Astronaut Captures Fantastic Shot of Aurora From Space
By Dave Mosher Email Author – July 18, 2011

A crew member floating inside the International Space Station snapped this long-exposure photo of the southern lights dancing through Earth’s atmosphere on July 16.

Such light shows occur when high-energy solar particles corralled by Earth’s magnetic field slam into atmospheric gas near the planet’s poles (in this case, somewhere over Antarctica).

At left is part of the space station’s solar arrays, and at center is space shuttle Atlantis’ robotic arm and inspection boom, which is backlit by the moon. One of Atlantis‘ wings, orbital maneuvering system pods and payload bay doors is seen at right.

The four-person crew of Atlantis recently piled in and closed the airlock between their spaceship and the space station in preparation for the last-ever shuttle undocking maneuver tomorrow at 2:28 a.m. EDT.

NASA expects the astronauts to return to Kennedy Space Center on Thursday, July 21 at 5:57 a.m. EDT.

Cluster Encounters ‘Natural Particle Accelerator’ Above Earth’s Atmosphere: How Northern and Southern Lights Are Generated

ScienceDaily (Feb. 1, 2011) — The European Space Agency’s Cluster satellites have flown through a natural particle accelerator just above Earth’s atmosphere. The data they collected are unlocking how most of the dramatic displays of the northern and southern lights are generated.

Two of Cluster’s four satellites found themselves in a natural particle accelerator above the northern hemisphere on 5 June 2009. The first to cross was satellite C3 at an altitude of 6400 km, followed five minutes later by C1 at 9000 km. This is the first time that scientists have measured such a region simultaneously using more than one satellite. The readings allow the electrical landscape of the acceleration region to be mapped. “This is like geography, only instead of the contours being the height of a landscape, they are the electrical potentials that span the region,” says Göran Marklund from the Royal Institute of Technology, Stockholm, Sweden.

These electrical potentials act in both uphill and downhill directions, accelerating particles towards and away from Earth, according to their charges. When particles strike the atmosphere, they create the shimmering curtains of light known as the aurora, or more commonly the northern and southern lights. About two-thirds of the bright auroras are estimated to be produced in this way.

Since 2006, the Cluster satellites have been drifting away from their initial orbits because they are being constantly nudged by the gravity of the Moon and the Sun. Fortuitously, the current orbit occasionally passes through the Auroral Acceleration Region, which spans 4000 km to 12000 km above our planet. …more (http://www NULL.sciencedaily NULL.com/releases/2011/02/110201122540 NULL.htm)