The Millennium that Defines Universe
1.01.2001

Welcome to millennium three. During millennium two, humanity continually redefined its concept of "Universe": first as spheres centered on the Earth, in mid-millennium as the Solar System, a few centuries ago as the Galaxy, and within the last century as the matter emanating from the Big Bang.

Martian Crater Shows Evidence of Dried Pond
3.06.1998

Did a pond once exist in this Martian crater? Recent photographs by the spacecraft Mars Global Surveyor, currently in orbit around Mars, show features unusual for Mars yet similar to a dried pond on Earth.

A Venusian Tick
23.08.1995

Data from the Magellan spacecraft has shown the Face of Venus to contain a host of volcanic features. This image shows an example of a fairly common type of venusian volcanic feature. Known...

Stars and Planets in the Halo of the Moon
21.03.2003

Photographed on March 13th from Caledon, Ontario, Canada, a bright Moon was surrounded by this lovely halo. Planet Jupiter and stars Procyon, Castor, and Pollux also appear within the circle of lunar light. Castor...

Noctilucent Clouds
19.06.2005

Sometimes it's night on the ground but day in the air. As the Earth rotates to eclipse the Sun, sunset rises up from the ground. Therefore, at sunset on the ground, sunlight still shines on clouds above.

Proxima Centauri: The Closest Star
4.12.2005

What is the closest star to our Sun? It is Proxima Centauri, the nearest member of the Alpha Centauri triple star system. Light takes only 4.22 years to reach us from Proxima Centauri. This...

M13: The Great Globular Cluster in Hercules
1.03.2000

M13 is one of the most prominent and best known globular clusters. Visible with binoculars in the constellation of Hercules, M13 is frequently one of the first objects found by curious sky gazers seeking celestials wonders beyond normal human vision.

A Sharp View of the Sun
18.09.2011

Here is one of the sharper views of the Sun ever taken. This stunning image shows remarkable details of a dark sunspot across the image bottom and numerous boiling granules which appear like kernels of corn across the top.

A Prominence on the Sun
19.09.2015

This eerie landscape of incandescent plasma suspended in looping and twisted magnetic fields stretched toward the Sun's eastern horizon on September 16. Captured through a backyard telescope and narrowband filter in light from ionized hydrogen, the scene reveals a gigantic prominence lofted above the solar limb.

Cirrus over Paris
22.06.2016

What's that over Paris? Cirrus. Typically, cirrus clouds appear white or gray when reflecting sunlight, can appear dark at sunset (or sunrise) against a better lit sky. Cirrus are among the highest types of clouds and are usually thin enough to see stars through.