A comet-like body gets torn apart by a neutron star in an illustration of what might have caused an unusual gamma-ray burst spotted by NASA's Swift satellite last December 25.
It's thought so-called long gamma-ray bursts happen when massive stars collapse and explode as supernovae. But last year's flash, dubbed the Christmas Day burst, was unlike any other gamma-ray burst yet seen, prompting researchers to consider alternate explanations.
One team proposes that an object about half the mass of the dwarf planet Ceres got within about a million kilometers of a neutron star that's 1.4 times the mass of the sun. As the comet approached the star, it got ripped apart by gravitational forces—just as the comet Shoemaker-Levy 9 (picture) broke up when it got too close to Jupiter.
A recently released picture from NASA's Spitzer Space Telescope shows the spiral structure of the galaxy M83, also known as the Southern Pinwheel. Astronomers think this galaxy is a smaller version of what our own Milky Way might look like if we could see it from the outside.
In a view reminiscent of a holiday wreath, the infrared picture reveals the galaxy's dusty spiral arms in green dotted with reddish white regions of intense star formation.
Image courtesy Caltech/NASA
A recently released high-resolution picture shows the edge of eroded deposits in the Electris region of Mars.
Snapped by NASA's Mars Reconnaissance Orbiter, the picture is intended to help scientists figure out what geologic process might have formed the deposit and how it has changed over time.
An Orionid meteor streaks over Alamut Castle in Iran in a recently released picture taken in October. The meteor is seen within its namesake constellation, Orion.
The mountain fortress of Alamut was built into the Alborz Mountains in the ninth century. Over the years the castle has been home to religious groups, feudal lords, and scholars, including the 13th-century Persian astronomer Nasir al-Din al-Tusi.
Bright swaths amid dense dust show where stars are forming in this infrared view of Cygnus X, a stellar "factory" believed to contain enough raw material to make two million stars like our sun.
Sitting 4,500 light-years away in the constellation Cygnus, the Swan, the star-forming region was first spotted by astronomers in the 1950s as a bright radio source.
Recently, scientists using NASA's Fermi Gamma-ray Space Telescope also detected intense gamma-ray emission within Cygnus X—possibly a sign that the region's cavities of gas and dust, carved by star birth, have managed to corral some of the mysterious particles known as cosmic rays.