What causes Venus’s extreme surface temperature

Venus is the hottest planet in the solar system, with average surface temperatures around 465°C—hot enough to melt lead. This extreme heat comes from a runaway greenhouse effect. 

Venus’s thick carbon dioxide atmosphere acts like an enormous thermal blanket, trapping sunlight that reaches the surface. The planet’s clouds of sulfuric acid reflect some sunlight back into space, but enough still penetrates to warm the surface. 

Once that heat is absorbed, it can’t escape because carbon dioxide blocks the infrared radiation trying to leave. Over millions of years, this created a feedback loop: trapped heat caused more evaporation of surface materials, adding more greenhouse gases to the atmosphere. 

Unlike Earth, Venus has no oceans or carbon cycle to balance things out. The result is a permanently overheated planet, where day or night, the temperature stays nearly the same—an inferno caused by its own atmosphere.