This artist's concept shows a view across a mysterious disk of young, blue stars encircling a supermassive black hole at the core of the neighboring Andromeda Galaxy. The region around the black hole is barely visible at the center of the disk. The background stars are the typical older, redder population of stars that inhabit the cores of most galaxies. NASA/ESA/A. Schaller/STScI
On December 27, 2004, a neutron star flared up so brightly, it temporarily blinded all the X-ray satellites in space for an instant, and lit up the Earth's upper atmosphere. This tremendous blast of energy was from a giant flare created by the neutron star's twisting magnetic field. Objects like this are called magnetars, and they produce magnetic fields trillions of time more powerful than those here on Earth. NASA
Our solitary sunsets here on Earth might not be all that common in the grand scheme of things. New observations from NASA's Spitzer Space Telescope have revealed that mature planetary systems -- dusty disks of asteroids, comets, and possibly planets -- are more frequent around close-knit twin, or binary, stars than single stars like our sun. NASA
Dusty grains -- including tiny specks of the minerals found in the gemstones peridot, sapphires, and rubies -- can be seen blowing in the winds of a quasar, or active black hole, in this artist's concept. The quasar is at the center of a distant galaxy. NASA/JPL-Caltech/T. Pyle (SSC)
Astronaut John H. Glenn, Jr., undergoes a simulated orbital flight as part of his training for Project Mercury in the Manned Spacecraft Center's procedure trainer at Langley Air Force Base, Virginia in 1961. NASA
NASA's Hubble Space Telescope snapped a view of what may be the youngest galaxy ever seen. This "late bloomer" may not have begun active star formation until about 13 billion years after the Big Bang. Called I Zwicky 18 (below, left), the galaxy may be as young as 500 million years old. This youngster has gone though several sudden bursts of star formation -- the first only some 500 million years ago and the latest only 4 million years ago. NASA/ESA/Y. Izotov/Main Astronomical Observatory, Kyiv/T. Thuan/University of Virginia
The X-15 program is widely considered the most successful research aircraft program in US history, leaving a legacy of scientific data and aeronautical firsts that remains unparalleled. Between June 8, 1959, and Oct. 24, 1968, a dozen pilots flew three rocket-powered X-15 research vehicles 199 times. NASA
This high-forward oblique view of Rima Ariadaeus on the moon was photographed by the Apollo 10 crew in May 1969. The Apollo 10 crew aimed a hand-held 70mm camera at the surface from lunar orbit for a series of images of this area. NASA
This is an artist's concept of the early formative years of our Milky Way galaxy, circa 12.7 billion years ago. That long ago, the majestic spiral arms of our galaxy had not yet formed; the sky was a sea of globular star clusters. The bright blue star cluster at center left is among hundreds of primeval globular star clusters that came together to build up the galaxy. NASA/Adolf Schaller/STScI
The spiral galaxy NGC 1512 is revealed via wavelengths from ultraviolet to infrared. NGC 1512 lies in the southern constellation of Horologium, located 30 million light years from Earth. The galaxy spans 70,000 light years, nearly as much as the Milky Way Galaxy. NASA
US health officials announced their estimate after world organizations warned the deadly virus might become a permanent part of west African life.
BySharon Begley and Tom Miles, Reuters
Global experts issued stark new warnings of the scale of West Africa's Ebola outbreak on Tuesday, with the U.S. government estimating between 550,000 and 1.4 million people might be infected in the region by January.