Telescope could focus light without a mirror or lens, page 1

Telescope could focus light without a mirror or lens

space.newscientist.com

A proposed space telescope would focus light primarily with a patterned sheet of metal rather than a large mirror or lens. The telescope would have amazingly sharp vision and could spot Earth-size planets around other stars, its backers say.

Telescopes used for astronomy normally focus light using a curved mirror. But there are limits to how large a mirror can be sent into space. That's because of the tremendous cost of lofting heavy objects into orbit, as well as the limited cargo capacity of launch rockets.

But a team of scientists is experimenting with a completely different approach for focusing light. It does not require a large primary mirror or lens, though it does use a smaller secondary mirror and lens.

The technique takes advantage of the wave nature of light, which causes light to bend around an object's edge. The same phenomenon, called diffraction, is the reason you can hear sounds coming from around the corner of a building.

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