NewScientist reports that “NASA’s FERMI satellite has confirmed a previous hint that there is more antimatter than expected coming from space. The bad news is that the result strongly almost certainly rules out Dark Matter as the source.”
In 2008 an excess of antimatter positrons was detected by the Russian-European PAMELA satellite. The new FERMI observations doubled the energy of positrons (up to 200 GigaElectronVolts – GeV) that could be detected. Unfortunately for the Dark Matter conjecture, extra positrons were found at these higher masses/energies.
Big Bang’s “missing mass” needs Dark Matter – which has never been detected – only theorized. To detect Dark Matter (which allegedly doesn’t interact with anything, except that it should invoke gravity to get galaxy rotation working and might have some weak force) anti-matter needs to disappear at a specific energy-mass level to indicate that Dark Matter exists at that energy-mass.
The disappearance of anti-matter at a specific energy-mass would mean that Dark Matter is combining with anti-matter at that energy-mass and both evaporated / were converted to energy.
An Italian experiment called DAMA suggests that Dark Matter particles may exist at 100 GeV. However some researchers believe these newer results eclipse the DAMA results.
While this does not necessarily mean that dark matter does not exist, it does mean anti-matter seen by the PAMELA experiment was not the elusive missing Dark Matter.
Unfortunately for all Dark Matter conjectures, researchers Gallo and Feng showed in 2008 that galaxy rotation curves are just fine; that they are perfectly understandable using Newtonian mechanics without resorting to speculative and exotic Dark Matter ideas.
Measurement of separate cosmic-ray electron and positron spectra with the Fermi Large Area Telescope, Fermi LAT Collaboration, 2011