Stars and the Solstice Sun
21.06.2007

If you could turn off the atmosphere's ability to scatter overwhelming sunlight, today's daytime sky might look something like this ... with the Sun surrounded by the stars of the constellations Taurus and Gemini. Of course, today is the Solstice.

Global Dust Storms Threaten Mars Rovers
25.07.2007

Will global dust storms terminate the robotic Martian rovers? Over the past month, windy dust storms have blocked much needed sunlight from reaching the solar panels of both the Spirit and Opportunity rovers exploring Mars.

Curious Cometary Knots in the Helix Nebula
13.04.2008

What causes unusual knots of gas and dust in planetary nebulas? Seen also in the Ring Nebula, the Dumbbell Nebula and the Eskimo Nebula, the knots' existence was not initially predicted and their origins are still not well understood.

APOD: 2024 March 19 Б A Picturesque Equinox Sunset
19.03.2024

What's that at the end of the road? The Sun. Many towns have roads that run east-west, and on two days each year, the Sun rises and sets right down the middle. Today, in some parts of the world (tomorrow in others), is one of those days: an equinox.

Galaxies in Space
8.03.2025

The plane of our Milky Way galaxy extends beyond the limb of planet Earth in this space age exposure captured by astronaut Don Pettit. His camera, with low light and long duration settings, was pointed out the window of a Dragon crew spacecraft docked with the International Space Station on January 29.

APOD: 2025 July 21 Б Cats Paw Nebula from Webb Space Telescope
21.07.2025

Nebulas are perhaps as famous for being identified with familiar shapes as perhaps cats are for getting into trouble. Still, no known cat could have created the vast Cat's Paw Nebula visible toward the constellation of the Scorpion (Scorpius).

Islands in the Photosphere
15.03.2001

Awash in a sea of plasma and anchored in magnetic fields, sunspots are planet-sized, dark islands in the solar photosphere, the bright surface of the Sun. Before the enlightened(!) age of cameras, solar observers created detailed drawings of sunspots as they changed and progressed across the visible solar disk.

Pulsar Wind in the Vela Nebula
19.07.2001

The Vela pulsar was born 10,000 years ago at the center of a supernova -- an exploding star. In this Chandra Observatory x-ray image, the pulsar still produces a glowing nebula at the heart of the expanding cloud of stellar debris.

Supernova 1987a Fireball Resolved
24.01.1997

Ten years ago the most notable supernova of modern times was observed. In February 1987, light reached Earth from a star which exploded in the nearby Large Magellanic Cloud galaxy. Supernova 1987a remains the closest supernova since the invention of the telescope.

Hale-Bopp and Andromeda
1.04.1997

Which is closer: the comet or the galaxy? Answer: the comet. In its trek through the inner Solar System, Comet Hale-Bopp has passed nearly in front of the Andromeda Galaxy (M31), seen on the lower left.