Hubble Deep Fields

The series of images for five different epochs starts from left in a clockwise direction. Following is a brief description for each one.

• The first slice shows the nearest objects in the field - foreground stars in our own galaxy, at a distance ranging up to a few tens of thousands of light years away. In comparison with the sweep of cosmic history, the light-travel time from these stars is just a brief instant.
• The next one shows galaxies from a time when the universe was about 3/4 of its present age. This is essentially what the universe looks like today.
• The third one shows what the universe looked like when it was about 1/2 of its present age. For the most part, galaxies still look very much like they do today. The Sun and Earth formed near the end of this era of cosmic history.
• The fourth picture shows what the universe looked like when it was about 1/4 of its present age. Some of the galaxies look peculiar because they are temporarily distorted by collisions with other galaxies. Others have the familiar spiral and elliptical shapes of mature present day galaxies.
• The last one shows an universe less than 3 billion years old. Many of the galaxies are small, oddly shaped, and immature. This is the era when first stars were born and protogalaxies were formed.

The Hubble Ultra Deep Field (HUDF) has provided the deepest image of the universe ever taken in visible light (see picture on the left). It shows a sampling of the oldest galaxies ever seen, galaxies that formed just after the dark ages, when the universe was about 700 million years old (5 percent of its present age). The field is studded with a wide range of galaxies of various sizes, shapes, and colors. In vibrant contrast to the image's 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 galaxies appear to be interacting. This new view is actually two separate images taken by Hubble's Advanced Camera for Surveys (ACS) and the Near Infrared Camera and Multi-object Spectrometer (NICMOS). They took the image during 3 months (from September

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24, 2003, to January 16, 2004) at the same spot, the HUDF is four times more sensitive, in some colors, than the original Hubble Deep Field (HDF) taken in 1995 and 1998.