The Farthest Visible Reaches of Space

About the Image

Close Up view of a galaxy which may be over 12 billion light years
away. The image is a NASA Hubble Space Telescope view of the faintest galaxies seen in the Universe, taken in infrared light with the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). To the left is a close-up view of an object which may be over 12 billion light years away.

The NICMOS image contains over 300 galaxies having spiral, elliptical and irregular shapes. Though most of these galaxies were first seen in 1995 when Hubble took a visible-light deep exposure of the same field, the infrared instrument NICMOS uncovered many new objects. Most of these objects are too small and faint to be apparent in the full field NICMOS view.

The field of view is 2 million light-years across, at its maximum, yet, on a cosmic scale, it represents only a thin pencil beam look across the Universe. The area of sky covered is merely 1/100th the apparent diameter of the full moon.

The right side of the image shows two close-up NICMOS views of candidate objects which may be over 12 billion light-years away. Each candidate is centered in the frame. The reddish color may mean all of the starlight has been stretched to infrared wavelengths by the Universe's expansion. Alternative explanations are that the objects are closer to us, but the light has been reddened by dust scattering. A new generation of telescopes will be needed to make follow-up observations capable of establishing true distance.

The image was taken in January 1998 and required an exposure time of 36 hours to detect objects down to a very faint 30th magnitude. Hubble was aimed in the direction of the constellation Ursa Major, in a region just above the handle of the Big Dipper. The colors used to make the image correspond to different wavelengths of light - blue, green, and red.


Distance Information

Some of the reddest and faintest of the newly detected objects may be over 12 billion light years (or 4000 Megaparsecs) away, as derived from a standard model of the Universe. However, a powerful new generation of telescopes will be needed to confirm the suspected distances of these objects. When 12 billion light years is translated into kilometers, there are a staggering number of zeros - it comes out to 113,520,000,000,000,000,000,000 km.

As time progresses, so will our ability to see futher and further away - giving us insight on the very beginnings of the Universe's existence!


How do We Calculate Distances of This Magnitude?

At these distances, objects' redshifts are used, with Hubble's Law, to determine the distance away.

Hubble's Law can be used to find distances of astronomical objects out to the limits of the observable Universe. For more information on Hubble's Law, please read the section on finding distances to the Nearest Superclusters.


Why Are These Distances Important To Astronomers?

Chandra Deep Field When we observe an object 12 billion light years away, we are observing the universe of 12 billion years ago. In a way, we are looking at the record of universe when it was much younger, when we observe these most distant objects. What did the universe look like back then? Can we catch a glimpse of the galaxies as they were just forming? This NICMOS image, and other similar images of the distant universe have given us important insights into the young universe. Another recent example is the deep Chandra image shown to the left, which shows that giant black holes were much more active back then!


Travel Time

At the rate of 17.3 km/sec (the rate Voyager is traveling away from the Sun), it would take 208,800,000,000,000 years to reach this distance. At the speed of light, it would take 12 billion years!


The NICMOS image and the text, the majority of which was from the press release, was created with support to Space Telescope Science Institute, operated by the Association of Universities for Research in Astronomy, Inc., from NASA contract NAS5-26555 and is reproduced with permission from AURA/STScI.

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The Cosmic Distance Scale was created by Maggie Masetti. Scientific Oversight was provided by Dr. Koji Mukai.

This file was last modified on Wednesday, 10-Dec-2003 15:23:52 EST