The search for extra-terrestrial life

It's called SETI at home. A program that you can leave running in the background on your PC. First it downloads a chunk of data from one of the big radio telescopes. This is a record of all that background white noise that the universe seems so full of. The program activates itself whenever it senses you are idle (fetching a cup of tea perhaps). It's job is to pick through the ones and zeros in the data chunk, and find anything that could be an organised signal.

So I downloaded it and am having great fun thinking that my computer might be the one (out of all the tens of thousands signed up) that will find that long-searched-for greetings card from a little green man or woman (though any colour would do).

But it strikes me as I watch it that the processing must be using some energy. And that energy must be multiplied by all the tens of thousands of computers taking part. It must equate to a volume of carbon dioxide. And CO2 - a greenhouse gas - is heating up the atmosphere. And global warming is one of the threats hanging over the future of the human race. And thus - through a (highly tenuous) train of logic - could the search for life on other planets be damaging the prospects of life on this one?

Perhaps not. It's all a matter of getting things in perspective. A couple of litres of CO2 aren't going to make much difference. Maybe, after all, helping us to get things in perspective will be the most important outcome of the SETI at home project.