5 août 2015

Kepler 452b


A-t-on découvert une seconde Terre?

Extrait de la renversante nouvelle:

(...) Kepler 452b, found by NASA’s Kepler Space Telescope, is located 1,400 light-years from us. It orbits a star that is 4% more massive and 10% brighter than our Sun. The planet itself is 1.6 times the size of Earth – making it a super-Earth – but the scientists are fairly sure that it is a rocky world, owing to its size and the type of star it orbits.

Its orbit, 384.84 Earth days and 5% more distant than our planet is from the Sun, places it right in its star’s habitable zone, where it is not too hot or cold for liquid water to form: the same region Earth is in around the Sun. This is not the first Earth-sized planet found in a habitable zone; last year, the world was abuzz with the discovery of Kepler 186f, more similar in size to Earth. But that planet orbited a red dwarf star, smaller and cooler than the Sun. Kepler 452b, excitingly, orbits almost an exact clone of the Sun.

(...) Although the mass of the planet can’t be directly determined yet, the scientists think it may be about five times that of Earth based on models. A rocky planet of this size and mass would likely still have active volcanism on the surface.

However, it should be noted that the star it orbits is 1.5 billion years older than our Sun. On the one hand, this increased energy from its star means that any oceans on its surface are likely being evaporated, lowering its chance of being habitable. On the other hand, this planet offers a fascinating opportunity to see what might become of Earth in the future.

(...) But one thing is for sure – the chances of us being alone in this universe are looking increasingly slim. Whether it’s Kepler 452b or Kepler 186f or some other undiscovered planet, somewhere out there, there must be a world with life waiting for us to find it.



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