The fun thing, New Scientist seems to be saying, about dark matter right now is that it’s really dark. Like, really, really not a glimmer of light at all:
Yet any hopes that the nature of the stuff would be quickly revealed by these first detections have been utterly dashed. The trouble is that dark matter appears to be different things to different detectors. It appears heavier in one detector than another; it appears more ready to interact in one experiment than another. In the most extreme case, it shows up in one instrument but not in another – even when both are made of identical material and are sitting virtually next door in the same underground lab.
“The present situation is pretty confusing,” admits Juan Collar of the University of Chicago, who is head of the CoGeNT dark matter experiment, based in the Soudan Underground Laboratory in Minnesota. It is seeing something – hundreds of somethings – each of which could be a dark matter particle striking the detector. But if CoGeNT and the other experiments are truly seeing dark matter, then it’s not what anybody thought it was.
The conflicting detections are not the only problem. Observations of dwarf galaxies are prompting a growing number of astronomers to change their minds about what properties they want dark matter to have. The thinking is that WIMPs will not cut it any more.
More problems have come courtesy of the Large Hadron Collider at CERN near Geneva, Switzerland. If our understanding of dark matter is correct, then we should be able to make WIMPs in the LHC’s high-energy collisions. So far none have shown up. WIMPs as we know them could soon be impossible.
“You can tweak all the dials in the theory and see if you can fit the detections, but the bottom line is that it is not really doable,” Feng says