Independent analyses of data from the Fermi Gamma-ray Space Telescope have found no trace of low-mass dark matter – the mysterious substance thought to make up much of the universe. The results appear to go against recent direct evidence for low-mass dark matter, although some physicists believe there is no conflict.
Dark matter is an invisible substance thought to make up nearly a quarter of the mass/energy of the universe. While its gravitational pull is needed to explain the properties of massive structures such as galaxies, it does not interact strongly with light and has therefore yet to be observed directly. The most popular candidates for dark matter are so-called weakly interacting massive particles (WIMPs). To spot these WIMPs directly, researchers have built detectors in underground labs where the low background noise ought to allow any signals to stand out. These detector experiments include DAMA and CRESST, both based underground at the Gran Sasso laboratory in central Italy, and CoGeNT, based in the Soudan mine in the US.