They say the average picture is worth a thousand words. If that’s true, then the photo that the Hubble Space Telescope recently delivered is worth a thousand times that. The photo gives humankind a glimpse into the farthest corners of the universe yet.
To take the picture, which is called eXtreme Deep Field, or XDF, Hubble gathered data over the course of ten years. The telescope focused on a tiny patch of sky in the southern constellation Fornax for more than 500 hours. By combining more than 2,000 images of the same field of space it was possible to register all the light emanating from that area. Only by accumulating light over so many observations can we see such distant objects, some of which are ten billion times too faint to be seen by the human eye. The XDF combines the images taken over 10 years of Hubble telescope views of that corner of the universe. As a NASA report on the XDF put it, “The history of galaxies — from soon after the first galaxies were born to the great galaxies of today, like our Milky Way — is laid out in this one remarkable image.”
The resulting picture gives scientists an unprecedented peek into the distant corners of our universe, offering up more detail of the outer limits space than ever before, and giving a greater degree of understanding of the nature and origins of the universe. The photo reveals thousands of galaxies billions of light-years away, stretching back almost to the time when the first stars began to shine. (The BBC has a more technical take, but basically: light from galaxies that far away takes billions of years to reach us, so when we see them we’re really looking back in time.) “The XDF is the deepest image of the sky ever obtained and reveals the faintest and most distant galaxies ever seen,” Garth Illingworth of the University of California at Santa Cruz, principal investigator of the Hubble Ultra Deep Field 2009 program, said in a statement from NASA. “XDF allows us to explore further back in time than ever before.”
The XDF is an update to an image compiled by Hubble in 2003 and 2004 called the “Hubble Ultra Deep Field.” That picture collected enough light to reveal thousands of distant galaxies. At the time, it was the deepest view of the universe. The XDF goes even farther, capturing objects some 13.2 billion light-years away — meaning 13.2 billion years into the past. The universe itself is thought to be about 13.7 billion years old, meaning that the farthest galaxy found in the XDF existed just 450 million years after the big bang — a blink of an eye in cosmological terms.
“It’s a really spectacular image,” Dr Michele Trenti, a team member from the University of Cambridge, told the BBC. “We stared at this patch of sky for about 22 days, and have obtained a very deep view of the distant Universe, and therefore we see how galaxies were looking in its infancy.”
Hubble is a joint project between NASA and the European Space Agency. It was launched in April 1990, and scientists expect it to function through at least 2018, when an even more powerful satellite, the James Webb Space Telescope, is scheduled to launch.