20+ hour, 38+ min ago   (934+ words) Scientists found that Mercury's roughest terrain may conceal ancient cliffs, suggesting the planet shrank substantially more than estimates showed. Mercury’s surface is crossed by long cliffs and ridges. They formed as the crust buckled to fit a planet that got…...

1+ day, 13+ hour ago   (1029+ words) A frozen object beyond Jupiter is venting carbon dioxide gas into space, revealing what can drive activity so far from the sun. A centaur, one of the icy bodies that orbit beyond Jupiter, has started venting gas into space, even…...

2+ day, 15+ hour ago   (900+ words) Little red dots should shine in X-rays if black holes power them. None did, until Chandra found one 11.8 billion light-years away that does. Astronomers have found a single object in the constellation Ursa Major that behaves like nothing else in…...

3+ day, 8+ hour ago   (1013+ words) Star formation has fallen by more than half over 4.5 billion years, even as the universe’s supply of atomic hydrogen has barely declined. Stars are being born across the universe at less than half the rate they were 4.5 billion years ago....

4+ day, 8+ hour ago   (963+ words) Astronomers found evidence that some ancient galaxies could be up to four times more massive than standard estimates, deepening a puzzle about the early universe. To weigh a galaxy, astronomers read its light. Most of that light comes from relatively…...

4+ day, 15+ hour ago   (825+ words) Black hole ringdowns could reveal signs of surrounding matter or new physics, giving scientists a new way to test gravity in extreme conditions. When two black holes collide and merge into one, the newly formed giant doesn’t just sit there....

6+ day, 12+ hour ago   (889+ words) Planets spin. So do stars and whole galaxies. Black holes should be no exception, but a spin is hard to catch, because the twist a rotating one puts into nearby space weakens sharply with distance. The orbit is a long,…...

1+ week, 3+ hour ago   (992+ words) Waves too quick for older telescopes to see ripple through the Sun's polar corona, and they carry a big share of the fast solar wind's energy. Solar physicists can work out how much energy it takes to push the Sun’s…...

1+ week, 13+ hour ago   (747+ words) Hubble reveals a vast cosmic bubble where massive stars cleared away gas, only for the compressed material around it to begin forming thousands of new stars. Today’s Image of the Day from the European Space Agency reveals a huge stellar…...

1+ week, 15+ hour ago   (950+ words) September brings brilliant Venus, the Harvest Moon, an equinox, and several easy-to-spot celestial sights in the night sky. September 2026 offers several good reasons to look up, and many of them are easy to find. Over the course of nearly two…...