Here's a video, called "gravity visualized," of a high school teacher using a rubber sheet to demonstrate how gravity works:
It addition to the fact that space does NOT curve significantly near earth, other questions about this "explanation" emerge.
Notice that when he puts a marble of the edge of the sheet, it immediately starts moving toward the depressed center where the weight is. But why? Because "space is curved?" Why doesn't it just sit where he places it? Because he is doing this whole experiment in earth's gravitational field, that's why. That's the only reason the rubber sheet is stretched downward to begin with. Like any other object on earth the marble heads "downhill" when it is not on a level plain. Why? Because it is attracted toward the center of the earth, not the center of the rubber sheet. "Spacetime" doesn't seem to be needed at all to explain this.
Edited by Moronium, 06 June 2018 - 02:41 AM.