Kepler was Launched to Search for Other Earths

Last Friday – Mar 6 – NASA’s Kepler mission was successfully launched into space. This is a very meaningful mission to us – a mission that will seek for other earths out there, and help us understand if planets like Earth are common in the universe.

Not like other missions where their targets keep on changing, Kepler will only stare at the same star field in the Cygnus-Lyra region for its entire mission, watching more than 100,000 stars hopefully to capture the transit of Earth-like planets when they pass in front of their parent star. When that happens, the planet will blocks a very very small fraction – only 1/10,000 – of the light from its parent star, causing tiny dips in the brightness of the star. If the dips are periodic, then we can be sure that we found a planet.


We can calculate the size of the planet from the change in brightness. The interval between transits will tell us the size of the planet’s orbit and estimate the planet’s temperature. These qualities determine possibilities for life on the planet.

Kepler mission will be an important step in answering the age-old question: Are we alone? It has the capabilities of detecting Earth-size or even smaller planets in the habitable zone of sun-like stars. The habitable zone is the distance from a star where liquid water can exist on the surface of a planet. If is too near, all the water will vaporised; if is too far, the water will be frozen ice.

And we believed that liquid water to be essential for the formation of life (we are our only example of life, and we need liquid water…). So, if we found a planet in the habitable zone, then we are a step nearer in our search of extraterrestrial life.

The first planets are expected to be found by Kepler are the “hot Jupiter” – gas giants that circle close and fast around their parent stars. Next are probably Neptune-sized planets, followed by rocky ones as small as Earth. The true “Earth” – where the planets are in the habitable zone – would take at least three years to discover and confirm.

Here are some quick facts about the Kepler mission:

> Kepler is the world’s first mission with the ability to find true Earth analogs – planets that orbit stars like our Sun in the habitable zone.

> By the end of Kepler’s 3.5-year mission, it will give us a good idea of how common or how rare other Earths are in our Milky Way galaxy.

> Kepler detects planets by looking for periodic dips in the brightness of stars – the transit method.

> Kepler has the largest camera ever launched into space, a 95-megapixel array of charge-coupled devices (CCD), like those in everyday digital cameras.

> Kepler’s telescope is so powerful that, from its view up in space, it could detect one person in a small town turning off a porch light at night.

One last note: Kepler carried my name with it into space, how cool is that!


~ by thChieh on March 11, 2009.

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