Close Distant Encounter?

This afternoon I heard something I'd never heard before: a very distant but distinct whump-whump at approximately 12:45 p.m. Edwards AFB is a long way away, but I wonder...


UPDATE: Yup, it was the shuttle I heard. In the comments, Barb has been very helpful and informative. And I guess this seals the deal. And now I'm not afraid to say that after the boom I heard a distant car alarm (probably due to the powerful vibrations of the boom even though it wasn't very loud--at least, compared to the jets I usually hear roaring at work, haha!). Very, very cool.