A prominence eruption from the sun is seen in this image taken by NASA's Solar Dynamics Observatory on March 30. With a telescope and the right kinds of filters, an amateur astronomer can view prominences on the sun, too. NASA/Handout/Reuters/File
The hot, blue star HE 0437-5439 has been tossed out of the center of our Milky Way galaxy with enough speed to escape the galaxy's gravitational clutches. The stellar outcast is rocketing through the Milky Way's distant outskirts at 1.6 million miles an hour, high above the galaxy's disk, about 200,000 light-years from the center. NASA, ESA, and G. Bacon (STScI)
This image of Neptune was taken in August, 1989, as Voyager 2 photographed the planet almost continuously. The gas giant was struck by a comet some 200 years ago, researchers have found. NASA/AP
This artist's impression shows an overview of the transiting planet HD 209458b. Using the NASA/ESA Hubble Space Telescope, for the first time, astronomers have observed the atmosphere of an extrasolar planet evaporating off into space (shown in blue in this illustration). The planet's outer atmosphere is extended and heated so much by the nearby star that it starts to escape the planet's gravity. Newscom/File
This composite imgage, made using X-rays from the Chandra observatory overlaid on an optical image from the Hubble Space Telescope, shows evidence of a recoiling black hole. Researchers think that the kickback was caused either by a slingshot effect produced in a triple black hole system, or from the effects of gravitational waves produced after two supermassive black holes merged a few million years earlier. X-ray: NASA/CXC/SAO/F.Civano et al. Optical: NASA/STScI
Climate change is making the space junk problem worse, by decreasing the density of earth's upper atmosphere. The objects shown here are an artist's impression based on actual density data. The objects are shown at an exaggerated size to make them visible at the scale shown.
Korea Space Launch Vehicle-1 (KSLV-1), or Naro-1, South Korea's first space rocket, is wheeled to its launch pad from the assembly complex at Naro Space Centre in Goheung, about 301 miles south of Seoul, in June. South Korea relaunched its first space rocket on June 9, the second attempt after it failed to enter its target orbit in August last year. Korea Aerospace Research Institute/Handout/Reuters
This artist's concept shows a galaxy with a supermassive black hole at its core. The black hole is shooting out jets of radio waves. NASA/JPL-Caltech
This artist's impression shows the gas giant WASP-12b being consumed by its white dwarf star, some 600 light-years away. NASA/ESA/G. Bacon
A Hubble image of NCG 1999 shows the 'hole in space.' Scientists think that the hole was made by a young stellar object. Hubble Heritage Team (STScI)/NASA
While Ukraine is not a NATO member, alliance members in Eastern and Central Europe fear they could be Russia's next targets, prompting the 28-nation bloc to seek a robust response.
ByJulie Pace, AP White House Correspondent
Confronted by a Kremlin-backed military offensive in Ukraine, President Barack Obama and Western allies will approve plans this week to position at least 4,000 troops and military equipment in Eastern Europe, bolstering NATO's security commitments to nervous member states near the Russian border.