Milky Way Illustrated
4.01.2005

What does our Milky Way Galaxy look like from afar? Since we are stuck inside, and since opaque dust truncates our view in visible light, nobody knows for sure. Drawn above, however, is a good guess based on many different types of observations.

Light from the First Stars
2.01.2007

What were the first stars like? No one is yet sure. Our Sun is not a first-generation star. It is not even second generation. The first stars to appear in the universe likely came and went about 13 billion years ago.

APOD: 2002 September 18- A Sagittarius Starscape
18.09.2002

Many vast star fields in the plane of our Milky Way Galaxy are rich in clouds of stars, dust, and gas. First and foremost, visible in the above picture are millions of stars, many of which are similar to our Sun.

Sagittarius Star Cloud
20.05.2001

Stars come in all different colors. The color of a star indicates its surface temperature, an important property used to assign each star a spectral type. Most stars in the above Sagittarius Star Cloud are orange or red and relatively faint, as our Sun would appear.

A July Dawn
7.08.2001

Those up before dawn in late July in the northern hemisphere could see planets, stars, and a spacecraft in a single quick glance before starting their day. Near the eastern horizon was bright Jupiter, and not far above and to its right was the very bright Venus.

The Milky Way in Stars and Dust
4.10.2005

The disk of our Milky Way Galaxy is home to hot nebulae, cold dust, and billions of stars. This disk can be seen from a dark location on Earth as a band of diffuse light across the sky.

Swirls and Stars in IC 4678
24.05.2005

Swirls of gas and dust enrich this little observed starfield toward the constellation of Sagittarius. Just to the side of the more often photographed Lagoon Nebula (M8) and the Trifid Nebula (M20) lies this busy patch of sky dubbed IC 4678.

Zooming in on the First Stars
10.06.2003

What became of the first stars? No known stars appear to be composed of truly primordial gas -- all of the stars around us have too many heavy elements. Our own Sun is thought to be a third generation star, with many second-generation stars seen in globular clusters.

Stellar Spectral Types: OBAFGKM
18.04.2004

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.

Bright Star Regulus near the Leo 1 Dwarf Galaxy
19.06.2006

The star on the upper left is so bright it is sometimes hard to notice the galaxy on the lower right. Both the star, Regulus, and the galaxy, Leo I, can be found within one degree of each other toward the constellation of Leo.