The surest indication that intelligent life is out there is that they have not tried to contact us. We, on the other hand, have been trying for decades to contact them - whoever, or whatever, they may be.

In 1977, the US sent a space probe called Voyager into the deep, dark radiated unknown. It was packed full of goodies, like a message from Jimmy Carter.

If I happened to inhabit the control tower at the edge of the Milky Way and heard this voice say, "Hi, I'm Jimmy Carter. Let me tell you about Plains, Georgia," I think I'd let it pass. Now if the probe had a message from Sophia Loren, who looked good in 1977, and looks even better now, I might just respond.

The probe has been stuffed with various teasers about life on Earth, like photographs of humanity. People in the 1970s? Those of a certain age, 50-plus, are still scarred by memories of that decade. Bell-bottomed trousers, love beads, long hair, platform shoes. That will get the galaxies buzzing with inquisitiveness all right.

Fashion, like history, repeats itself and there are days when I see all the young dudes (and some not so young) wearing clothes in the trendier spots in Beijing that owe something to the decade that taste forgot. Jackets with lapels wider than some fixed-wing aircraft and floral shirts that can play havoc with the senses. With such offerings, maintaining radio silence is an option that would have few detractors among those who have yet to make contact.

Voyager travels fast, very fast. Just how fast? It zips through space at a leisurely 56,000 km/h in third gear. By the time you have read this sentence it has gone ... well, it's easy to work out, so I won't bother. But you get the drift.

This is a serious piece of machinery that does not slam on the brakes.

Voyager is now on the edge of the Milky Way about to enter really, really deep space. And not a word. Not even one "howya", or "hi there" or even "g'day", let alone "may the force be with you".

Not a beep to suggest we have company. Not surprising, I suppose, because I am reliably informed (well, actually I don't know if I am reliably informed as I know zilch about space travel, which makes it difficult to contradict anyone who wants to inform me) that Voyager, in terms of space trekking, has hardly started.

Actually, there are two probes, and Voyager 2 was launched a few weeks before Voyager 1. They did things like that in the 1970s.

Scientists calculate that if there is something out there then it would be in a galaxy about 250,000 light years away.

This area, they believe, holds the most promise for species to answer Carter's message of goodwill. Just why scientists believe this is a mystery. Not many people on Earth bothered with Carter's messages of goodwill when he was in the White House.