Critical mass
Dark matter, mysterious particles that hold the universe together, makes up 23 percent of the universe’s matter.
‘If we could detect dark matter, it would answer what is it that makes up most of the universe,’ said Richard Schnee, an assistant professor of physics. ‘We don’t know exactly what it is. But if the dark matter weren’t moving slowly through the galaxy, the galaxy wouldn’t be here, and we wouldn’t be here.’
Schnee and two other collaborators, Mark Kos, a postdoctoral researcher in the physics department, and Joseph Kiveni, a physics graduate student, are attempting to detect evidence of dark matter by developing software as part of an international research project, Cryogenic Dark Matter Search. The research by the three Syracuse University physicists will be published in an article on dark matter in Science magazine. The research was also published on its Web site Feb. 11.
The Cryogenic Dark Matter Search is a collaborative project between 85 different universities, including international schools in Switzerland and Canada, Kos said.
There is missing mass in the universe that is not visible, and dark matter is thought to be that missing mass, Kos said. One well-accepted theory is that dark matter is weakly interacting mass particles.
Schnee, Kos and Kiveni are working to find dark matter by developing software that will make the findings of the Cryogenic Dark Matter Search more precise, Kos said.
The software weeds out all the movement of the atoms caused by any particles that aren’t dark matter, such as radioactivity and light rays, Schnee said.
The Cryogenic Dark Matter Search tests to see if dark matter is made up of particles of mass by recording the movement of the atoms of crystals in an underground lab in Minnesota. This facility has the most sensitive dark matter detection in the world, said Schnee, who is the science coordinator for the Cryogenic Dark Matter Search experiment.
‘Hundreds of thousands of particles of dark matter are moving between us right now,’ Schnee said.
A particle of dark matter will very rarely bump into an atom, and the Cryogenic Dark Matter Search is attempting to record those rare collisions, Schnee said.
Waiting for atoms to be hit by subatomic, slow-moving particles takes a long time, Schnee said. So far the project had discovered two potential dark matter particles, he said. The Cryogenic Dark Matter Search has been recording data since 2001.
These slow-moving particles are smaller than atoms and got the name ‘dark matter’ because they do not absorb or reflect light, Schnee said. This means they are invisible to the human eye, no matter how strong the microscope.
Schnee said there is evidence like a cosmological phenomenon that shows there must be something else with mass – dark matter – that is producing a gravitational pull, Schnee said.
Dark matter’s existence is questioned, though, Schnee said. One explanation for the unexplained gravitational pull between planets is simply that scientists have underestimated gravity’s strength, he said.
‘But you can see dark matter through the way the galaxies move,’ Schnee said. ‘There must be something tugging on them to go faster. Something else has to be interacting gravitationally.’
If the Cryogenic Dark Matter Search can prove the existence of dark matter, the discovery can have wide-reaching implications in cosmology and particle physics, Schnee said.
‘Depending on what we found out, the particle might also teach us about the fundamental rules of nature,’ Schnee said. ‘If we are able to detect this particle and also study it, then we could also learn more things about the early universe.’
Published on February 23, 2010 at 12:00 pm
