Astronomy Picture Of the Day (APOD)Ski Mars
These brightly reflecting fields of snow or frost are on the slopes of a crater rim in the northern hemisphere of Mars. They are 500 meters or so long and have lasted through about eight months of the Red Planet's spring and summer weather.
PG 1115+080: A Gravitational Cloverleaf
All four blue images in the above photograph are the same object. The gravitational lens effect of the red, foreground, elliptical galaxy visible near image center creates a cloverleaf image of the single distant quasar. Light from the quasar is pulled around the massive galaxy in different paths, corresponding to different images.
An Anomalous SETI Signal
No one knows for sure what caused this signal. The bright colors on the blue background indicate that an anomalous signal was received here on Earth by a radio telescope involved in a Search for Extraterrestrial Intelligence (SETI). A search for these signals is ongoing by several groups including volunteer members of the SETI League.
NGC 1850: Gas Clouds and Star Clusters
There's nothing like it in our own Galaxy. Globular clusters as young as NGC 1850 don't exist here. Globular clusters only 40 millions of years old can still be found in the neighboring LMC galaxy, though, but perhaps none so unusual as NGC 1850.
The Coma Cluster of Galaxies
Almost every object in the above photograph is a galaxy. The Coma Cluster of Galaxies pictured is one of the densest clusters known - it contains thousands of galaxies. Each of these galaxies house billions of stars - just as our own Milky Way Galaxy does.
Stars Without Galaxies
Galaxies are made up of stars, but are all stars found within galaxies? Using the Hubble Space Telescope, researchers exploring the Virgo Cluster of galaxies have now found about 600 red giant stars adrift in intergalactic space. Above is an artist's vision of the sky from a hypothetical planet of such a lonely sun.
The Moon's surface is covered with craters, scars of frequent impacts during the early history of the solar system. Now, recent results from the Lunar Prospector spacecraft support the idea that the Moon itself formed from the debris of a giant impact of a mars-sized planetary body with the
March of the Planets
This March stargazers have been treated to eye-catching formations of bright planets in western evening skies. On March 3rd, looking toward a beautiful sunset from a beach on the Hawaiian isle of Maui, photographer Rick Scott recorded this fleeting, four-planet "hockey stick" array.
Brown Dwarf Gliese 229B
The spot near the bottom is an image of an unusual type of object: a brown dwarf. A brown dwarf is sometimes called a "failed star" because it does not have enough mass to shine by nuclear fusion.
A Chamaeleon Sky
A photogenic group of nebulae can be found in Chamaeleon, a constellation visible predominantly in skies south of the Earth's equator. Towards Chamaeleon, dark molecular clouds and bright planetary nebula NGC 3195 can be found. Visible near the center of the above photograph is a reflection nebula surrounding a young bright star.