Venus is often referred to as Earth's evil twin. This is because they are both very similar, yet very different. Venus is about the same size as Earth, and has a similar composition. It is also the closest planet to earth so it is similar in distance to the sun. But what makes it so different? Venus is probably the most deadly and inhospitable planet because of its scorching heat, immense pressure, a toxic atmosphere, and no water. (That's why its called the EVIL twin.) Its atmosphere is so thick because Venus has no ozone layer in its atmosphere. It is presumed that Venus once had many oceans and sources of water, however, they all evaporated with the loss of the ozone layer and the extreme heat that brought. Some scientists presume this is what earth will be if global warming continues.