The planet known for having a dense atmosphere is Venus. Venus has a thick layer of clouds made primarily of carbon dioxide, with clouds of sulfuric acid, creating a powerful greenhouse effect that traps heat. This results in surface temperatures hot enough to melt lead, making Venus the hottest planet in our solar system. The atmospheric pressure on Venus is about 92 times that of Earth, which is equivalent to being nearly a mile underwater. These extreme conditions make Venus a subject of fascination and study in planetary science and atmospheric research.