published in air
The climate of a planet mainly depends upon its mass, its distance from the sun and the composition of its atmosphere. Mars is a very cold planet, further from the Sun than the Earth. It is small and its atmosphere is very thin (the Earth’s atmosphere is 100 times thicker). Its atmosphere is mainly composed of carbon dioxide. The majority of the carbon dioxide on Mars is present as ice on the ground. All such factors lead to a –50°C average temperature of the soil of Mars. Venus has the same mass as the Earth but a thinner atmosphere, 96% of which is composed of carbon dioxide. It is much closer to the Sun than the Earth and the temperature of its soil is +460°C. In the absence of the atmosphere working as a “greenhouse”, the temperature of the Earth’s soil would be –20°C approximately. The climatic conditions of Mars and Venus are very different from those of the Earth but are more stable in time and forecasts are easier. On the contrary, millions of years of history show that the Earth’s climate is unstable and forecasts are much more difficult.