Messier 81
27.03.2025

One of the brightest galaxies in planet Earth's sky is similar in size to our Milky Way Galaxy: big, beautiful Messier 81. Also known as NGC 3031 or Bode's galaxy for its 18th century discoverer, this grand spiral can be found toward the northern constellation of Ursa Major, the Great Bear.

Dark Spots on Neptune
21.08.2001

Neptune has spots. The Solar System's outermost gas giant shows a nearly uniform blue hue created by small amounts of methane drifting in a thick atmosphere of nearly colorless hydrogen and helium. Dark spots do appear, however, that are anti-cyclones: large high-pressure systems that swirl in Neptune's cold cloud tops.

Unusual Rocks in Death Valley
10.04.2002

How did those big rocks end up on that strange terrain? One of the more unusual places here on Earth occurs inside Death Valley, California, USA. There a dried lakebed named Racetrack Playa exists that is almost perfectly flat, with the odd exception of some very large stones, one of which is pictured above.

Titan: Saturn's Smog Moon
23.09.1995

The largest moon of Saturn is a rare wonder. Titan is the only one of Saturn's moons with an atmosphere, and one of only two moons in the Solar System with this distinction (Neptune's Triton is the other).

NGC 1818: A Young Globular Cluster
29.12.2002

Globular clusters once ruled the Milky Way. Back in the old days, back when our Galaxy first formed, perhaps thousands of globular clusters roamed our Galaxy. Today, there are perhaps 200 left. Many globular clusters were destroyed over the eons by repeated fateful encounters with each other or the Galactic center.

Hyakutake: Comet Atmosphere
10.04.1998

The atmosphere of a comet comes and goes. Approaching the sun, it swells as material from the icy cometary nucleus is warmed and evaporated by increasing sunlight. Immense but tenuous and fleeting, the inner atmosphere or inner "coma" of comet Hyakutake is seen in this false color picture.

Orion Nebula: The 2MASS View
12.06.1998

Few astronomical sights excite the imagination like the nearby stellar nursery known as the Orion Nebula. The Nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1,500 light-years away.

Reflecting Merope
4.12.2004

In the well known Pleiades star cluster, a star's light is slowly destroying this wandering cloud of gas and dust. Above, the star Merope lies just off the upper left edge of this picture from the Hubble Space Telescope.

Mars and the Star Clusters
19.04.2006

This evening's skyscape includes a view similar to this one, recorded in western skies on April 16 - an orange-hued planet Mars wandering near rich open star cluster M35. Also notable is fainter star cluster NGC 2158, just above and left of M35.

APOD: 2007 February 20- White Ridges on Mars
20.02.2007

What created these white ridges on Mars? The images showing the white ridges, including some of the highest resolution images ever taken from Martian orbit, were recorded last year by the Mars Reconnaissance Orbiter (MRO).