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Friday, December 30, 2011

Meet the Kepler space telescope

I’ve mentioned the Kepler space telescope (pictured left) in lots of posts, so I thought it was high time we got a closer look at it.

Kepler is the name of both the telescope and the mission that uses it.  Named after the 17th century astronomer Johannes Kepler, the Kepler telescope was launched in March of 2009 with the goal of finding Earth-like planets. 

Kepler finds planets via the ‘transit method’.  If, from our vantage point, a planet passes in front of its star, we’ll see a compensatory dimming in the light from that star.   Because several of these transits are required to confirm the presence of a planet, it can take years to verify each finding.  As a comparison, an alien civilization looking in our direction would wait four years to see as many transits of the Earth across the Sun.

The Kepler telescope is not rotated to view different aspects of the sky.  Instead, it monitors a single patch of sky, continuously observing the same 100,000 plus stars.  How successful is this strategy?  As of the beginning of this month, the Kepler mission has found over two thousand candidate planets and confirmed thirty-three of them.  You can see a list of these planets along with their properties here.

Where exactly is the Kepler space telescope?  Orbiting the sun, as you can see from the following animation.  Note, objects in this video are not to scale.

In reality, the Kepler telescope is about 3 meters by 5 metersIn contrast, the Hubble Space Telescope, launched in 1990, orbits the Earth rather than the sun and is about 13 meters by 4 meters.