Which of the following can actually escape from inside a black hole's event horizon?

• A. Light ($\mathrm{photons}$)
• B. Nothing, not even $\mathrm{information}$
• C. Gravitational waves
• D. $\mathrm{Neutrinos}$

Answer: (B)

Verified step by step guidance

1. Understand the concept of a black hole's event horizon: it is the boundary beyond which nothing can escape the gravitational pull of the black hole, not even light.
2. Recall that photons (light particles) cannot escape from inside the event horizon because the escape velocity there exceeds the speed of light, which is the universal speed limit.
3. Consider gravitational waves, which are ripples in spacetime caused by massive accelerating objects; these waves are generated outside or near the event horizon but cannot escape from inside it.
4. Neutrinos, like photons, are particles that travel at or near the speed of light, so they also cannot escape once they are inside the event horizon.
5. Conclude that according to current physics understanding, nothing, including information, can escape from inside the event horizon of a black hole.