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  • Astronomers have found dozens of potentially habitable planets outside of our solar system.

  • That's dozens of chances to discover the first alien life.

  • Or, you know, plenty of places we could park our first interstellar colonies.

  • But with so many options, how do we know which is best?

  • You might think that most Earth-like planets should be at the top of our list.

  • After all, we've got everything we need.

  • Water, land, an atmosphere, and trillions of life forms lapping it all up.

  • But according to a small group of researchers, there are bigger and better planets out there.

  • They're called super-Earths.

  • Super-Earths may be some of the most common planets in our galaxy.

  • Since 2009, Kepler Space Telescope has discovered about 4000 exoplanets.

  • 30 percent of them are super-Earths, and a few percent of those super-Earths orbit within their host star's habitable zone.

  • That's the Goldilocks Zone, where the planet's surface is just the right temperature for liquid water.

  • Not too cold, not too hot.

  • Now, there's a chance some of these super-Earths aren't rocky worlds like Earth.

  • The larger ones could be made out of mostly hydrogen and helium gas, like Jupiter and Saturn, which would not be very hospitable for life.

  • But the reality is, astronomers are still gathering details as more data comes in.

  • So, in the meantime, let's explore what life on a rocky, habitable super-Earth might be like.

  • Liquid water is just the start.

  • These planets can be almost double Earth's radius, and up to ten-times more massive.

  • And all that extra mass is what researchers think could really make super-Earths the perfect home.

  • That's because more massive planets have a stronger gravitational pull.

  • Super-Earth Kepler 20b, for example is nearly double the size of Earth, and it's ten-times more massive.

  • This makes its surface gravity almost three-times stronger.

  • That stronger gravity means that the planet can hold on to more air molecules and form a thicker atmosphere, which is great for protecting against harmful space radiation.

  • It also means mountains and hills would erode a lot faster, leaving a relatively flatter surface, compared to Earth.

  • Now that might sound boring, but scientists think this could actually spawn dozens of shallow islands all across the planet.

  • Those in turn, could be the perfect place for life to form and evolve.

  • Just as biodiversity in Earth's oceans is richest in shallow waters near coastlines, such an "archipelago world" might be enormously advantageous to life.

  • There's just one problem, leaving this tropical paradise would be extremely difficult.

  • The escape velocity on Kepler 20b is more than double compared to Earth's, which means either rockets would need more fuel to reach their destinations...

  • Like for example, a mission similar to the Apollo Moon Landing would require twice the amount of fuel.

  • Or, rockets would have to carry only a fraction of the payload.

  • For instance, SpaceX's Falcon Heavy can launch 50,000 kilograms of payload into Earth's orbit.

  • Whereas it could only launch 40 kilograms into orbit around a super-Earth like Kepler 20b.

  • That's about the weight of a German Shepherd.

  • Suffice it to say, leaving a super-Earth would be a far greater challenge.

  • But if it looked like this, would you really want to say goodbye?

  • We'll never know for sure until we visit one.

  • What questions do you have about space?

  • Leave your queries and the comments below.

  • And thanks for watching.

Astronomers have found dozens of potentially habitable planets outside of our solar system.

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