Notifications
Clear all
Topic starter
Largest Moons in the Solar System
The 20 largest natural satellites, ordered by diameter. For the complete, continuously updated list of all ~290+ known moons, see NASA Solar System Moons or the JPL Planetary Satellite pages.
| Name | Parent | Diameter (km) | Mass (×10^20 kg) | Orbital Period (days) | Distance from Parent (km) | Discovered | Notable feature |
|---|---|---|---|---|---|---|---|
| Ganymede | Jupiter | 5268 | 1482 | 7.155 | 1,070,400 | 1610 (Galileo) | Largest moon in the solar system; only moon with its own magnetic field |
| Titan | Saturn | 5150 | 1345 | 15.95 | 1,221,870 | 1655 (Huygens) | Only moon with a substantial atmosphere and surface liquid (methane lakes) |
| Callisto | Jupiter | 4821 | 1076 | 16.69 | 1,882,700 | 1610 (Galileo) | Most heavily cratered object in the solar system |
| Io | Jupiter | 3643 | 893 | 1.769 | 421,700 | 1610 (Galileo) | Most volcanically active body known |
| Moon (Luna) | Earth | 3474 | 735 | 27.32 | 384,400 | — | Largest moon relative to its planet (excl. Pluto–Charon) |
| Europa | Jupiter | 3122 | 480 | 3.551 | 671,100 | 1610 (Galileo) | Subsurface ocean; prime astrobiology target |
| Triton | Neptune | 2707 | 215 | 5.877 (retrograde) | 354,759 | 1846 (Lassell) | Only large moon with a retrograde orbit; likely a captured Kuiper Belt object |
| Titania | Uranus | 1578 | 34.0 | 8.706 | 436,300 | 1787 (Herschel) | Largest moon of Uranus |
| Rhea | Saturn | 1527 | 23.1 | 4.52 | 527,108 | 1672 (Cassini) | Saturn's second-largest moon |
| Oberon | Uranus | 1523 | 30.1 | 13.46 | 583,500 | 1787 (Herschel) | Outermost major moon of Uranus |
| Iapetus | Saturn | 1469 | 18.1 | 79.32 | 3,560,820 | 1671 (Cassini) | Striking two-tone (light/dark) surface coloration |
| Charon | Pluto | 1207 | 15.9 | 6.387 | 19,591 | 1978 (Christy) | So large relative to Pluto that they orbit a shared barycenter outside Pluto |
| Umbriel | Uranus | 1170 | 12.8 | 4.144 | 266,000 | 1851 (Lassell) | Darkest of Uranus's major moons |
| Ariel | Uranus | 1158 | 12.5 | 2.520 | 191,020 | 1851 (Lassell) | Brightest of Uranus's major moons |
| Dione | Saturn | 1123 | 10.95 | 2.737 | 377,396 | 1684 (Cassini) | Bright wispy terrain from tectonic fracturing |
| Tethys | Saturn | 1062 | 6.17 | 1.888 | 294,619 | 1684 (Cassini) | Giant Odysseus impact crater; very low density (mostly ice) |
| Enceladus | Saturn | 504 | 1.08 | 1.370 | 237,948 | 1789 (Herschel) | Active water-ice geysers from a subsurface ocean; astrobiology target |
| Miranda | Uranus | 472 | 0.64 | 1.413 | 129,390 | 1948 (Kuiper) | Extreme, jumbled terrain suggesting past catastrophic disruption |
| Proteus | Neptune | 420 | 0.44 | 1.122 | 117,647 | 1989 (Voyager 2) | Second-largest irregular-shaped moon in the solar system |
| Mimas | Saturn | 396 | 0.379 | 0.942 | 185,539 | 1789 (Herschel) | "Death Star" moon due to giant Herschel crater |
Largest Asteroids in the Solar System
Ceres is excluded here as it is classified as a dwarf planet (see the planets/dwarf planets table). Ordered by diameter. Full catalogue (over 1.3 million numbered asteroids) is searchable at the JPL Small-Body Database Lookup.
| Number / Name | Diameter (km) | Distance from Sun (AU) | Eccentricity | Orbital Period (years) | Discovered | Notable feature |
|---|---|---|---|---|---|---|
| 4 Vesta | 525 | 2.362 | 0.0887 | 3.63 | 1807 (Olbers) | Brightest asteroid as seen from Earth; visited by NASA's Dawn mission (2011-2012) |
| 2 Pallas | 512 | 2.773 | 0.2313 | 4.62 | 1802 (Olbers) | Highly inclined, eccentric orbit; heavily cratered ("golf ball") surface |
| 10 Hygiea | 431 | 3.139 | 0.1146 | 5.56 | 1849 (De Gasparis) | Largest carbonaceous (C-type) asteroid; nearly spherical, a dwarf-planet candidate |
| 704 Interamnia | 326 | 3.062 | 0.1543 | 5.36 | 1910 (Cerulli) | Very dark surface (albedo ~0.07); poorly studied |
| 52 Europa | 315 | 3.095 | 0.1020 | 5.44 | 1858 (Goldschmidt) | Not to be confused with Jupiter's larger, more famous moon of the same name |
| 511 Davida | 289 | 3.168 | 0.1869 | 5.64 | 1903 (Dugan) | One of the largest C-type (carbonaceous) asteroids |
| 87 Sylvia | 286 | 3.485 | 0.0800 | 6.51 | 1866 (Pogson) | First asteroid discovered to have two moons (Romulus and Remus) |
| 16 Psyche | 226 | 2.92 | 0.134 | 4.99 | 1852 (De Gasparis) | Unusually metal-rich (iron-nickel); target of NASA's Psyche mission (launched 2023) |
| 15 Eunomia | 268 | 2.643 | 0.187 | 4.30 | 1851 (De Gasparis) | Largest S-type (stony) asteroid |
| 3 Juno | 258 | 2.672 | 0.2555 | 4.37 | 1804 (Harding) | One of the first four asteroids discovered |
Notable Near-Earth Asteroids
Small, but scientifically or publicly significant due to close Earth approaches or spacecraft missions.
| Name | Diameter (km) | Notable feature |
|---|---|---|
| 99942 Apophis | ~0.34 | Will pass within ~32,000 km of Earth on 13 April 2029 (closer than geostationary satellites); no impact risk |
| 101955 Bennu | ~0.49 | Sample returned to Earth by NASA's OSIRIS-REx mission (2023); small chance of a distant-future Earth encounter being studied |
| 162173 Ryugu | ~0.90 | Sampled by Japan's Hayabusa2 mission (2019), samples returned to Earth in 2020 |
Notable Comets
Ranked by fame/significance rather than size, since most cometary nuclei are only roughly measured. Full catalogue at the JPL Small-Body Database Lookup (search by comet designation) or the JPL discovery statistics pages.
| Designation | Name | Orbital Period | Perihelion (AU) | Aphelion (AU) | Nucleus (km) | Notable fact |
|---|---|---|---|---|---|---|
| 1P/Halley | Halley's Comet | ~76 years | 0.586 | 35.1 | 15 x 8 (mean ~11) | Most famous periodic comet; retrograde orbit; next perihelion 2061 |
| 2P/Encke | Encke | 3.3 years | 0.34 | 4.09 | ~4.8 | Shortest confirmed orbital period of any named comet |
| 55P/Tempel-Tuttle | Tempel-Tuttle | 33 years | 0.98 | 19.7 | ~3.6 | Parent body of the Leonid meteor shower |
| 109P/Swift-Tuttle | Swift-Tuttle | 133.3 years | 0.96 | 51.2 | ~26 | Parent body of the Perseid meteor shower; next perihelion 2126 |
| 9P/Tempel 1 | Tempel 1 | 5.58 years | 1.54 | 4.75 | ~6 x 5 | Target of NASA's Deep Impact (2005) and Stardust-NExT (2011) missions |
| 81P/Wild 2 | Wild 2 | 6.41 years | 1.59 | 5.30 | ~5.5 | Sampled by NASA's Stardust mission; samples returned to Earth 2006 |
| 67P/Churyumov-Gerasimenko | 67P | 6.44 years | 1.24 | 5.68 | ~4.3 (max) | Orbited and landed on by ESA's Rosetta/Philae mission (2014-2016) |
| 17P/Holmes | Holmes | 6.9 years | 2.05 | 5.18 | ~3.4 | Underwent a massive 2007 outburst, briefly becoming the largest object in the solar system by coma size |
| 73P/Schwassmann-Wachmann 3 | SW3 | 5.4 years | 0.94 | 5.2 | ~1.1 (fragments) | Famously fragmented into dozens of pieces starting in 1995 |
| C/1995 O1 | Hale-Bopp | ~2,500 years | 0.914 | 354 | ~60 | Exceptionally bright Great Comet of 1997; visible to the naked eye for a record ~18 months |
| C/1996 B2 | Hyakutake | ~70,000 years | 0.230 | ~3400 | ~4.2 | Passed within 0.1 AU of Earth in 1996; one of the closest cometary approaches in centuries |
| D/1993 F2 | Shoemaker-Levy 9 | — | — | — | ~1-2 (fragments) | Broke apart and collided with Jupiter in July 1994; first observed impact of two solar system bodies |
| C/2012 S1 | ISON | — | 0.0124 | — | ~0.5-2 (est.) | Anticipated "great comet" that disintegrated during its close 2013 perihelion passage |
| C/2020 F3 | NEOWISE | ~6,800 years | 0.29 | ~700 | ~5 | Brightest naked-eye comet visible from the Northern Hemisphere since Hale-Bopp |
| C/2014 UN271 | Bernardinelli-Bernstein | ~600,000+ years | ~11 (in 2031) | ~40,000 | ~100-150 | Largest cometary nucleus ever measured; will not approach closer than Saturn's orbit |
This topic was modified 3 days ago by RayTomes
Posted : 20/07/2026 5:05 pm