It's likely not the first time you'll hear scientists compare an exoplanet to Jupiter. According to a team of astronomers, though, this one called the 51 Eridani b isn't only similar in size -- it's "very much what models suggest Jupiter was like in its infancy." 51 Eri b, which has an atmosphere rich in methane, was spotted using the Gemini Planet Imager's new instrument mounted on the Gemini South Telescope in Chile. The instrument is as big as a small car, was made to filter out atmospheric turbulence and was optimized to spot faint planets next to bright stars. This exoplanet, for instance, is a million times less luminous than its host star, which is only 20 million years old or so; our own sun is already 4.5 billion years old.