New Avenues Opened in the Search for Dark Matter
Dark matter is a hypothesized type of matter used by cosmologists to explain the presence of effects of mass where no mass can be detected. It cannot be seen with telescopes because it apparently does not emit or absorb light, or any other kind of electromagnetic radiation at observable levels. Astronomers have come to a near consensus that most of the mass in the Universe is composed of dark matter or dark energy.
Until now, the focus in dark matter detection research for the past years has been primarily based on the hypothetical WIMPs, or weakly interacting massive particles. WIMPs solve many of the theoretical problems relating to dark matter, particularly since they don't interact through electromagnetism and therefore cannot be seen. Furthermore, since they do not react with strong nuclear force, they do not interact with atomic particles. As a result, they only interact with other WIMPs.
While researchers are working hard on developing and implementing detection methods to test the possible reactions that these theoretical WIMPs might be (and theoretically should be) having on normal atoms, others, such as those present at the meeting last week, are looking to broaden the avenues of theoretical research possible in the field.
Many researchers feel that the scientific community has been unduly taking the WIMP explanation for dark matter for granted. Lisa Randall of Harvard expressed her relief that last week's conference discussed other possibilities: "For years I went to conferences where people said, 'We know what dark matter is and we're just cutting out the parameter space'. I thought that was strange, because we really don't know what dark matter is."
Other avenues discussed at the conference included alternate types of particles, such as axions or neutrinos, the latter of which are very similar to WIMPs with the exception of their significantly smaller size. The researchers also discussed the even more radical idea that dark matter does not exist at all, a notion that could only be reconciled by adjusting the laws of gravity.
It appears that a dramatic divide may soon form between the WIMP investigators, and those wanting to explore new territories of research. While some are ready to abandon previous research and start from scratch, others believe that given the technological advances towards and the investment in WIMP detection, it is now, more than ever, time to investigate the possibility of the existence of WIMPs.