Simplify the following text for a Grade 9 native English-speaking person.
Original: In the search for extrasolar planets Neptune has been used as a metonym : discovered bodies of similar mass are often referred to as `` Neptunes '' , just as astronomers refer to various extra-solar bodies as `` Jupiters '' .
Simplified: Some discovered planets that have similar masses like Neptune are often called as `` Neptunes '' . just as astronomers refer to various extra-solar `` Jupiters . ''