This artist's impression shows the Cygnus X-1 binary star system, one of the brightest X-ray sources in the sky. Data suggest that there is a small, very dense object about nine times the mass of the sun in this star system. The object could be a black hole, but, strangely, it appears to have formed without a supernova. ESA/NASA
NGC 4414 is a spiral galaxy some 62 million light-years awa, in the constellation Coma Berenices, near Leo. It was imaged by the Hubble Space Telescope in 1995. Newscom/File
This artist's conception shows the three suns and the newly discovered Jupiter-sized planet orbiting one of them from the vantage point of a moon of the planet. The large yellow sun is creeping over the horizon, but more distant orange and red suns are still visible in the sky. The 2005 discovery of the planet in the constellation Cygnus, 149 light years from Earth, called into doubt prevailing theories about how planets form around stars and the interplay of gravity in other solar systems. SHNS photo illustration courtesy California Institute of Technology/Newscom/File
This future aircraft design concept for supersonic flight over land comes from the team led by the Lockheed Martin Corporation. The team's simulation shows possibility for achieving overland flight by dramatically lowering the level of sonic booms through the use of an 'inverted-V' engine-under wing configuration. Other revolutionary technologies help achieve range, payload and environmental goals. This supersonic cruise concept is among the designs presented in April 2010 to the NASA Aeronautics Research Mission Directorate.
NASA astronaut Clayton Anderson, STS-131 mission specialist, watches a water bubble float freely between him and the camera, showing his image refracted, on the middeck of space shuttle Discovery while docked with the International Space Station on April 12. UPI/NASA/Newscom/File
A Saturn I booster model is set up for testing in NASA Lewis (now Glenn) Research Center's 8'x6' Supersonic Wind Tunnel in 1960. The model had eight working rocket engines with 250 pounds of thrust each. The tests simulated actual flight conditions, providing valuable information to optimize vehicle stability and air pressure distribution. NASA
A sunset captured last month by astronauts aboard the International Space Station shows the many layers of the Earth's atmosphere. At bottom, is the Earth's surface at night. Above that, appearing in orange and yellow, is the Earth's troposphere, which contains approximately 75 percent of the atmosphere's mass almost all of its clouds. Above the troposphere, seen as a light blue band, is the stratosphere, where jet airliners cruise. Beyond the stratosphere, the atmosphere thins out into the darkness of outer space. NASA
A composite satellite image of the world at night is seen. NASA
Canadian space tourist and founder of Cirque du Soleil Guy Laliberte clows around prior to his blast off from a Russian leased Kazakh Baikonur cosmodrome on September 30, 2009 in a Russian Soyuz TMA-16 rocket to the International Space Station. AFP Photo/Alexander Nemenov
Like early explorers mapping the continents of our globe, astronomers are busy charting the spiral structure of our galaxy, the Milky Way. Using infrared images from NASA's Spitzer Space Telescope, scientists have discovered that the Milky Way's elegant spiral structure is dominated by just two arms wrapping off the ends of a central bar of stars. Previously, our galaxy was thought to possess four major arms. This artist's concept illustrates the new view of the Milky Way, along with other findings presented at the 212th American Astronomical Society meeting. NASA/JPL-Caltech
At least 60,000 mostly Kurdish refugees have entered Turkey since Thursday after Islamic State militants surrounded a Kurdish stronghold in northern Syria. Some are calling for US airstrikes to stop the group's advance.
ByDominique Soguel, Correspondent
Tens of thousands of Syrians have crossed into Turkey in recent days, fleeing an Islamic State offensive that has opened up another front in Syria's civil war as the US weighs a bombing campaign there.