How do black holes “consume” light?
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We think of gravity as a force that pulls things together. This is accurate for all our calculations, and it’s easy to conceptualize. However, it’s not how it actually works. If it was, there would be a way to “block” gravity by putting something in between you and the source of gravity. There is no way to “block” gravity.
A better way to think of it is think of spacetime as the largest superfreeway conjunction in the world. Everything is moving all the time. Nothing is every stationary because every is moving relative to something else. The paths themselves are changed by gravity. A seemingly straight line curves. We see the distance between two points as straight because light is coming to us and telling us it is straight, but light is going very, very, very fast. If you go slower, you take a different path that veers towards the center of the greater mass you are closest to. This is easy to prove. Throw a ball at an object that is a mile away. Why didn’t you hit the object? Well because the ball took a curved path and crashed into the ground. That’s the difference spacetime exerts on a path relative to the speed of the object relative to the center of mass.
If you launched a projectile fast enough, it would find a path to escape earth, but every slower path would simply crash on earth. This speed is known as “escape velocity”. Essentially, you have to be going a minimum speed to find a path that will eventually lead away from the center of mass.
Now, as the mass increases and the diameter of the mass decreases, the escape velocity from the surface keeps increasing until… you guessed it, it reaches the speed of light. At this speed, there is no speed below the speed of light where you will be able to leave the center of mass. When the escape velocity exceeds the speed of light, light can’t escape. Hence, it’s a “black” hole.
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