Environment

The Hottest And Coldest Planets Of Our Solar System

Despite being closer to the sun, Mercury is not the hottest planet in the solar system as the planet Venus holds this title.

Planets vary in temperatures as they vary in structure and distance from the sun. Temperatures are influenced by the distance of planets from the sun - as the distance increases, the temperature decreases. Both interior and exterior factors are responsible for temperature variations within the planets. The nature and composition of the atmosphere, for example, determines the amount of heat radiated and how much heat the planet retains.

Venus

Venus is the second planet from the sun and the hottest in the solar system. Its temperatures can reach 464ºC. The high temperatures are due to a dense atmosphere with a thick cloud cover. Carbon dioxide makes up the bulk of the planet’s atmospheric gasses thus acting as a blanket that keeps heat from escaping the planet. The temperatures are regular throughout the year with slightly negligible variations. In contrast to other planets, its small elliptical tilt of 3º does not affect temperatures, allowing them to remain steady.

Mercury

Mercury is the first and smallest planet in the solar system. Although it is nearest to the sun, it is the second hottest. Unlike Venus, Mercury lacks an atmosphere thus experiences varying temperatures throughout the day. The temperature may fall to -93ºC or rise to 427ºC with an average of 167ºC. The temperatures on Mercury are under a direct influence from the sun. Therefore, the side facing the sun is often scorching while that on the shadowed side is freezing. Astronomers believe the polar regions of Mercury are never reached by the sun and therefore could be colder than the cloud tops of Jupiter.

Pluto

Pluto is a dwarf planet made of ice and rock. Originally thought to be the ninth planet, Pluto is the furthest from the sun and has recorded the coldest temperatures at an average of -225ºC. The temperatures in Pluto are influenced by its closeness to the sun – when the planet is close to the sun, temperatures warm up enough to sublime nitrogen within Pluto’s atmosphere. Surface temperatures are cooler than atmospheric temperatures due to the influence of methane which creates a temperature inversion. Pressure waves in the atmosphere reduce the temperatures making them cooler than expected.

Neptune

Ever since the disqualification of Pluto as a planet, Neptune is considered the coldest planet with average temperatures of -200ºC. Neptune is the eighth planet in the solar system composed of primarily hydrogen and helium gasses. Neptune experiences pressure and temperature variations depending on the altitude. Due to its distance from the sun, the temperatures on Neptune are influenced more by the radiation within it than from the sun. Its elliptical tilt of 23.4º warms up the sun-facing side raising temperatures by about 10º - enough to allow methane to escape. In their interior, planets also experience temperature variations which occur during their movement around the sun or as an influence of internal factors such as winds and pressure changes. Gaseous planets lack a defined surface temperature as compared to terrestrial planets.

Average temperatures of other planets are: Earth (15ºC), Mars (-65ºC), Jupiter (-110ºC), Saturn (-140ºC) and Uranus (-195ºC).

The Hottest And Coldest Planets Of Our Solar System

RankPlanetMean Temperature (C)
1Venus 464
2 Mercury167
3 Earth15
4 Mars-65
5 Jupiter-110
6 Saturn-140
7 Uranus-195
8 Neptune-200
9 Pluto-225

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