Troy E. Meink’s comments were the first public acknowledgment of American weapons in orbit. The Pentagon has been preparing for potential conflict in space with Russia or China.

Thousands of planets have been discovered beyond our solar system, offering clues to where life might thrive and whether Earth is truly unique.

The Times’s Science section is introducing new columns, projects and more as part of its online relaunch.

New estimates using the planet’s surface wrinkles show that our smallest planet is growing even smaller, at a faster clip than expected.

Mar Carretero-Castrillo, an astrophysicist, returned to her remote village in Spain to be in the path of totality. Hundreds of partygoers came too.

During early calibration tests, the MOTHRA telescope’s array of lenses, which will soon number 1,140, captured stellar debris dissolving into space around the Helix Nebula.

Check the weather forecast, path and time of the eclipse near you.

The Perseids will be most active on Wednesday into Thursday morning, on the moonless night after a total solar eclipse.

We’re answering some questions about the solar eclipse on Aug. 12, and providing a place for you to ask more of them.

Amateur and professional astronomers pointed their telescopes at the impact site. Most did not detect anything.

The second stage of a Falcon 9 rocket, which sent two private landers to the moon last year, will collide with the moon early Wednesday morning.

Flaming chunks of metal crash into homes, farms and parking lots. Who’s to blame? And who pays for the damage?

A spacecraft meant to push NASA’s Swift Observatory to a higher orbit malfunctioned and started tumbling several days ago. Engineers think it can still succeed.

The end of July brings the Alpha Capricornids and the Southern Delta Aquarids, both of which will be most active on Thursday night into Friday morning.

Researchers at Caltech and Sophia Space, a start-up, have developed a technology using solar power to prevent computer equipment from overheating in orbit.

It was the 13th test overall of Starship. The success is a boon to NASA’s moon plans and SpaceX’s hopes to deploy a million data centers in orbit.

Charles Ross spent 50 years building “Star Axis,” a naked-eye observatory in New Mexico. Now his masterwork is ready. How to share it with a changed world?

It’s the first potentially habitable world known to host an atmosphere, making it a lead contender in the search for life beyond our solar system.

The 33 engines of the rocket’s booster stage had begun to ignite during Thursday’s launch attempt, but were then shut down. SpaceX will try again on another day.

The first tweets from the public appeared on July 15, 2006, several months after a soft launch. It was rebranded as X after being acquired by Elon Musk.