The grandfather paradox is just one of the thorny logical problems that arise with the concept of time travel. But one physicist says he has resolved them.

Like stretch marks left on skin that expanded too quickly or cracks embedded in freezing ice, cosmic strings are artifacts of what the universe looked like in the moments before it rapidly changed ...

Euclid space telescope sent some images back to Earth during an early testing phase. While reviewing the pictures, astronomer ...

Vanderbilt University physicist Lorenzo Gavassino isn't so sure this is as big an obstacle as time-traveler pessimists have ...

In a rotating universe, space-time could warp into loops ... raising questions about how it behaves in time loops. On a time loop, entropy’s reversal could theoretically undo aging, memory ...

Massive objects bend space-time around them, making things appear ... relativity – although attempts such as string theory and loop quantum gravity have so far failed to come up with the goods.