Space rock 10199 Chariklo is no threat to Earth. The small celestial body — about 250 kilometers (155 miles) in diameter — has an orbit around the sun that places it between Saturn and Uranus, meaning that until recently, astronomers had no call to look closely at it. But when Chariklo passed in front of star UCAC4 248-108672 in June last year, astronomers at observatories in South America decided to take a closer look, and found something unexpected: like a miniature version of one of our solar systems gas giants, 10199 Chariklo has a system of rings. Felipe Braga-Ribas, astronomer at Brazils Observatório Nacional, explained his shock.