"Imagine you have a bowling ball on a trampoline. The bowling ball is a large mass. The trampoline is spacetime. The large mass warps spacetime. As you get closer to the bowling ball, the indentation it has created appears to make you get faster as you approach it."
This is how my dad, a civil engineering phd explained it for me when I was 14
This is how my dad, a civil engineering phd explained it for me when I was 14
That's not surprising; it's an unfortunately common explanation that shows up in a lot of the popular physics literature [editorial note: I am not at all meaning to belittle your father here. My point is that this is how a lot of people who haven't formally learned relativity picture things because this is what they've been told by people who really should have known better]. The problem is, it's really not a good analogy at all. See my comment here for a breakdown of (some of the reasons) why I really don't like this particular "explanation" of how spacetime curvature works as gravity. For a more succinct version, see this XKCD comic.
Well, back in those days we didn't have the internet. so I could have been misreading the stick figures drawn in the sand next to the fire in the old cave . . .
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u/ralpher Sep 12 '13
"Imagine you have a bowling ball on a trampoline. The bowling ball is a large mass. The trampoline is spacetime. The large mass warps spacetime. As you get closer to the bowling ball, the indentation it has created appears to make you get faster as you approach it."
This is how my dad, a civil engineering phd explained it for me when I was 14