Earth and other planets

Universe > Earth and the solar system > Earth and other planets

There are 8 planets in our Solar system that revolve around the Sun. The third closest planet to the Sun is the Earth. The inner part of our solar system has four terrestrial (solid) planets (Mercury, Venus, Earth and Mars) while the outer part has four giant planets (Jupiter, Saturn, Uranus, Neptune) composed mainly by gas and ice. All planets are very small compared to our Sun. Our Sun makes up 99.86% of the Solar systems total mass while all planets combined along with their moons and asteroids make up only 0.14%.

Connection to Big Idea about energy: The orbits of the celestial objects of our solar system (planets, comets, asteroids) are described by the conic sections (for example ellipses). The kind and the properties of the conic section that a celestial object will follow is determined by the specific orbital energy between the object and the Sun which is the constant sum of their mutual potential energy and their total kinetic energy divided by the reduced mass.

Connection to Big Idea about forces: All objects in the Universe are attracted to each other via the gravitational force. In our solar system, this force acts to hold the Earth and other planets in orbital motion around our central star, the Sun.

Connection to Big Idea about Earth: Earth is able to host life due to its precise position in respect to our star, the Sun. The zone around a star that allows the formation of life it is called the habitable zone. Earth is the only planet in our system that is lying in the habitable zone. Another critical parameter that allows the creation and maintenance of life on Earth is the existence of the planets Jupiter and Saturn. The two gas giant planets protect Earth from frequent collision with celestial fast moving objects such as comets since the two planets attract them due to their immense gravitational fields.  

Subjects related: Environmental Sciences, Physics

Age ranges: 10-11,11-12,12-13,13-14,14-15,15-16