Question 1

True or false: A black hole's event horizon shrinks if you add mass to it.

Accepted Answer

False. Adding mass increases the Schwarzschild radius (the horizon's size). The horizon grows proportionally to the mass.

Question 2

True or false: The event horizon is the same thing as the singularity at the center of a black hole.

Accepted Answer

False. The event horizon is the boundary; the singularity is the infinitely dense point at the center. They are distinct features.

Question 3

True or false: The event horizon is a physical surface you could stand on if your spaceship were strong enough.

Accepted Answer

False. The event horizon is not a solid surface—it's a mathematical boundary in spacetime. Nothing can remain stationary there; you'd be dragged inward.

Question 4

True or false: The supermassive black hole M87* has an event horizon diameter larger than Pluto's orbit.

Accepted Answer

True. M87*'s event horizon radius is about 20 billion km, making its diameter roughly 40 billion km, far exceeding Pluto's orbital diameter of approximately 15 billion km.

Question 5

True or false: The event horizon of a rotating black hole is surrounded by a region called the ergosphere where spacetime itself is dragged along.

Accepted Answer

True. In the ergosphere, frame-dragging forces any object to co-rotate with the black hole, even light. It lies outside the horizon.

Question 6

True or false: At the event horizon, time appears to stop for an outside observer watching something fall in.

Accepted Answer

True. Due to extreme gravitational time dilation, an infalling object appears frozen at the horizon to distant viewers, though it crosses in finite proper time.

Question 7

True or false: According to general relativity, nothing can escape from inside the event horizon of a black hole.

Accepted Answer

True. In Einstein's theory, the event horizon is the boundary beyond which the gravitational pull is so strong that even light cannot exit, making it a region of no return.

Question 8

True or false: If you fell into a black hole, you would be instantly incinerated by intense heat at the event horizon.

Accepted Answer

False. For a large black hole, the horizon is actually cold (near absolute zero). The 'firewall' paradox is theoretical, not confirmed by observation.

Event horizon Trivia Questions