Discovery and exploration of the Solar System Domenico Cassini later discovered four more moons of Saturn and the Cassini division in Saturn's rings. Edmond Halley realised in 1705 that repeated sightings of a comet were recording the same object, returning regularly once every 75–76 years. This was the first evidence that anything other than the planets orbited the Sun. Around this time (1704), the term "Solar System" first appeared in English. In 1781, William Herschel was looking for binary stars in the constellation of Taurus when he observed what he thought was a new comet. Its orbit revealed that it was a new planet, Uranus, the first
Origins Space Telescope interstellar medium to the inner regions of planet-forming disks, from interstellar clouds, to protoplanetary disks, to Earth itself—in order to understand the abundance and availability of water for habitable planets. In the Solar System, it will chart the role of comets in delivering water to the early Earth by tracing their molecular heredity of deuterium/hydrogen ratio. The Origins Space Telescope would perform astrometry and astrophysics in the mid- to far-infrared range by using a filled aperture telescope with an effective diameter likely between 8 m and 15 m. The telescope will require cryocooler systems to actively cool detectors at ∼50