A Cluster Too Far
8.09.1998

Why is this galaxy cluster so red? Nearby clusters have galaxies with colors that are much more yellow and blue. A leading explanation is that this cluster of galaxies lies so far across our universe (z~1) that cosmological time dilation significantly reddens the light.

The Galaxy and the Quasar
7.10.2002

Is the galaxy in the center connected to the quasar on the upper right? Disagreements about systems like this have raged for decades and have been used to challenge the foundations of modern cosmology.

Comet Halley and the Milky Way
3.10.1997

Comet Halley was photographed superposed in front of the disk of our Milky Way Galaxy in 1986 by the Kuiper Airborne Observatory. Comet Halley is the bright white streak near this photograph's center. Comet Halley is the most famous comet in history, and returns to the inner Solar System every 76 years.

NGC 1365: A Nearby Barred Spiral Galaxy
24.06.1999

Many spiral galaxies have bars across their centers. Even our own Milky Way Galaxy is thought to have a bar, but perhaps not so prominent as the one in NGC 1365, shown above. The persistence and motion of the bar imply relatively massive spiral arms.

Full Observatory Moon
27.01.2024

A popular name for January's full moon in the northern hemisphere is the Full Wolf Moon. As the new year's first full moon, it rises over Las Campanas Observatory in this dramatic Earth-and-moonscape. Peering from the foreground like astronomical eyes are the observatory's twin 6.5 meter diameter Magellan telescopes.

Curiosity Surveys Lower Mount Sharp on Mars
28.12.2016

If you could stand on Mars -- what might you see? If you were the Curiosity rover, then just last month you would have contemplated the featured image -- a breathtaking panorama of the lower portion of Mount Sharp. The colors have been adjusted to mimic lighting familiar to Earthlings.

Shadow Cone of a Total Solar Eclipse
6.01.2003

Sometimes, during a total eclipse of the Sun, a strange shadow of darkness can be seen stretching off into the distance. Called a shadow cone, they are visible because the Earth's atmosphere is not completely transparent, scattering sunlight and hence appearing blue during the day.

Planetary Nebula NGC 7027 in Infrared
25.03.1998

NGC 7027 is one of the smallest known planetary nebulae. Even so, NGC 7027 is 14,000 times larger than the Earth-Sun distance. Planetary nebula are so named because the first few discovered appeared similar to planets. Planetary nebula are actually dying stars, though, that have recently run out of nuclear fuel.

The Wolf s Moon
20.01.2012

A Full Moon rising can be a dramatic celestial sight, and Full Moons can have many names. Captured on January 8 from Ötersund, Sweden, this evocative moonrise portrait might make you feel the cold of winter in the north.

The Orion Nebula in Hydrogen
22.11.2000

The Great Nebula in Orion can be found just below and to the left of the easily identifiable belt of three stars in the popular constellation Orion. This fuzzy patch, visible to the unaided eye, contains one of the closest stellar nurseries, lying at a distance of about 1500 light years.