The Solar System is the gravitationally bound system of the Sun and the planets or cosmic objects that orbit it. In simple words, it is the collection of eight planets and their moons, together with smaller bodies in the form of asteroids, meteoroids, and comets.
Our planetary system is located in an outer spiral arm of the Milky Way galaxy. Our planetary system is called as “solar system” because Sun hosts the solar system and Sun is the center of our planetary system and everything around the system revolves within the gravitational force of the sun. According to NASA, Our Sun is named Sol, after the Latin word for Sun, “Solis,” and anything related to the Sun we call “solar.”
As we all know, there are eight planets in our solar system. But once upon a time Pluto and Ceres were also considered as planets until various new theories and discoveries poked scientific debate. Hence to end those misconceptions regarding planets following are the basic criteria for being a planet:
- It must orbit a star (sun) in its own orbit.
- It must be big enough to have enough gravity to form a spherical shape.
- It must not be a moon (satellite) of any other planet.
- It must clear debris or clear any cosmic object around its orbit.
Hence, Pluto and Ceres are considered dwarf planets now.
Based on the composition planets are divided into two categories. They are Terrestrial and Jovian. Asteroid belt containing dust and rocks separates Terrestrial and Jovian planets.
– Terrestrial planets:- It includes Mercury, Venus, Earth, and Mars. Being front of the asteroid belt these planets are called planets of the inner solar system. Terrestrial planets are primarily made up of rocky materials. Such planets have solid surfaces with no ring system. These planets are relatively small and have very few or even no moons.
– Jovian planets:- It includes Jupiter, Saturn, Uranus, and Neptune. These planets are known as planets of the outer solar system. Jupiter and Saturn are Gas Giants mostly made up of helium and hydrogen meanwhile Uranus and Neptune are Ice Giants containing rocky ice, a mixture of water, methane, and ammonia. Jovian planets support ring systems, have multiple moons and are immense large in size with no solid surfaces. Asteroid belt orbits terrestrial planets where lies Ceres and Kuiper Belt orbits Jovian planets where lies Pluto and is the origin of many comets. Beyond the Kuiper belt, there is the presence of Oort Cloud that contains much icy debris. Oort Cloud can be considered as the end of the solar system as it is that said gravitational force of sun acts till Oort Cloud.
Thank you Suwarna Pyakurel, +2-SOS HGS Sanothimi