About four hundred thousand million stars circle the core of our own Milky Way galaxy. This is a colossal number - equal to about fifty return trips between Melbourne and Perth, measured in millimetres.

We now know that just about every star probably has its own retinue of planets orbiting around it. Wherever we have the technology to detect planets around other stars, we find them.

Our planetary system isn't special in any way. We're made of the same chemicals, our gravity, temperature and orbital dynamics are no different from those of countless others. In astronomical terms, our little corner of the cosmos is very average.
Except for one thing.

Life. We know we’re here. But where are the aliens? Even if only one planet in a million has intelligent life, there should still be forty thousand of them in our galaxy.
Yet we've failed to pick up the least sign of them. We've searched millions of stars looking for artificial signals. If anyone else was out there - within a couple of hundred light years at least - we would have found them by now.

But perhaps aliens don't transmit huge amounts of radio noise into space like we do. The only reason we pump megawatts of TV, radar and all the rest of it out in all directions is that it's cheaper than setting up closed-beam transmitters, laser and maser links, or laying optical cables everywhere. Perhaps the aliens are already doing this.

Or - and this is the scary bit - maybe technological civilisations are naturally shortlived. The jury is still out on the long-term viability of technological civilisation on Earth.

Technology brings a species huge power. It could be that most species fail to deal with the social, psychological and ecological challenges this creates. We’ve had cars and planes and automated factories for only a hundred years or so, yet we already face extinction from about six different directions - population, climate change, nuclear weapons, pollution and economists are a few that spring to mind immediately - purely because of our inability to make basic social changes to ensure our own safety.

Or perhaps intelligent life really is very rare. Although there are a huge number of planets floating around, biological evolution is hard. Primitive anaerobic life existed shortly after the Earth formed. The basic chemistry of self-replicating molecules started quite readily. But it took over two billion years - half the age of the Earth, and half the history of life on our planet - before DNA appeared and these simple cells evolved nuclei and complex, "modern" structures.

Then another 1.5 billion years went by before any kind of multi-celled creatures appeared - a total of 80% of the history of life on Earth.

Everything else - fish, dinosaurs, insects, the lot - all happened in only the last 20% of the story.

But even if there is a sensible reason for not finding any radio signals from planets around other stars, why haven't we been visited by spaceships from elsewhere?
Of course, many people think we already have. The UFO debate is filled with strong views, and for myself all I can say is that in the thousands of hours I’ve spent looking at the sky through telescopes, I’ve yet to see a single one. If aliens really are here, surely it wouldn't be too much to ask one to land its flying saucer on the MCG at half-time on Grand Final day so we could all see it.

The strongest point against UFOs is the difficulty of crossing interstellar travel space. The distances involved are just plain silly. Our fastest interstellar probe, Voyager 2, will take about 70,000 years to get to the nearest star. This is at a speed that would get you from Bendigo to Melbourne in about 15 seconds.

Still, we could knock a few zeroes off that figure if we tried. Even with our current science we could build interstellar ships right now. Ships propelled by light-sails, powered by launching lasers, fusion ramjets collecting interstellar hydrogen with invisible magnetic scoops thousands of kilometres wide, or powered by nuclear explosions in a shielded reaction chamber - these are all perfectly feasible even with current technical knowledge, and could take us to the stars in mere centuries.

And even if it did take millennia, so what? We could build multi-generational space arks, launched by crews whose descendants would become the colonists of a new world. We might develop techniques for long-term human hibernation, or most llikely send robotic ships containing the frozen embryos of the first generation of human colonists, and the machines to raise them, as well as the animals and plants to accompany them.
All these things we could do with forseeable technology. Warp drives and faster-than-light travel however, are something else completely.

This business of zapping around between stars in a few days isn’t just difficult. The problem’s not a technological one, of building bigger and better spaceships. It breaks just about every law in physics.

Maybe it’s not impossible. Laws are made to be broken. But by any physics we now understand, travelling faster than light is on a par with travelling slower than stop.
There's another possibility though.

Perhaps there are ancient civilisations out there, advanced races that have survived their own Times of Troubles and established mature and stable civilisations, perhaps millions of years old.

It’s the next step for our own civilisation, if we survive our current racial suicidal adolescence.

Even if only one technological species in a thousand makes it, and doesn’t blow itself to pieces, there should be millions of them out there.

Or, maybe not.

For the universe is young - very young. Thirteen billion years is a blink of an eye compared to the aeons to come. Even in its present form - burning hydrogen in stars - the cosmos will survive for ten or even a hundred times as long as it has existed up till now. The Earth formed about 5 billion years ago - one-third of the age of the universe.

Prior to the Sun's formation, few stars had much of the heavy elements and metals required for terrestrial worlds like ours, or the magic atom carbon, whose unique chemistry enables it to form the basis of all life on the Earth, because these had to be cooked - synthesised - in the cores of earlier generations of short-lived stars.

Only hydrogen and helium were created in the Big Bang. Consequently most stars smaller than the Sun are metal-poor, less likely to bear Earthlike planets. In fact, all stars ever formed with less than 80% of the Sun's mass are still burning - the universe isn't old enough for any of them to have run out of fuel yet.

What if the reason we can find no aliens out there is that there are none - yet? What if - in our region of this young universe at least - we're the first? Will we buck the odds on our own looming self-destruction? Will coming centuries see our race embark on heroic journeys to the planets and then the stars, greater than any ever sailed upon the oceans of the Earth, as we actually become one of the first great starfaring civilisations to reach outward and fill the galaxy with life?

Wouldn’t that be more fun than watching gameshows and sport on TV?