Astronomy Picture Of the Day (APOD)Galaxy Group HCG 87
Posing for this cosmic family photo are the galaxies of HCG (Hickson Compact Group) 87, about four hundred million light-years distant toward the amphibious constellation Capricornus. The large edge-on spiral near picture center...
Frosty Mountains on Mars
What causes the unusual white color on some Martian mountains? The answer can be guessed by noticing that the bright areas disappear as springtime takes hold in the south of Mars: dry ice. Unlike water ice, dry carbon dioxide ice sublimates directly to gas from its frozen state.
Orange Sun Simmering
Even a quiet Sun is a busy place. The above image, taken in a single color of light called Hydrogen Alpha, records a great amount of detail of the simmering surface of our parent star.
Launch of the Spirit Rover Toward Mars
Next stop: Mars. Last month the first of two missions to Mars was launched from Cape Canaveral, Florida, USA above a Boeing Delta II rocket. Pictured above, solid fuel boosters are seen falling away as light from residual exhaust is reflected by the soaring rocket.
The Aquarius Dwarf
Our Milky Way Galaxy is not alone. It is part of a gathering of about 50 galaxies known as the Local Group. Members include the Great Andromeda Galaxy (M31), M32, M33, the Large Magellanic Cloud, the Small Magellanic Cloud, Dwingeloo 1, several small irregular galaxies, and many dwarf elliptical and dwarf spheroidal galaxies.
Spiral Galaxy NGC 7742
This might resemble a fried egg you've had for breakfast, but it's actually much larger. In fact, ringed by blue-tinted star forming regions and faintly visible spiral arms, the yolk-yellow center of this face-on spiral galaxy, NGC 7742, is about 3,000 light-years across.
Dumbbell Nebula Halo
In 1764, French astronomer Charles Messier sighted this gorgeous cosmic cloud which he described as an oval nebula without stars. Cataloged as M27, it is now popularly known as the Dumbbell Nebula...
Mars at the Moon s Edge
What was that bright "star" near the Moon last week? Mars of course, as the Red Planet wandered near the wanning gibbous Moon early last Thursday morning, passing behind the lunar orb when viewed from some locations in South and Central America, the Carribean, and Florida.
GRACE Maps the Gravity of Earth
Why do some places on Earth have higher gravity than others? Sometimes the reason is unknown. To help better understand the Earth's surface, slight distance changes between a pair of identically orbiting satellites named GRACE have been used to create the best ever map of Earth's gravitational field.
A Tornado on Planet Earth
Large storms on Earth can spawn unusual, small, violent clouds known as tornadoes. Tornado clouds swirl as fast as hundreds of kilometers per second and, when they touch down, can destroy nearly everything in their long, narrow path. Many tornadoes last only a few minutes, but the largest and most dangerous can endure for hours.