July 11 (UPI) -- Scientists believe an interstellar comet discovered earlier this month could be one of the oldest that astronomers have ever encountered. University of Oxford scientists said the 3I/ATLAS comet could be some 3 billion years older than our solar system, which is believed to be 4.5 billion years old. The comet was first reported by NASA's Asteroid Terrestrial-impact Last Alert System or ATLAS survey telescope in Chile on July 1, while so-called "pre-discovery" observations date