Why Venus is hotter than Mercury: CO2 and the greenhouse effect explained

Mercury sits closer to the Sun, but Venus holds the record for the hottest surface in our solar system at about 867°F (464°C). The key difference is not distance but atmosphere. Mercury has almost no atmosphere, so heat escapes at night. Venus is wrapped in a thick layer of carbon dioxide, about 96.5% CO2, with clouds of sulfuric acid, which traps heat and keeps the planet scorching around the clock. This is a textbook example of the greenhouse effect. The same physics that warms Venus applies to Earth, though our atmosphere has far less CO2. Understanding how Venus became a runaway greenhouse can inform how we think about carbon emissions and climate stability on our own planet.