Astronomy

New observations from the James Webb Space Telescope show that the potentially hazardous asteroid 2024 YR4 is a building-sized space rock

The next year of science on the James Webb Space Telescope has been announced amid mounting budgetary uncertainty that could affect the unparalleled observatory

Swarms of satellites launched by SpaceX and other companies are disrupting astronomical observations. Here's how scientists are coping

Evidence of alien worlds goes back farther than you think

The threat from near-Earth asteroid 2024 YR4 may have subsided, but discoveries of other hazardous space rocks are set to soar as new observatories come online

Defining the word “moon” is harder than you might think

Astronomers are racing to protect the dark skies as private companies seek to place large advertisements in Earth orbit

The final results from the Atacama Cosmology Telescope offer the sharpest, most sensitive view of the early cosmos that anyone has ever seen

Four small, newly discovered worlds are less than six light-years away from Earth, and their discovery reinforces a cautionary tale from planet hunting’s prehistory

In colorful photographs of galaxies, stars, planets, and more, what you see isn’t necessarily what you get

The March 13–14 lunar eclipse will be an all-night affair you won’t want to miss

Whether aliens could detect our modern civilization depends on what signs they’re looking for—and, crucially, their distance from us