What’s the Smallest Known Asteroid? What About the Largest?
Asteroids constantly zoom around our solar system and sometimes smash into planets, including Earth. As such, in the name of planetary defense NASA conducted a test, dubbed DART (Double Asteroid Redirection Test), to deflect a space rock like the one that wiped out the dinosaurs (or the one Bruce Willis blew up at the end of the movie Armageddon). Not all asteroids are planet killers, however. While some are monster-size, others are quite tiny. Meanwhile, the smallest asteroid is a matter of some debate. "There's not an official cutoff," said Yan Fernandez, an astronomer at the University of Central Florida, "so different people have different ideas about what counts as an asteroid."
LiveScience