COBE Dipole: Speeding Through the Universe
8.03.1997

Our Earth is not at rest. The Earth moves around the Sun. The Sun orbits the center of the Milky Way Galaxy. The Milky Way Galaxy orbits in the Local Group. The Local Group falls toward the Virgo Cluster of Galaxies.

The Belt of Venus over the Valley of the Moon
21.10.2003

Although you've surely seen it, you might not have noticed it. During a cloudless twilight, just before sunrise or after sunset, part of the atmosphere above the horizon appears slightly off-color, slightly pink.

Equinox and Harvest Moon
24.09.2010

Did you enjoy the moonlight last night? The Full Moon closest to autumnal equinox and the beginning of Fall is traditionally known as the Harvest Moon, rising opposite the Sun and illuminating fields at harvest time after sunset. This year's northern hemisphere autumnal equinox occurred yesterday, September 23rd, at 03:09 Universal Time.

Comet Lovejoy over Paranal
28.12.2011

Comet Lovejoy (C/2011 W3) survived its close encounter with the Sun earlier this month, taking its place among wonders of the southern skies just in time for Christmas. Seen here before sunrise from Paranal Observatory in Chile, the sungrazing comet's tails stretch far above the eastern horizon.

Mercury Meets Crescent Venus
29.05.2020

That's not a bright star and crescent Moon caught between branches of a eucalyptus tree. It's Venus in a crescent phase and Mercury. Near the western horizon after sunset, the two inner planets closely shared this telescopic field of view on May 22, seen from a balcony in Civitavecchia, Italy.

Auroras over Northern Canada
9.10.2022

Gusting solar winds and blasts of charged particles from the Sun resulted in several rewarding nights of auroras back in 2014 December, near the peak of the last 11-year solar cycle. The featured image captured dramatic auroras stretching across a sky near the town of Yellowknife in northern Canada.

Mercury: A Cratered Inferno
2.01.1999

Mercury's surface looks similar to our Moon's. Each is heavily cratered and made of rock. Mercury's diameter is about 4800 km, while the Moon's is slightly less at about 3500 km (compared with about 12,700 km for the Earth). But Mercury is unique in many ways.

Where is Upsilon Andromedae
22.04.1999

Astronomers recently announced the detection of three large planets orbiting the star Upsilon Andromedae - the first planetary system known to orbit a normal star other than our Sun. These planets were not directly photographed but found through a Doppler technique developed to use large telescopes to search nearby stars for wobbling planetary signatures.

The Belt of Venus over the Valley of the Moon
4.04.2010

Although you've surely seen it, you might not have noticed it. During a cloudless twilight, just before sunrise or after sunset, part of the atmosphere above the horizon appears slightly off-color, slightly pink.

A First Glimpse of the Great American Eclipse
1.09.2017

Making landfall in Oregon, the Moon's dark umbral shadow toured the United States on August 21. Those gathered along its coast to coast path were witness to a total eclipse of the Sun, possibly the most widely shared celestial event in history.