Two of the biggest mysteries in physics are: where is all the dark matter that scientists know is in the universe but can't see??and are there extra dimensions beyond the 3 we can see? A team of scientists now think these mysteries may be connected. "For the most part, these two questions have been treated separately in the past, and for the first time we're making a direct link," says Konstantin Matchev. "We're suggesting that the dark matter may be due to extra dimensions."
This could lead to the first concrete evidence of dark matter, which may make up 30% of the universe. Evidence of its existence comes from the difference between the rate galaxies rotate and the number of stars within them. There aren't enough stars or planets to account for the speed, meaning dark matter must also be present, but no one knows what it's made of or where it is.
We can see 3 dimensions, and time is thought of as the 4th dimension. However, scientists know there are at least 10 dimensions, even if we can't imagine what they could be. These additional dimensions might be curled up into a ball even smaller than atoms, which may be where all that dark matter is hiding. "This phenomenon of extra dimensions provides a completely new dark-matter candidate," Matchev says. "We named it Kaluza-Klein dark matter, after the two physicists who first proposed theories with extra dimensions in the early 1920s."
An experiment at the South Pole could provide the solution. Known as the Antarctic Muon Neutrino Detector Array (AMANDA), it can detect particles with no electrical charge and no mass, such as high-energy neutrinos, which would be created when dark-matter particles collide with each other. The detection of these neutrinos would provide evidence of dark matter. Matchev says, "Most of the stuff produced by dark-matter particle collisions is probably absorbed in the dense cores of the sun or the Earth, but the neutrinos, being so weakly interacting, escape and may reach our detectors."
A future antimatter detector, the Alpha Magnetic Spectrometer, which will be taken aborard the International Space Station in 2005, will detect positrons, which are also created when the dark-matter particles collide. "If we see more positrons than we expect, then we know there is something going on," Matchev says. "What is more, the positron signal is rather unique for Kaluza-Klein dark matter and may thus provide the first evidence of extra dimensions."
Could this be where ET is hiding?
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