Space Pictures This Week: Hidden Aurora, Mars Devil, More

Aurora in Hiding

Photograph by Thilo Bubek

Auroras tint the clouds green in a picture of the night sky over Breivikeidet, Norway, taken September 9. The northern lights display was most likely a product of charged particles hurled off the sun a few days earlier.

On September 6 sunspot 1283 produced two major eruptions, including an X2-class solar flare. Such flares are often associated with coronal mass ejections, huge clouds of particles that—when they careen toward Earth—can spark aurora-inducing geomagnetic storms.

Published September 12, 2011

Dangling Dione

Image courtesy Caltech/SSI/NASA

The icy moon Dione seems to hang under the rings of Saturn in a picture from NASA's Cassini spacecraft released September 5.

A recent study found that Dione has an atmosphere, albeit a thin one, that's constantly being recharged as particles from Saturn splatter on its surface.

Published September 12, 2011

Border Zone

Photograph courtesy NASA

An orange line snaking across the landscape marks the fenced, floodlit border zone between India and Pakistan, as seen in a picture taken from the International Space Station and released September 5. The fence is designed to discourage smuggling and arms trafficking.

The bright cluster of nighttime lights nearest to the border shows the Pakistani city of Lahore, while a similar cluster of lights to the upper left in this frame is the Indian capital of New Delhi.

Published September 12, 2011

Martian Devil

Image courtesy U. Arizona/NASA

A dust devil casts a long shadow over the Martian landscape in a picture from the HiRISE camera aboard NASA's Mars Reconnaissance Orbiter released September 7.

Martian dust devils, which can tower five to six miles (eight to ten kilometers) high, form when summer heat gets the ground warmer than the air above it.

As warm air close to the ground rises, plumes of cooler air fall to replace it, creating vertical circulation. If a gust of wind blows through, it can send the circulating air spinning horizontally, triggering a dust devil.

Published September 12, 2011

Mars Ice Pits

Image courtesy U. Arizona/NASA

Rounded walls of pits create blob-like patterns across Mars's southern ice cap in a picture from NASA's Mars Reconnaissance Orbiter released September 7.

Although most of the carbon dioxide ice on Mars is seasonal, a roughly ten-foot-thick (three-meter-thick) layer on the red planet's south pole stays cold enough to remain year-round.

The color outlining the flat-bottomed pits may be due to dust mixed into the ice, as summertime heat defrosts parts of the pit walls.

Published September 12, 2011

Examining Tisdale 2

Photograph courtesy Caltech/NASA

Bright material coats the top of a rock on Mars dubbed Tisdale 2, as seen in a picture taken by the Mars rover Opportunity and released September 1. The rock is about 12 inches (30 centimeters) tall.

Opportunity went on to examine the texture and composition of Tisdale 2, which was apparently ejected when a huge impact created the nearby 66-foot-wide (20-meter-wide) crater known as Odyssey.

Published September 12, 2011