Astronomers using the Hubble Space Telescope have snapped the deepest picture of space yet. The new image, which depicts the so-called Hubble Ultra Deep Field (HUDF), captures about 10,000 galaxies, many of which formed just a few hundred million years after the big bang. The image should help scientists determine how the first stars reheated the cold, dark expanse as the universe emerged from its dark ages.
The latest view is a composite of data collected by two Hubble instruments, the Advanced Camera for Surveys (ACS) and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). Both instruments can detect galaxies much too faint to be seen by ground-based telescopes. (Recent observations by earthbound telescopes of two far-flung galaxies required a phenomenon known as gravitational lensing, which magnifies distant objects.) Between September 24, 2003, and January 16, 2004, Hubble orbited Earth 400 times and scanned a section of sky in the constellation Fornax, collecting a million-second-long exposure. With the new results, "Hubble takes us to within a stone¿s throw of the big bang itself," remarks project leader Massimo Stiavelli of the Space Telescope Science Institute in Baltimore, Md.
So far astronomers have identified about 1,000 of the objects captured in the HUDF. "Included among them are some of the intensely faint and red points of light in the ACS image, prime candidates for distant galaxies," says Sangeeta Malhotra of the Space Telescope Science Institute. "Based on these observations, some of these objects are among the farthest and youngest galaxies ever seen."
NASA recently canceled a scheduled shuttle flight to install new equipment on Hubble, and without maintenance, the telescope will fail in the next few years. With Hubble's fate looking bleak, astronomers will have to wait some time before getting their next detailed glimpse into the early universe: the James Webb Space Telescope, which will study galaxy formation, won't launch until 2011.