Some of the probes NASA has conducted on near flying asteroids have performed some pretty amazing studies of these eccentric celestial bodies. In 1994 the Galileo probe got within 1000 miles of the asteroid Ida and discovered that Ida actually had its own moon.
Other probes have fired impactors into asteroids and even landed on an asteroid to produce some amazing scientific data for us. There is much to learn about asteroids in our love of astronomy and that knowledge only makes our enjoyment of seeing them in the cosmos even more exciting.