How Many Moons?
Image Source: http://www.sxc.hu/photo/1385352
When you look up at the night sky, how many moons do you see? It could be a lot more than you think. And one day we might bring some of them down to earth.
“Boldly going where no man has gone before,” runs part of the famous opening monologue of vintage sci-fi TV favourite Star Trek. As far as our planet goes, there are few places left to explore other than the deep secrets of the darkest parts of our oceans. But the skies – or rather the space – beyond our atmosphere are positively teeming with possibilities.
We’re not talking about warp drives, faster than light technologies or any of the other devices so beloved at the Cineplex. Or of crushing, years long travel. We’re talking about a quick blast from our surface and a matter of days or just a few weeks to find asteroids and small moons within earth’s orbit to both explore and exploit for their history as well as their raw materials.
While we generally think of the earth as having only one moon – the one visible to the naked eye on any good and cloudless night – there is reason to think that there may actually be dozens, hundreds or even thousands of other moons – essentially small space rocks – that are pulled into earth’s orbit by its gravitational field. Also called satellites, these rocks, many of which may only be a few metres across, might have spent millennia travelling across the universe before being pulled into the orbit of our own sun, and then, intersecting with our own gravitational influence.
Many of these moons spend only a brief time in the shade of our planet – many beyond easy detection in the shade of the Moon – before hurtling off into deep space once more. Occasionally they may be pulled into our atmosphere – like meteors – only to disintegrate like a celestial firework display. It’s been hypothesized that the Cyrillid meteor shower seen on the night of February 09 1913 with an incredible arc of over 9,000km stretching from Canada to the Caribbean was actually of one such moon.
There are certainly precedents within our solar system. Planets like Jupiter, many times the size of Earth and further away from the sun, regularly detach such asteroids from there orbit and pull them into its own such as the comet Shoemaker-Levy 9 which was pulled apart in a collision with the planet in 1994.
One reason for the resurgence of interest in these moons – unseen since the Apollo space mission days of the 1970s – is the potential riches these moons possess. On the one hand they are a historical treasure trove. Researchers have spent hundreds of millions of dollars sending probes to distant asteroids like Itokawa to collect dust and rock samples. Those missions are often lengthy and fraught with problems and problem-solving. The Hayabusa probes journey to and from Itokawa was incident prone with frequent power and mechanical failures during its seven-year odyssey.
Similar historical data may be contained within these moons and rather than a seven year trip, they might require nothing more than a quick trip of a few days or weeks to reach. Add to that their relatively small size and it could even be feasible to bring an entire moon back to earth, instead of simply harvesting a few dust and surface samples. That alone would be an enormous boost to our knowledge: the freedom to examine the moon at our leisure and to conduct the kind of sophisticated lab tests that a space-based robotic probe is unable to carry out.
Corporations are also starting to show interest in the contents of space. Beyond their knowledge value, moons and asteroids also have a potentially enormous dollar value. According to NASA’s own statistics, there are more than 9,000 asteroids measuring more than 100m across in Earth’s orbit. Containing elements such as iron and nickel – which are in plentiful supply on our planet – their true value lies in far more rare and expensive metals including platinum, iridium and palladium.
A new company, Planetary Resources, founded by Google’s Larry Page and Eric Schmidt, and including noted film-maker James Cameron as an advisor, aims to mine some of these minerals. Scientifically it’s possible, now the company just has to build the technology to make the theory a reality. The company hopes to send out a fleet of robotic craft within the next five years to survey some of the most likely asteroids or moons.
Then, if they can get the extraction costs down to a level where their payloads are profitable, a new generation of robotic drillers and storage craft will start to bring these materials from beyond our skies to use on our planet, bringing a touch of space to our everyday lives.