SPACE PHOTOS THIS WEEK: Tiny Galaxy, Sun's Iron, More

Reappearing Rhea

Image courtesy NASA, JPL, Space Science Institute

December 29, 2009--Saturn's moon Rhea peeks out from behind the ringed planet's largest moon, Titan, in a recently released image taken by NASA's Cassini orbiter. Rhea, Saturn's second largest moon, isn't even a third the size of hulking Titan.

Watching the gravitational effects as one moon passes close to another can help astronomers better calculate the moons' orbits.

January 6, 2010

Homunculus Nebula

Image courtesy J.C. Martin et. al., Gemini Observatory/AURA

January 4, 2010--A stellar "autopsy" has revealed a previously unseen part of the Homunculus Nebula, the lobes of gas and dust surrounding the dying star Eta Carinae. This newly released infrared picture, taken by the Gemini South telescope in Chile, shows a faint blue glow under the nebula's "skin"--proof of an internal structure that researchers have dubbed the Little Homunculus.

The never before seen structure surprised astronomers, one of whom likened the discovery to finding "a third lung, an extra liver, or something more exotic" in the body of a murder victim.

January 6, 2010

Surprising Stream

Image courtesy Nidever, et al., NRAO/AUI/NSF and Meilinger, Leiden-Argentine-Bonn Survey, Parkes Observatory, Westerbork Observatory, Arecibo Observatory

January 4, 2009--Vast emissions of hydrogen (red) arc below our Milky Way galaxy (white and blue) in an image derived from new data from the Robert C. Byrd Green Bank Telescope. The hydrogen comes from the two Magellanic Cloud galaxies (white spots at lower right).

The new picture shows that the so-called Magellanic Stream is roughly 40 percent longer than thought--suggesting a turbulent origin some 2.5 billion years ago. At that time, the Magellanic Clouds "may have passed close to each other, triggering massive bursts of star formation," David Nidever, of the University of Virginia, said in a statement.

The ancient activity likely sparked stellar winds and explosions, sending the first wisps of the Magellanic Stream stretching toward the Milky Way, he added.

January 6, 2010

Eclipse Emissions

Image courtesy Habbal, et al.

January 4, 2010--Swirls of red and green represent highly charged iron streaming from the sun's upper atmosphere, captured by a NASA Goddard Space Flight Center astronomer during a total solar eclipse in 2008.

Ground-based eclipse pictures from 2006, 2008, and 2009 are offering some of the first images of iron-ion emissions from the solar corona. The images show that these emissions extend outward at distances equal to one and a half times the sun's width. Pictures taken during solar eclipses can help scientists understand the solar corona, which affects potentially dangerous space weather.

January 6, 2010