Astronomers said Wednesday that they had found a miniature version of our own solar system 5,000 light-years across the galaxy — the first planetary system that really looks like our own, with outer giant planets and room for smaller inner planets. “It looks like a scale model of our solar system,” said Scott Gaudi, an assistant professor of astronomy at Ohio State University. Dr. Gaudi led an international team of 69 professional and amateur astronomers who announced the discovery in a news conference with reporters. Their results are being published Friday in the journal Science. The discovery, they said, means...