

This image courtesy of the European Southern Observatory (ESO) shows an artist's impression of an active galaxy that has jets. The central engine is thought to be a supermassive black hole surrounded by an accretion disc and enshrouded in a thick doughnut-shaped structure of gas and dust, which astronomers call a "torus". The torus of dust and gas can be seen orbiting a flatter disc of swirling gas. In the center, the supermassive black hole is surrounded by a flat accretion disc of rapidly orbiting material. The jets are emitted at right angles from the plane of the disc.
This artist's impression shows a celestial body about the size of our moon slamming at great speed into a body the size of Mercury. NASA's Spitzer Space Telescope found evidence that a high-speed collision of this sort occurred a few thousand years ago around a young star, called HD 172555, still in the early stages of planet formation. The star is about 100 light-years from Earth.
The Aurora Borealis, or Northern Lights, as viewed from space. Auroras are caused by atoms in the upper atmosphere colliding with solar wind particles that are accelerated along the Earth's magnetic field lines.
Backdropped by Earth's horizon and the blackness of space, the Japanese Kibo complex of the International Space Station was snapped by a NASA Expedition 23 crew member while the space shuttle Atlantis was docked with the station in May.
The Crab Nebula, the result of a supernova noted by Earth-bound skywatchers in 1054 AD, is filled with mysterious filaments that are not only tremendously complex, but appear to have less mass than expelled in the original supernova and a higher speed than expected from a free explosion. The Crab Nebula spans about 10 light-years. In the nebula's very center lies a pulsar: a neutron star as massive as the Sun but with only the size of a small town. The Crab Pulsar rotates about 30 times each second.
The Japan Aerospace Exploration Agency’s Hayabusa spacecraft streaked across the sky through the clouds as it re-entered Earth’s atmosphere over the Woomera Test Range in Australia on June 13. In Kingoonya, the spacecraft’s re-entry was visible to the human eye for only 15 seconds.
An undated handout picture released by Nasa's Ames Research Center shows an artist's impression of a proposed Mars plane. Scientists are flying robot planes over a desolate region of the Canadian Arctic as a rehearsal for the future aerial exploration of Mars. The three unmanned aerial vehicles have a 17-meter wingspan and are equipped with onboard cameras. They are being used to see whether unmanned aircraft can obtain better pictures of Martian geology and landscape than spacecraft.
The Seagull nebula, seen in this infrared mosaic from NASA's Wide-field Infrared Survey Explorer draws its common name from its resemblance to a gull in flight. But it depends on your point of view. When the image is rotated 180 degrees it bears a passing resemblance to a galloping lizard -- or perhaps a dragon or a dinosaur. The image spans an area about seven times as wide as the full moon, and three times as high, straddling the border between the constellations Monoceros and Canis Major. So you might say this lizard is running with the Big Dog, while the gull is flying from it.
This NASA image shows the Hubble Space Telescope as it floats away from the space shuttle Atlantis after the STS-125 crew completed work on the telescope, May 19, 2009. The crew conducted five spacewalks to complete the final service mission to the telescope.
The space shuttle Discovery sitting on launch pad 39-A on August 27, 2009 at the Kennedy Space Center in Florida. NASA said on July 1 that it was postponing the final two space shuttle launches before the program is phased out, citing a delay in needed equipment. The US space agency set November 1 for the launch of space shuttle Discovery's STS-133 mission, which had been planned for September 16. NASA said the shuttle Endeavour mission was rescheduled February 26 instead of late November.