The Universe within 15 billion Light Years
The Visible Universe
 Number of superclusters in the visible universe = 270 000 |
| Number of galaxy groups in the visible universe = 500 million |
| Number of large galaxies in the visible universe = 10 billion |
| Number of dwarf galaxies in the visible universe = 100 billion |
| Number of stars in the visible universe = 2000 billion billion |
About the Map
This map attempts to show the entire visible Universe. The
galaxies in the universe tend to collect into vast sheets and superclusters of
galaxies surrounding large voids giving the universe a cellular appearance. Because
light in the universe only travels at a fixed speed we see objects at the edge of
the universe when it was very young up to 15 billion years ago.
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| Additional Maps |
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The universe has been partially mapped out to about 2 billion light years.
Here is a map showing many of the major superclusters within 2 billion light
years.
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| Data and Catalogs |
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This page is a brief explanation of the Big Bang and it explains how the
universe is expanding and why there is no centre or edge of the expanding
universe.
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The Size of the Universe
The visible universe appears to have a radius of 15 billion light years simply
because the universe is about 15 billion years old. The light from more distant
objects simply has not had time to reach us. For this reason everybody in the
universe will find themselves at the middle of their own visible universe. The
precise scale of the universe is complicated by the fact that the universe is
expanding. Galaxies we see near the edge of the visible universe emitted their
light when they were much closer to us, and they will now be much further away.
The true size of the universe is probably much larger than the visible universe.
The geometry of the universe suggests that it has an infinite size and that it will
expand forever. The visible universe must be a minute speck in a far larger
totality.
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The Hubble Deep Field
In December 1995 the Hubble Space Telescope was pointed at a blank area of the
sky in Ursa Major for ten days. It produced one of the most famous astronomy
pictures of modern times -
the Hubble Deep Field
Image. A part of it is shown here. Almost every object in this image is a galaxy
typically lying 5 to 10 billion light years away. The galaxies revealed here are all
shapes and colours, some are young and blue, whereas others are old, red and dusty.
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A Slice of the Universe
By collecting distances to thousands of galaxies in a narrow strip of the sky,
it is possible to produce a 'slice' of the universe, like this one shown below
from the 2dF Galaxy Redshift Survey
which looks out into the universe to 3.5 billion light years, although not much data
was collected for galaxies beyond 3 billion light years. These types of plots show
how clustered the galaxies in the universe really are, even on the largest scales.
About 50 000 galaxies are plotted.
