The Early Universe
14.06.1997

What did our universe look like when it was young? To answer this, cosmologists run sophisticated computer programs tracking the locations of millions of particles. The above animated frame is the result of such a calculation and shows how our universe might have looked when it was just a fracton of its current age.

A Star Cluster in Motion
30.07.2002

Star clusters are a swarm of complex motions. The stars that compose globular clusters and many open clusters all orbit the cluster center, occasionally interacting, gravitationally, with a close-passing star. The orbits of stars around the cluster are typically not as circular as the orbits of planets in our solar system.

Crescent Rhea Occults Crescent Saturn
3.01.2015

Soft hues, partially lit orbs, a thin trace of the ring, and slight shadows highlight this understated view of the majestic surroundings of the giant planet Saturn. Looking nearly back toward the Sun, the robot Cassini spacecraft now orbiting Saturn captured crescent phases of Saturn and its moon Rhea in color a few years ago.

Four Years of Saturn
6.04.2007

Saturn and its magnificent ring system can offer even casual astronomers the most memorable of telescopic sights. Wandering between Leo and Cancer this month, a bright Saturn is well placed for viewing in evening skies. But from our earthbound perspective, the tilt of Saturn's rings does change with time.

Our Story in One Minute
14.11.2012

Could you tell the story of human existence in a minute? This thrilling video culls together multiple teasing snippets in an attempt to do just that. And sets it to music. Briefly depicted, from...

The Milky Way Over Paranal
23.01.2007

It's not the sky that's falling. More accurately, the Earth is rising. The Earth's rotation gives a continually changing view to all Earth observers, including those measuring the universe at the Paranal Observatory.

The Sun Unleashed
10.06.2011

On June 7, the Sun unleashed only a medium sized solar flare as rotation carried active regions of sunpots toward the solar limb. But that flare was followed by an astounding gush of magnetized plasma seen erupting at the Sun's edge in this extreme ultraviolet image from the Solar Dynamics Observatory.

SuitSat1: A Spacesuit Floats Free
20.02.2006

Who dunnit? Like a scene from a space mystery movie, a spacesuit floated away from the International Space Station earlier this month, but no investigation was needed. It was pushed out by the space station crew.

Flying Over Asteroid Eros
27.03.2000

What would it look like to fly over an asteroid? Spacecraft NEAR Shoemaker in orbit around asteroid 433 Eros found out earlier this month when it recorded its first fly-over sequence. The saddle region of the Sun-orbiting space-mountain appears to zip past the camera in this condensed hour-long time-lapse sequence.

APOD: 2023 November 12 Б Gibbous Moon beyond Swedish Mountain
12.11.2023

This is a gibbous Moon. More Earthlings are familiar with a full moon, when the entire face of Luna is lit by the Sun, and a crescent moon, when only a sliver of the Moon's face is lit.