|Image of the HUDF includes galaxies of various ages, sizes, shapes, and colors. The smallest, reddest galaxies, of which there are approximately 10,000, are some of the most distant galaxies to have been imaged by an optical telescope, existing at the time shortly after the Big Bang |
Pic by JJ Harrison
The Hubble Ultra-Deep Field (HUDF) is the deepest image of the universe ever taken. The image is of a small region of space in the constellation Fornax, composited from Hubble Space Telescope data accumulated over a period from September 24, 2003, through to January 16, 2004.
Pointed at a single piece of space for several months — a spot covering less than one-tenth of one-millionth of the sky, it is the deepest image of the universe ever taken, looking back approximately 13 billion years (between 400 and 800 million years after the Big Bang), and it will be used to search for galaxies that existed at that time. The HUDF image was taken in a section of the sky with a low density of bright stars in the near-field, allowing much better viewing of dimmer, more distant objects. The image contains an estimated 10,000 galaxies. In August and September 2009, the Hubble's Deep Field was expanded using the infrared channel of the recently attached Wide Field Camera 3 (WFC3). When combined with existing HUDF data, astronomers were able to identify a new list of potentially very distant galaxies.
Located southwest of Orion in the southern-hemisphere constellation Fornax, the image covers 11.0 square arcminutes. This is just one-seventieth the solid angle subtended by the full moon as viewed from Earth, smaller than a 1 mm-by-1 mm square of paper held 1 meter away, and equal to roughly one thirteen-millionth of the total area of the sky. The image is oriented so that the upper left corner points toward north (−46.4°) on the celestial sphere.
Can you just imagine how many galaxies are out there? If that one small picture shows about 10,000 galaxies, can you just imagine the enormity of galaxies out there? Unbelievable. To put things in perspective - you take that 10,000 galaxies from that postage-stamp sized piece of the sky and multiply it by the number of postage-stamp-sized pieces of sky... we are talking hundreds of billions! It's unfathomable!