Mega? Why this superlative prefix all of a sudden? No, this is not about the mass of rock and water we are busy wrecking, but a new one.

A new planet? Where? Meet Kepler-10c, which is popularly called Mega-Earth. US space agency NASA discovered the planet which is twice the size of Earth. This heavenly body, however, holds 17 times our planet’s mass.

On June 3, NASA and the Harvard-Smithsonian Center for Astrophysics announced their findings about Kepler-10c.

In fact, Nasa’s Kepler space telescope had discovered Kepler-10c in 2011 itself, but scientists have now used a special telescope to view and figure out the vital stats of this planet. The size and features of Kepler-10c are so unusual that scientists would like to place it in a new class of exoplanets.

Interesting. Where is this super planet exactly located? The Mega-Earth roams around a star that is much like our Sun. It lies some 560 light years away from us — in a constellation called Draco. I hope you remember your high-school physics — a light year is 9.4 trillion kilometres. The radius of Kepler-10c is slightly more than double that of the Earth, and that’s why astronomers initially thought it would be a bonsai version of Neptune, the gassy planet that is four times larger than Earth.

And it wasn’t? No. Kepler-10b’s mass indicates it is rocky ball, much like Earth.

Is this the first case of a big rocky ball hanging in space? No. Kepler-10b, a planet that neighbours Mega-Earth was the first confirmed rocky world outside our solar system. But it is very close to its star, completing a full orbit in just 20 hours.

Why is this more important then? This discovery changes some of our understandings on the universe and the existence of life in it. The Kepler-10 system of planets is about 11 billion years old; which shows it could have formed less than three billion years after the Big Bang.

As we have learned in school, the early universe contained only hydrogen and helium. In this scenario, any hefty formation would take in hydrogen gas as it grows and become a gas giant. Rocky planets need heavier elements such as silicon and iron as ingredients.

These elements had to be created in the first generations of stars. That is, when these stars exploded, scientists say, they sprayed these elements through the space, helping build future planets and stars. This should have taken billions of years.

So Kepler-10c was formed before the supply actually started? Right. Kepler-10c tells us the universe could form such huge rocks even during the time when heavy elements were scarce. This is great news for those searching extra-terrestrial life. “And if you can make rocks, you can make life,” says researcher Dimitar Sasselov, who was part of the new study. Scientists say if old stars can host rocky Earths too, that shows we may have a good chance of finding places in our cosmos where we can live.

Good to know, given the way we are spoiling our chance to live here… You’re (big) bang on!

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