The final mission before the landmark Apollo 11, Apollo 10 served as a dress rehearsal, testing every aspect of the Moon landing except for the actual landing itself. On May 18, the crew of Commander ...

The smallest planet appears after sunset as the waxing Moon reaches First Quarter and star clusters shine in the sky this ...

Ganymede and Europa transit Jupiter tonight, while Io disappears in an occultation. West Coast observers can catch a double ...

RCW 36 boasts an open cluster of massive young stars at its heart, surrounded by glowing clouds of hydrogen gas.

In the Ask Astro column of the April 2026 issue is a photograph of planetary nebula NGC 6302. The caption says that NGC 6302 ...

Venus and Jupiter are visible in the evening, while there's a conjunction of Mars and Uranus in the predawn sky.

As July begins, three planets adorn the early evening sky, while more solar system worlds are visible before dawn.

Space exploration is not just something we watch others do. It is an endeavor we can join from our backyards.

In 1878, Williamina Fleming immigrated to Boston from Scotland with her husband – but he abandoned her shortly after they ...

Saturn dominates the predawn sky, while Mars is rising earlier each day. The Red Planet is still a bit challenging — can you ...

Over billions of years, a planet will have encountered all the small bodies in its vicinity enough times to clear its orbit of them.

Born at the same time, the star that formed Sirius B started out more massive and evolved more quickly than its companion, Sirius A.