Physicist Qi Lai and colleagues propose that the puzzling gravitational-wave event GW190521, detected in 2019, may have been a wormhole echo rather than a black hole merger. The team suggests the ...

Before our universe existed, another one may have collapsed in on itself, and some of its black holes may have survived the ...

Quantum mechanics is a kind of hard limit: certain pairs of properties, such as position and momentum, cannot be known ...