Strings, Strange Quarks, Mirror Matter – What's Next?

Ghostly Asteroids Offer Dark Clues To Missing Matter

"Astronomers have lost thousands of comets. A University of Melbourne physicist thinks they may still be there, just invisible and some of them potentially on a collision course with Earth."

"Dr Robert Foot suggests that many of the missing comets could be made of an exotic material called 'mirror matter', a new type of invisible matter that a small group of physicists believe could be the elusive 'dark matter'. Dark matter is considered the cosmic scaffolding that makes up most of the universe, but nobody can identify it."