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What dark matter is

Its gravity shows up in galaxy rotation, gravitational lensing, the cosmic microwave background and the growth of structure, all consistent with the same amount. Direct detection experiments have ruled out much of the favored parameter space for WIMPs without a signal. Axions, sterile neutrinos and primordial black holes remain candidates, and a minority argue for modified gravity instead.

Posed 1933, Fritz Zwicky; 1970s, Vera Rubin's rotation curves.

What would settle it

A direct-detection signal confirmed by independent experiments

Sources

The dark sector · Cosmos

Relations to this page

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