Explorations an Introduction to Astronomy Thomas T. Arny Instructor Resources Chapter Images Chapter 14, Figure 12 Figure 14.12 Objects on a waterbed make depressions analogous to the curvature of space created by a mass. According to the general theory of relativity, that curvature produces the effect of gravity. We can see the similarity by placing a marble at the edge of the depression and watching it roll inward, as if attracted to the body that makes the depression.
Bigger bodies make bigger depressions, and so a marble rolls in faster.
However, a very big body may tear the waterbed, creating an analog of a black hole. The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use and Privacy Policy .