Now, a balloon-borne telescope to study exoplanets

New York, Jan 13: It's a literally lofty idea of studying space.

A balloon-borne telescope afloat in the stratosphere could offer a direct view of planets in other solar systems, all for a fraction of what it would cost to do the job from space, a team of researchers say. ''It's one of those ideas that actually has a remote chance of making it off the drawing board,'' says team leader Wes Traub, a senior research scientist at NASA's Jet Propulsion Lab in Pasadena, California, US.

Astronomers have so far identified 270 exoplanets orbiting distant stars.

Traub and his collaborators say that at least some planets can be viewed just as easily, and far more cheaply, from the stratosphere. ''It's almost like being in space,'' Mr Traub told New Scientist.

Previous studies have shown that light from distant stars remains relatively undisturbed while passing through the stratosphere, a region of the atmosphere stretching from 10 to 50 km above the surface, where turbulence is low.

The team piggy-backed a small experiment aboard the Solar Bolometric Imager, a balloon-borne observatory that flies at an average altitude of 36 km and concluded that movement of air around the gondola were not serious enough to disrupt the image of a distant planet.

Astronomers have expressed reservations whether a balloon-borne telescope could be controlled with enough precision to take the images of exoplanets.

According to Mr Traub the project-- Planetscope-- would have an estimated cost of 10 million dollars, roughly one per cent the cost of a space-based planet imager.

''It's the kind of thing that needs to be tried, because it's much cheaper than going to space,'' says Mike A'Hearn of the University of Maryland.

UNI