A solar system is a collection of planets, meteors, and other things that revolve around a big star. Everything that is gravitationally dragged into the sun's orbit is included in our solar system. While our galaxy contains at least 200 billion additional stars, the sun is the focal point of Earth's solar system.
Our solar system was not always so peaceful. In fact, it used to be a lot more crowded with planets that over time moved away from the sun. Four major planets still exist today, but scientists think there may have been dozens of smaller planets in our solar system in its earliest years.
The Kuiper belt is a ring-like structure of frozen objects that orbits beyond Neptune's influence. It was first discovered in 1951 by Dutch-American astronomer Jan Oort who found that objects once thought to be satellites of the planets were actually moving faster than expected because they were caught in an invisible field generated by some of the planets in our solar system. Today, scientists know that the Kuiper belt contains many small moons as well as large bodies such as Pluto. The discovery of these objects showed us that our solar system used to be much more active hundreds of millions of years ago when the planets were forming.
In conclusion, a solar system is a group of planets that orbit a star. Our solar system has eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
What exactly is a solar system? The solar system, in addition to the Sun, comprises of the celestial bodies that revolve around it: eight planets, dwarf planets, satellites, asteroids, comets, meteoroids, and interplanetary gas.
Earth's Satellites Earth has two types of satellite: natural satellites, which include the Moon, and artificial satellites such as the International Space Station (ISS) and Rosetta. Natural satellites orbit their primaries in an almost circular path, but artificial satellites can have very eccentric orbits. The term "satellite" comes from the Latin word for moon, sideris.
Mars' Satellites Mars has two types of satellite: Phobos and Deimos. Phobos is larger than Deimos and orbits around Mars every 687.4 miles (1116 km). It completes one orbit in about 12 hours, whereas Deimos takes 93.9 million years to complete one orbit!
Jupiter's Satellites Jupiter has four major moons: Io, Europa, Ganymede, and Callisto. All four were formed by the impact of material from outside the planet. Io is the most volcanically active body in the Solar System. It lies inside Jupiter's largest magnetic field, so it is completely covered by clouds made of sulfur dioxide gas.
Planets are enormous natural objects that move around or circle stars. The Sun is orbited by eight planets. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune are the planets closest to the Sun. They are all gas giants except for Pluto which is a dwarf planet.
What is so great about planets? They are huge, they are important in our lives, they make us feel small, and they show us how beautiful the universe is. As far as we know, everything on Earth has been called a planet at one time or another. Even objects such as comets and asteroids have been classed as planets until they enter an orbit around the Sun that takes them too far from the Sun to be considered a planet anymore.
Why do we care about planets? Because they affect our lives every day. A planet can be in the wrong place at the wrong time and collide with Earth, causing damage and killing people. Or it could be the cause of damage to Earth when it enters the wrong orbit. For example, if Mars had not gone into a deep freeze millions of years ago, it might have had water ice under its surface which would have turned into vapor when the sun came out after the last ice age and blotted out the sky with clouds. This would have caused major problems for humans and may have destroyed our species entirely.
The solar system has eight planets.
There are billions, if not trillions, of rogue objects circling the sun in our solar system. These spacefarers are too tiny to be named planets and are given the designations comets, asteroids, meteoroids, or meteors or meteorites if they reach Earth.
Comets are icy bodies that orbit the Sun far beyond the asteroid belt. They are so named because they appear to be clouds or dust bands across the sky. When viewed with a telescope, comets show as fuzzy balls of ice and dust.
Asteroids are rocky bodies that circle the Sun within the asteroid belt. They are so named because the first ones discovered seemed like stars until astronomers learned they were solid objects. Asteroids range in size from soccer balls to large cities, but they are all made of rock. Some are very rich in iron, others in silicon and oxygen. Most asteroids are found in orbits that take them between the orbits of Mars and Jupiter. However many interplanetary travelers are found in orbits taking them much farther from the Sun - including some that pass as close as 0.05 AU (55 million miles).
Meteoroids are small parts of asteroids or comets that fall to Earth. They are usually less than 50 microns (0.002 inches) across. Meteoroids are very rare: only about one in every million falls to Earth as a meteor.