Space Photos This Week: Sun Spikes, Odd Magnetar, More

Dust and Sulfur

Image courtesy NASA

Pale dust plumes blow over the ocean off Namibia in a picture taken by NASA's Terra satellite on August 10. As easterly trade winds blow from the Indian Ocean over Africa, they lose moisture. The hot, dry winds can stir up fine sediments from stream beds as they cross southwestern Africa, generating the plumes.

The picture also captured a vein of iridescent green running parallel to the Namibian coast. There, natural processes in the water column create hydrogen sulfide, which interacts with oxygen-rich surface waters to cause pure sulfur to precipitate. The yellow sulfur makes the water appear green to the satellite's sensors.

Published August 25, 2010

Planets Get Pulverized

Image courtesy NASA

Pairs of stars in close orbit with each other might not be the best places to look for Earthlike worlds, according to a study published August 19 that found a surprising amount of dust around three mature stellar pairs.

The tightly orbiting star pairs are all surrounded by large debris disks, but they're also too old to still have so much dust left over from their births. Instead, astronomers think the stars have been circling closer toward their partners, triggering gravitational shake ups that led to planetary collisions.

"It's theoretically possible that habitable planets could exist around these types of stars," team leader Jeremy Drake, of the Harvard-Smithsonian Center for Astrophysics, said in a statement. "So if there happened to be any life there, it could be doomed."

Published August 25, 2010

Mysterious Magnetar

Image courtesy ESO

Strong magnetic field lines encompass a magnetar—a type of neutron star—in an artist's conception of the star cluster Westerlund 1 released August 18. Based on the magnetar's age, astronomers with the European Southern Observatory calculate that it must have been created when a star at least 40 times as massive as the sun exploded as a supernova.

The find challenges current theories for how massive a star has to be to create a black hole when it dies. Previously, scientists had thought stars between 10 and 25 times the sun's mass would form neutron stars, while those above 25 times the sun's mass would produce black holes.

One theory is that the star that formed the mysterious magnetar was born with a companion. Over time the two stars' orbital interactions ejected huge amounts of mass from the system. So when the star went supernova, it had lost enough mass to generate a neutron star.

Published August 25, 2010

Pakistan Floods

Image courtesy NASA

Two false-color views of the Indus River region of Pakistan show bright red vegetation on August 8 (left) bisected by pale blue floodwaters on August 10, as seen by NASA's Terra satellite.

More than 1,500 people have been killed and millions have been left homeless due to flooding triggered by heavy monsoon rains, according to the Associated Press.

(Also see: "Pakistan Flooding Because of Farms?")

Published August 25, 2010

Saturnian Nights

Image courtesy NASA

Saturn's geyser moon Enceladus seems to hang beyond the planet's rings in a picture taken by NASA's Cassini spacecraft and released August 24. Faint plumes of water ice are just visible spewing from the moon's south polar region.

The Cassini probe was facing Saturn's night side when it took this picture. The bright crescent shows where sunlight was being scattered through the planet's upper atmosphere.

In turn, light reflected off Saturn brightens the face of Enceladus, as seen by the spacecraft—although the imaging team artificially lightened the moon relative to the planet and rings to make the plumes easier to see.

Published August 25, 2010