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- A high-flying balloon which soared over Antarctica has
answered one of cosmology's greatest questions by revealing that the universe
is "flat".
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- To astronomers, flat means that the usual rules of geometry
are observed - light travels in straight lines, not curves. But since Albert
Einstein proposed that the universe was "curved", the debate
has been open.
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- "It will mean rewriting the text books on the history
of the universe." - Professor Peter Ade Scientific opinion has moved
towards a flat universe and the latest data confirm this with greater certainty
than ever before.
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- Another result of the study is the prediction that the
universe will eventually stop expanding from the Big Bang, but will not
collapse into a "Big Crunch".
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- "It's a tremendously exciting result - and one that
will mean rewriting the text books on the history of the universe,"
said one of the research team, Professor Peter Ade at Queen Mary College,
University of London.
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- Faint heat
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- The new information is an exquisitely accurate map of
the very faint afterglow of heat left behind by the Big Bang. This is called
the Cosmic Microwave Background and is equivalent to the tiny warmth given
off by something just a few degrees above absolute zero, -273 degC.
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- The detectors were cooled to -273 degrees Celsius
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- Tiny temperature variations in the CMB, just 0.1% at
most, allow scientists to test different models of how the Universe began
and expanded.
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- The map was made by an international team led by Paulo
de Bernardis of the University of Rome La Sapienza. He said: "It's
really exciting to be able to see some of the fundamental structures of
the Universe in their embryonic state.
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- The achievement, he said, was distinguishing the CMB
from other interference: "The light we have detected has travelled
across the entire Universe and we are perfectly able to distinguish it
from the light generated in our own galaxy."
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- Sky high boomerang
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- The project to map the CMB was called Boomerang (Balloon
Observations of Millimetric Extragalactic Radiation and Geophysics).
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- On release, Bomerang soared skywards
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- The measurements were made using a very sensitive telescope
suspended from a balloon 40,000 metres (131,000 feet) above Antarctica.
The instrument flew around the frozen continent between 29 December 1998
and 8 January 1999.
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- It has taken since then to process the one billion measurements.
The calculations alone would have taken six years to complete if run on
a desktop computer. On the Cray T3E supercomputer at the Lawrence Berkeley
National Laboratory, US, they took less than three weeks.
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- The fundamental cosmic parameters derived from the work
are accurate to within just a few percent.
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- The research is published in the journal Nature and in
an accompanying commentary, Wayne Hu, of the US School of Natural Sciences,
New Jersey, said: "The Boomerang result supports a flat Universe.
A perfectly flat Universe will remain at the critical density, because
there is not enough matter to make it recollapse in a 'Big Crunch'."
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