Giant Ring of Black Holes
Just in time for Valentine's Day comes a new image of a ring -- not of jewels -- but of black holes. This composite image of Arp 147, a pair of interacting galaxies located about 430 million light years from Earth, shows X-rays from the NASA's Chandra X-ray Observatory (pink) and optical data from the Hubble Space Telescope (red, green, blue) produced by the Space Telescope Science Institute, or STScI.
Arp 147 contains the remnant of a spiral galaxy (right) that collided with the elliptical galaxy on the left. This collision has produced an expanding wave of star formation that shows up as a blue ring containing in abundance of massive young stars. These stars race through their evolution in a few million years or less and explode as supernovas, leaving behind neutron stars and black holes.
A fraction of the neutron stars and black holes will have companion stars, and may become bright X-ray sources as they pull in matter from their companions. The nine X-ray sources scattered around the ring in Arp 147 are so bright that they must be black holes, with masses that are likely ten to twenty times that of the sun.
An X-ray source is also detected in the nucleus of the red galaxy on the left and may be powered by a poorly-fed supermassive black hole. This source is not obvious in the composite image but can easily be seen in the X-ray image. Other objects unrelated to Arp 147 are also visible: a foreground star in the lower left of the image and a background quasar as the pink source above and to the left of the red galaxy.
Infrared observations with NASA's Spitzer Space Telescope and ultraviolet observations with NASA's Galaxy Evolution Explorer (GALEX) have allowed estimates of the rate of star formation in the ring. These estimates, combined with the use of models for the evolution of binary stars have allowed the authors to conclude that the most intense star formation may have ended some 15 million years ago, in Earth's time frame. These results were published in the October 1st, 2010 issue of The Astrophysical Journal. The authors were Saul Rappaport and Alan Levine from the Massachusetts Institute of Technology, David Pooley from Eureka Scientific and Benjamin Steinhorn, also from MIT.
Image Credit: X-ray: NASA/CXC/MIT/S .Rappaport et al., Optical: NASA/STScI
Full-Size Image | 3,000 x 2,400 pixels @ 24 bits per pixel | 493 KB
http://www.nasa.gov/images/content/516472main_arp147_full.jpg
The Glare of the Sun
This view of Antares, the Apollo 14 Lunar Module as it sat on the moon's Fra Mauro Highlands, reflects a circular flare caused by the brilliant sun. The unusual ball of light was said by the astronauts to have a jewel-like appearance. At extreme left, the lower slope of Cone Crater can be seen.
Image Credit: NASA
Full-Size Image | 3,000 x 3,000 pixels @ 24 bits per pixel | 1.2 MB
http://www.nasa.gov/images/content/513609main_GPN-2000-001144_full.jpg
Opportunity's Empty Nest
This image taken by the panoramic camera aboard the Mars Exploration Rover Opportunity shows the rover's empty lander, the Challenger Memorial Station, at Meridiani Planum, Mars. The image was acquired on the rover's 24 sol, or Martian day. Time. This mosaic image consists of 12 color images acquired with the camera's red, green and blue filters. The color balance has been set to approximate the colors that a human eye would see. Opportunity is celebrating its seventh anniversary on the Red Planet, having landed on Jan. 25, 2004, Universal Time (Jan. 24, Pacific Time), for what was to be a 90-day mission.
Image Credit: NASA/JPL/Cornell
Full-Size Image | 4,367 x 2,997 pixels @ 24 bits per pixel | 724 KB
http://www.nasa.gov/images/content/511920main_PIA05460_full.jpg
Blue on Mars
This image shows part of the floor of Rabe Crater, a large impact crater in Mars' southern highlands.
Dark dunes--accumulations of wind blown sand--cover part of crater's floor, and contrast with the surrounding bright-colored outcrops. The extreme close-up view reveals a thumbprint-like texture of smaller ridges and troughs covering the surfaces of the larger dunes. These smaller ripples are also formed and shaped by blowing wind in the thin atmosphere of Mars.
One puzzling question is why the dunes are dark compared with the relative bright layered material contained within the crater. The probable answer is that the source of the dark sand is not local to this crater; rather, this topographic depression has acted as a sand trap.
This image was originally released Oct. 24, 2007.
Image Credit: NASA/JPL-Caltech/University of Arizona
Full-Size Image | 2,560 x 1,920 pixels @ 24 bits per pixel | 541 KB
http://www.nasa.gov/images/content/517510main_PIA13728_full.jpg
Maiden Voyage
Astronauts Story Musgrave, left, and Don Peterson float in the cargo bay of the Earth-orbiting space shuttle Challenger during their April 7, 1983, spacewalk on the STS-6 mission. Their "floating" is restricted via tethers to safety slide wires. Thanks to the tether and slide wire combination, Peterson is able to translate, or move, along the port side hand rails.
First called STA-099, Challenger was built to serve as a test vehicle for the Space Shuttle program. Challenger, the second orbiter to join NASA's Space Shuttle fleet, arrived at Kennedy Space Center in Florida in July 1982.
Challenger launched on her maiden voyage, STS-6, on April 4, 1983 and saw the first spacewalk of the shuttle program, as well as the deployment of the first satellite--the Tracking and Data Relay System. The orbiter launched the first American woman, Sally Ride, into space on mission STS-7 and was the first to carry two U.S. female astronauts on mission STS-41-G.
The first orbiter to launch and land at night on mission STS-8, Challenger also made the first Space Shuttle landing at Kennedy Space Center, concluding mission STS 41-B. Spacelabs 2 and 3 flew aboard the ship on missions STS 51-F and STS 51-B, as did the first German-dedicated Spacelab on STS 61-A. A host of scientific experiments and satellite deployments were performed during Challenger's missions.
Challenger's service to America's space program ended in tragedy on Jan. 28, 1986. Just 73 seconds into mission STS-51L, a booster failure caused an explosion that resulted in the loss of seven astronauts, as well as the vehicle.
Image Credit: NASA
Full-Size Image | 4,095 x 2,755 pixels @ 24 bits per pixel | 1.3 MB
http://www.nasa.gov/images/content/512432main_maiden_voyage_full.jpg
جواب بصورت نقل قول
نوشته شده توسط shabe.saket
.gif "N Aggressive (14)")
.gif "N Aggressive (26)")
محتوای مخفی: p.s. :p 
