While dark matter doesn’t shine or fraternize with known particles, in the right sort of collision these particles could annihilate in a shower of familiar matter and antimatter that would then go out with a puff of gamma rays. A measurement of these offshoots would represent the first evidence of dark matter that wasn’t exclusively gravitational in nature. Yet dark matter wasn’t the only thing that could be generating the excess gamma rays. They could shine from cosmic lighthouses known as millisecond pulsars — magnetically charged neutron stars that make 1000 turns each second. A group of undiscovered pulsars too dim to be picked out individually could be bathing the center of the galaxy in extra gamma rays. Experts express optimism that with these inputs, the current modeling wars could settle down in a matter of years. And now that the gamma ray glow is back on the table, hopes for dark matter look somewhat brighter. “If the galactic center excess is back in the game, potentially we are seeing the first signal of dark matter.”

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