12th January 2011
This is exciting stuff ! The holy grail of the planet hunters is to discover small, rocky Earth sized planets orbiting distant stars. Planets happily going around their sun in the cozy habitable zone, meaning that the solvent of life H2O, can exist in liquid form. We’ve had some interesting news recently, such as with the exoplanet Gliese 581g
But Nasa’s Kepler Mission has been specifically designed and built to sniff out small rocky planets orbiting other stars out there in the Milky Way…planets similar in size to Earth, and in or near that cozy habitable zone. The mission has kicked off the search in style by finding its first planet. No not a bloated “Hot Jupiter” or a “Super Earth”, but a solid rocky planet that you could actually stand on (although it wouldn’t be advisable unless you’re wearing asbestos boots, and factor 3,000 sunscreen). This planet Kepler-10b, is a world just 1.4 times the size of Earth, and with a mass of 4.6 times. Kepler-10b is the smallest planet yet found outside our own solar system, a real milestone in the hunt for “other Earths”. This place though at 560 light years away will have no chance of sustaining life as it is far too hot, with no atmosphere, and nowhere near its habitable zone. It gets scorched by its parent star to a blistering 1,300 C in the daytime, and races round its orbit once every 0.84 days. It is so hot because Kepler-10b orbits very close, at a distance 20 times nearer to its star than Mercury orbits to our Sun. The host star is a lot older too, at nearly 12 billion years compared to our Sun’s more youthful 4.5 billion.
The Kepler Mission was launched on March 7th 2009, and is designed to look for planets orbiting other stars by detecting tiny fluctuations in the star’s brightness caused by a planet, or planets passing in front. The mission will hopefully answer the questions of how many Earth sized planets are actually out there, and how many of them are in that important habitable zone of their host star.
Just what will the Kepler mission uncover out there in our Galaxy? What other worlds exist? Are habitable planets rare or common? This is just one aspect on the journey to answer that one question, the biggest question, the one that probably everyone on the planet has pondered. Are we alone in the cosmos? As the great Carl Sagan said, “Somewhere, something incredible is waiting to be known”.
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