Sunset: Planet Earth
20.03.2008

Today, the Sun crosses the celestial equator heading north at 0548 UT. Known as the equinox, the geocentric astronomical event marks the first day of spring in the northern hemisphere and autumn in the south.

Noctilucent Clouds Over Germany
24.06.2009

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.

New Year Sun Grazer
16.01.2010

Intense and overwhelming, the direct glare of the Sun is blocked by the smooth occulting disk in this image from the sun-staring SOHO spacecraft. Taken on January 3rd, an extreme ultraviolet image of the Sun to scale, is superimposed at the center of the disk.

Moonquakes Surprisingly Common
10.10.2010

Why are there so many moonquakes? A recent reanalysis of seismometers left on the moon by the Apollo moon landings has revealed a surprising number of moonquakes occurring within 30 kilometers of the surface. In fact, 28 moonquakes were detected in data recorded between 1972 and 1977.

Lunar Farside
9.04.2011

Tidally locked in synchronous rotation, the Moon always presents its familiar nearside to denizens of planet Earth. From lunar orbit, the Moon's farside can become familiar, though. In fact this sharp picture, a mosaic from the Lunar Reconnaissance Orbiter's wide angle camera, is centered on the lunar farside.

Warped Spiral Galaxy ESO 510 13
4.03.2012

How did spiral galaxy ESO 510-13 get bent out of shape? The disks of many spirals are thin and flat, but not solid. Spiral disks are loose conglomerations of billions of stars and diffuse gas all gravitationally orbiting a galaxy center.

Messier 9 Close Up
23.03.2012

Renown 18th century astronomer Charles Messier described this 9th entry in his famous astronomical catalog as "Nebula, without star, in the right leg of Ophiuchus ...". But Messier 9 (M9) does have stars, known to modern astronomers as a globular cluster of over 300,000 stars within a diameter of about 90 light-years.

Cas A: Optical and X ray
17.01.2013

The aftermath of a cosmic cataclysm, supernova remnant Cassiopeia A (Cas A) is a comfortable 11,000 light-years away. Light from the Cas A supernova, the death explosion of a massive star, first reached Earth just 330 years ago.

Matijevic Hill Panorama
25.01.2013

On January 25 (UT) 2004, the Opportunity rover fell to Mars, making today the 9th anniversary of its landing. After more than 3,200 sols (Mars solar days) the golf cart-sized robot from Earth is still actively exploring the Red Planet, though its original mission plan was for three months.

Satellite Station and Southern Skies
31.05.2014

This clear night skyscape captures the colorful glow of aurora australis, the southern lights, just outside the port city of Hobart, Tasmania, Australia, planet Earth. As if staring into the dreamlike scene, the Tasmanian Earth Resources Satellite Station poses in the center, illuminated by nearby city lights.