What is the hottest planet in our solar system?

The hottest planet in our solar system is Venus, not Mercury despite its closer proximity to the Sun. While Mercury is closer, it lacks an atmosphere to trap heat. Venus, however, has an incredibly dense atmosphere composed primarily of carbon dioxide. This creates a runaway greenhouse effect, trapping solar radiation and resulting in surface temperatures averaging around 464°C (867°F). This is hot enough to melt lead.

Here's a breakdown of why Venus is hotter:

• Runaway Greenhouse Effect: The thick CO2 atmosphere traps heat incredibly efficiently, preventing it from radiating back into space. This effect is far more significant than the simple proximity to the sun.
• Dense Atmosphere: The pressure at the surface of Venus is about 90 times that of Earth's, further contributing to the intense heat.
• Lack of Water: The absence of liquid water on the surface means there is no water cycle to moderate temperatures.

Therefore, although Mercury is closer to the sun, Venus's extreme greenhouse effect makes it by far the hottest planet in our solar system.