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
Sixth Party System Sixth Party System Experts have debated whether national politics in the United States of America is in the era of a Sixth Party System, or whether the Fifth Party System continues in some form to the present. Opinions also differ on when a Sixth Party System may have begun, with suggested dates ranging from the 1960s to the 1990s. Maisel and Brewer (2011) argue that the consensus among specialists is that the Sixth System is underway based on American electoral politics since the 1960s: The perceived Sixth Party System is characterized by an electoral shift from the electoral coalitions of