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Update: NASA's Kepler space telescope has suffered a hardware malfunction threatening to end its life, a potentially sad finale to an important mission. This gallery of its greatest hits ran in November 2012, when the telescope completed its initial mission and prepared for a four-year extension. We are again offering this look at its best work, along with a few updated exoplanets it found in the meantime.
After three and a half years, NASA’s prolific planet-hunting Kepler space telescope is getting ready to enter its extended mission.
Over the last two decades, astronomers have discovered many extrasolar planets but each new system has been startlingly different than the last. Kepler was built to figure out the overarching properties of planetary systems by uncovering thousands of new planets. In particular, its goal is to figure out exactly how many stars in our galaxy have Earth-sized planets orbiting in a place where liquid water, and possibly life, could exist on the surface. Launched in 2009, Kepler released its first scientific findings a few months later.
Kepler hunts out planets by staring really hard at a star. Every once in a while, the instrument may catch a little blip where the star’s brightness decreases fractionally. It goes, 'Wait, did I just imagine that or was that a real thing?' If the telescope can see that tiny decrease in light on a regular basis, it might indicate a planet passing in front of that star and blocking out its light. After many follow-up observations, Kepler can confirm if a planet is really there and even determine some of its properties, such as its size.
Because it is looking to get good statistics on the percentage of stars with planets, Kepler is meticulously watching about 150,000 stars simultaneously. Using this method, the telescope has identified more than 2,300 potential candidates and confirmed the existence of more than 100 planets. Astronomers estimate that around 5 percent of all stars have Earth-sized planets.
Though scientists thought that by now they would have bagged their prize – an Earth-sized planet in its star’s habitable zone – the mission instead proved that stars are noisier than previously thought. The extended mission of up to four years will ensure that this remarkable instrument will zoom in on ever more planets and, very likely, one that resembles this blue marble we call home.
Here, we take a look at Kepler’s last three years of successful exoplanet hunting and some of the best discoveries it has made. We look forward to many more exciting findings and, of course, many more awesome "bullshit artist renderings."
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