Venus: The facts

Second planet from the Sun Similar in size and mass to Earth Thick, poisonous atmosphere of carbon dioxide and sulphuric acid Greenhouse effect keeps the surface hot enough for molten metal to flow

We've seen major missions to Jupiter and Saturn in the last few years - Galileo, and Cassini, which is on its way now - and there's a big programme to explore Mars. Venus has somehow got left out.

It's not that the other planets aren't interesting but this is the one that is perhaps the most interesting of all.

It just doesn't happen to have a priority in anybody's programme at the moment except the Japanese, who are relative beginners in this field.

So, European scientists have got together and resolved to fix this.

What can Venus teach us about Earth?

Everybody knows there's a big problem with the greenhouse effect on the Earth.

Nasa's Magellan mission ended in 1994

There's also an enormous greenhouse effect on Venus.

Venus is a very Earth-like planet - it's the same size and made of the same stuff - and has this very extreme case of what we're worried about on Earth, and we need to understand it.

The other thing is that the general circulation of the atmosphere - the way the winds blow on average - is very rapid and we have no physical understanding of what the mechanisms are that are causing it.

This is alarming for the Earth's nearest neighbour and the most Earth-like planet.

What could we learn about climate change on Earth?

One of the things we are trying to do on the Earth these days is predict to what extent the Earth is going to move towards being more Venus-like.

I think that there's wide agreement that that's happening. If we're going to be able to understand what's happening here and predict how it's going to go in the future, a valuable place to start would be to look at a similar planet that's undergone that transition already and to understand what happened and how the greenhouse effect actually operates under these similar but different conditions on our neighbouring planet.

Why should the UK back the mission?

The money that needs to be spent has already been committed by the UK because we pay for the Esa budget. So, new money doesn't have to be found - it's just a question of where the UK has its priorities.

Past missions to Venus

Nasa's mission Magellan orbited the planet for 4 years before plunging into its atmosphere in 1994 Nasa's Mariners 2, 5 and 10 also visited Venus Soviet missions have landed several spacecraft on Venus Chemical analyses of rocks indicate a composition similar to that of volcanic rocks found on Earth

The UK's priorities tend to be fairly old-fashioned. There's a strong emphasis on ground-based astronomy, which is a 19th Century technique, and in space experiments there's a strong emphasis on what they call space physics - particles and fields of space and so on - which had its hey day in the 1950s.

What we're trying to do is get a little bit up to date, in line with the other European countries and the other major nations in the world, and see some priority in this country for planetary exploration, which is really the hottest topic in space going into the 21st Century.

Professor Taylor will be speaking on the subject on Wednesday 10 April at the National Astronomy Meeting in Bristol.