A brilliant green aurora seems to flow like a river in the skies over Tromsø, Norway (map), in a long-exposure picture taken between late Saturday and early Sunday.
Aurorae are created as charged particles, which are constantly streaming from the sun, travel along Earth's magnetic field lines and collide with atoms in the planet's atmosphere. The light shows can be more intense—and can sometimes be seen farther from the Poles—during solar storms.
Dust and gas envelop the Arches star cluster, the densest known gathering of young stars in the Milky Way, as seen in an artist's impression released this week in NASA's Image of the Day gallery.
This view of the cluster is based on infrared data from the Hubble Space Telescope and ground-based observatories. Observing via infrared light allows these telescopes to peer through the haze that obscures our galaxy's hub and see objects in the deepest reaches of the Milky Way.
Image courtesy NASA/ESA/STScI
Moon Over Discovery
The moon shines bright over the space shuttleDiscovery as the craft is rolled onto Launch Pad 39A at NASA's Kennedy Space Center in Florida on September 20.
Discovery is slated to lift off November 1 for the International Space Station, a journey that—so far—marks the last scheduled flight for the aging shuttle.
Photograph courtesy Tony Gray, NASA
A moonless October midnight over the remote Atacama Desert in northern Chile allowed photographer Stéphane Guisard to capture this all-sky view free of light pollution.
In addition to untold numbers of stars, the shot reveals the Large and Small Magellanic Clouds, satellite galaxies of our Milky Way (at left), as well as the bright dot of Jupiter (at right)—all set against the soft glow of the zodiacal light, the reflection of sunlight off dust in the plane of the solar system.
The orbiting probe is uniquely outfitted to spot smaller, fainter comets close to the sun, including this likely member of the Kreutz sungrazer family, thought to be fragments from the breakup of a giant comet at least 2,000 years ago.
Visible from October 19 to 21, this small comet apparently disintegrated as it neared our star.
Image courtesy SOHO/NASA
Looping magnetic field lines (white) dance across the sun in a composite picture that overlays maps of magnetic activity on an extreme ultraviolet image of the star, taken October 20.
The picture, made using data from NASA's Solar Dynamics Observatory, shows that the field lines are densest around magnetically active regions of the sun, but the lines also link out to less active areas across the star's surface.
Image courtesy SDO/NASA
Blocks of bright, layered rocks lie embedded in darker material in a picture of Mars's Holden Crater, taken by the Mars Reconnaissance Orbiter and released October 21.
The layers are thought to have been deposited by a giant flood that occurred when an ancient body of water breached the rim of Holden Crater. That means the rocks likely contain records of a wetter, warmer period early in Martian history, according to NASA.