MCQ Detailed View

In our solar system, temperature varies greatly from planet to planet depending on distance from the Sun, atmosphere, and internal heat. While one might assume that the farthest planet, Neptune, would be the coldest, it is actually Uranus that records the lowest temperatures.

The average temperature on Uranus is about –224°C (–371°F), making it the coldest planet in the solar system. This is colder than Neptune, whose average temperature is around –214°C. The reason lies not only in distance from the Sun but also in planetary characteristics.

Unlike other gas giants, Uranus radiates almost no internal heat. Planets such as Jupiter, Saturn, and Neptune generate heat from their interiors due to residual formation energy and gravitational contraction. Uranus, however, seems to lack this internal heat source, which leaves it much colder. Scientists believe a catastrophic event billions of years ago — possibly a massive collision that knocked Uranus onto its side — may have caused it to lose most of its primordial heat.

Let’s compare Uranus with other options:

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  Earth: Average temperature is +15°C, making it suitable for life.

  
  


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  Venus: Despite being farther from the Sun than Mercury, it is the hottest planet because of its thick carbon dioxide atmosphere and greenhouse effect, with surface temperatures around 465°C.

  
  


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  Mercury: Temperatures vary widely due to lack of atmosphere — from +430°C during the day to –180°C at night.

  
  


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  Uranus: Extremely cold, with a methane-rich atmosphere that contributes to its bluish-green color and frigid conditions.

  
  

Therefore, Uranus is scientifically recognized as the coldest planet in the solar system, an interesting fact that highlights how distance from the Sun is not the only factor in planetary climate.