A ninth planet the size of Neptune may be hidden in the far reaches of the solar system, but the evidence has left some experts skeptical.

The 950-foot hunk of primordial matter is classified as a "potentially hazardous asteroid," but that doesn't mean it has a ...

In a rare cosmic event, an asteroid the size of a football stadium is about to fly by Earth. Earlier this year, another ...

Venus begins a season-long absence from the sky, hidden by the glow of the Sun as it slowly passes behind our star, not returning to our view until August. It reaches superior conjunction on June 4, ...