|
Most moons in the Solar System are tidally locked to their parent planet. This means the same side of the natural satellite always faces its planet. The only known exception is Saturn's moon Hyperion, which rotates chaotically due to the gravitational influence of Titan.
|
|
The moons in our Solar System mostly were named after mythological characters from a variety of cultures. The exception is Uranus which was named for characters in William Shakespeare's plays and from Alexander Pope's poem "Rape of the Lock."
|
|
First moons are given provisional designations and then the International Astronomical Union approves an official name once the discovery is confirmed.
|
|
Earth has one large natural satellite, known as the Moon and sometimes referred to as Luna. It probably was formed when a large body about the size of Mars collided with Earth, ejecting a lot of material from our planet into orbit and formed the Moon approximately 4.5 billion years ago.
|
|
Twelve American astronauts landed on Earth's Moon during NASA's Apollo program from 1969 to 1972 and brought back rock samples. During that mission, astronaut Neil Armstrong was the first man to walk on the surface of the Earth's moon.
|
|
Inner planets Mercury and Venus do not have any moons.
|
|
In 1610, Galileo Galilei and Simon Marius independently discover four moons orbiting Jupiter and are known as the Galilean satellites in honor of Galileo's discovery. The discovery also confirms that the planets in our Solar System orbit the sun.
|
|
There are two moons of Mars, Phobos and Deimos which were discovered by Asaph Hall in 1877. Both have a nearly circular orbit and travel close to the plane of the planet's equator. Phobos is slowly moving closer to Mars and could crash into the planet in 40 to 50 million years.
|
|
Jupiter has at least 67 moons in orbit around it, the largest amount of natural satellites around any of the planets. It's 4 largest moons are Ganymede, Callisto, lo and Europa, and are known as the Galilean Moons which are named after their discoverer Galileo Galilei.
|
|
Saturn has at least 62 moons around it, ranging from very small to very large, such as Titan that was first observed in 1655 by Christiaan Huygens. Saturn's two moons, Janus and Epimetheus, swap orbits every 4 years.
|
|
Uranus is known to have 27 orbiting around it. In 1781, Uranus was discovered by William Herschel, who also observed the two largest moons, Titania and Oberon, in 1787.
|
|
Neptune has at least 14 moons, with the largest being Triton, discovered by William Lassell in 1846 one day after the discovery of Neptune. The most distant moon of Neptune is Neso which takes 26 years to make one trip around the planet.
|
|
Pluto has 5 moons, with its largest being Charon that is about half the size of Pluto.
|
