Jan

Our solar system

A planet is a star with three major characteristics: to be in orbit around a star, to have a more or less spherical shape and to have created a vacuum around it (that is to say, to no longer have a body of size comparable to its own in a close orbit).

The main planets in our solar system are:

Mercury

Surface with many craters, due to meteorite impacts / presence of ice at the poles / non-existent atmosphere except for the presence of traces of gas / large temperature differences between -172°C to 427°C / no satellite.

Venus

Surface with many mountains, canyon, volcanoes and riddled with craters without any trace of water / atmosphere composed of carbon dioxide (CO2), nitrogen (N2), sulfur dioxide (S2) and sulfuric acid ( H2S) / very important greenhouse effect / average temperature of 453°C / no satellite.

Earth

Surface rich in minerals, presence of crater and varied relief / large quantity of water (in different forms but essentially salty), characteristic of the presence of life / atmosphere composed of nitrogen (N2), oxygen (O2), d argon (Ar), carbon dioxide (CO2), water vapor (H2O) and other gases / temperatures varying between -60°C and 50°C / known satellite The Moon.

March

Red surface characterized by the presence of hematite (mineral species composed of iron oxide, titanium, aluminum), manganese and water) with a very varied relief and numerous craters) / presence of ice at the poles / atmosphere composed of carbon dioxide (CO2), nitrogen (N2), argon (Ar) and oxygen (O2) / significant temperature differences between -123°C to 37°C / presence of strong winds / two known satellites Phobos and Deimos.

Jupiter

Largest planet in the solar system / no trace of water / significant atmosphere composed of hydrogen (H2), helium (He), ammonia (NH3), methane (CH4) and ethane (C2H6) / temperature outside the clouds around -153°C / strong winds that can reach more than 500 km h / 67 known satellites including Ganymede, Lo and Europe.

Saturn

Presence of thousands of colored rings made of ice and rocks / no trace of water / significant atmosphere composed of hydrogen (H2), helium (He), ammonia (NH3) and methane (CH4) / temperature outside the clouds about -185°C / 62 known satellites including Titan.

Uranus

Qualified as an ice giant / presence of greenish gases forming an atmosphere of hydrogen (H2), helium (He) and methane (CH4) / no trace of water / temperature outside the clouds around -214°C / 27 known satellites.

Neptune

Qualified as an ice giant / presence of bluish gases forming an atmosphere of hydrogen (H2), helium (He) and methane (CH4) / no trace of water / temperature outside the clouds around -225°C / strong winds that can go to more than 2000 km h / 14 known satellites.

These planets fall into three main groups:

A. Terrestrial planets, essentially composed of rocks and metals, also possessing a solid surface. This is the case for Mercury, Venus, Earth and Mars, which have several solid envelopes (usually three: the crust, the mantle and the core).

B. The Jovian planets, essentially composed of gaseous elements and are the largest in our solar system. They have a thick atmosphere (even if they are gaseous) and would probably have a solid rocky core according to scientific research. This is the case for Jupiter, Saturn, Uranus and Neptune.

C. Dwarf planets, a recently created category, have the main characteristics of planets, but with the difference that they share their orbit with other bodies such as asteroids. Below are the five planets concerned:

Eris

The most massive known dwarf planet, located beyond the Kuiper belt, discovered in 2003 and identified in 2005.