Astronomy Picture Of the Day (APOD)Saturns Moon Dione from Cassini
What causes the bright streaks on Dione? Recent and likely future images of this unusual moon by the robot Cassini spacecraft now orbiting Saturn might help us find out. The above image was taken at the end of October from a distance of about one million kilometers.
Lake Effect Snow on Earth
What are those strange clouds stretching out from these lakes? The clouds are caused by cold air moving over a warm water and result in bands of lake-effect snow. The rising bands of moistened, warmed air that drop lake-effect snow alternate with clear bands of falling cold air.
Saturns Moon Tethys from Cassini
Tethys is one of the larger and closer moons of Saturn. The Cassini spacecraft now orbiting Saturn passed near the frozen moon at the end of October, capturing the most detailed images since the Voyager spacecrafts in the early 1980s.
Doomed Star Eta Carinae
Eta Carinae may be about to explode. But no one knows when - it may be next year, it may be one million years from now. Eta Carinae's mass - about 100 times greater than our Sun - makes it an excellent candidate for a full blown supernova.
NGC 2683: Spiral Edge On
This gorgeous island universe, cataloged as NGC 2683, lies a mere 16 million light-years distant in the northern constellation Lynx. A spiral galaxy comparable to our own Milky Way, NGC 2683 is seen nearly edge-on in this cosmic vista, with more distant galaxies scattered in the background.
Magnetars In The Sky
Indicated on this infrared image of the galactic center region are positions of candidate magnetars -- believed to be the strongest magnets in the galaxy. Classified by observers as Soft Gamma Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs), these cosmic powerhouses are likely city-sized, spinning, highly-magnetized neutron stars. How strong is a magnetar's magnetic field?
What the Hubble Saw
In this striking 41 inch by 38 inch quilt, astronomy enthusiast Judy Ross has interpreted some of the Hubble Space Telescope's best galactic and extragalactic vistas. Featured in past APODs, clockwise from...
A Radar View of Titan
Where are Titan's craters? Throughout our Solar System's five billion-year history, dangerous rocks and chunks of ice have continually slammed into planets and moons - usually creating numerous long lasting impact craters. When the robot spacecraft Cassini swooped past Saturn's moon Titan last month, however, radar images showed few craters.
Leonid Meteors Streak
The 2004 Leonids meteor shower had its ups and downs. Although average rates were significantly less than many previous years, as expected, at least two unexpected "mini-outbursts" of several bright meteors over a few minutes were reported.
Where do gamma ray bursts occur? To help find out, NASA launched the Swift satellite on Saturday, as pictured above. What Swift is designed to do better than any previous satellite is to quickly locate these enigmatic explosions in both sky position and distance.