Planets
All planets except Mercury and Venus have at least one moon. Saturn has the greatest number of moons—18. In 1995, the Hubble Space Telescope detected what appeared to be four additional moons of Saturn; however, that discovery has yet to be confirmed. Planet | Number of Moons | Names of Moons | Mercury | 0 | | Venus | 0 | | Earth | 1 | The Moon (sometimes called Luna) | Mars | 2 | Phobos, Deimos |
| Jupiter | 16* | Metis, Adrastea, Amalthea, Thebe, Io, Europa, Ganymede, Callisto, Leda, Himalia, Lysithia, Elara, Ananke, Carme, Pasiphae, Sinope | Saturn | 18* | Atlas, 1981S13 (unnamed as yet), Prometheus, Pandora, Epimetheus, Janus, Mimas, Enceladus, Ththys, Telesto, Calypso, Dione, Helene, Rhea, Titan, Hyperion, Iapetus, Phoebe | Uranus | 15 | Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Puck, Miranda, Ariel, Umbriel, Titania, Oberon, | Neptune | 8 | Naiad, Thalassa, Despina, Galatea, Larissa, Proteus, Triton, Nereid, | Pluto | 1 | Charon |
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Formation hypotheses
The nebular hypothesis was first proposed in 1734 by Emanuel Swedenborg[2] and later elaborated and expanded upon by Immanuel Kant in 1755. A similar theory was independently formulated by Pierre-Simon Laplace in 1796.[3]
In 1749, Georges-Louis Leclerc, Comte de Buffon conceived the idea that the planets were formed when a comet collided with the Sun, sending matter out to form the planets. However, Laplace refuted this idea in 1796, showing that any planets formed in such a way would eventually crash into the Sun. Laplace felt that the near-circular orbits of the planets were a necessary consequence of their formation.[4]Today, comets are known to be far too small to have created the Solar System in this way.[4]
In 1755, Immanuel Kant speculated that observed nebulae may in fact be regions of star and planet formation. In 1796, Laplace elaborated by arguing that the nebula collapsed into a
| Jupiter | 16* | Metis, Adrastea, Amalthea, Thebe, Io, Europa, Ganymede, Callisto, Leda, Himalia, Lysithia, Elara, Ananke, Carme, Pasiphae, Sinope | Saturn | 18* | Atlas, 1981S13 (unnamed as yet), Prometheus, Pandora, Epimetheus, Janus, Mimas, Enceladus, Ththys, Telesto, Calypso, Dione, Helene, Rhea, Titan, Hyperion, Iapetus, Phoebe | Uranus | 15 | Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Puck, Miranda, Ariel, Umbriel, Titania, Oberon, | Neptune | 8 | Naiad, Thalassa, Despina, Galatea, Larissa, Proteus, Triton, Nereid, | Pluto | 1 | Charon |
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Formation hypotheses
The nebular hypothesis was first proposed in 1734 by Emanuel Swedenborg[2] and later elaborated and expanded upon by Immanuel Kant in 1755. A similar theory was independently formulated by Pierre-Simon Laplace in 1796.[3]
In 1749, Georges-Louis Leclerc, Comte de Buffon conceived the idea that the planets were formed when a comet collided with the Sun, sending matter out to form the planets. However, Laplace refuted this idea in 1796, showing that any planets formed in such a way would eventually crash into the Sun. Laplace felt that the near-circular orbits of the planets were a necessary consequence of their formation.[4]Today, comets are known to be far too small to have created the Solar System in this way.[4]
In 1755, Immanuel Kant speculated that observed nebulae may in fact be regions of star and planet formation. In 1796, Laplace elaborated by arguing that the nebula collapsed into a