APOD

Explanation: The Great Nebula in Orion, an immense, nearby starbirth region, is one the most famous of all…

Explanation: Is our universe haunted? It might look that way on this dark matter map. The gravity of…

Explanation: This Rosetta spacecraft selfie was snapped on October 7th, 2014. At the time the comet-chasing spacecraft was…

Explanation: Looking toward the north from Mullion, New South Wales, Australia, the Andromeda Galaxy never gets more than…

Explanation: Explanation : What is Treble Clef? This unusual radio structure extends over 2 million light-years and resembles…

Explanation: The city lights outshine the stars in the City That Never Sleeps. Who would have thought that…

Explanation: What a cosmic coincidence! In today’s image, Mars joins the Beehive cluster (M44 or Praesepe) below an…

Explanation: This stairway in Chile brings you only a little bit closer to heaven. But ooh, the sky…

Explanation: How many moons can you see? The best answer is five: four orbiting Jupiter and Luna orbiting…

Explanation: Scientists are melting holes in the bottom of the world. In fact, almost 100 holes melted near…

Explanation: Tidally locked in synchronous rotation, the Moon always presents its familiar nearside to denizens of planet Earth.…

Explanation: Stickney Crater, the largest crater on the martian moon Phobos, is named for Chloe Angeline Stickney Hall,…