Earth's 'evil twin' gives up its deadly secrets

n theory, the planet should be a good place to look for life. It is virtually the same size, mass and density as Earth, is our closest neighbour, and was formed at about the same time, about 4.5 billion years ago, from the same materials.

In reality, it is highly unlikely that any form of life remotely similar to that on Earth could survive on the surface.

It is hot enough to melt lead, has an atmospheric pressure 92 times our own and is covered by thick clouds of sulphuric acid.

The scorching temperatures are caused mainly by a runaway greenhouse effect that keeps heat trapped in a heavy atmosphere composed of 96 per cent carbon dioxide.

As carbon dioxide emissions have increased on Earth by 30 per cent since the Industrial Revolution, climate scientists believe that the mission will provide vital clues about how increased quantities of the gas affect the atmospheric system.

Information on how Venus's clouds affect the energy balance between the incoming and reflected solar radiation will also help to explain the mechanisms of global warming.