Before and after images reveal the supernova (Peter Nugent/Palomar Transient Factory )

Supernova fireworks in the Pinwheel

A supernova of a type that is used to help measure the size and expansion of the universe has been discovered in nearby galaxy M101, the Pinwheel.

Comet Elenin on August 6 from NASA's Stereo-B spacecraft (NASA)

Comet Elenin is no threat say NASA

NASA today stepped in to try to allay baseless fears that a comet heading into the solar system from deep space will trigger disaster on Earth.

The 50,000 year old Meteor Crater in Arizona.

Impact threat to Earth is still real

A new study on comet and asteroid impact craters has found that the Earth is just as likely to be struck now as it was hundreds of millions of years ago.