Mercury,
March/April 2003 Table of Contents
by
Matthew Colless
The
2dF Galaxy Redshift Survey has given us a 3-D map of the local universe,
which is helping to usher in an era of precision cosmology.
Maps
tell us where we are and how to get to where we are going. But maps
can also provide vivid insights into fundamental truths about the
world we live in. A globe of Earth, for example, is the clearest
illustration of the bald statement that "the world is round." Such
revelations are not confined to geography: the depths of time are
shockingly revealed by a geological map that peels back the rock
strata, showing that a single location was once a mountain range,
then beneath the sea, and then a mountain range once again.
Maps
have also been fundamental to understanding our place in the universe
beyond Earth. Cosmographies — maps of the universe — are as old
as human civilization, and have gone hand in hand with cosmogonies
describing the creation of the world. Such maps have been at the
heart of scientific revolutions. How to draw the map of the solar
system was the scientific issue at the heart of the Copernican revolution,
fronting the deeper philosophical controversy over the anthropocentric
world-view.
Until
the 20th century, however, all such maps were, at least beyond the
borders of the solar system, entirely speculative. Beyond the planets
— far beyond — were the stars and the nebulae, but their arrangement
and distances were essentially unknown.
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The
2dF Galaxy Redshift Survey compiled these two maps of the
North (left) and South Galactic Poles. The maps show the distribution
of galaxies out to more than a billion light-years. Courtesy
of the 2dFGRS team and Paul Bourke (Swinburne University Centre
for Astrophysics and Supercomputing). |
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