We don't actually see the flying saucer stop whirring, at least not yet. It kind of lands and keeps spinning and making noise for a while.
The bar patrons stop to have a debate on whether the flying saucer is a spaceship or not; I would say "yes", but the astronomer is unwilling to jump to conclusions. While I disagree, I rather wish the US Congress displayed his level of skepticism the next time a blogger tells them about a UFO.