Feb 28 (NHK) - A team of researchers in Japan says it has found the amount of what is called "dark matter" in the universe to be smaller than what was predicted by Albert Einstein's theory.
Dark matter, which scientists say makes up one-fourth of the universe, cannot be observed directly, as it produces no light. But it has mass and causes gravity, thereby affecting the speed at which the universe expands.
Satoshi Miyazaki, associate professor of the National Astronomical Observatory of Japan, and other researchers used a special camera on the Subaru telescope in Hawaii to conduct a wide-area survey of the distribution of dark matter in the universe.
The area covers 0.4 percent of the universe that can be observed from the Earth.
The researchers found 65 spots where dark matter is believed to be concentrated.
They say the number is about 20 percent smaller than that predicted based on Einstein's theory of general relativity, which is the basis for current cosmological models of an expanding universe.
They say the smaller-than-expected number of spots where dark matter is concentrated points to the possibility that the universe may have been expanding at a faster pace than Einstein's theory indicates, making it more difficult for dark matter to become concentrated.
The team plans to expand its survey area to see if it is necessary to revise the theory.
Miyazaki said he expects the survey to shed light on the force that is causing the universe to expand.
