“Since the speed of gravity is the speed of light, the towers should have collapsed before we saw them collapse. Weeeeeeeeeeeeeeeeeeeeeeeeeeeeeee!”
That would be neat if true, but it is very, very wrong.
The speed of light is 3.0x10^8 m/s in any direction.
The acceleration of gravity is 9.8 m/s^2 toward the ground.
That a very parochial viewpoint... The acceleration of gravity under the event horizon of a black hole is.. who knows?
But it probably isn't 9.8 Meters per second 2 ...
I think the point that the original post was making was that the author of the website was confusing "speed" of gravity with "acceleration" of gravity. Two related but different qualities of motion.
I believe that there are some very smart scientists trying to figure out how to measure the "speed" of gravity (how fast does the effect of the force of gravity propagate?) and others attempting to figure out how to find the "acceleration" of light (if it even has any acceleration!). So far, neither group has had much luck... absent the discovery of gravity waves and a means to create said waves, I doubt we will be able to test for the speed of propagation of gravity.
Uh, acceleration and speed are not the same.
Uh, acceleration and speed are not the same.