I thought a little about gravity today as I was walking down the halls of my college building. Really, when you think about it, we're all spinning, and what we think is right side up and upside down actually changes, but we can't tell. Just thinking about it felt a little disorienting, but a pretty cool though, nonetheless. It's like lying on your back in the tall grass at night and staring at the stars. The stars look like they move accross the sky with time, but actually Earth is moving! We're flying around the sun at 18 and a half miles per second (that's 64800 miles and hour!) and spinning at about 1000 miles an hour. If the Earth were to stop spinning suddenly, the atmosphere would still be zipping along nicely at around 1,000 miles an hour. As a result, everything not attached to bedrock would pretty much be scoured clean. Makes you a little dizzy, huh? :)