Space Telescope Finds Farthest Galaxies Yet  

Astronomers using the Hubble Space Telescope (HST) unveiled the deepest look into the universe yet, a portrait of what could be the most distant galaxies ever seen. Too bad it won't be around for much longer, as NASA plans to let the orbiting marvel degrade into a flying piece of junk. The new image, called the Hubble Ultra Deep Field (HUDF), includes objects that until now have been too faint to be seen and includes ancient galaxies that emerged just 700 million years after the Big Bang from what astronomers call the "dark ages" of the universe.

"This image is the deepest view in the visible that we've ever taken, where an object about as bright as a firefly on the Moon would be visible," said Massimo Stiavelli, of the Space Telescope Science Institute (STScI) in Baltimore and the UHDF project leader.

Stiavelli said the new image is six times more sensitive than previous deep sky surveys and four times better than even Hubble's last faraway looks, the Hubble Deep Fields (HDFs), taken in 1995 and 1998.

The HUDF field contains an estimated 10,000 galaxies in a patch of sky in the constellation Fornax, a region just below the constellation Orion, that appears in an area of the sky that appears largely empty if observed by ground-based instruments. The image is about one-tenth the diameter of the full moon and took Hubble one million seconds to take. To cover the entire sky with such detail would take the HST one million years, astronomers said. The HUDF is the result of two separate exposures, one taken by Hubble's Advanced Camera for Surveys (ACS) and the other by the Near Infrared Camera and Multi-object Spectrometer (NICMOS). Astronomers can tell how old a galaxy is by measuring the light it emits, specifically the amount of light that has been shifted toward the red end of the spectrum. The higher red shift a galaxy has, the more distant it is and the earlier it existed in the universe.

Astronomers are eager to see the Hubble receive a stay of execution in the form of future servicing missions by NASA's space shuttles to extend the telescope's lifetime. Adam Riess, a supernova researcher for STScI, said an extension could help astronomers find supernova early in the universe's lifetime. However, NASA Administrator Shawn O'Keefe claims the shuttle fleet will not be able to participate in HST servicing missions, now that the panel investigating the 2003 Columbia crash has placed new, stringent operating restrictions on the orbiter program.
 
"There are no supernovae in this deep field, but the results show that supernova in the early universe could be found if Hubble could be extended," Riess said. "Those could provide valuable insight into dark energy and fate of the universe."

FMI: www.nasa.gov