(FORTUNE Magazine) – We could be alone in the galaxy, but it is unlikely. That is why a manned mission to Mars is so important. If we found life -- fossils, bacteria, anything -- we'd know that nature carried out its experiments on two Earth- like planets in one solar system, and succeeded. What about life elsewhere communicating with us? The earth began to be dazzlingly bright at TV frequencies in the mid-1960s. Think of Johnny Carson or Phil Donahue going out into space. The signal sweeps past the stars around us at the speed of light. The closest star that may have planets is Alpha Centauri, four light-years away. Other promising ones are 12 light-years away. If you assume the mid-1960s radiation reached them in 1977, and they were alert and responded, we could have a reply just about now. Think what they might tell us. We would be primitive compared to them, so I think they would share their knowledge. Many planets could have life a billion years older than ours. What would such advanced life be like? Who knows what a billion years of technical advance could mean? They could tell us how to arrange our genetic endowments and avoid dread disease. They might know clean, unlimited sources of energy -- even the secret of immortality. In the 1990s we will deal with climate and environmental issues by using research, gathering facts to back up what are now only guesses by all parties. I want to see small satellites instrumented specifically to study those phenomena that are the greatest source of uncertainty in global warming predictions, clouds and the oceans. But NASA is more prone to megaprojects and wants to build a huge, expensive platform in space that won't fly until the end of the decade.