Main Features of our Solar System

Main Features of our Solar System

  • The solar system consists of the Sun at the centre, the eight planets, their moons, and all other celestial bodies that orbit the Sun, like asteroids, meteoroids, comets and dwarf planets.

  • The eight planets, in order from the Sun, are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. Pluto was earlier considered the ninth planet but has been reclassified as a dwarf planet.

  • The Sun is a star and makes up about 99.86% of the mass of the solar system. It is composed primarily of hydrogen and helium.

  • The inner four planets (Mercury, Venus, Earth, Mars) are called terrestrial planets as they have a rocky composition. The outer four planets (Jupiter, Saturn, Uranus, Neptune) are known as gas giants - Jupiter and Saturn are mainly composed of helium and hydrogen, while Uranus and Neptune, also known as the ice giants, have a higher proportion of ‘ices’ such as water, ammonia and methane.

  • The Asteroid Belt, lying approximately between Mars and Jupiter, contains irregularly shaped bodies called asteroids or minor planets.

  • Beyond Neptune’s orbit is the Kuiper Belt, a large region populated by small bodies - similar to the Asteroid Belt but many times wider. It is also the region where many comets originate.

  • The Oort Cloud is believed to exist at the very outer edges of the solar system, consisting of icy bodies and is believed to be the source of long-period comets.

  • Planets orbit the Sun in paths called orbits which are almost circular (elliptical). Each planet’s orbit around the Sun is in a slightly different plane.

  • The time it takes a planet to complete one orbit is considered a ‘year’ on that planet. The farther a planet is from the Sun, the longer its year.

  • The force of gravity from the Sun keeps the planets, asteroids, comets, etc. in their orbits.

  • Our solar system is located in the Milky Way galaxy, in a region known as the Orion Arm. There are billions of other galaxies in the Universe.

  • All stars, including the Sun, have a lifespan and go through a life cycle - they are born within nebulae, maintain stability for several billion years, and then evolve and die, often leading to a supernova explosion and leaving behind a white dwarf, neutron star, or black hole.