The fabric of the universe seems like it's sewn tight, but it's likely that even now, tiny ripples are stretching and compressing space and time. How can we be sure? In this week's "Ask a Physicist," we'll find out.
The other day I was quietly sitting in my office in Philadelphia, and was kind of startled to find the ground shaking underneath me. For an east-coaster, this is seriously messed up. We're just not used to the idea that something as seemingly stable as the earth can decide to suddenly thrash about.