A galactic collision sparked a powerful "explosion" of star formation that until now had been hidden from view by a cloak of dense gases, as seen in a NASA's Spitzer Space Telescope picture released last week.
Known as II Zw 096, the object was once a merging pair of pinwheel-shaped galaxies, but the act of colliding has ripped one of the spirals to shreds. As the galaxies merge, giant clouds of gas inside them pass through each other, forming dense pockets of matter that collapse into new stars.
The burst of star formation (red blob at center) seen by Spitzer's infrared eye spans just 700 light-years. Based on its brightness, astronomers think the region is cranking out a hundred times the sun's mass in new stars each year.
Image courtesy NASA/JPL-Caltech/STScI/H. Inami
The wheel of the cosmos turns behind the remains of a historic tower in Iran in a long-exposure picture taken this month.
The frame captures about three hours of stellar motion over the Alborz mountain range, which borders the southern end of the Caspian Sea (map). According to photographer Babak Tafreshi, towers such as this may have been used by ancient astronomers to maintain accurate calendars.
Mineral salts make a network of lagoons shine like inlaid gems in a natural-color picture of Ukraine's Crimean Peninsula (map) taken by NASA's Landsat 5 orbiter and released this week. In the summer, the warmed marsh waters give off unpleasant odors, lending the region the nicknames "Rotten Sea" or "Putrid Sea."
Around the lagoons, boxy agricultural fields and circular irrigation systems turn the landscape into a geometric tapestry stitched together by curving highways. Part of the Black Sea is visible as a darker patch at lower left.
According to NASA, AE Aurigae was likely born in the Trapezium star cluster in the constellation Orion. At the time the star had a partner, making a binary pair with the star Mu Columbae. But about 2.5 million years ago, the pair collided with another set of binary stars, and the tussle sent AE Aurigae and Mu Columbae hurtling in opposite directions.
AE Aurigae is currently part of a relatively cool nebula that glows with only reflected light. But the star appears to be on fire, because the body's radiation is stripping electrons from a pocket of surrounding gas and heating nearby dust, causing the cloud to glow with its own emitted light.
The moon appears full when the lunar orb is on the opposite side of Earth from the sun, so that we see the fully illuminated disk. A moon that's more than half lighted and is on its way to becoming full is called a waxing gibbous moon.
SOHO was able to spot the comet's approach by blocking out the sun's glare with a device called a coronagraph. The white circle inside the red disk created by the coronagraph represents the sun's actual size.
Image courtesy SOHO/STEREO/NASA
Dark material seems to ooze down the side of Robinson crater in a picture of the moon taken by NASA's Lunar Reconnaissance Orbiter. The image, released last week, shows a swath of land about 2,035 feet (620 meters) wide on the crater's northern slope.
The flows are thought to have been created by rock avalanches that long ago charged down the crater wall. Similar features on Mars have been interpreted as recent mudflows. It's unlikely liquid water ever existed on the moon's surface, though, so scientists think some of the Martian flow patterns might also be due to dry avalanches.