Add Yahoo as a preferred source to see more of our stories on Google. In what is the first discovery of an Einstein zig-zag lens in the universe, a team of international astronomers have sighted two ...

A compound lens forged by two galaxies is helping astronomers get a bead on the Hubble Constant and dark energy. Reading time 3 minutes A light source in space originally believed to be a galaxy ...

The F-number of a photographic lens is a measure of its light-gathering ability, and is expressed as its aperture diameter divided by its focal length. Lenses with low F-numbers are prized by ...

Five hundred million years ago, the oceans teemed with trillions of trilobites - creatures that were distant cousins of horseshoe crabs. All trilobites had a wide range of vision, thanks to their ...