Prior to and during this past weekend's World Series games in Denver, there was a lot of sportscaster banter about how pitches fly differently at Denver's higher altitude. Breaking balls don't break quite the same way. Curveballs curve a little differently.

Normally, sportscasters are the last people in the world you'd want to listen to anytime a bit of science figures in, but in this case, according to physicist and baseball fan Alan Nathan, they were right.

Check out his detailed explanations of the physics of baseball here.—Gregory Mone

When PopSci published Will Snyder's article on terraforming Mars, we opined that the Mars Society's colonial flag could use some sprucing up, so we asked readers to submit their own designs. The week the article appeared, 42 Martian-flag mockups turned up in our inbox. Some featured elaborate designs and detailed explanations (which we've printed in their entirety in the slideshow), while others simply included a name. A couple flags were even sent anonymously.