A U.S. astronomer says he has designed a device that would aid in the discovery of more Earthlike planets far off in the solar system.

A team led by Professor Webster Cash of the University of Colorado in the western U.S. has created a huge, daisy-shaped "starshield" that would be launched into space along with a telescope trailing thousands of kilometers behind it.

Writing in Thursday's edition of the scientific journal Nature, Dr. Cash says the shield would open up when it reaches an orbit more than one million kilometers away from Earth. It would allow the telescope to chemically analyze the atmosphere of distant planets for signs of life without being overshadowed by the light from its parent star.

He says astronomers would be able to identify planetary features such as oceans, polar caps and cloud banks.