Lean pickings in Milky Way

INFINITY AND BEYOND: The Milky Way ... so much bigger than the latest dairy payout.

NOW THAT we've just done a drive-by on Pluto - the last of what used to be the nine bona fide planets of the solar system - we're a bit stuck for new planets to check out.

The nearest other star system to us is Alpha Centauri, a triple star set-up of which Proxima Centauri is the closest. But there's a problem ... it's a long, long, long way away.

It's about 4.4 light years away, with one light year being about nine trillion kilometres. So, roughly 39,900,000,000,000km. This is very nearly as many spare American dollars that China now has available for overseas investments of their choosing, so we're talking serious numbers here.

Put another way, Nasa's New Horizons spacecraft that just buzzed Pluto at nearly 60,000km/h took more than nine years to make the journey. At that speed, getting to Proxima Centauri would take 78,000 years. That's a long time to keep the butter fresh.

It is sometimes salutary to dwell for a moment or two on the sheer scale of stuff out there. It helps keep the trauma of your favourite contender taking a spill in Dancing With The Galahs in perspective.

Estimates vary hugely but, as part of the Milky Way galaxy, our sun is just one of about 200 billion stars. And that's just the stars - not any attached planetary systems.

One estimate for the number of actual other galaxies out there in the so-called universe is 70 billion trillion! But wait ... this is just for what is euphemistically known as the observable universe.

So, in other words, no one actually has a clue as to what else is beyond the various mites of light and electro-magnetic signals the astrophysicists now glean from the outer realms of the currently "observable". It could all just keep on going on and on and on ... well, literally ad infinitum. Shucks, the Buddha might be right after all.

However, what it means is forget about getting anywhere near these celestial territories in the type of tin cans we send the Major Toms out in now. Assuming it's at all possible, it would need some sort of conceptual breakthrough, such as taking a short-cut through a parallel universe, or space/time warp, or whatever.

For the meantime, it looks like we're stuck with messing around with our house paddock planets, with the odd comet, asteroid or fag-end celestial body thrown in. As with the successful robotic Mars Curiosity Rover, these exercises in diminishing returns need not necessarily involve boots on the ground.

But speaking of the house paddock, boots on the ground, and diminishing returns brings to mind our own Milky Way ...

The dollar signs that scorched across the sky a few years back when the payouts for milk fat solids were at their zenith and farm conversion was at a rate Billy Graham would have been proud of, have been seriously scorched on re-entry from orbit.

Over-leveraged farmers and overstocked paddocks have led to overdrawn bank accounts, and overstressed farmers and ecosystems. Boom and bust in the cow shed every couple of decades or so seems as predictable as the similarly timed stock market blowouts. What's different this time is the sheer scale of the collateral damage.

Now might not be a good time to change the flag. The crossbar on the Southern Cross is a well-used celestial pointer to Alpha Centauri. If we trash this planet, it may be handy to remind us where to head for a possible replacement - although current thinking is that the nearest habitable planet is a further 80 trillion kilometres further on.

As for the mysterious triple star mention in our national anthem, perhaps it's referencing the triple star formation of Alpha Centauri. Maybe we've been through the whole cycle before, and we just forgot the lessons of first time around. Either way, there's got to be another Way.