Just like photographers assembling a portfolio of the best photos they have captured, astronomers have also assembled a new photo of the farthest-ever view of the universe with the help of 10 years of photographs taken by NASA’s Hubble Space Telescope.
The photo, called the eXtreme Deep Field (XDF), was assembled by combining photographs of a patch of sky at the center of the original Hubble Ultra Deep Field. The XDF is a small fraction of the angular diameter of the full moon.
According to NASA, the Hubble Ultra Deep Field is an image of a small area of space in the constellation Fornax, which was created using Hubble Space Telescope data from 2003 and 2004. It revealed thousands of galaxies, both nearby and very distant, by collecting faint light over many hours of observation. Thus, it became the deepest image of the universe ever taken at that time.
The new XDF image is claimed to be even more sensitive with about 5,500 galaxies within its smaller field of view.
"The XDF is the deepest image of the sky ever obtained and reveals the faintest and most distant galaxies ever seen,” said Garth Illingworth of the University of California at Santa Cruz, principal investigator of the Hubble Ultra Deep Field 2009 program. “XDF allows us to explore further back in time than ever before.”
The XDF reveals galaxies that span back 13.2 billion years in time while the universe is itself 13.7 billion years old.
“Most of the galaxies in the XDF are seen when they were young, small, and growing, often violently as they collided and merged together,” read a NASA statement.
“The early universe was a time of dramatic birth for galaxies containing brilliant blue stars extraordinarily brighter than our sun. The light from those past events is just arriving at Earth now, and so the XDF is a ‘time tunnel into the distant past’. The youngest galaxy found in the XDF existed just 450 million years after the universe's birth in the big bang.”
Launched in 1990, Hubble gave astronomers their first view of the actual forms and shapes of galaxies when they were young. This provided convincing and direct visual evidence that the universe is truly changing as it ages.
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency.
Photo caption: This image from 2009 shows an updated version of the Hubble Ultra Deep Field. The new eXtreme Deep Field could be considered a more detailed view of a portion of this image. Credit: NASA
Photo caption: This illustration compares the angular size of the XDF field to the angular size of the full moon. A finger held at arm's length would appear to be about twice the width of the moon in this image. Note that this illustration does not show the actual observation of the XDF relative to the location of the moon. Credit: NASA