Editing Hubble Ultra-Deep Field (section)

== Hubble eXtreme Deep Field ==
[[File:Hubble Extreme Deep Field (full resolution).png|thumb|300px|Hubble eXtreme Deep Field (HXDF) taken in 2012]]

The Hubble eXtreme Deep Field (HXDF), released on September 25, 2012, is an image of a portion of space in the center of the Hubble Ultra Deep Field image. Representing a total of two million seconds (about 23 days) of exposure time collected over 10 years, the image covers an area of 2.3 arcminutes by 2 arcminutes,<ref>{{cite web |url=http://hubblesite.org/newscenter/archive/releases/2012/37/fastfacts/ |title=Hubble Goes to the eXtreme to Assemble Farthest Ever View of the Universe |date=September 25, 2012 |access-date=February 26, 2014 |url-status=dead |archive-url=https://web.archive.org/web/20131006025409/http://hubblesite.org/newscenter/archive/releases/2012/37/fastfacts/ |archive-date=October 6, 2013}}</ref> or about 80% of the area of the HUDF. This represents about one thirty-two millionth of the sky.

The HXDF contains about 5,500 galaxies, the oldest of which are seen as they were 13.2 billion years ago. The faintest galaxies are one ten-billionth the brightness of what the human eye can see. The red galaxies in the image are the remnants of galaxies after major collisions during their elderly years. Many of the smaller galaxies in the image are very young galaxies that eventually developed into major galaxies, similar to the Milky Way and other galaxies in our galactic neighborhood.<ref name=xdf />

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XDF-scale.jpg|XDF size compared with the size of the [[Moon]]
XDF-separated.jpg|HXDF image shows mature galaxies in the foreground plane, nearly mature galaxies from 5 to 9 billion years ago, and [[Protogalaxy|protogalaxies]] beyond 9 billion years.
Hubble Goes to the eXtreme to Assemble Farthest Ever View of the Universe.ogv|Video (02:42) about how the Hubble eXtreme Deep Field image was made.
</gallery>