In a glimpse of the early universe, astronomers have observed a galaxy as it appeared just 800 million years after the Big ...

New measurements using gravitational lensing suggest the universe’s current expansion rate does not agree with signals from ...

Three thought experiments involving “demons” have haunted physics for centuries. What should we make of them today?

From a particle smasher encircling the moon to an “impossible” laser, five scientists reveal the experiments they would run ...

Galaxy clusters are the most massive objects in the universe held together by gravity, containing up to several thousand ...