Tripping the Light Fantastic
Gravity prevents light from escaping a black hole in the Einsteinian sense, not the Newtonian: The force can't "pull" on light, because light has no mass. Rather, gravity warps space-time back on itself to such a degree that light resembles a hamster in a wheel, running for all it's worth but getting nowhere [source: Royal Greenwich Observatory].
Picture a black hole as a waterfall of space, where space pours past photons just as quickly as they "swim" through it -- that is, at light speed [source: Hamilton].
Black Hole Effects on Space and Time
From a distance, a black hole acts like any massive, gravitational object: Until it's right on top of you, it follows classical mechanics and Newton's law of universal gravitation, which tells us the attraction between two objects is proportional to their masses and drops off rapidly with distance. In other words, there's no gravitational difference between R136a1, a blue dwarf star weighing 265 suns, and a 265-solar-mass black hole [source: Fazekas].
Approach close enough for a black hole to wrap you in its gravitational sleeper hold, however, and you're grappling with a different set of rules: Einstein's general theory of relativity, which predicted black holes, says that gravity also warps space and time, and that extreme gravity does it, like Vanilla Ice, to the extreme.
If you wanted to study a black hole from a starship, you'd find that, the closer you got to the monstrous mass, the more oomph your engines would have to kick out to maintain a circular orbit. At first, firing off the occasional rocket burst would suffice to stabilize you; closer in, and you'd have to expend enormous energy just to maintain an irregular orbit. Closer still, and nonstop rocket burn would be all that stood between you and annihilation.
Once you ran out of fuel (or succumbed to space madness and turned off the engines), you would spiral in to the black hole's event horizon, a boundary beyond which nothing, not even light, can escape. From there, you'd have a date with destiny: Nothing you could do would stop your inexorable journey toward the singularity, a core of infinitely distorted space-time where physics as we know it curls up in a ball and whimpers.
All through your approach, time would have slowed -- a lot. From your point of view, nothing would have changed but, to a friend watching from far away, time around you would flow less like greased lightning and more like sap on a cold February morning. Just outside the event horizon, you would appear to stop. Since light cannot escape the event horizon, that would be the last your friend would see of you.
Gravitational time warps occur universally but are usually too feeble to be noticed. On Earth, for example, you would age one-billionth of a second less each year at sea level than you would atop Mount Everest [source: Harvard-Smithsonian].
Within a black hole, time twists even more. In fact, when we say you can't avoid falling into the singularity, it isn't just because of the intense gravity or space warping: Rather, time within a black hole warps to such a degree that the singularity literally lies in your future. Trying to prevent reaching the singularity would be like attempting to halt time.
Read on to see what would happen if our solar system chanced upon such a flume of force.