Moons of the Solar System: The Complete List [2023 Update]

As of June 2023, there are 290 confirmed moons in our solar system. A moon, also known as a natural satellite, is a celestial body that orbits planets, and asteroids. This number includes only the planetary moons (moons orbiting a planet) plus Pluto’s moons. Here is the list of the known planetary moons in the solar system.

Planets Mercury and Venus have no moons. Other planets in the solar system have one or more moons orbiting them.

As of June 2023, with 146 confirmed moons, Saturn is the planet that has the most moons in Solar System.

Moons come in many shapes, sizes, and types. A few have atmospheres and even hidden oceans beneath their surfaces. Most planetary moons probably formed from the discs of gas and dust circulating around planets in the early solar system. Though, some of them are “captured” objects that formed elsewhere and fell into orbit around larger worlds.

Complete List of the Moons of the Solar System

Earth: 1 moon

1. Moon. Radius: 1,737.4 km (1,080 mi).

Mars: 2 moons

1. Deimos: Named after the Roman god of dread, Deimos is the smaller of Mars’s two moons. Dimensions: 15 km x 12.2 km x 11 km (9.3 x 7.6 x 6.8 mi).
2. Phobos: The larger moon of Mars, gouged and nearly shattered by a giant impact crater. Dimensions: 27 x 22 x 18 km (16.8 x 13.7 x 11.2 mi).

Jupiter: 95 moons

Jupiter has 53 named moons and another 39 awaiting official names. The largest and most massive moon in the solar system, Ganymede, orbits Jupiter. One of the moons of Jupiter, S/2003, is considered lost.

1. Adrastea: Discovered in July 1979 by the Voyager science team. Dimensions: 20 x 16 x 14 km (12.4 x 9.9 x 8.7 mi).
2. Aitne: Discovered on December 9, 2001, by the American astronomer Scott Sander Sheppard (born 1977). It is a member of the Carme group, a family of Jovian satellites that have similar orbits and appearances and are therefore thought to have a common origin. Mean diameter: 3 km (1.9 mi).
3. Amalthea: Discovered on September 9, 1892, by the American astronomer Edward Emerson Barnard (December 16, 1857 – February 6, 1923). Dimensions: 250 x 146 x 128 km (155 x 90.1 x 79.6 mi).
4. Ananke: Discovered on September 28, 1951, by the American astronomer Seth Barnes Nicholson (November 12, 1891 – July 2, 1963) on a photograph made with the 100-inch (2.5 m) Hooker telescope at the Mount Wilson Observatory in California. Mean diameter: 29.1±0.6 km (about 18 mi).
5. Aoede: Discovered on February 8, 2003, by Scott S. Sheppard, David C. Jewitt, Jan T. Kleyna, Yanga R. Fernandez, and Henry H. Hsieh at the Mauna Kea Observatory in Hawaii. Mean diameter: 4 km (2.5 mi).
6. Arche: Discovered on October 31, 2002, by Scott S. Sheppard. It is also a member of the Carme group. Mean diameter: 3 km (1.9 mi).
7. Autonoe: Discovered on December 10, 2001, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna at the Mauna Kea Observatory in Hawaii. Mean diameter: 4 km (2.5 mi).
8. Callirrhoe: Discovered on October 19, 1999, via the 36-inch telescope on Kitt Peak, in the course of observations by the Spacewatch program of the University of Arizona. Mean diameter: 9.6±1.3 km (about 6 mi).
9. Callisto: Discovered by Galileo Galilei on January 7, 1610. It is the most heavily cratered object in our solar system. Mean radius: 2410.3±1.5 km (about 1497 mi).
10. Carme: Discovered on July 30, 1938, by Seth Barnes Nicholson with the 100-inch (2.5 m) Hooker telescope at the Mount Wilson Observatory in California. Mean diameter: 46.7±0.9 km (about 29 mi).
11. Carpo: Discovered on February 26, 2003, by Scott S. Sheppard and others from the University of Hawaii’s Institute for Astronomy using the 12-ft. (3.6-m) Canada-France-Hawaii telescope at the Mauna Kea Observatory in Hawaii. Mean diameter: 3 km (1.9 mi).
12. Chaldene: Discovered on November 23, 2000, by Scott S. Sheppard, David C. Jewitt, Yange R. Fernandez, and Eugene Magnier at an observatory on Mauna Kea in Hawaii. Mean diameter: 4 km (2.5 mi).
13. Cyllene: Discovered on February 9, 2003, by Scott S. Sheppard and his team from the University of Hawaii at the Mauna Kea Observatory in Hawaii. Mean diameter: 2 km (1.25 mi).
14. Dia: Discovered on December 5, 2000, by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2000 with an observation arc of 26 days. But, initial observations were not followed up, and Dia was not observed for more than a decade after 2000. This apparent disappearance led some astronomers to consider the moon lost. One theory was that it had crashed into Himalia, the largest irregular satellite of Jupiter, creating a faint ring around Jupiter. However, it was rediscovered on September 11, 2012. Mean diameter: 4 km (2.5 mi).
15. Eirene: Discovered in February 2003 by Scott Sander Sheppard at the Mauna Kea Observatory in Hawaii. Mean diameter: 4 km (2.5 mi).
16. Elara: Discovered on January 5, 1905, by the American astronomer Charles Dillon Perrine (July 28, 1867 – June 21, 1951) in photographs taken with the Crossley 36-inch (0.9 meters) reflector of the Lick Observatory on Mount Hamilton at the University of California, San Jose. Mean diameter: 79.9±1.7 km (about 50 mi).
17. Erinome: Discovered on Nov. 23, 2000, by Scott S. Sheppard, David C. Jewitt, Yanga R. Fernandez, and Eugene Magnier at the Mauna Kea Observatory in Hawaii. Mean diameter: 3 km (1.9 mi).
18. Ersa: This tiny moon of Jupiter was first spotted in 2017 by Scott S. Sheppard. The discovery announcement was made in July 2018. Mean diameter: 3 km (1.9 mi).
19. Euanthe: Discovered on December 11, 2001, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna at the Mauna Kea Observatory in Hawaii. Mean diameter: 3 km (1.9 mi).
20. Eukelade: Discovered on Feb. 6, 2003, by Scott S. Sheppard at the Mauna Kea Observatory in Hawaii. Mean diameter: 4 km (2.5 mi).
21. Eupheme: Discovered on March 4, 2003, by Scott S. Sheppard at the Mauna Kea Observatory in Hawaii. Mean diameter: 2 km (1.25 mi).
22. Euporie: Discovered on December 11, 2001, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna at the Mauna Kea Observatory in Hawaii. Mean diameter: 2 km (1.25 mi).
23. Europa: The sixth-largest moon in the Solar System, Europa was discovered in 1610 by Galileo Galilei. The apparent youth and smoothness of the surface have led to the hypothesis that a water ocean exists beneath the surface. That’s why it might be the best place to look for environments where life could exist. Mean radius: 1560.8±0.5 km (970 mi, 0.245 Earths).
24. Eurydome: Discovered on December 9, 2001, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna at the Mauna Kea Observatory in Hawaii. Mean diameter: 3 km (1.9 mi).
25. Ganymede: Discovered by Galileo Galilei on January 7, 1610, it is the largest satellite in our solar system. It is even larger than Mercury and Pluto, and three-quarters the size of Mars. Mean radius 2634.1±0.3 km (0.413 Earths).

Related: What if Ganymede was the Earth’s second moon?

26. Harpalyke: Discovered on November 23, 2000, by Scott S. Sheppard, David C. Jewitt, Yanga R. Fernandez, and Eugene Magnier at the Mauna Kea Observatory in Hawaii. Mean diameter: 4 km (2.5 mi).
27. Hegemone: Discovered on Feb. 8, 2003, by Scott S. Sheppard, David C. Jewitt, Jan T. Kleyna, Yanga R. Fernandez, and Henry H. Hsieh at the Mauna Kea Observatory in Hawaii. Mean diameter: 3 km (1.9 mi).
28. Helike: Discovered on February 6, 2003, by Scott S. Sheppard at the Mauna Kea Observatory in Hawaii. Mean diameter: 4 km (2.5 mi).
29. Hermippe: Discovered on December 9, 2001, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna at the Mauna Kea Observatory in Hawaii. Mean diameter: 4 km (2.5 mi).
30. Herse: Discovered on February 27, 2003, by Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, and Lynne Allen. Mean diameter: 2 km (1.25 mi).
31. Himalia: Discovered on December 3, 1904, by Charles Dillon Perrine in photographs taken with the Crossley 36-inch (0.9 meters) reflector of the Lick Observatory on Mount Hamilton at the University of California, San Jose. Dimensions: 150±20 x 120±20 km (about 90 x 75 mi) (Cassini estimate).
32. Io: Discovered in 1610 by Galileo Galilei, it is the most volcanically active body in the solar system. It is slightly larger than Earth’s moon. Mean radius: 1821.6±0.5 km (about 1132 mi, 0.286 Earths).
33. Iocaste: Discovered November 23, 2000, by Scott S. Sheppard, David C. Jewitt, Yanga R. Fernandez, and Eugene Magnier at the Mauna Kea Observatory in Hawaii. Mean diameter: 5 km (3.1 mi).
34. Isonoe: Discovered November 23, 2000, by Scott S. Sheppard, David C. Jewitt, Yanga R. Fernandez, and Eugene Magnier at the Mauna Kea Observatory in Hawaii. Mean diameter: 4 km (2.5 mi).
35. Jupiter LI: This tiny moon is one of several moons of Jupiter discovered by Earth-based telescopes with improved search techniques by R. Jacobson, M. Brozović, B. Gladman, and M. Alexandersen in 2010. Mean diameter: 2 km (1.25 mi).
36. Jupiter LII: Discovered by Christian Veillet in 2010. Mean diameter: 1 km (0.62 mi).
37. Kale: Discovered on December 9, 2001, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna at the Mauna Kea Observatory in Hawaii. Mean diameter: 2 km (1.25 mi).
38. Kallichore: Discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2003. It is a member of the Carme group, a family of Jovian satellites that have similar orbits and appearances and are therefore thought to have a common origin. Mean diameter: 2 km (1.25 mi).
39. Kalyke: Discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2000. It is also a member of the Carme group. Mean diameter: 6.9±1.3 km (about 4.3 mi).
40. Kore: Discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2003. It is considered a member of the Pasiphae group, a family of Jovian satellites that have similar orbits and are therefore thought to have a common origin. Mean diameter: 2 km (1.25 mi).
41. Leda: Discovered on September 14, 1974, by the American astronomer Charles Thomas Kowal (November 8, 1940 – November 28, 2011) on plates taken from September 11 through 13, 1974 with the 122-cm Schmidt telescope at Mount Palomar. Mean diameter: 21.5±1.7 km (about 13 mi).
42. Lysithea: Discovered on July 6, 1938, by the American astronomer Seth Barnes Nicholson (November 12, 1891 – July 2, 1963) with the 100-inch (2.5 m) Hooker telescope at the Mount Wilson Observatory. Mean diameter: 42.2±0.7 km (about 26 mi).
43. Megaclite: Discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2000, it is considered a member of the Pasiphae group, a family of Jovian satellites that have similar orbits and are therefore thought to have a common origin. Mean diameter: 6 km (3.7 mi).
44. Metis: Discovered in March 1979 by the Voyager science team. Dimensions: 60 x 40 x 34 km (37 x 25 x 21 mi).
45. Mneme: Discovered by teams of astronomers led by Brett J. Gladman and Scott S. Sheppard in 2003, it is a member of the Ananke group, a family of Jovian satellites that have similar orbits and are therefore thought to have a common origin. Mean diameter: 2 km (1.25 mi).
46. Orthosie: Discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2001, it is a member of the Ananke group, a family of Jovian satellites that have similar orbits and are therefore thought to have a common origin. Mean diameter: 2 km (1.25 mi).
47. Pandia: This tiny moon of Jupiter was first spotted in 2017. The discovery announcement was made in July 2018. Mean diameter: 3 km (1.9 mi).
48. Pasiphaë: Discovered on January 27, 1908, by the British astronomer Philibert Jacques Melotte (29 January 1880 – 30 March 1961) with the Greenwich Observatory’s 30-inch Cassegrain telescope. Mean diameter: 57.8±0.8 km (about 36 miles).
49. Pasithee: Discovered on Dec. 11, 2001, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna at the Mauna Kea Observatory in Hawaii. Mean diameter: 2 km (1.25 mi).
50. Philophrosyne: Discovered in April 2003 by Scott S. Sheppard at the Mauna Kea Observatory in Hawaii. Mean diameter: 2 km (1.25 mi).
51. Praxidike: Discovered on Nov. 23, 2000, by Scott S. Sheppard, David C. Jewitt, Yanga R. Fernandez, and Eugene Magnier at the Mauna Kea Observatory in Hawaii. Mean diameter: 7.0±0.7 km (about 4 mi).
52. S/2003 J10: Discovered in February 2003 by Scott Sander Sheppard at the Mauna Kea Observatory in Hawaii. Mean diameter: 2 km (1.25 mi).
53. S/2003 J12: Discovered between February 6 and March 7, 2003, by Scott S. Sheppard and others from the University of Hawaii’s Institute for Astronomy at the Mauna Kea Observatory in Hawaii. Mean diameter: 1 km (0.62 mi).
54. S/2003 J16: Discovered in April 2003 by Brett J. Gladman at the Mauna Kea Observatory in Hawaii. Mean diameter: 2 km (1.25 mi).
55. S/2003 J18 (now Jupiter LV): Discovered in April 2003 by Brett Joseph Gladman at the Mauna Kea Observatory, Hawaii. Mean diameter: 2 km (1.25 mi).
56. S/2003 J19 (now Jupiter LXI): Discovered in February 2003 by Brett J. Gladman at the Mauna Kea Observatory in Hawaii. Mean diameter: 2 km (1.25 mi).
57. S/2003 J2: Discovered in February or March 2003 at the Mauna Kea Observatory in Hawaii by Scott S. Sheppard, David C. Jewitt, Jan T. Kleyna, Yanga R. Fernandez, and Henry H. Hsieh. Mean diameter: 2 km (1.25 mi).
58. S/2003 J23: Discovered in 2003 by Scott S. Sheppard at the Mauna Kea Observatory in Hawaii. Mean diameter: 2 km (1.25 mi).
59. S/2003 J4: Discovered in 2003 by Scott S. Sheppard, David C. Jewitt, Jan T. Kleyna, Yanga R. Fernandez, and Henry H. Hsieh at the Mauna Kea Observatory in Hawaii. Mean diameter: 2 km (1.25 mi).
60. S/2003 J9: Discovered in February 2003 by Scott Sander Sheppard Sheppard at the Mauna Kea Observatory in Hawaii. Mean diameter: 1 km (0.62 mi).
61. S/2003 J 24: Discovered by Scott S. Sheppard et al. in 2003. It was independently found by amateur astronomer Kai Ly, who reported it on June 30, 2021. It was formally announced on November 15, 2021, by the Minor Planet Center. Mean diameter: 2 km (1.25 mi).
62. S/2011 J 1 (now Jupiter LXXII): Discovered in 2011 by Scott S. Sheppard with digital images obtained with the Magellan-Baade 6.5 meter telescope at Las Campanas Observatory. Mean diameter: 2 km (1.25 mi).
63. S/2011 J 2 (now Jupiter LVI): Discovered in 2011 by Scott S. Sheppard with digital images obtained with the Magellan-Baade 6.5 meter telescope at Las Campanas Observatory. Mean diameter: 1 km (0.62 mi).
64. S/2011 J 3: Discovered by Scott S. Sheppard on September 27, 2011, using the 6.5-meter Magellan-Baade Telescope at Las Campanas Observatory, Chile. It was announced by the Minor Planet Center on December 20, 2022, after observations were collected over a long enough time span to confirm the satellite’s orbit. Mean diameter: 3 km (1.9 mi).
65. S/2016 J 1 (now Jupiter LIV): Discovered by Scott S. Sheppard in 2016, but not announced until June 2, 2017. Mean diameter: 1 km (0.62 mi).
66. S/2016 J 3: Discovered by Scott S. Sheppard on March 9, 2016, using the 6.5-meter Magellan-Baade Telescope at Las Campanas Observatory, Chile. It was announced by the Minor Planet Center on January 5, 2023, after observations were collected over a long enough time span to confirm the satellite’s orbit. Mean diameter: ~2 km (1.25 mi).
67. S/2016 J 4: discovered by Scott S. Sheppard on March 9, 2016, using the 6.5-meter Magellan-Baade Telescope at Las Campanas Observatory, Chile. It was announced by the Minor Planet Center on January 24, 2023. Mean diameter: ~1 km (0.62 mi).
68. S/2017 J 1 (now Jupiter LIX): This tiny moon of Jupiter was first spotted in 2016. The discovery announcement was made in July 2017. Mean diameter: ~2 km (1.25 mi).
69. S/2017 J 2 (now Jupiter LXIII): Discovered by Scott S. Sheppard and his team in 2017, but not announced until July 17, 2018. Mean diameter: 2 km (1.25 mi).
70. S/2017 J 3 (now Jupiter LXIV): Discovered by Scott S. Sheppard and his team in 2017, but not announced until July 17, 2018. Mean diameter: 2 km (1.25 mi).
71. S/2017 J 5 (now Jupiter LXVI): Discovered by Scott S. Sheppard and his team in 2017, but not announced until July 17, 2018. Mean diameter: 2 km (1.25 mi).
72. S/2017 J 6 (now Jupiter LXVII): Discovered by Scott S. Sheppard and his team in 2017, but not announced until July 17, 2018. Mean diameter: 2 km (1.25 mi).
73. S/2017 J 7 (now Jupiter LXVIII): Discovered by Scott S. Sheppard and his team in 2017, but not announced until July 17, 2018. Mean diameter: 2 km (1.25 mi).
74. S/2017 J 8 (now Jupiter LXIX): Discovered by Scott S. Sheppard and his team in 2017, but not announced until July 17, 2018. Mean diameter: 1 km (0.62 mi).
75. S/2017 J 9 (now Jupiter LXX): Discovered by Scott S. Sheppard and his team in 2017, but not announced until July 17, 2018. Mean diameter: 3 km (1.9 mi).
76. S/2018 J 2: Discovered by Scott S. Sheppard on May 12, 2018, using the 4-meter Víctor M. Blanco Telescope at Cerro Tololo Observatory, Chile. It was announced by the Minor Planet Center on December 20, 2022. Mean diameter: 3 km (1.9 mi).
77. S/2018 J 3: Discovered by Scott S. Sheppard on May 12, 2018, using the 6.5-meter Magellan-Baade Telescope at Las Campanas Observatory, Chile. It was announced by the Minor Planet Center on January 19, 2023. Mean diameter: about 1 km (0.62 mi).
78. S/2018 J 4: Discovered by Scott S. Sheppard on May 11, 2018, using the 4.0-meter Víctor M. Blanco Telescope at Cerro Tololo Observatory, Chile. It was announced by the Minor Planet Center on January 20, 2023, after observations were collected over a long enough time span to confirm the satellite’s orbit. Mean diameter: about 2 km (1.24 mi).
79. S/2021 J 1: Discovered by Scott S. Sheppard on August 12, 2021, using the 6.5-meter Magellan-Baade Telescope at Las Campanas Observatory, Chile. It was announced by the Minor Planet Center on January 5, 2023. Mean diameter: about 1 km (0.62 mi).
80. S/2021 J 2: Discovered by Scott S. Sheppard on August 12, 2021, using the 6.5-meter Magellan-Baade Telescope at Las Campanas Observatory, Chile. It was announced by the Minor Planet Center on January 19, 2023. Mean diameter: about 1 km (0.62 mi).
81. S/2021 J 3: Discovered by Scott S. Sheppard on August 12, 2021, using the 6.5-meter Magellan-Baade Telescope at Las Campanas Observatory, Chile. It was announced by the Minor Planet Center on January 19, 2023. Mean diameter: about 2 km (1.24 mi).
82. S/2021 J 4: Discovered by Scott S. Sheppard on August 14, 2021, using the 6.5-meter Magellan-Baade Telescope at Las Campanas Observatory, Chile. It was announced by the Minor Planet Center on January 19, 2023. Mean diameter: about 1 km (0.62 mi).
83. S/2021 J 5: Discovered by Scott S. Sheppard, David J. Tholen, and Chad Trujillo on September 5, 2021, using the 8.2-meter Subaru Telescope at Mauna Kea Observatory, Hawaii. It was announced by the Minor Planet Center on January 19, 2023. Mean diameter: about 2 km (1.24 mi).
84. S/2021 J 6: Discovered by Scott S. Sheppard, David J. Tholen, and Chad Trujillo on September 5, 2021, using the 8.2-meter Subaru Telescope at Mauna Kea Observatory, Hawaii. It was announced by the Minor Planet Center on January 20, 2023. Mean diameter: about 1 km (0.62 mi).
85. S/2022 J 1: Discovered by Scott S. Sheppard on August 30, 2022, using the 4.0-meter Víctor M. Blanco Telescope at Cerro Tololo Observatory, Chile. It was announced by the Minor Planet Center on February 22, 2023. Mean diameter: about 2 km (1.24 mi).
86. S/2022 J 2: Discovered by Scott S. Sheppard on October 15, 2022, using the 6.5-meter Magellan-Baade Telescope at Las Campanas Observatory, Chile. It was announced by the Minor Planet Center on February 22, 2023. Mean diameter: about 1 km (0.62 mi).
87. S/2022 J 3: Discovered by Scott S. Sheppard on August 30, 2022, using the 4.0-meter Víctor M. Blanco Telescope at Cerro Tololo Observatory, Chile. It was announced by the Minor Planet Center on February 22, 2023. Mean diameter: about 1 km (0.62 mi).
88. Sinope: Discovered on July 21, 1914, by Seth Barnes Nicholson on photographic plates taken with the Lick Observatory’s 36-inch (0.9 meters) telescope. Mean diameter: 35.0±0.6 km (about 22 mi).
89. Sponde: Discovered on December 9, 2001, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna at the Mauna Kea Observatory in Hawaii. Mean diameter: 2 km (1.25 mi).
90. Taygete: Discovered on November 25, 2000, by Scott S. Sheppard, David C. Jewitt, Yanga R. Fernandez, and Eugene Magnier at the Mauna Kea Observatory in Hawaii. Mean diameter: 5 km (3.1 mi).
91. Thebe: Discovered in 1980 by the Voyager science team from images taken by Voyager 1. Dimensions: 116 x 98 x 84 km (72x 61 x 52 mi).
92. Thelxinoe: Discovered on February 9, 2003, by Scott S. Sheppard and Brett J. Gladman at the Mauna Kea Observatory in Hawaii. Mean diameter: 2 km (1.25 mi).
93. Themisto: Discovered on Sept. 30, 1975, by American astronomers Charles Thomas Kowal (November 8, 1940 – November 28, 2011) and Elizabeth Roemer (September 4, 1929 – April 8, 2016). Mean diameter: 9 km (5.6 mi).
94. Thyone: Discovered on December 11, 2001, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna at the Mauna Kea Observatory in Hawaii. Mean diameter: 4 km (2.5 mi).
95. Valetudo: Discovered by Scott S. Sheppard and his team in data acquired by the 6.5-m Magellan-Baade telescope of the Las Campanas Observatory in 2016, but was not announced until July 17, 2018. Mean diameter: 1 km (0.62 mi).

Related: The Moons of the Solar System in Perspective

Saturn: 146 moons

53 moons of Saturn are confirmed and named and another 29 moons are awaiting confirmation of discovery and official naming.

1. Aegaeon: Scientists imaged this moonlet on August 15, 2008, and then confirmed its presence by finding it in two earlier images. Dimensions: 1.4 km x 0.5 km x 0.4 km (0.9 mi x 0.3 mi x 0.25 mi).
2. Aegir: Discovered on December 12, 2004 (one of 12 Saturnian moons found that day), by Scott S. Sheppard, David L. Jewitt, and Jan T. Kleyna using a wide-field camera on the Subaru 8.2-m reflector telescope on Mauna Kea, Hawaii. Mean diameter: 6 km (3.7 mi).
3. Albiorix: Discovered on November 9, 2000, by American astronomers Matthew J. Holman and Timothy B. Spahr, using the 6.5-m reflector telescope at the Fred Lawrence Whipple Observatory on Mt. Hopkins, near Amado, Ariz. Mean diameter: 28.6±5.4 km (about 18 mi).
4. Alvaldi: Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 8, 2019, from observations taken between December 12, 2004, and February 25, 2006. Mean diameter: 5 km (3.1 mi).
5. Angrboda: Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 7, 2019, from observations taken between December 12, 2004, and February 1, 2006. Mean diameter: 3 km (1.9 mi).
6. Anthe: Discovered on May 30, 2007, by The Cassini Imaging team, although a check back revealed Anthe in Cassini images as early as June 2004. Mean diameter: 1.8 km (1.1 mi).
7. Atlas: Discovered in 1980 by Richard J. Terrile and the Voyager 1 team from photographs taken during its encounter with Saturn. Dimensions: 40.8 x 35.4 x 18.8 km (25.4 x 22 x 11.7 mi).
8. Bebhionn: Discovered on December 12, 2004, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna, using the wide-field camera on the 8.2-m Subaru telescope on Mauna Kea, Hawaii, with orbital elements computed by Brian Marsden. Mean diameter: 6 km (3.7 mi).
9. Beli: Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 7, 2019, from observations taken between December 12, 2004, and March 21, 2007. Mean diameter: 4 km (2.5 mi).
10. Bergelmir: Discovered on December 12, 2004, one of 12 Saturnian moons found that day by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna, using the wide-field camera on the Subaru 8.3-m reflector telescope on Mauna Kea, Hawaii. Mean diameter: 5 km (3.1 mi).
11. Bestla: Discovered on December 12, 2004, one of 12 Saturnian moons found that day by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna, using the wide-field camera on the Subaru 8.3-m reflector telescope on Mauna Kea, Hawaii. Mean diameter: 7 km (4.3 mi).
12. Calypso: Discovered by Dan Pascu (American astronomer), P. Kenneth Seidelmann (American astronomer), William A. Baum (American astronomer, 1924-2012), and Douglas G. Currie (American astronomer) in March 1980 using a ground-based telescope. Dimensions: 30.2 x 23 x 14 km (18.8 x 14.3 x 8.7 mi).
13. Daphnis: Discovered by the Cassini mission team on May 1, 2005. Dimensions: 8.6 x 8.2 x 6.4 km (5.3 x 5.1 x 4 mi).
14. Dione: Discovered by the Italian astronomer Giovanni Domenico Cassini (8 June 1625 – 14 September 1712) in 1684. Mean radius: 561.4±0.4 km (about 350 mi).
15. Eggther: Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 7, 2019, from observations taken between December 12, 2004, and March 21, 2007. Mean diameter: 6 km (3.7 mi).
16. Enceladus: discovered on August 28, 1789, by German-born British astronomer William Herschel (15 November 1738 – 25 August 1822), it is Saturn’s sixth-largest moon. Enceladus is mostly covered by fresh, clean ice, making it one of the most reflective bodies of the Solar System. It is also one of the most scientifically compelling bodies in our solar system. Mean radius: 252.1±0.2 km (about 156.6 mi).

Related: We may have already detected signs of alien microbes on Saturn’s moon Enceladus

17. Epimetheus: French astronomer Audouin Dollfus (12 November 1924 – 1 October 2010) observed a moon on December 15, 1966, for which he proposed the name “Janus.” On December 18 of the same year, Richard Walker made a similar observation, now credited as the discovery of Epimetheus. Mean radius: 58.1±1.8 km (about 36 mi).
18. Erriapus: Discovered on September 23, 2000, by Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, Hans Scholl, Matthew J. Holman, Brian G. Marsden, Phillip D. Nicholson, and Joseph A. Burns at the Mauna Kea Observatory on the island of Hawaii. Mean diameter: 10 km (6.2 mi).
19. Farbauti: Discovered on December 12, 2004, one of 12 Saturnian moons found that day by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna, using the wide-field camera on the Subaru 8.3-m reflector telescope on Mauna Kea, Hawaii. Mean diameter: 5 km (3.1 mi).
20. Fenrir: Discovered on December 12, 2004, one of 12 Saturnian moons found that day by Scott S. Sheppard, David L. Jewitt, and Jan T. Kleyna, using a wide-field camera on the Subaru 8.2-m reflector telescope on Mauna Kea, Hawaii. Mean diameter: 4 km (2.5 mi).
21. Fornjot: Discovered on December 12, 2004, one of 12 Saturnian moons found that day by Scott S. Sheppard, David L. Jewitt, and Jan T. Kleyna, using a wide-field camera on the Subaru 8.2-m reflector telescope on Mauna Kea, Hawaii. Mean diameter: 6 km (3.7 mi).
22. Geirrod: Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 8, 2019, from observations taken between December 12, 2004, and March 22, 2007. Mean diameter: 4 km (2.5 mi).
23. Gerd: Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 8, 2019, from observations taken between December 12, 2004, and March 22, 2007. Mean diameter: 4 km (2.5 mi).
24. Greip: Discovered on March 6, 2006, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna using the Subaru 8.3-m reflector telescope on Mauna Kea, Hawaii. Mean diameter: 5 km (3.1 mi).
25. Gridr: Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 8, 2019, from observations taken between December 12, 2004, and March 22, 2007. Mean diameter: 4 km (2.5 mi).
26. Gunnlod: Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 8, 2019, from observations taken between December 12, 2004, and January 19, 2007. Mean diameter: 4 km (2.5 mi).
27. Hati: Discovered on December 12, 2004, one of 12 Saturnian moons found that day by Scott S. Sheppard, David L. Jewitt, and Jan T. Kleyna, using a wide-field camera on the Subaru 8.2-m reflector telescope on Mauna Kea, Hawaii. Mean diameter: 5 km (3.1 mi).
28. Helene: Discovered on March 1, 1980, during the Earth ring-plane crossing by J. Lecacheux and others. Dimensions: 43.4 x 38.2 x 26 km (27 x 23.7 x 16.2 mi).
29. Hyperion: Discovered by the American astronomer William Cranch Bond (September 9, 1789 – January 29, 1859), his son George Phillips Bond (May 20, 1825 – February 17, 1865), and the English astronomer William Lassell (18 June 1799 – 5 October 1880) in 1848. It is distinguished by its irregular shape, its chaotic rotation, and its unexplained sponge-like appearance. Hyperion was the first non-round moon to be discovered. Dimensions: 360.2 km x 266 km x 205.4 km (223.8 mi x 165.3 mi x 127.6 mi).
30. Hyrrokkin: Discovered on December 12, 2004, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna using the Subaru 8.3-m reflector telescope on Mauna Kea, Hawaii. Mean diameter: 8 km (5 mi).
31. Iapetus: Discovered by Giovanni Cassini on October 25, 1671. It is the 3rd-largest natural satellite of Saturn and the 11th-largest in the Solar System. Dimensions: 1,492 x 1,492 x 1,424 km (927 x 927 x 885 mi).
32. Ijiraq: Discovered on Sept. 23, 2000, by Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, Hans Scholl, Matthew J. Holman, Brian G. Marsden, Phillip D. Nicholson, and Joseph A. Burns. Mean diameter: 13 km (8 mi).
33. Janus: First observed by Audouin Dollfus on December 15, 1966. He also proposed the name. Dimensions: 203 x 185 x 152.6 km (126 x 115 x 95 mi).
34. Jarnsaxa: Discovered on March 6, 2006, by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna using the Subaru 8.3-m reflector telescope on Mauna Kea, Hawaii. Mean diameter: 6 km (3.7 mi).
35. Kari: Discovered on March 6, 2006, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna, based on data obtained with the Subaru 8.3-m reflector telescope on Mauna Kea, Hawaii, during the months of January to April 2006. Mean diameter: 6 km (3.7 mi).
36. Kiviuq: Discovered on August 7, 2000, by Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, Hans Scholl, Matthew J. Holman, Brian G. Marsden, Phillip D. Nicholson, and Joseph A. Burns at the European Southern Observatory in La Silla, Chile. Mean diameter: 17 km (10.6 mi).
37. Loge: Discovered on March 6, 2006, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna using the Subaru 8.3-m reflector telescope on Mauna Kea, Hawaii. Mean diameter: 5 km (3.1 mi).
38. Methone: Discovered by The Cassini Imaging Team on June 1, 2004. It is a small, egg-shaped moon. Dimensions: 3.88 x 2.58 x 2.42 km (2.4 x 1.6 x 1.5 mi).
39. Mimas: The “death star moon” was discovered on September 17, 1789, by the English astronomer William Herschel, using his 40-foot reflector telescope. Dimensions: 415.6 x 393.4 x 381.2 km (258.3 x 244.4 x 236.8 mi).
40. Mundilfari: Discovered in 2000 by Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, Hans Scholl, Matthew J. Holman, Brian G. Marsden, Phillip D. Nicholson, and Joseph A. Burns using the 3.6-m Canada-France-Hawaii reflector on Mauna Kea in Hawaii. Mean diameter: 7 km (4.3 mi).
41. Narvi: Discovered on April 8, 2003, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna, from photos taken from Feb. 5 to 3 April 3. Mean diameter: 7 km (4.3 mi).
42. Paaliaq: Discovered on August 7, 2000, by Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, Hans Scholl, Matthew J. Holman, Brian G. Marsden, Phillip D. Nicholson, and Joseph A. Burns at the European Southern Observatory in La Silla, Chile. Mean diameter: 25 km (15.5 mi).
43. Pallene: Discovered by The Cassini Imaging Team on June 1, 2004. Mean diameter: 5 km (3.1 mi).
44. Pan: Discovered by Senior Research Scientist at the SETI Institute, Mark R. Showalter in 1990 using images taken by the Voyager 2 spacecraft nine years earlier. Dimensions: 34.4 x 31.4 x 20.8 km (21.4 x 19.5 x 13 mi).
45. Pandora: Discovered in 1980 from photos taken by the Voyager 1. Dimensions: 104 x 81 x 64 km (64.6 x 50.3 x 39.8 mi).
46. Phoebe: Discovered in August 1898 by American astronomer William Pickering (February 15, 1858 – January 16, 1938). Mean radius: 106.5±0.7 km (about 66 mi).
47. Polydeuces: Discovered by the Cassini mission team on October 21, 2004, and upon further review of Cassini images, scientists found it in images from April 9 of the same year. Dimensions: 3 x 2.5 x 2 km (1.9 x 1.6 x 1.25 mi).
48. Prometheus: Discovered by the Voyager 1 science team in October 1980. Dimensions: 135.6 x 79.4 x 59.4 km (84.3 x 49.3 x 36.9 mi).
49. Rhea: Discovered by Giovanni Cassini on December 23, 1672. It is the second-largest moon of Saturn and the 9th-largest moon in the Solar System. It is the smallest body in the Solar System for which precise measurements have confirmed a shape consistent with hydrostatic equilibrium (nearly round shape). An astronomical body is in a state of hydrostatic equilibrium (HE) when its self-gravitational force is balanced by its internal pressure; the body is neither expanding nor contracting. Hydrostatic equilibrium is the distinguishing criterion between dwarf planets and small solar system bodies and features in astrophysics and planetary geology. Said qualification of equilibrium indicates that the shape of the object is symmetrically ellipsoid, where any irregular surface features are consequent to a relatively thin solid crust. In addition to the Sun, there are a dozen or so equilibrium objects confirmed to exist in the Solar System. Mean radius: 763.8±1.0 km (about 475 mi).
50. S/2004 S7: Discovered on December 12, 2004, one of 12 Saturnian moons found that day by Scott S. Sheppard, David L. Jewitt, and Jan T. Kleyna. Mean diameter: 6 km (3.7 mi).
51. S/2004 S12: Discovered on December 12, 2004, one of 12 Saturnian moons found that day by Scott S. Sheppard, David L. Jewitt, and Jan T. Kleyna. Mean diameter: 5 km (3.1 mi).
52. S/2004 S13: Discovered on December 12, 2004, one of 12 Saturnian moons found that day by Scott S. Sheppard, David L. Jewitt, and Jan T. Kleyna. Mean diameter: 6 km (3.7 mi).
53. S/2004 S17: Discovered on December 12, 2004, one of 12 Saturnian moons found that day by Scott S. Sheppard, David L. Jewitt, and Jan T. Kleyna. Mean diameter: 4 km (2.5 mi).
54. S/2004 S21 (S5602a): One of 20 new Saturn moons announced on October 7, 2019. Mean diameter: 6 km (3.7 mi).
55. S/2004 S24 (S8881b): One of 20 new Saturn moons announced on October 7, 2019. Mean diameter: 6 km (3.7 mi).
56. S/2004 S26 (S8353a): One of 20 new Saturn moons announced on October 7, 2019. Mean diameter: 8 km (5 mi).
57. S/2004 S28 (S8386a): One of 20 new Saturn moons announced on October 7, 2019. Mean diameter: 8 km (5 mi).
58. S/2004 S29 (S2428b): One of 20 new Saturn moons announced on October 7, 2019. Mean diameter: 8 km (5 mi).
59. S/2004 S31 (T522499): One of 20 new Saturn moons announced on October 7, 2019. Mean diameter: 8 km (5 mi).
60. S/2004 S34 (S5613a2): One of 20 new Saturn moons announced on October 7, 2019. Mean diameter: 8 km (5 mi).
61. S/2004 S36 (S5593a2): One of 20 new Saturn moons announced on October 7, 2019. Mean diameter: 6 km (3.7 mi).
62. S/2004 S37 (S5605a2): One of 20 new Saturn moons announced on October 7, 2019. Mean diameter: 8 km (5 mi).
63. S/2004 S39 (S64454x): One of 20 new Saturn moons announced on October 7, 2019. Mean diameter: 4 km (2.5 mi).
64. S/2004 S40: Discovered in 2004, announced in 2023.
65. S/2004 S41: Discovered in 2004, announced in 2023.
66. S/2004 S42: Discovered in 2004, announced in 2023.
67. S/2004 S43: Discovered in 2004, announced in 2023.
68. S/2004 S44: Discovered in 2004, announced in 2023.
69. S/2004 S45: Discovered in 2004, announced in 2023.
70. S/2004 S46: Discovered in 2004, announced in 2023.
71. S/2004 S47: Discovered in 2004, announced in 2023.
72. S/2004 S48: Discovered in 2004, announced in 2023.
73. S/2004 S49: Discovered in 2004, announced in 2023.
74. S/2004 S50: Discovered in 2004, announced in 2023.
75. S/2004 S51: Discovered in 2004, announced in 2023.
76. S/2004 S52: Discovered in 2004, announced in 2023.
77. S/2004 S53: Discovered in 2004, announced in 2023.
78. S/2005 S4: Discovered in 2005, announced in 2023.
79. S/2005 S5: Discovered in 2005, announced in 2023.
80. S/2006 S1: Discovered on March 6, 2006, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna. Mean diameter: 5 km (3.1 mi).
81. S/2006 S3: Discovered on March 6, 2006, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna. Mean diameter: 6 km (3.7 mi).
82. S/2006 S9: Discovered in 2006, announced in 2023.
83. S/2006 S10: Discovered in 2006, announced in 2023.
84. S/2006 S11: Discovered in 2006, announced in 2023.
85. S/2006 S12: Discovered in 2006, announced in 2023.
86. S/2006 S13: Discovered in 2006, announced in 2023.
87. S/2006 S14: Discovered in 2006, announced in 2023.
88. S/2006 S15: Discovered in 2006, announced in 2023.
89. S/2006 S16: Discovered in 2006, announced in 2023.
90. S/2006 S17: Discovered in 2006, announced in 2023.
91. S/2006 S18: Discovered in 2006, announced in 2023.
92. S/2006 S19: Discovered in 2006, announced in 2023.
93. S/2006 S20: Discovered in 2006, announced in 2023.
94. S/2007 S2: Discovered in 2007 by Scott S. Sheppard, David L. Jewitt, and Jan T. Kleyna. Mean diameter: 6 km (3.7 mi).
95. S/2007 S3: Discovered in 2007 by Scott S. Sheppard, David L. Jewitt, and Jan T. Kleyna. Mean diameter: 5 km (3.1 mi).
96. S/2007 S 5: Discovered in 2007, announced in 2023.
97. S/2007 S 6: Discovered in 2007, announced in 2023.
98. S/2007 S 7: Discovered in 2007, announced in 2023.
99. S/2007 S 8: Discovered in 2007, announced in 2023.
100. S/2007 S 9: Discovered in 2007, announced in 2023.
101. S/2009 S1: This tiny new moonlet, situated about 300 miles (480 kilometers) inward from the outer edge of the B ring, was found by detection of its shadow which stretches 25 miles, or 41 kilometers, across the rings. Mean diameter: 300 meters (984 feet).
102. S/2019 S1: Discovered in 2019, announced in 2023.
103. S/2019 S2: Discovered in 2019, announced in 2023.
104. S/2019 S3: Discovered in 2019, announced in 2023.
105. S/2019 S4: Discovered in 2019, announced in 2023.
106. S/2019 S5: Discovered in 2019, announced in 2023.
107. S/2019 S6: Discovered in 2019, announced in 2023.
108. S/2019 S7: Discovered in 2019, announced in 2023.
109. S/2019 S8: Discovered in 2019, announced in 2023.
110. S/2019 S9: Discovered in 2019, announced in 2023.
111. S/2019 S10: Discovered in 2019, announced in 2023.
112. S/2019 S11: Discovered in 2019, announced in 2023.
113. S/2019 S12: Discovered in 2019, announced in 2023.
114. S/2019 S13: Discovered in 2019, announced in 2023.
115. S/2019 S14: Discovered in 2019, announced in 2023.
116. S/2019 S15: Discovered in 2019, announced in 2023.
117. S/2019 S16: Discovered in 2019, announced in 2023.
118. S/2019 S17: Discovered in 2019, announced in 2023.
119. S/2019 S18: Discovered in 2019, announced in 2023.
120. S/2019 S19: Discovered in 2019, announced in 2023.
121. S/2019 S20: Discovered in 2019, announced in 2023.
122. S/2019 S21: Discovered in 2019, announced in 2023.
123. S/2020 S1: Discovered in 2020, announced in 2023.
124. S/2020 S2: Discovered in 2020, announced in 2023.
125. S/2020 S3: Discovered in 2020, announced in 2023.
126. S/2020 S4: Discovered in 2020, announced in 2023.
127. S/2020 S5: Discovered in 2020, announced in 2023.
128. S/2020 S6: Discovered in 2020, announced in 2023.
129. S/2020 S7: Discovered in 2020, announced in 2023.
130. S/2020 S8: Discovered in 2020, announced in 2023.
131. S/2020 S9: Discovered in 2020, announced in 2023.
132. S/2020 S10: Discovered in 2020, announced in 2023.
133. Siarnaq: Discovered on September 23, 2000, by Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, Hans Scholl, Matthew J. Holman, Brian G. Marsden, Phillip D. Nicholson, and Joseph A. Burns. Mean diameter: 39.3±5.9 km (about 25 mi).
134. Skathi: Discovered on September 23, 2000, by Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, Hans Scholl, Matthew J. Holman, Brian G. Marsden, Phillip D. Nicholson, and Joseph A. Burns. Mean diameter: 8 km (5 mi).
135. Skoll: Discovered on March 6, 2006, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna. Mean diameter: 5 km (3.1 mi).
136. Skrymir: Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 7, 2019, from observations taken between December 12, 2004, and March 22, 2007. Mean diameter: 4 km (2.5 mi).
137. Surtur: Discovered on March 6, 2006, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna using the Subaru 8.3-m reflector telescope on Mauna Kea, Hawaii. Mean diameter: 6 km (3.7 mi).
138. Suttungr: Discovered in 2000 by Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, Hans Scholl, Matthew J. Holman, Brian G. Marsden, Phillip D. Nicholson, and Joseph A. Burns. Mean diameter: 7 km (4.3 mi).
139. Tarqeq: Discovered on January 16, 2007, by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna. Mean diameter: 6 km (3.7 mi).
140. Tarvos: Discovered on September 23, 2000, by Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, Hans Scholl, Matthew J. Holman, Brian G. Marsden, Phillip D. Nicholson, and Joseph A. Burns. Mean diameter: 15 km (9.3 mi).
141. Telesto: Discovered in 1980 using ground-based observations by Brad Smith, Harold Reitsema, Stephen Larson, and John Fountain. Mean radius: 12.4 km (7.7 mi).
142. Tethys: Discovered by Giovanni Cassini on March 21, 1684. Mean diameter: 1062.2±1.2 km (about 660 mi).
143. Thiazzi: Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 8, 2019, from observations taken between December 12, 2004, and March 22, 2007. Mean diameter: 4 km (2.5 mi).
144. Thrymr: Discovered in 2000 by Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, Hans Scholl, Matthew J. Holman, Brian G. Marsden, Phillip D. Nicholson, and Joseph A. Burns. Mean diameter: 8 km (5 mi).
145. Titan: Discovered in 1655 by the Dutch astronomer Christiaan Huygens (14 April 1629 – 8 July 1695), it is Saturn’s largest moon, and the second-largest natural satellite in the Solar System (after Ganymede). It is the only moon known to have a dense atmosphere, and the only known moon or planet other than Earth on which clear evidence of stable bodies of surface liquid has been found. Mean radius 2574.73±0.09 km (0.404 Earths, 1.480 Moons) (about 1600 mi).
146. Ymir: Discovered in 2000 by Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, Hans Scholl, Matthew J. Holman, Brian G. Marsden, Phillip D. Nicholson, and Joseph A. Burns. Mean diameter: 19 km (11.8 mi).

Related: Living on Mars is a terrible idea, we should colonize Titan, instead, scientist says

Uranus: 27 moons

Uranus‘ moons are unique in being named for Shakespearean characters, along with a couple of the moons being named for characters from the works of the English poet Alexander Pope (21 May 1688 – 30 May 1744).

1. Ariel: Discovered on October 24, 1851, by William Lassell, one of 19th century England’s grand amateur astronomers, who used the fortune he made in the brewery business to finance his telescopes. Mean radius: 578.9±0.6 km (about 360 mi).
2. Belinda: Discovered on January 13, 1986, in images taken by Voyager 2. Dimensions: 128 x 64 x 64 km (79.5 x 39.8 x 39.8 mi).
3. Bianca: Discovered on January 23, 1986, in images taken by Voyager 2. Dimensions: 64 x 46 x 46 km (39.8 x 28.6 x 28.6 mi).
4. Caliban: Discovered on September 6, 1997, at Palomar Observatory by B. Gladman, P. Nicholson, J. A. Burns, and J. Kavelaars. Mean diameter: 42 km (26 mi).
5. Cordelia: Discovered on January 20, 1986, in images taken by Voyager 2. Dimensions: 50 x 36 x 36 km (31 x 22.4 x 22.4 mi).
6. Cressida: Discovered on January 9, 1986, in images taken by Voyager 2. Dimensions: 92 x 74 x 74 km (57.2 x 46 x 46 mi).
7. Cupid: Discovered on August 25, 2003, by M.R. Showalter and J.J. Lissauer, using the Hubble Space Telescope. Mean radius: 9 km (5.6 mi).
8. Desdemona: Discovered on January 13, 1986, in images taken by Voyager 2. Dimensions: 90 x 54 x 54 km (56 x 33.6 x 33.6 mi).
9. Ferdinand: Discovered on August 13, 2001, by Dan Milisavljevic, Matthew J. Holman, John J. Kavelaars, and Tommy Grav, at the Cerro Tololo Inter-American Observatory. Mean radius: 6 km (3.7 mi).
10. Francisco: Discovered on August 13, 2001, at Cerro Tololo Inter-American Observatory by John J. Kavalaars, Matthew J. Holman, Dan Milisavljevic, and Tommy Grav. Mean radius: 11 km (6.8 mi).
11. Juliet: Discovered on January 3, 1986, in images taken by Voyager 2. Dimensions: 150 x 74 x 74 km (93.2 x 46 x 46 mi).
12. Mab: Discovered on August 23, 2003, by Mark R. Showalter and Jack J. Lissauer, using the Hubble Space Telescope. Mean radius: 6-12 km (3.7-7.4 mi).
13. Margaret: Discovered by Scott S. Sheppard, et al. in 2003. It is considered an irregular moon of Uranus because of the eccentricity and inclination of its orbit, but it is the only such moon that travels in a prograde direction. Mean radius: 10 km (6.2 mi).
14. Miranda: Discovered in telescopic photos of the Uranian system by the Dutch astronomer Gerard P. Kuiper (7 December 1905 – 23 December 1973) on February 16, 1948, at the McDonald Observatory in western Texas. It has a surface unlike any other moon that’s been seen. It has giant fault canyons as much as 12 times as deep as the Grand Canyon, terraced layers and surfaces that appear very old, and others that look much younger. Mean radius: 235.8±0.7 km (about 146 mi).
15. Oberon: Discovered on January 11, 1787, by William Herschel. It is the second largest and second most massive of the Uranian moons, and the ninth most massive moon in the Solar System. Mean radius: 761.4±2.6 km (about 473 mi) (0.1194 Earths).
16. Ophelia: Discovered in January 1986 in images sent back by the Voyager 2 spacecraft during its flyby of Uranus. Dimensions: 54 x 38 x 38 km (33.5 x 23.6 x 23.6 mi).
17. Perdita: Discovered 13 years after its picture was taken by Voyager 2 during the spacecraft’s flyby in 1986. Mean radius: 15±3 km (about 18.6 mi).
18. Portia: Discovered in January 1986 in images sent back by the Voyager 2 spacecraft during its flyby of Uranus. Dimensions: 156 x 126 x 126 km (97 x 78.3 x 78.3 mi).
19. Prospero: Discovered on July 18, 1999, by Matthew J. Holman, John J. Kavelaars, Brett J. Gladman, Jean-Marc Petit, and Hans Scholl using the Canada-France-Hawaii Telescope at the Mauna Kea Observatory on the island of Hawaii. Mean radius: 25 km (15.5 mi).
20. Puck: Discovered in December 1985 in images sent back by the Voyager 2 spacecraft during its flyby of Uranus. Mean radius: 81± 2 km (about 50 mi).
21. Rosalind: Discovered by the Voyager 2 science team on 13 January 1986. Mean radius: 36±6 km (about 23 mi).
22. Setebos: Discovered on July 18, 1999, by the Canadian astronomer John J. Kavelaars et al, it is a small, dark moon (assuming an albedo of 0.04) that orbits Uranus in the opposite direction from the regular moons and the planet’s rotation (known as a retrograde orbit). Mean radius: 24 km (15 mi).
23. Stephano: Discovered on July 18, 1999, by Brett Gladman, Matthew Holman, John J. Kavelaars, Jean-Marc Petit, and Hans Scholl using the Canada-France-Hawaii Telescope at the Mauna Kea Observatory on the island of Hawaii. Mean radius: 16 km (10 mi).
24. Sycorax: Discovered on Sept. 6, 1997, by Philip D. Nicholson, Brett J. Gladman, Joseph A. Burns, and John J. Kavelaars using the 200-inch Hale Telescope at Palomar Observatory. Mean diameter: 157 km (98 mi).
25. Titania: Discovered on January 11, 1787, by British astronomer William Herschel. It is the largest of the moons of Uranus and the eighth-largest moon in the Solar System. Mean radius: 788.4±0.6 km (490 mi) (0.1235 Earths).
26. Trinculo: Discovered on August 13, 2001, by Matthew Holman, John J. Kavelaars and Dan Milisavljevic at the Dominion Astrophysical Observatory in Victoria, British Columbia, and by using the 4-m reflector at the Cerro Tololo Inter-American Observatory. Mean radius: 9 km (5.6 mi).
27. Umbriel: Discovered on October 24, 1851, by the English astronomer William Lassell. Mean radius: 584.7±2.8 km (about 363 mi) (0.092 Earths).

Neptune: 14 moons

1. Despina: Discovered in July 1989 by the Voyager 2 science team. Dimensions: 180 x 148 x 128 km (112 x 92 x 80 mi).
2. Galatea: Discovered in July 1989 by the Voyager 2 science team. Dimensions: 204 x 184 x 144 km (127 x 114 x 89 mi).
3. Halimede: Discovered on August 14, 2002, by Matthew J. Holman, John J. Kavelaars, Tommy Grav, Wesley C. Fraser, and Dan Milisavljevic. Mean diameter: 62 km (38.5 mi).
4. Hippocamp: Discovered on July 1, 2013, this tiny moon may be a piece of the larger Neptune moon Proteus. Mean radius: 17.4±2.0 km (about 11 mi).
5. Laomedeia: Discovered on August 13, 2002, by Matthew J. Holman, John J. Kavelaars, Tommy Grav, Wesley C. Fraser, and Dan Milisavljevic. Mean diameter: 42 km (26 mi).
6. Larissa: Although it was initially spotted by H. Reitsema, W. Hubbard, L. Lebofsky, and D. Tholen through ground-based telescopes in 1981, Larissa was officially discovered in July 1989 by the Voyager 2 science team. Dimensions: 216 x 204 x 168 km (134 x 127 x 104 mi).
7. Naiad: It was the last moon to be discovered during the Voyager 2 flyby in September 1989. Dimensions: 96 x 60 x 52 km (60 x 37 x 32 mi).
8. Nereid: Discovered on May 1, 1949, by Gerard P. Kuiper with a ground-based telescope. Mean diameter: 357±13 km (about 220 mi).
9. Neso: Discovered in 2002 by Matthew J. Holman, John J. Kavelaars, Tommy Grav, Wesley C. Fraser, and Dan Milisavljevic using the 4-m Blanco telescope at Cerro Tololo Observatory in Chile. Mean diameter: 60 km (37.3 mi).
10. Proteus: Discovered in 1989 by the Voyager 2 spacecraft. Dimensions: 424 x 390 x 396 km (163 x 242 x 246 mi).
11. Psamathe: Discovered by Scott S. Sheppard, David C. Jewitt, and Jan T. Kleyna on August 29, 2003, using the 8.3-m Subaru reflector at the Mauna Kea Observatory on the island of Hawaii. Mean diameter: 40 km (25 mi).
12. Sao: Discovered on August 14, 2002, by Tommy Grav, Matthew J. Holman, John J. Kavelaars, Wesley C. Fraser, and Dan Milisavljevic. Mean diameter: 44 km (27 mi).
13. Thalassa: Discovered in August 1989 in images taken by Voyager 2. Dimensions: 108 x 100 x 52 km (67 x 62 x 32 mi).
14. Triton: It is the first Neptunian moon to be discovered, on October 10, 1846, by English astronomer William Lassell. Triton is the only known satellite in our solar system to have a surface made mainly of nitrogen ice. Mean radius: 1,353.4±0.9 km (about 841 mi) (0.2122 Earth).

Related: Top 10 Largest Non-Planets In Our Solar System

Pluto: 5 moons

Pluto’s entire moon system is believed to have formed by a collision between the dwarf planet and another Kuiper Belt Object early in the history of the solar system.

1. Charon: It was discovered in 1978 at the United States Naval Observatory in Washington, D.C., by James Christy, using photographic plates taken at the United States Naval Observatory Flagstaff Station (NOFS). At half the size of Pluto, Charon is the largest of Pluto’s moons and the largest known satellite relative to its parent body. Pluto and Charon are tidally locked. Mean radius: 606.0±0.5 km (about 376 mi).

2. Hydra: Discovered in June 2005, by the American astronomer Hal Weaver and a large team of astronomers using the Hubble Space Telescope. Dimensions: 50.9 x 36.1 x 30.9 km (31.6 x 22.4 x 19.2 mi).
3. Kerberos: Its existence was announced on July 20, 2011. This tiny moon appears to be smaller than scientists expected and has a highly-reflective surface. Dimensions: 19 x 10 x 9 km (11.8 x 6.2 x 5.6 mi).
4. Nix: Discovered in June 2005 by Hal Weaver and a large team of astronomers using the Hubble Space Telescope. Dimensions: 49.8 x 33.2 x 31.1 km (31 x 20.6 x 19.3 mi).
5. Styx: Discovered on June 26, 2012, by a large team led by Mark Showalter using the Hubble Space Telescope. It is the smallest known moon of Pluto. Dimensions: 16 x 9 x 8 km (10 x 5.6 x 5 mi).

Sources

• NASA Solar System website
• Jupiter moons on the NASA Solar System website
• Saturn moons on the NASA Solar System website
• Moons of Jupiter on Wikipedia
• Hydrostatic equilibrium on Wikipedia
• Hydrostatic equilibrium on asterism.org
• Saturnian Satellite Fact Sheet on the NASA website
• Uranus Moons on the NASA Solar System website
• Neptune Moons on the NASA Solar System website
• Pluto Moons on the NASA Solar System website

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M. Özgür Nevres

I am a software developer and a science enthusiast. I was graduated from the Istanbul Technical University (ITU), Computer Engineering. In the past, I worked at the Istanbul Technical University Science Center as a science instructor. I write about the planet Earth and science on this website, ourplnt.com. I am also an animal lover! I take care of stray cats & dogs. This website's all income goes directly to our furry friends. Please consider supporting me on Patreon, so I can help more animals!

Latest posts by M. Özgür Nevres (see all)

• Space Shuttle Endeavour’s Touchdown Meets Columbia’s Salute [An amazing photo from the past] - February 29, 2024
• Moon Landings: All-Time List [1966-2024] - February 23, 2024
• From Orbit to Ordinary: 10 Earthly Applications of Space Technology - January 23, 2024