NGC 4676: When Mice Collide
12.06.2004

These two mighty galaxies are pulling each other apart. Known as "The Mice" because they have such long tails, each spiral galaxy has likely already passed through the other. They will probably collide again and again until they coalesce.

The Galaxy Within Centaurus A
4.03.2006

Peering deep inside Centaurus A, the closest active galaxy to Earth, the Spitzer Space Telescope's penetrating infrared cameras recorded this startling vista in February 2004. About 1,000 light-years across, the twisted cosmic...

Z is for Mars
22.04.2006

This composite of images spaced about a week apart - from late July 2005 (bottom right) through February 2006 (top left) - traces the retrograde motion of ruddy-colored Mars through planet Earth's night sky. On November 7th, 2005 the Red Planet was opposite the Sun in Earth's sky (at opposition).

Rings Around Beta Pictoris
8.02.2000

An unusual dust disk surrounds nearby star Beta Pictoris. Discovered in 1983, astronomers are still learning just how unusual this disk is. Recent images and computer simulations indicate that the disk contains several elliptical dust rings larger than our own Solar System.

Mars Polar Lander Target Ellipse
4.12.1999

South is up in this recent composite color picture of Mars Polar Lander's target region near the Martian South Pole taken on November 28. Imaged by the orbiting Mars Global Surveyor's wide angle camera, the area covered is 105 kilometers across with the expected landing ellipse superposed.

The Incredible Expanding Cats Eye
16.09.1999

Watch closely. As this animation blinks between two Hubble Space Telescope images of NGC 6543 - the first from 1994 and the second from 1997 - the intricate filaments of this nebula are seen to shift. The shift is due to the actual expansion of this gaseous shroud shed by a dying star!

NGC 4449: Close Up of a Small Galaxy
10.07.2007

Grand spiral galaxies often seem to get all the glory. Their newly formed, bright, blue star clusters along beautiful, symmetric spiral arms are guaranteed to attract attention. But small irregular galaxies form stars too, like NGC 4449, located about 12 million light-years away.

Jupiter Eclipsing Ganymede
6.01.2009

How hazy is Jupiter's upper atmosphere? To help find out, astronomers deployed the Hubble Space Telescope to watch Jupiter eclipse its moon Ganymede. Although Ganymede circles Jupiter once a week, it usually passes above or below the planet, so that a good eclipse occurs more rarely.

An Extraordinary Spiral from LL Pegasi
14.09.2010

What created the strange spiral structure on the left? No one is sure, although it is likely related to a star in a binary star system entering the planetary nebula phase, when its outer atmosphere is ejected.

Abell 2744: Pandoras Cluster of Galaxies
29.06.2011

Why is this cluster of galaxies so jumbled? Far from a smooth distribution, Abell 2744 not only has knots of galaxies, but the X-ray emitting hot gas (colored red) in the cluster appears distributed differently than the dark matter.