Question: I know that anything can be sucked in by the gravitational pull of a black hole, but as light has no mass, how is it trapped?

Nick Wright answered on 11 Mar 2014:

Well, light has a sort of mass actually. Have you ever heard of the equation “E = m c squared” ? Einstein wrote that equation and it says that the mass and energy of any particle (including light) are in some ways the same thing. Because light has an energy, it also has some sort of mass, and it’s this mass that gravity pulls on.

We can actually see the power of gravity pulling on light during a solar eclipse because we can see that the stars near the sun all have their light bent a little by the gravity from the sun, and this makes them look like they’re in slightly different positions compared to where they would have been if the sun was not there.