Physics

Textbooks say that the moon was formed after a Mars-size mass smashed the young Earth. But new evidence has cast doubt on that story, leaving researchers to dream up new ways to get a giant rock into orbit.

Astronomers thought that all Type Ia supernovas shine with the same brightness, making them incredibly useful cosmic yardsticks. But uncertainty over what causes these explosions has led researchers to reconsider their assumptions.

The astrophysicist Andrea Ghez spent two decades proving that a supermassive black hole anchors the center of the Milky Way galaxy. Her new plan? Test what happens when things get too close.

Take chemistry, add energy, get life. The first tests of Jeremy England’s provocative origin-of-life hypothesis are in, and they appear to show how order can arise from nothing.

Supernova hunters were able to train their telescopes on a recent eruption just hours after it exploded. What they found only adds to the growing list of questions surrounding these cosmic blasts.

The team that discovered gravitational waves put their data online. Now an independent group of researchers claims that they’ve found what might be a serious problem.

Breathless media coverage notwithstanding, the cases for and against a hypothetical Planet Nine in the outskirts of the solar system remain inconclusive.

The newly developed theory of emergent gravity, proposed as an alternative to dark matter, struggles in one of its first trials.

Recent calculations tie together two conjectures about gravity, potentially revealing new truths about its elusive quantum nature.