Four-and-a-half billion years ago, a massive world—possibly as big as the moon or even Mars—orbited our sun before crashing into another celestial body and shattering into rubble. Now, in a paper published in the journal Earth and Planetary Science Letters, scientists report the first definitive evidence that this lost planetary embryo (protoplanet) existed. Its unique geological makeup challenges long-held assumptions about how planets evolve.

China's Tianwen-2 sample-return mission is well on its way to its target, an asteroid called Kamo'oalewa. The spacecraft left Earth in May 2025 and should return in late 2027 with samples of a space rock that scientists had assumed originated from the moon. However, a new study published in Nature Communications suggests that we may be mistaken about the asteroid's origin.

The astronauts circling Earth on the Artemis mission sent back beautiful clear photos of the continents, clouds, and oceans. But we might be the exception. Many planets in the universe may be hazed in clouds of soot, according to a new study by University of Chicago scientists. Their analysis explains a curious trend seen by astronomers training telescopes on distant planets beyond our own solar system. Many of these worlds had atmospheres that returned strangely featureless readings.