Interstellar Comets Like Borisov May Not Be All That Rare

In 2019, astronomers spotted something incredible in our backyard: a rogue comet from another star system. Named Borisov, the icy snowball traveled 110,000 miles per hour and marked the first and only interstellar comet ever detected by humans. 

But what if these interstellar visitors—comets, meteors, asteroids and other...