In the extremely early universe, primordial black holes could acquire a "dark charge," giving them an unnaturally long lifetime. This makes them an interesting, if exotic, candidate for dark matter, new research suggests.
In the 1970s, Stephen Hawking discovered that black holes aren't entirely black. Through a complex interaction between their event horizons and the quantum fields that soak space-time around them, they can slowly but steadily emit radiation. This causes black holes to lose mass, and in fact the smaller they become the more brightly they glow, until they disappear altogether in a shower of particles and radiation.
