of the ocean are we thinking?

So melting temperature of ice, or maybe depressed by 10 degrees Celsius below that if it's a very salty ocean, similar to cold oceans on Earth.

And how would the flexing differ if there's this big liquid ocean versus if there's no ocean there?

If there's no ocean, Europa should flex by only about one meter in amplitude.

But if there's an ocean in there, then it flexes with an amplitude of 30 meters.

And that will come out pretty clearly in the gravity data.

Another argument for how thick the ice shell is, we see these very strange features on the surface that are arcuate in shape, but like multiple arcs put together.

We call them cycloids, and it's not something you'd expect to see on an icy moon.

And we think they form if a crack propagates at just the right speed, about the speed someone would walk, and is following the changing stress field of Europa being squeezed as it orbits around Jupiter.

And if there were no ocean down there, there wouldn't be enough of an amplitude of that motion to explain the cracking.

But if there is an ocean, then it could explain the cracking.

All that tidal flexing pushes magma in the outer core up, closer to the seafloor.

Water flowing through the crust above it is heated and it picks up minerals from the ground, ejecting them into the ocean.

And where we find these on Earth, we also find life.

Thousands of meters below the surface, with no sunlight, these vents are oases for ocean life.

The lifeforms down here rely on unique bacteria.

Bacteria that feed on the minerals from the vents, rather than from the energy provided by the sun.

How long are we thinking that Europa has had an ocean?

That amount of time could give life the opportunity to evolve in those oceans.

Organisms can use methane, carbon dioxide, sulfur reactions.

Any chemical reaction you can think of that might happen in the ocean can potentially be used as a fuel for that organism's metabolism.

So we're not talking about searching for fishes or whales or squids or something down there, but looking for single-celled organisms.

We were so concerned there might be life on Europa that when the Galileo mission was ending in 2003, it was deliberately crashed into Jupiter to avoid the risk of contaminating Europa.