Hobbies And Interests
The Sun
The Sun is a typical star composed of hot gases that are involved in constant nuclear fusion reactions. It is 870,000 miles in diameter and estimated to be 4.5 billion years old. The temperature at the very core of the Sun is thought to be close to 22.5 million degrees Fahrenheit, while the surface of this star is much cooler at 7,000 degrees Fahrenheit.
Planets
There are eight planets in the solar system. In order from the Sun, they are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Easily the largest of these is Jupiter, with a diameter at its equator of 88,736 miles. Mercury, Venus, Earth and Mars are called the inner planets and also are known as terrestrial planets, while Jupiter, Saturn, Uranus and Neptune are called outer planets or gas giants. The inner planets have a rocky core and are significantly smaller than the outer ones, which are composed mostly of gases, have multiple satellites called moons and have rings of fine ice crystals and rock. Mercury takes just 88 Earth days to complete one orbit of the Sun, since it is the closest planet at only 28 million miles from the star. Neptune, the far outer planet, takes 165 Earth years to orbit the Sun, being an average distance of 2.8 billion miles from it.
Dwarf planets
In 2006, the International Astronomical Union came up with a designation for those heavenly bodies that are smaller than planets but larger than asteroids and comets. These dwarf planets are Pluto, Ceres, Makemake, Eris and Haumea. Pluto, which is beyond even the orbit of Neptune, was considered a planet since its discovery in 1930 until it was reclassified as a dwarf planet. Ceres lies in the area between Mars and Jupiter known as the asteroid belt while Pluto, Makemake, Eris and Haumea orbit the Sun in the far outer fringes of the solar system known as the Kuiper Belt. Astronomers have found hundreds of objects in this area comprised of rock and ice, with many more thought to still be unseen by human eyes.
Asteroids
The asteroids are rocky bodies that scientists theorize are made up of material from when the solar system first formed. There are more than 100,000 separate asteroids in the vast area between Mars and Jupiter; this makes some scientists feel that they are the remains of a planet that broke apart. The largest of the asteroids are given names, with some of the bigger ones like Pallas, Juno and Vesta being hundreds of miles in diameter.
Comets and meteors
Comets are composed of ice and dust. They orbit the Sun in paths that differ from those of the planets, coming close to it and then swinging around the star to disappear into the great emptiness of space. When a comet gets close enough to the Sun, the heat causes it to evaporate and a glowing tail of gases and dust forms a "tail" that extends millions of miles from the comet. Comets such as Halley's come back at regular intervals as they orbit the Sun. A meteor is a piece of rock, metal or dust that enters the Earth's atmosphere at terrific speeds and burns up. Meteors are normally small, but larger ones can sometimes survive the trip through the atmosphere and reach the surface of the Earth, where they create craters and huge explosions as they vaporize.