Astronomy Picture of the Day

2002-04-06

Gamma-rays are the most energetic form of electromagnetic radiation. But these high energy photons penetrate and interact in normal materials and cannot be focused by lenses and mirrors like those in optical telescopes. So how do you make an ...

2002-04-05

What causes the mysterious gamma-ray bursts? Indicated in this Hubble Space Telescope exposure of an otherwise unremarkable field in the constellation Crater, is the dwindling optical afterglow of a gamma-ray burst first detected by the Beppo-SAX ...

2002-04-04 Jimmy Westlake

Comet Ikeya-Zhang ("ee-KAY-uh JONG") has become a most photogenic comet. This lovely early evening view of the comet in Rocky Mountain skies looks northwest over ridges and low clouds. The time exposure was recorded on March 31st from an 8,000 ...

2002-04-03

How much mass do flocculent spirals hide? The above true color image of flocculent spiral galaxy NGC 4414 was taken with the Hubble Space Telescope to help answer this question. Flocculent spirals -- galaxies without well defined spiral arms -- ...

2002-04-02 ORBIMAGE

What is causing the water in Florida Bay to turn black? The mysterious black color could be seen as early as last December in images taken by the SeaWIFS instrument on board the Earth-orbiting SeaStar satellite. During the darkest period in ...

2002-04-01

Using the new camera on the recently refitted Hubble Space Telescope, astronomers have been able to confirm that the Moon is made of green cheese. The telling clue was the resolution of a numeric date after which the Moon may go bad. ...

2002-03-31

What's causing those odd rings in supernova 1987A? In 1987, the brightestsupernova in recent history occurred in the Large Magellanic Clouds. At the center of the picture is an object central to the remains of the violent stellar explosion. ...

2002-03-30

The surface of Venus is perpetually covered by a veil of thick clouds and remains hidden from even the powerful telescopic eyes of earth-bound astronomers. But in the early 1990s, using imaging radar, the Venus orbiting Magellan spacecraft was ...

2002-03-29

NGC 4631 is a big beautiful spiral galaxy seen edge-on only 25 million light-years away towards the small northern constellation Canes Venatici. This galaxy's slightly distorted wedge shape suggests to some a cosmic herring and to others the ...

2002-03-28

The Centaurus Cluster is a swarm of hundreds of galaxies a mere 170 million light-years away. Like other immense galaxy clusters, the Centaurus Cluster is filled with gas at temperatures of 10 million degrees or more, making the cluster a ...