This puzzle is known as the problem of time, and it remains one of the most persistent obstacles to a unified theory of physics. Despite enormous progress in cosmology and particle physics, we still ...

Gravity used to be the most dependable rule in the cosmic rulebook, the quiet background force that never changed its mind. Now a series of discoveries and bold claims are turning that certainty into ...

Interstellar comet 3I/ATLAS and its unusual gas-to-dust chemistry Crewed and robotic lunar missions advancing sustained exploration Asteroid characterization and deflection studies supporting ...