Results of this research by Dr. Richard Lieu, a UAH physics professor, and Dr. Jonathan Mittaz, a UAH research associate, were published Monday in the "Astrophysical Journal."
Proving Einstein right might become a problem for the standard cosmological model of how the universe was formed because Einstein's theory also predicts that the cosmic microwave background shouldn't look the way it does, according to Lieu
The problem, he
says, is that cool spots in the microwave background are too uniform in size to have traveled across almost 14 billion light years from the edges of the universe to Earth.
"Einstein's theory of how gravity attracts light, coupled with the uneven distribution of matter in the near universe, says you should have a spread of sizes around the average, with some of these cool spots noticeably larger and others noticeably smaller," he
The problem, says Lieu
, is that not only is the average about right, but far too many of the spots themselves are "just right" with too little variation in sizes.Given the uneven distribution of matter in an expanding universe, he
says, we should see a broader size distribution among the cool spots by the time that radiation reaches Earth.
The distribution of matter and the expanding universe are important because they have opposite effects on the "shape" of space and the paths taken by light, microwaves and other radiation as they zip through the cosmos.
An expanding universe would tend to "stretch" space, causing radiation to disperse as it flies through.That dispersion would make objects appear to an observer to be smaller than they really are, as if the light went through a concave lens.
"As far as we know," said Lieu
, "the expansion takes place smoothly everywhere.
"But you don't see this fluctuation," said Lieu
If the cool spots are too uniform to have traveled to Earth from near the beginning of time, Lieu
says cosmologists are left with several alternative explanations.
The first is that the cosmological parameters (including the Hubble constant, the amount of dark matter, etc.) used to predict the original, pre-lensed sizes of the cool and hot spots in the microwave background might be wrong.These parameters could be adjusted to predict a narrower range of sizes on either side of the "pre-lensed" average.
Then, after the effect of gravitational lensing is folded in, the resulting average size and size dispersion would agree with what WMAP actually saw, said Lieu
."This approach is the most conservative, but would still result in an overhaul of the standard model."
"Or, could it be that although the radiation itself is from far away, some of these cool spot structures are caused by nearby physical processes and aren't really remnants of the universe's creation?"Lieu
In research published April 10 in the "Astrophysical Journal, Letters," Lieu
and Mittaz found that evidence provided by WMAP point to a slightly "super critical" universe, where there is more matter (and gravity) than what the standard interpretation of the WMAP data says.