Our solar system had enlarged considerably, when in 1781 the planet Uranus was discovered by William Herschel (Hannover 15.11.1738 - Slough 25.08.1822). Although the planet is visible even with the naked eye it had to be discovered as a planet because it had been taken to be a star in the constellation of Taurus since the antiquary. John Flamsteed had even given it the name “34 Tauri”. When Herschel discovered it on 13.03.1781 he first took it for a new comet. But few days later it turned out that the dimensions of our solar system had doubled.

But in the path of Uranus there appeared soime distubances. One reason for that could be another planet behind Uranus. In 1845 the planet, Neptune was found by John Couch Adams (Lane east 05.06.1819 - Cambridge 20.01.1892). Although his calculations were very exact, no none believed him at first. Indepenat from Adams the french astronom Urbain Jean Joseph Leverrier (11.03.1811 - Paris 23.09.1872) calculated the position of the planet in 1846. On 23.09.1848 the planet waw finally sighted with the telescope of Johann Gottfried Galle (Grävenhainichen 09.06.1812 - Potsdam 19.07.1910) and his assistant  Heinrich d’Arrest.

The existance of Neptune was presumed only on the base of disturbances in the path of Uranus and calculated with the aid of Newton’s law of gravity.

Only a few years later astronomes assumed on the basis of disturbances in the path of Mercury that there might be a planet between the Sun and Mercury. A french doctor named Lescarbault even claimed to have seen it. Leverrier gave this phantome planet the name Vulcan. Much later it turned out that these disturbances in the path of Mercury were caused by the strong suction of the sun. This was also proven through Newtons law of gravity and Albert Einstenin’s(Ulm 14.03.1879 - Pricetown 18.04.1955) theory of relativity, which he had written in 1915.

The existance of the last planet in our solar system was already supposed many years before hisdiscovery by Percival Lowell ) Boston 13.03.1855 - 12-11.1916) who described his position somewhat exactly na who even recorded it on one of his photo plates in his observatory on 19.03.1915 and on 07.04.1915 without that anybody would have realized it. Clyde Tombaught discovered the planet finally on 18.02.1930 and called it Pluto. In the last 2 1/2 centuries 3 new planets were discovered in our solar system. The known part of our solar system has been magnifoldly enlargened with that. Now Scientists are wondering wether there are any othe solar systems where there has developed live on another planet that orbits a distant sun.