The hottest planet in our Solar System

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Logically speaking, the planet closest to the Sun would be the hottest, and in most star systems, such is the case. However, the case in our solar system, is different.

The planet closest to the Sun is Mercury. For all planets, the side facing the Sun is a lot warmer than the side that is facing away from the Sun. For example, the sunny side of Mercury may reach temperatures of 430 degrees Celsius, while the opposite side plummets to nearly -200 degrees Celsius. We have special telescopes on Earth which collect specific wavelengths of the infrared light emitted by planets to determine their temperature.

Now in this blog we will focus on the sunny side of planets since we want to determine the hottest one. Now since Mercury is the closest to the Sun, it would have to be the hottest right? No, not really. Let us talk about Venus.

Venus has a dense atmosphere consisting of a lot of CO2 which is a greenhouse gas. Because of this dense atmosphere, not much sunlight reaches Venus’ surface however, thanks to these greenhouse gases present in the atmosphere, what ever little sunlight enters Venus, gets trapped causing the planet to get hotter effectively like an oven. As more sunlight enters and gets trapped, the planet gets hotter and hotter causing the surface temperatures to go up as high as 475 degrees Celsius; which is hot enough to melt lead.

So far the Soviet Union had managed to send several probes to the surface of Venus through the Verena missions which were the first to touch down on another planet. They emitted data for only a short time period because the extreme heat and pressure.

Images of Venus from the Verena Spacecraft

This is why we must prevent the concentration of greenhouse gases in the Earth’s atmosphere so that it doesn’t end up like Venus. It is believed that once Venus has Earth-like conditions suitable for life.

Because of the dense atmosphere, the heat stays trapped in the nighttime too, so it is as hot during the night as it is during the day. So to conclude, Venus is the hottest planet in our Solar System, not Mercury.