Astronomy Picture Of the Day (APOD)LINEAR s Tail and Two Nuclei
Arcing toward southern skies in late March, this faint comet LINEAR - the one officially designated C/2001 A2 (LINEAR) - brightened unexpectedly. The outburst, apparently due to the fragmentation of its nucleus, delighted observers as the comet eventually increased to naked-eye brightness.
Stellar Spectral Types: OBAFGKM
Astronomers divide stars into different spectral types. First started in the 1800s, the spectral type was originally meant to classify the strength of hydrogen absorption lines. A few types that best describe the temperature of the star remain in use today.
Working in Space
High above planet Earth, a human helps an ailing machine. The machine, in this potentially touching story, is the Hubble Space Telescope, which is not in the picture. The human is Astronaut Steven L.
Close up of the Face on Mars
Wouldn't it be fun if clouds were turtles? Wouldn't it be fun if the laundry on the bedroom chair was a friendly monster? Wouldn't it be fun if rock mesas on Mars were faces or interplanetary monuments? Clouds, though, are small water droplets, floating on air.
Comet Hale-Bopp Over Val Parola Pass
Comet Hale-Bopp became much brighter than any surrounding stars. It was seen even over bright city lights. Out away from city lights, however, it put on quite a spectacular show. Here Comet Hale-Bopp was photographed above Val Parola Pass in the Dolomite mountains surrounding Cortina d'Ampezzo, Italy.
NGC 6826: The Blinking Eye
The colorful planetary nebula phase of a sun-like star's life is brief. Almost in the "blink of an eye" - cosmically speaking - the star's outer layers are cast off, forming an expanding emission nebula. This nebula lasts perhaps 10 thousand years compared to a 10 billion year stellar life span.
Saturn The Giant
Forty years ago today (May 25, 1961) U.S. president John Kennedy announced the goal of landing Americans on the Moon by the end of the decade. Kennedy's ambitious speech triggered a nearly unprecedented peacetime technological mobilization and one result was the Saturn V moon rocket.
X Ray Stars of 47 Tucanae
A deep optical image (left) of 47 Tucanae shows an ancient globular star cluster so dense and crowded that individual stars can not be distinguished in its closely packed core. An x-ray image of its central regions (inset right) from the Chandra Observatory reveals a wealth of x-ray stars hidden there.
Strange Orange Soil on the Moon
How did orange soil appear on the Moon? This mystery began when astronaut Harrison Schmidt noticed the off-color patch near Apollo 17's Taurus-Littrow landing site in 1972. Schmidt and fellow astronaut Eugene Cernan scooped up some of the unusual orange soil for detailed inspection back on Earth.
Spiral Galaxy NGC 1232
Galaxies are fascinating not only for what is visible, but for what is invisible. Grand spiral galaxy NGC 1232, captured in detail by one of the new Very Large Telescopes, is a good example.