A Distant Destiny
14.01.1998

Watching galaxies recede, observational astronomers of the 20th century discovered an astounding fact - the Universe is expanding. Will it continue to expand forever? The speed of light is finite so looking into the distant Universe is equivalent to looking at the distant past.

Maria Mitchell Inspires a Generation
10.10.1998

"Do not look at stars as bright spots only - try to take in the vastness of the universe." October 1st was the 151st anniversary of the day Maria Mitchell swept the sky with her telescope and discovered the comet of 1847 (comet Mitchell 1847VI).

Zooming in to the Pelican Nebula
2.07.2007

Where on the sky is the Pelican Nebula? APOD features many objects on the night sky, but usually does not have the resources to show exactly where on the night sky each objects lies.

Sunlight Through Saturns Rings
24.06.2000

Normally, earth-bound astronomers view Saturn's spectacular ring system fully illuminated by reflected sunlight. However, this intriguing picture was made to take advantage of an unusual orientation, with the Sun actually illuminating the rings from below. The three bright ring features are visible because the rings themselves are not solid.

Saturn with Moons Tethys and Dione
31.05.1997

Saturn and two of its larger moons - Tethys and Dione - were photographed by the Voyager 1 spacecraft which flew by the planet in November of 1980. This picture gives an indication of Saturn's extensive ring system, which can be seen casting a shadow on the planet, as does Tethys.

NGC 7635: The Bubble Nebula
17.11.1998

What created this huge space bubble? A massive star that is not only bright and blue, but also emitting a fast stellar wind of ionized gas. The Bubble Nebula is actually the smallest...

The First Lunar Observatory
8.06.1996

The first and only lunar astronomical observatory was deployed by the Apollo 16 crew in 1972. The Far Ultraviolet Camera / Spectrograph used a 3-inch diameter telescope to photograph the Earth, various nebulae, star clusters, and the Large Magellanic Cloud.

Two Billion Years After the Big Bang
7.09.1996

What did the universe look like two billion years after the Big Bang? According to this computer model, the universe was filled with irregular looking objects like the ones shown above. The simulation then predicts that these blobs of stars and gas collide to form galaxies more similar to the ones we see today.

Orange Sun Simmering
29.07.2003

Even a quiet Sun is a busy place. The above image, taken in a single color of light called Hydrogen Alpha, records a great amount of detail of the simmering surface of our parent star.

Nearby Spiral M33
21.07.1998

M33 is a prominent nearby spiral galaxy. Nicknamed the Triangulum, M33 is one of the larger members of the Local Group of Galaxies. Two massive spiral galaxies dominate the Local Group: M31 and our Milky Way Galaxy. M33 is the only other spiral galaxy known in the Local Group.