Hello! I'm Dr. Celeste, a planetary scientist specializing in the study of the solar system's inner planets. I've spent years researching the fascinating characteristics of Mercury, Venus, Earth, and Mars, and I'm happy to explain why Mercury, despite its proximity to the sun, isn't the hottest planet in our solar system.

The common misconception that Mercury should be the hottest planet stems from its orbital proximity to the sun. While it's true that Mercury receives the highest solar radiation out of all the planets, its lack of a substantial atmosphere plays a crucial role in determining its actual temperature.

Here's the breakdown:

* Venus: A thick blanket of atmosphere: Venus boasts a remarkably dense atmosphere, primarily composed of carbon dioxide, with clouds of sulfuric acid. This thick atmosphere acts as a powerful greenhouse trap, allowing sunlight to pass through but preventing the resulting heat from escaping back into space. This phenomenon, known as the greenhouse effect, is responsible for Venus's scorching surface temperatures, reaching a staggering 464°C (867°F), making it the hottest planet in our solar system.

* Mercury: A thin and fleeting atmosphere: In contrast, Mercury has an extremely thin atmosphere, known as an exosphere, that's essentially negligible compared to Venus's thick blanket. Mercury's exosphere is so thin that it offers little to no insulation against the sun's heat during the day. However, during the night, without this minimal atmosphere to retain any heat, Mercury experiences extreme temperature fluctuations, dropping to a frigid -173°C (-279°F).

* The impact of solar radiation: While Mercury receives the highest solar radiation, its lack of a substantial atmosphere means that most of this heat is reflected back into space, especially during the long Mercurian night. This rapid heat loss results in the planet's extreme temperature swings, making its average temperature significantly lower than Venus's.

* Other factors: Additionally, Mercury's slow rotation (its day is 59 Earth days long) allows its surface to heat up during the long day and cool down during the equally long night. This contributes to the extreme temperature difference between its day and night sides, further emphasizing the importance of an atmosphere in regulating planetary temperature.

**In conclusion, while Mercury receives the most intense solar radiation, its lack of a substantial atmosphere and its slow rotation contribute to its extreme temperature swings, making Venus, with its thick atmosphere and potent greenhouse effect, the true champion of hot planets in our solar system.**

I hope this explanation clarifies why Mercury, despite its proximity to the sun, isn't the hottest planet. It's fascinating to see how atmospheric characteristics can drastically alter a planet's surface temperature, even when they're directly exposed to the same source of heat.
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Carbon dioxide has the tendency to absorb heat which in turn increases the temperature. Mercury's atmosphere does not contain carbon dioxide (because of which all the heat is returned to space). Venus contains a high percentage of carbon dioxide due to which it is hottest planet.read more >>