space-time

Dark matter could be even weirder than anyone thought, say cosmologists who are suggesting this mysterious substance could interact with itself in a higher dimensional universe.

Many theories of the early universe predict that the cosmos should be flooded with cracks in space-time, called cosmic strings, but no cosmic strings have been detected yet.

Evidence of collisions between black holes and neutron stars suggests dark matter might consist of concentrations of primordial black holes.

A weird, super-powerful particle that's not truly a particle could have dominated the universe when it was just a second old, releasing a flood of ripples that permeated all of space-time.

Physicists suggest harnessing the gravitational pull of black holes to create ferocious particle accelerators. The trick? Carefully set everything up so the particles don't get lost forever.

In one upside-down, hypothetical version of the universe, a bizarre type of black hole could exist that is stranger than an M.C. Escher sketch: charged black holes.

What happens when you turn space-time upside-down?

Using gravitational waves to approximate pi, physicists see no problem with Einstein's theory of general relativity.

Is space-time ultimately smooth at the tiniest of scales, or something else? It seems impossible to measure, but researchers are beginning to look down. Deep down.