Final answer:
The solar energy trapped by gases in Venus's atmosphere causes the greenhouse effect due to the high concentration of CO₂, which acts like a blanket retaining heat and leading to extremely high surface temperatures.
Step-by-step explanation:
The solar energy trapped by gases in Venus's atmosphere causes the greenhouse effect. Venus's atmosphere is made up of approximately 96% carbon dioxide (CO₂), which is a potent greenhouse gas. The CO₂ acts as a thick blanket, capturing the infrared radiation (heat) from the planet's surface and preventing it from escaping back into space. This causes a significant increase in temperature on the surface due to the heat being trapped. The surface of Venus is therefore a lot warmer than it would be without this atmospheric composition, leading to temperatures high enough to melt lead. The radiation balance is only achieved when the planet radiates as much energy as it receives from the Sun, but due to the heavy CO₂ atmosphere, this requires the lower atmosphere of Venus to reach very high temperatures. The amplification of this effect can lead to what's known as the runaway greenhouse effect, where the planet continues to get hotter.