LOS ANGELES,
Sept. 30 (Xinhua)-- Using a microwave probe of U.S. space agency NASA,
scientists said they have evidence that the universe has a shape somewhat akin
to an egg, rather than the expected round.
This would explain some curious anomalies over the
universe's expanse, the scientists reported in the journal Physical Review
Letters.
The researchers reached the conclusion by observing
the universe with the Wilkinson Microwave Anisotropy Probe, which was launched
by NASA in 2001 to measure fluctuations in the cosmic microwave background
radiation.
The measurements of the probe agreed with a
conventional spherical model of the observable universe, said the researchers.
But when the data were measured on the largest scale, for instance taking in the
entire night sky, the radiation was too low.
The Wilkinson Microwave Anisotropy Probe data have
confirmed the anomaly concerning the low quadrupole amplitude compared to the
best-fit Lambda-cold dark matter prediction, the researchers wrote in their
paper.
"We show that by allowing the large-scale spatial
geometry of our universe to be plane symmetric with eccentricity at decouplingor
order 10-2," they added.
"The quadrupole amplitude can be drastically reduced
without affecting higher multipoles of the angular power spectrum of the
temperature anisotropy."
These anomalies may signal "a nontrivial cosmic
topology" that is different from the sphere, indicated the researchers led by
Leonardo Campanelli of the University of Ferrara in Italy.
They found that the radiation discrepancies
disappeared if the universe was shaped like an ellipsoid, with an eccentricity
of about one per cent. Enditem
