Telescope launched to hunt for Earth-like planets

Last Updated: Saturday, March 7, 2009 1:01 AM ET

CBC News

The Kepler telescope was launched into space Friday night from Cape Canaveral, on its way to search for other Earth-like planets.

The planet-hunting telescope, named after the German 17th-century astrophysicist Johannes Kepler, blasted off aboard a Delta II rocket at 10:49 p.m. in Florida.

Scientists stress that the Kepler — about 4.5 metres tall and three metres in diameter — will not be looking for life but rather potentially habitable planets. The mission will cost US$600 million, from start to finish.

It is scheduled to spend 3½ years in an Earth-trailing orbit around the sun staring at roughly 100,000 stars between 600 and 3,000 light years away in the so-called habitable, or Goldilocks, zone.

That's where planets are neither too close nor too far from their star, and where conditions could be ripe for liquid water on the surface.

"If one of them has a planet like the Earth going around it and if that planet happens to pass in front of that star, the star will get just a little dimmer, then a little brighter for a while as the planet eclipses it," CBC's science correspondent Bob McDonald said.

Looking for repetition

McDonald said scientists will then have to see it do it again a year later — the length of time it takes Earth to go around the sun, which would mean the planet is just the right distance, so it is not too hot or too cold.

"If they can do that 3½ years from now, they say, there’s the stars with these planets. Then we’ll have to go back and look at them with bigger telescopes to see if there's anything living there and what they're really like.

"But the first step is to say, 'Are they there at all?' That's the first question because at the moment we don't know."

Over the past decade and a half, more than 300 planets have been found to be orbiting stars outside our solar system. But these are largely gas giants like Jupiter. Kepler is designed to zero in on smaller, rocky, Earth-like planets.

The launch comes on the heels of a failed flight of a NASA science satellite from California, the Orbiting Carbon Observatory, just over a week ago.

It used a different rocket than the one for Kepler. Nonetheless, engineers pored over every detail to find any similarities, delaying Kepler's launch by a day.