CMB polarization discovered?
Notice how the journalist manages to convert:
"it's in line with theoretical predictions."
into a much stronger statement:
> verifies the theoretical framework that supports modern cosmological
> theory.
But i guess the DASI people will need to struggle to get as much
media attention as MAP...
i haven't followed the debate on CMB polarization, so i don't
know how seriously a detection can constrain any models. Maybe
Micha� F has done some reading on this...?
pozdrawiam
boud
> ---------- Forwarded message ----------
> Date: Thu, 19 Sep 2002 16:26:58 -0400 (EDT)
> From: David Spergel <dns@...
> To: all(a)astro.Princeton.EDU
> Subject: Fwd: U Chi: Microwave Background Announcement (fwd)
...
>**This material was sent earlier under embargo to reporters and the
>embargo having expired, is now sent to press officers.**
>
>THE FOLLOWING RELEASE WAS RECEIVED FROM THE UNIVERSITY OF CHICAGO,
>IN ILLINOIS, AND IS FORWARDED FOR YOUR INFORMATION. (FORWARDING
>DOES NOT IMPLY ENDORSEMENT BY THE AMERICAN ASTRONOMICAL SOCIETY.)
>Steve Maran, American Astronomical Society
>
>September 19, 2002
>Contact: Steve Koppes
>773-702-8366
>E-mail: s-koppes(a)uchicago.edu
>
>Discovery supports astronomers'
>paradoxical views of the universe
>
>The universe really is as surprising as scientists have come to
>suspect it is, according to a discovery that University of Chicago
>astrophysicists will announce Thursday, Sept. 19, at the COSMO-02
>conference at Adler Planetarium and Astronomy Museum. The discovery,
>which astrophysicists have pursued with increasingly sensitive
>instruments for more than two decades, verifies the theoretical
>framework that supports modern cosmological theory.
>
>Using a radio telescope called the Degree Angular Scale
>Interferometer (DASI) at the National Science Foundation's
>Amundsen-Scott South Pole Station, the Chicago scientists measured
>the minute polarization of the cosmic microwave background, the
>sky-pervading afterglow of the big bang.
>
>Most light is unpolarized, its many individual waves jumbled
>together, each wave flickering up and down in a different plane as it
>speeds toward Earth. Unpolarized light becomes polarized whenever it
>is reflected or scattered. This is the principle behind polarizing
>sunglasses that remove the glare from the hood of a car or the
>surface of a pool. In both cases the sunglasses only permit waves
>that tend to flicker up and down in the same plane to pass.
>
>The polarization of the cosmic microwave background was produced by
>the scattering of cosmic light when it last interacted with matter,
>nearly 14 billion years ago. If no polarization had been found,
>astrophysicists would have to reject all their interpretations of the
>remarkable data they have compiled in recent years, said John
>Carlstrom, the S. Chandrasekhar Distinguished Service Professor in
>Astronomy & Astrophysics at the University of Chicago.
>
>"Instead of stating that we think we really understand the origin and
>evolution of the universe with high confidence, we would be saying
>that we just don't know," said Carlstrom, who will announce the
>discovery. "Polarization is predicted. It's been detected and it's in
>line with theoretical predictions. We're stuck with this preposterous
>universe."
>
>It's a universe in which ordinary matter, the stuff of which humans,
>stars and galaxies are made, accounts for less than five percent of
>the universe's total mass and energy. The vast majority of the
>universe, meanwhile, is made of a mysterious force that astronomers
>call "dark energy." This vague name reflects the fact that scientists
>simply do not know what it is. They only know that it acts in
>opposition to gravity, accelerating the expansion of the universe.
>
>In addition to the dark energy theory, cosmic inflation theory
>improbably proposes that the universe underwent a gigantic growth
>spurt in a fraction of a second just moments after the big bang.
>
>"This beautiful framework of contemporary cosmology has many things
>in it we don't understand, but we believe in the framework," said
>Clem Pryke, Assistant Professor in Astronomy & Astrophysics at the
>University of Chicago and a member of the DASI team. "This new result
>was a crucial test for the framework to pass."
>
>Carlstrom's other collaborators on the polarization discovery were
>John Kovac and Erik Leitch, University of Chicago; and Nils Halverson
>and Bill Holzapfel, University of California, Berkeley.
>
>The discovery follows in the wake of another important DASI finding.
>Last year Carlstrom's team precisely measured temperature differences
>in the cosmic microwave background, further supporting for the cosmic
>inflation theory.
>
>The polarization signal is more than 10 times fainter than the
>temperature differences that DASI detected earlier. DASI's first
>discovery came after it collected data for 92 days from 32 spots in
>the sky. But DASI needed to watch two spots in the sky for more than
>200 days to detect the polarization.
>
>The discovery opens a new era in cosmic microwave background
>experiments, said the Chicago astrophysicists. They predict that
>increasingly sensitive detections of polarization will yield many
>more discoveries. "It's going to triple the amount of information
>that we get from the cosmic microwave background," said Kovac, a
>Ph.D. student in Physics. "It's like going from the picture on a
>black-and-white TV to color."
>
>The polarization is a signpost from when the universe was only
>400,000 years old, when matter and energy were only just beginning to
>separate from one another. "What's unique about polarization is that
>it directly measures the dynamics in the early universe," Carlstrom
>said.
>
>Temperature differences revealed patterns of lumpy matter frozen in
>the early universe, but by measuring polarization, astronomers can
>actually see how the early universe was moving.
>
>In the coming years, astronomers will attempt to use the CMB
>polarization to measure gravity waves, a form of radiation predicted
>by general relativity that corresponds to ripples in the fabric of
>space-time, said Michael Turner, the Bruce and Diana Rauner
>Distinguished Service Professor in Astronomy & Astrophysics at the
>University of Chicago.
>
>"Detection of the polarization opens a new door to exploring the
>earliest moments and answering the deep questions before us," Turner
>said.
> ###
>sk/02-79
>
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