M51: The Whirlpool Galaxy
18.12.1995

The Whirlpool Galaxy is frequently given as an example of a galaxy with classic spiral design. At only 15 million light years distant, M51, also cataloged as NGC 5194, is also one of the brighter and more picturesque galaxies on the sky.

Why is QSO 1229+204 so Bright?
24.08.1996

What causes the center of this barred spiral galaxy to light up brighter than almost anything in the universe? The quasar there is a good fraction of the way across our observable universe...

Carl Sagan 1934-1996
26.12.1996

Carl Sagan died last Friday at the age of 62. Sagan was the world's most famous astronomer. Among his many activities as a scientist, he contributed to the discovery that the atmosphere...

Saturn's Cleanest Moon: Enceladus
25.11.1995

Enceladus orbits Saturn between the smaller Mimas and the larger Tethys. Enceladus is composed mostly of water ice and has the cleanest and purest ice surface in the Solar System. It's surface therefore appears nearly white. The surface also has many unusual groves and relatively few craters, like Jupiter's moon Ganymede.

A Milky Way Band
24.02.1999

Most bright stars in our Milky Way Galaxy reside in a disk. Since our Sun also resides in this disk, these stars appear to us as a diffuse band that circles the sky. The above panorama of a southern band of the Milky Way's disk was taken from Australia.

ESO202-G23: Merging Galaxies
1.01.1999

ESO202-G

Comet Hyakutake and the Milky Way
17.08.1998

Two years ago, the Great Comet of 1996, Comet Hyakutake, inched across our northern sky during its long orbit around the Sun. Visible above as the bright spot with the faint tail near...

Milky Way Road Trip
5.09.2008

In search of planets and the summer Milky Way, astronomer Tunç Tezel took an evening road trip. Last Saturday, after driving the winding road up Uludag, a mountain near Bursa, Turkey, he was rewarded by this beautiful skyview to the south.

The Mileage of Light
28.05.2011

If you're driving down a dark road on a starry night, you might want to check the odometer. Earlier this month, when traveling astronomer Dennis Mammana did he was greeted with the significant mileage reading of 186,282 miles. That's the number of miles light travels in one second.

An X-ray Hot Supernova in M81
3.12.1995

In 1993, a star in the galaxy M81 exploded. Above is a picture of the hot material ejected by this supernova explosion. The picture was taken in X-rays with the Advanced Satellite for Cosmology and Astrophysics (ASCA).