Discovery and exploration of the Solar System Earth to be orbited by an artificial satellite ("Luna 10"), followed by Mars in 1971 ("Mariner 9"), Venus in 1975 ("Venera 9"), Jupiter in 1995 ("Galileo"), the asteroid 433 Eros in 2000 ("NEAR Shoemaker"), Saturn in 2004 ("Cassini–Huygens"), and Mercury and Vesta in 2011 ("MESSENGER" and "Dawn" respectively). "Dawn" is orbiting the asteroid–dwarf planet Ceres as of 2015. The first probe to land on another Solar System body was the Soviet "Luna 2" probe, which impacted the Moon in 1959. Since then, increasingly distant planets have been reached, with probes landing on or impacting the surfaces of Venus in 1966
Planet Nine the disk had a distant inner edge, 100–200 AU, a planet encountering Neptune would have a 20% chance of being captured in an orbit similar to that proposed for Planet Nine. The observed clustering is more likely if the inner edge is at 200 AU. Unlike the gas nebula the planetesimal disk is likely to be long lived, potentially allowing a later capture. Planet Nine could have been captured from beyond the Solar System during a close encounter between the Sun and another star in its birth cluster. Three-body interactions during these encounters can perturb the path of planets on