medieval horn

[pynchonoid]

<http://www.alphagalileo.org/index.cfm?fuseaction=readRelease&Releaseid=17900&ts=e3RzICcyMDA0LTA0LTE1IDE2OjI2OjQ4J30=>

For further information, please contact:
Claire Bowles 
New Scientist 
claire.bowles at rbi.co.uk 
0207 331 2751 

Posted By:
New Scientist


14 April 2004 Is space rolled up like a funnel? 
under embargo until 14 Apr 2004 18:00 GMT

COULD the universe be shaped like a medieval horn? It
may sound like a surrealist's dream, but according to
Frank Steiner at the University of Ulm in Germany,
recent observations hint that the cosmos is stretched
out into a long funnel, with a narrow tube at one end
flaring out into a bell. It would also mean that space
is finite.

Adopting such an apparently outlandish model could
explain two puzzling observations. The first is the
pattern of hot and cold spots in the cosmic microwave
background radiation, which shows what the universe
looked like just 380,000 years after the big bang. It
was charted in detail last year by NASA's Wilkinson
Microwave Anisotropy Probe. WMAP found that the
pattern fades on the largest scales: there are no
clear hot or cold blobs more than about 60 degrees
across.

Steiner and his group claim that a finite, horn-shaped
universe fits this observation
(arxiv.org/astro-ph/0403597). It simply doesn't have
room to hold very big blobs. The present-day volume of
their model universe is nearly 1032 cubic light years.
Back when the universe was only 380,000 years old it
would have been a fraction of that size, too small to
allow big fluctuations.

In the model, technically called a Picard topology,
the universe curves in a strange way. One end is
infinitely long, but so narrow that it has a finite
volume. At the other end, the horn flares out, but not
for ever- if you could fly towards the flared end in a
spaceship, at some point you would find yourself
flying back in on the other side of the horn (see
Diagram). Horn-shaped models were suggested in the
1990s to fit a similar anomaly seen by the COBE
satellite, but Steiner's group is the first to show
that this idea fits the WMAP data. Last year, another
group claimed that the universe might be finite (New
Scientist, 11 October 2003, p 6).

In this group's model, space had a soccer ball-like
shape. But the model has run into trouble. It should
have left a clear signature on the microwave sky- a
set of circles that mirror each other's spot patterns-
but these circles do not seem to be there.

The horn universe is harder to pin down. It would also
make matching circles, but the pattern depends on what
part of the horn we are in. "Our published search for
matching circles probably doesn't rule out the Picard
topology," says Neil Cornish of Montana State
University in Bozeman.

And the idea has another advantage. In the flat space
of conventional cosmology, the smallest blobs on
microwave sky maps ought to be round. But they are
not. "If you look at the small structures, they look
like little ellipses," says Steiner. The curve of the
horn-shaped universe could be just right to explain
this. If you look at any little piece of the horn, it
is saddle-shaped like a Pringles potato chip- curving
down in one direction and up in the perpendicular one.

This "negatively curved" space would act like a warped
lens, distorting the image of round primordial blobs
in a way that makes them look elliptical to us.
Mathematicians can construct an infinite number of
different kinds of negatively curved space, most of
them with one or more horns, and many of which might
fit the data, but the Picard topology is one of the
simplest.

This model would force scientists to abandon the
"cosmological principle", the idea that all parts of
the cosmos are roughly the same. "If one happens to
find oneself a long way up the narrow end of the horn,
things indeed look very strange, with two very small
dimensions," says Holger Then, a member of the team.
At an extreme enough point, you would be able to see
the back of your own head. It would be an interesting
place to explore- but we are probably too far from the
narrow end of the horn to examine it with telescopes.

Both of the crucial observations are still ambiguous,
however, and may be statistical flukes. Over the next
year or so, WMAP and other experiments will test
whether large blobs really are lacking and whether
small ones really are elliptical. If they are, then
our universe is curved like a Pringle, shaped like a
horn, and named after a Star Trek character. You
couldn't make it up.

Written by Stephen Battersby



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