An American astronomer says a giant flower-shaped space shield could be the best way to find Earth-like planets outside our solar system:
By blocking out the glare of the stars they orbit, the space shield would give scientists detailed pictures of extrasolar planets for the first time.
Almost 200 planets have been discovered orbiting other stars in recent years. All of them are giant planets and most were found using indirect measurements such as how their gravity made their parent stars wobble. Finding smaller, Earth-sized planets is impossible using current methods. Webster Cash, director of the Centre for Astrophysics and Space Astronomy at the University of Colorado in Boulder, designed a way to get around the problem: a pair of spacecraft, a starshade (the astronomical equivalent of sunglasses) and a telescope that together work as a giant pinhole camera called the New Worlds Observer (NWO). The shade would be shaped like the petals of a sunflower, a shape that Professor Cash calculated would be most effective for blocking the light of distant stars. Any planets around the blocked star, even if they were as small as the Earth, would show up as bright specks of light.