In Korean, these names are more often written in Hangul rather than Chinese characters, e.g. 명왕성 for Pluto. In Vietnamese, calques are more common than directly reading these names as Sino-Vietnamese, e.g. sao Thuỷ rather than Thuỷ tinh for Mercury. Pluto is not sao Minh Vương but sao Diêm Vương " Yama star". [100] a b Margot, Jean-Luc (2015). "A quantitative criterion for defining planets". The Astronomical Journal. 150 (6): 185. arXiv: 1507.06300. Bibcode: 2015AJ....150..185M. doi: 10.1088/0004-6256/150/6/185. S2CID 51684830. The semi-major axis gives the size of the orbit. It is the distance from the midpoint to the longest diameter of its elliptical orbit. This distance is not the same as its apastron, because no planet's orbit has its star at its exact centre. [182]

It is smaller than Earth's moon; its orbit is highly elliptical, falling inside Neptune's orbit at some points and far beyond it at others; and Pluto's orbit doesn't fall on the same plane as all the other planets —instead, it orbits 17.1 degrees above or below. Kurtik, G. E. (June 1999). "The identification of Inanna with the planet Venus: A criterion for the time determination of the recognition of constellations in ancient Mesopotamia". Astronomical & Astrophysical Transactions. 17 (6): 501–513. Bibcode: 1999A&AT...17..501K. doi: 10.1080/10556799908244112. ISSN 1055-6796.

Lyttleton, Raymond A. (1936). "On the possible results of an encounter of Pluto with the Neptunian system". Monthly Notices of the Royal Astronomical Society. 97 (2): 108–115. Bibcode: 1936MNRAS..97..108L. doi: 10.1093/mnras/97.2.108.

Color legend: terrestrial planets gas giants ice giants (both categories of giant planets) dwarf planets Estados Unidos "conquista" Haumea". ABC (in Spanish). 20 September 2008 . Retrieved 18 September 2008. Aaboe, Asger (1991), "The culture of Babylonia: Babylonian mathematics, astrology, and astronomy", in Boardman, John; Edwards, I. E. S.; Hammond, N. G. L.; Sollberger, E.; Walker, C. B. F (eds.), The Assyrian and Babylonian Empires and other States of the Near East, from the Eighth to the Sixth Centuries B.C., The Cambridge Ancient History, vol.3, Cambridge: Cambridge University Press, pp.276–292, ISBN 978-0521227179 Sean Solomon, Larry Nittler & Brian Anderson, eds. (2018) Mercury: The View after MESSENGER. Cambridge Planetary Science series no. 21, Cambridge University Press, pp. 72–73. Explore the solar system in greater detail with these interactive resources from NASA. Discover the wonders of the solar system with this educational material from ESA. See where the planets are in their current orbit of the sun with this interactive orrery from NASA. BibliographyPark, Ryan S.; Folkner, William M.; Konopliv, Alexander S.; Williams, James G.; etal. (2017). "Precession of Mercury's Perihelion from Ranging to the MESSENGER Spacecraft". The Astronomical Journal. 153 (3): 121. Bibcode: 2017AJ....153..121P. doi: 10.3847/1538-3881/aa5be2. hdl: 1721.1/109312. S2CID 125439949. A famous feature in its swirling clouds is Jupiter's Great Red Spot, a giant storm more than 10,000 miles wide, first observed in 1831 by amateur astronomer Samuel Heinrich Schwabe. It has raged at more than 400 mph for the last 150 years, at least.

Astronomers had long suspected that a band of icy material known as the Kuiper Belt existed past the orbit of Neptune extending from about 30 to 55 times the distance of Earth to the sun, and from the last decade of the 20th century up to now, they have found more than a thousand of such objects. Scientists estimate the Kuiper Belt is likely home to hundreds of thousands of icy bodies larger than 60 miles (100 km) wide, as well as an estimated trillion or more comets. Between Mars and Jupiter lies the asteroid belt. Asteroids are minor planets, and according to NASA there are approximately between 1.1 and 1.9 million asteroids in the main asteroid belt larger than 0.6 miles (1 km) in diameter and millions more smaller asteroids. Dreyer, J. L. E. (1912). The Scientific Papers of Sir William Herschel. Vol.1. Royal Society and Royal Astronomical Society. p.100.a b c d e f g h Lakdawalla, Emily (21 April 2020). "What Is A Planet?". The Planetary Society. Archived from the original on 22 January 2022 . Retrieved 3 April 2022. O'Connor, J. J.; Robertson, E. F. "Aryabhata the Elder". MacTutor History of Mathematics archive . Retrieved 10 July 2022. The IAU noted that this definition could be expected to evolve as knowledge improves. [75] A 2022 review article discussing the history and rationale of this definition suggested that the words "in young star clusters" should be deleted in clause 3, as such objects have now been found elsewhere, and that the term "sub-brown dwarfs" should be replaced by the more current "free-floating planetary mass objects". [74]