Point of no return

One of the main features of black holes is the event horizon, a region of space-time beyond which nothing can escape, not even light. If you throw anything into a black hole, it's lost forever — to an extent. Stephen Hawking discovered that, thanks to a phenomenon known as quantum tunneling, black holes could actually produce a tiny bit of radiation, which would come to be known as Hawking radiation. Over a long time, black holes could even evaporate away due to this radiation.
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Black Holes Could Actually Be Colliding Wormholes