Which is hot Mercury or Venus


Why is Venus hotter than Mercury?

Why is the average temperature of Venus higher than that of Mercury, even though it is significantly further away from the Sun? The key word to answer this question is the "greenhouse effect". It is of vital importance for the earth and the understanding of the climatology of other planets. The greenhouse effect describes the ability of atmospheric gas compositions to store absorbed heat are divided into different wavelength ranges, each of which is characterized by a specific energy spectrum, such as visible light, for example infrared or UV radiation, which is also emitted by the sun.

Although this radiation is not visible, it can be measured physically and made visible through technical processes. After the electromagnetic radiation arriving from the sun has penetrated the earth's atmosphere, it hits the earth's surface. Part of the energy is absorbed there. The radiation is then reflected back into space. Fortunately there are some gases in the atmosphere such as CO2, methane or water vapor that do not release the radiation reflected back from the surface into space but store it on earth. This leads to warming in the long term. In short: some greenhouse gases in the atmosphere prevent the penetrating thermal radiation from the sun from being released back into space.

After all, Venus is significantly farther from the Sun than Mercury. The temperature of a planet is largely determined by the efficiency of the greenhouse effect. Since the atmosphere of Venus consists almost entirely of CO2, the heat-storing effect on it is enormous! Why this atmospheric development came about and why the earth has little CO2 compared to Venus has not yet been clearly clarified. However, volcanic activity could have been a decisive mechanism that drove the development paths of the two planets so starkly apart.