Galaxies, galaxies everywhere - as far as
NASA's Hubble Space Telescope can see. This
view of nearly 10,000 galaxies is the deepest
visible-light image of the cosmos. Called the
Hubble Ultra Deep Field, this galaxy-studded
view represents a "deep" core sample of the
universe, cutting across billions of
light-years.
The snapshot includes galaxies of various
ages, sizes, shapes, and colors. The smallest,
reddest galaxies, about 100, may be among the
most distant known, existing when the universe
was just 800 million years old. The nearest
galaxies - the larger, brighter, well-defined
spirals and ellipticals - thrived about 1
billion years ago, when the cosmos was 13
billion years old.
In vibrant contrast to the rich harvest of
classic spiral and elliptical galaxies, there
is a zoo of oddball galaxies littering the
field. Some look like toothpicks; others like
links on a bracelet. A few appear to be
interacting. These oddball galaxies chronicle
a period when the universe was younger and
more chaotic. Order and structure were just
beginning to emerge.
The Ultra Deep Field observations, taken by
the Advanced Camera for Surveys, represent a
narrow, deep view of the cosmos. Peering into
the Ultra Deep Field is like looking through
an eight-foot-long soda straw.
In ground-based photographs, the patch of sky
in which the galaxies reside (just one-tenth
the diameter of the full Moon) is largely
empty. Located in the constellation Fornax,
the region is so empty that only a handful of
stars within the Milky Way galaxy can be seen
in the image.
In this image, blue and green correspond to
colors that can be seen by the human eye, such
as hot, young, blue stars and the glow of
Sun-like stars in the disks of galaxies. Red
represents near-infrared light, which is
invisible to the human eye, such as the red
glow of dust-enshrouded galaxies.
The image required 800 exposures taken over
the course of 400 Hubble orbits around Earth.
The total amount of exposure time was 11.3
days, taken between Sept. 24, 2003 and Jan.
16, 2004.
|