There are over 100 moons in orbit around the eight major planets of our Sun’s family. Most of our Solar System’s many moons are icy, relatively small objects, that contain small quantities of rocky material, and circle the quartet of giant gaseous planets in the colder outer region of our Solar System. The giant planets– Jupiter, Saturn, Uranus and Neptune–are enshrouded by layers and layers of gas, and are orbited by myriad moons and sparkling icy moonlets. In dramatic contrast the solid quartet of small inner Solar System planets–Mercury, Venus, Earth and Mars–are almost entirely barren of moons. Mercury and Venus have none, and Mars is orbited by a duo of small, shapeless little moons named Phobos and Deimos, that are likely asteroids that escaped from the Main Asteroid Belt situated between Mars and Jupiter. The wandering potato-shaped duo, during their long journey through interplanetaary space, traveled too close to the gravitational pull of Mars, and thus experienced a sea-change from migrating asteroids to the moons of a major planet.
In the warm and well-lit inner region of our Solar System, only Earth is orbited by a large Moon–and it is the fifth largest moon in our Sun’s family.
A moon is a natural satellite circling another body that itself is in orbit around its Star. A moon is kept in its place both by its host’s gravitational pull, as well as by its own gravity. Some planets have moons; some do not. Several asteroids are now known to be orbited by tiny moons of their own, and some dwarf planets–such as Pluto–are also circled by moons. One of Pluto’s five moons, Charon, is approximately 50% the size of Pluto. It has been proposed that Charon may really be a large chunk of Pluto itself that was ripped off as the result of a violent collision with another migrating object long ago. Because Charon is about half the size of Pluto, the two small worlds are sometimes classified as a double planet.
Several theories have been proposed over the years that attempt to explain how Earth’s Moon was born. One theory suggests that our Moon was once actually part of Earth, and that it budded off about 4.5 billion years ago. According to this scenario, the Pacific Ocean basin is the most likely place for Moon-birth to have occurred. A second theory proposes that the Earth and Moon were both born at about the same time from the original protoplanetary accretion disk, made up of gas and dust, from which our Sun and its family of familiar objects emerged. The third model suggests that Earth’s Moon was born elsewhere in our Solar System, and was ultimately snared by Earth’s gravitational embrace when it passed too close to our ancient planet. The fourth theory states that the interactions of Earth-orbiting and Sun-orbiting planetesimals (ancient planetary building blocks) in the early days of our Solar System caused them to fragment. According to this theory, Earth’s Moon eventually coalesced out of the pulverized debris of the shattered ancient planetesimals.
However, the Giant Impact Theory is considered to be the most probable explanation for the birth of Earth’s large Moon. When the tragedy that was the Mars-sized Theia crashed into Earth billions of years ago, the blast resulted in part of the ancient Earth’s crust to be launched into into space. This primeval catastrophe hurled myriad tiny moonlets screaming into the sky above our ancient planet. Some of this material was ultimately captured into Earth-orbit approximately 4.5 billion years ago–where it was finally pulled together by gravity to evolve into a single large Moon–Earth’s Moon.
Until Galileo Galilei discovered the four Galilean moons of Jupiter in 1610, it was thought that Earth’s large Moon was the Moon, because it was the only one known to exist. The discovery of the quartet of Galilean moons—Io, Europa, Ganymede and Callisto put the matter into its proper perspective. Earth’s Moon is not alone in our Solar System. In addition, there is also evidence that exomoons orbit some of the exoplanets that circle stars beyond our own Sun.
However, Earth’s Moon is the largest moon in our Solar System relative to the size of its host planet. For this reason, Earth and its Moon are sometimes considered to be a double planet–in a way similar to Pluto and its largest moon Charon. Earth’s Moon is also one of the densest natural satellites in our Sun’s family–second only to Jupiter’s innermost Galilean moon, Io.
As the fifth largest moon in our Solar System, only Ganymede (Jupiter), Titan (Saturn), Callisto (Jupiter) and Io (Jupiter) are bigger than Earth’s lunar companion.
Even though Theia came to a violent end, it did not die in vain. It’s been recognized for years that the doomed Theia made the emergence of life possible on our planet. This is because it is responsible for creating a comfortable abode for living creatures. The Moon–born from the wreckage of Theia–moderates Earth’s wobble on its axis, thus creating a stable climate. Earth’s Moon is also the source of ocean tides which form a rhythm that has guided human beings since ancient times. mkv movies download 2019 .