It has long puzzled scientists that there were enormously massive galaxies that were already old and no longer forming new stars in the very early universe, approx. 3 billion years after the Big Bang.
A ring of dust around the nearby star Fomalhaut is created by the collision of thousands of comets every day.
The fat, doughnut-shaped clouds of dust that surround about half of supermassive black holes could be the remnants of planets and asteroids that have smashed into each other at incredible speeds.
Uranus was knocked on its side not by a single massive collision, as previously thought, but by a series of small thumps, researchers say.
British scientists are looking for signs that we live in a multiverse - with multiple alternative universes existing in their own individual bubbles.
The Large Hadron Collider is up and running, and has produced its first high-energy collisions.