M13: The Great Globular Cluster in Hercules
15.11.2007

M13 is modestly recognized as the Great Globular Cluster in Hercules. A system of stars numbering in the hundreds of thousands, it is one of the brightest globular star clusters in the northern sky.

Jagged Shadows May Indicate Saturn Ring Particles
15.04.2009

What's causing unusual jagged shadows on Saturn's rings? No one is yet sure. As Saturn nears equinox, its rings increasingly show only their thin edge to the Earth and Sun. As a result, Saturn's moons now commonly cast long shadows onto the rings.

Unknown Dark Material on Mercury
6.07.2009

What is that strange material on Mercury? When flying by Mercury last October, the robotic MESSENGER spacecraft imaged much of the solar system's innermost planet in unprecedented detail. As common in science, new data bring new mysteries.

Young Stars in the Rho Ophiuchi Cloud
13.11.2009

Cosmic dust clouds and embedded newborn stars glow at infrared wavelengths in this tantalizing false-color view from the Spitzer Space Telescope. Pictured is of one of the closest star forming regions, part of the Rho Ophiuchi cloud complex some 400 light-years distant near the southern edge of the pronounceable constellation Ophiuchus.

Omega Centauri: The Brightest Globular Cluster
1.05.2013

This huge ball of stars predates our Sun. Long before humankind evolved, before dinosaurs roamed, and even before our Earth existed, ancient globs of stars condensed and orbited a young Milky Way Galaxy. Of the 200 or so globular clusters that survive today, Omega Centauri is the largest, containing over ten million stars.

Orion Nebula in Oxygen, Hydrogen, and Sulfur
4.06.2013

Few astronomical sights excite the imagination like the nearby stellar nursery known as the Orion Nebula. The Nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud.

Noctilucent Clouds over Moscow
27.06.2013

This panoramic night scene from June 8 looks out across a Moscow skyline from atop the main building of Lomonosov Moscow State University. Shining in the darkened sky above are widespread noctilucent clouds. From...

Time Lapse Auroras Over Norway
29.12.2013

Sometimes, after your eyes adapt to the dark, a spectacular sky appears. Such was the case in 2011 March when one of the largest auroral displays in recent years appeared over northern locations like the border between Norway and Russia.

Phases of the Moon
10.03.2018

Look at the Moon every night and its visible sunlit portion gradually changes. In phases progressing from New Moon to Full Moon to New Moon again, a lunar cycle or lunation is completed in about 29.5 days.

Total Solar Eclipse Corona in HDF
30.04.2018

How great was the Great American Eclipse? The featured HDR image shows it to be perhaps greater than we knew. On August 21 of last year, the Moon blocked the Sun for a few minutes along a narrow path across the USA.