ST. LOUIS ? Quark stars, exotic objects thathave yet to be directly observed, are part of a new theory to explain some ofthe brightest stellar explosions recorded in the universe.

Thanks to a new development in nuclear physics theory, scientists exploring expanding fireballs that mimic the early universe have new signs to look for as they map out the transition from primordial ...

For a large star, death is a bit of a squeeze. Once its nuclear fuel is spent, its core collapses, sparking a dramatic supernova explosion that blasts away the outer layers. The body left is a cold, ...