The solar system is a collection of planets and other celestial bodies that orbit a central star, with Earth being part of the one that orbits the Sun. The planets are defined by the International Astronomical Union and are grouped into inner and Jovian planets based on their physical properties and arrangement in space. The gravitational pull of the sun is responsible for the elliptical orbits of the planets, and planetary motion was first accurately described by Johannes Kepler and later explained by Isaac Newton.
A solar system is defined as the collection of planets and other celestial bodies – such as asteroids, comets and meteors – that orbit a central star. Most often when we talk about a solar system, we’re talking about the one that Earth is a part of: the group of planets and other celestial bodies that orbit the star we call the Sun.
In our solar system, celestial bodies that surround the sun and are held by its gravity include dwarf planets and natural satellites, as well as asteroids, comets and meteors. There are now considered to be eight planets, which in order from the sun outward are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Although considered a planet for many years, Pluto was reclassified in 2006 and is now called a dwarf planet.
The planets are now defined by the International Astronomical Union according to several criteria. To be considered a planet, a celestial body must:
don’t be a star
orbit a star
have sufficient mass to be nearly spherical
it has cleared its orbit of other objects
The planets in our solar system have a lot in common: they all rotate on their axis as they revolve around the sun in the same direction. However, the planets in our system have different physical properties and, based on these properties and their arrangement in space, they are commonly grouped into the inner planets and Jovian planets. Jupiter is an alternative name for the god Jupiter.
The inner planets of our solar system, those closest to the sun, are Mercury, Venus, Mars and the Earth. These planets are smaller and denser, with solid crusts and molten interiors. Three of the four – all except Mercury – have a gaseous atmosphere. Jovian planets are larger and less dense, with thick atmospheres.
The gravitational pull of the sun is responsible for the elliptical orbits of the planets in our solar system. Johannes Kepler first accurately described planetary motion in the early 1600s. It was Isaac Newton who demonstrated that Kepler’s laws of planetary motion applied to other celestial bodies in the solar system and were the result of the sun’s gravitational pull.
Protect your devices with Threat Protection by NordVPN
