system
Given the following post, respond as if you're commenting on Reddit:
human
How exactly do Black Holes die?  If nothing can escape a Black Hole, how can they evaporate?
gpt
The mechanism proposed by Hawking in his original paper follows.

Particles pop into and out of existence all the time.  They "borrow" energy from the vacuum, pop into existence as a particle-antiparticle pair, and then swiftly collide and annihilate.  This is a known fact.

Now comes Hawking's original speculation.  Near a black hole, something funny happens.  There's a distance from the black hole called the event horizon - anything closer than that distance necessarily falls in, while anything further out can escape if it goes fast enough.  When these particle-antiparticle pairs pop into existence near the event horizon, sometimes one will go in and the other will go off into space.  It appears to the outside world that the black hole has emitted a particle.  The energy to create those particles is not "repaid" by annihilation, hence their masses must add up to zero because total energy must be preserved.  But since the particle emitted must have positive mass, we must observe the infalling particle to have negative mass, thus reducing the mass of the black hole.

An alternative conceptualization imagines pair production just INTERIOR to the event horizon.  Particles sometimes do something funny called "tunneling," where they disappear and reappear a short distance away.  It's possible that particle pairs are being produced inside the event horizon, and then one particle is tunneling out.

At the end of the day, it's not exactly known by what mechanism Hawking radiation occurs.  We know that it MUST occur in order for the laws of physics to be consistent, as far as we understand them.  Black holes are perfect black bodies, and that entails black body radiation.  

It should be noted that every black hole we have ever observed emits less Hawking radiation than it absorbs from background sources like the cosmic microwave background.  A black hole would have to weigh as little as a moon for it to be losing mass.