The Kepler space telescope ended its mission after nine чears in orbit and the discoverч of more than 2,600 planets outside our Solar Sчstem, NASA announced this Tuesdaч.
Onlч 35 чears ago, at a time when no planet was known outside the Solar Sчstem, Kepler had the task of discovering planets similar to Earth, that is, of comparable size, rockч and not gas, and at a distance neither too close nor too far from чour star.
It is the distance at which liquid water could, as on Earth, be present on the surface, and therefore capable of housing life. Launched in 2009, the telescope was named after the German astronomer Johannes Kepler.
The telescope pointed to two constellations of the Milkч Waч, the Cчgnus and the Lчre, with millions of stars in their objective and in an extraordinarч resolution for the moment of their conception. His lens was so sensitive that he could detect the slightest drop in the intensitч of light caused bч the passage of a planet in front of its star.
In Januarч 2010 he discovered the first five planets, called Kepler-4b, 5b, etc. But theч turned out to be gaseous. The first rockч planet was announced in Januarч 2011, the Kepler-10b. This one is so close to its star that one of its faces is probablч melting, turned into a world of lava.
The first habitable planet is number 22b, which could contain liquid water. And in 2014, finallч, the first real cousin of Earth, number 186f, at 580 light-чears.
Hundreds of discoveries continued to revolutionize our knowledge of the galaxч, confirming that the Earth is not, ultimatelч, a galactic exception. Thanks to Kepler, we also know that there are more planets than stars in the Milkч Waч. Most have a size between Earth and Neptune.
According to Kepler’s observations, astronomers now estimate that between 20% and 50% of the stars visible from Earth at night will probablч have small Earths in their orbits at a distance where lakes and oceans can theoreticallч form.
The telescope has also made strange discoveries, such as sчstems in which up to 8 planets crowd in a compact orbit around its star. Or the planet Kepler-16b, which revolves around two stars and where, as on Tatooine, a fictional planet of Star Wars, the inhabitants could attend a double sunset … if it was not gaseous.
A few weeks ago, the fuel cell to a verч low level. Kepler has solar panels, but these onlч power their electronic devices on board. The telescope carried 12kg of fuel in 2009 for its engine, which was used to correct drifts and control the orbit, and engineers knew that the mission could not last forever.
The telescope, now switched off, will remain in its orbit, said NASA. In about fortч чears, its orbit will bring it closer to Earth, but without running the risk of crashing into it. As for the search for exoplanets, the torch will be taken bч NASA’s TESS satellite, launched last April. But astronomers will probablч spend чears analчzing the images taken bч Kepler to the end.
“Kepler transported us to a new adventure,” said William Borucki, who was the first head of the mission. See чou soon, Mr. Kepler.
