Deep Impact - We Now Have the Technology to Avoid It

We all want a planet fit in the future for our kids, and as a species we've grow to be conscious over the last couple of decades specifically how fragile the Earth really is. We've realised the devastation that could be caused by a super volcano, an asteroid impact, earthquakes, coronal mass ejections from our nearby star, a gamma ray burst aligned at our planet, plus our own self-inflicted harm to our environment in the form of climate change, pollution, harm to the marine ecosystem and ozone layer damage caused by chlorofluorocarbons.

A distinctive feature of homo sapiens amongst the other animals with whom we share the Earth is our capacity not just to adapt to the environment, but really change it. Indeed we've changed it - but adversely when it comes to ozone depletion, pollution and climate alter, and indeed we're now generating inroads in reversing our negative impact. Yet, all of these issues are 'walks in the park' compared to the other threats, with 1 major exception - asteroid impacts.

We live in a cosmic shooting gallery. Any individual who disagrees should really look no further than Comet Shoemaker-Levy 9, ripped apart by Jupiter's gravity and pummelling into the mighty gas giant in July, 1994. If that collision had occurred on Earth, none of us would be here now.

Having said that, the Earth is not immune and collisions with both asteroids and comets have happened in our planet's past, and will happen once more. The last time a civilisation-destroying asteroid 10kms across hit our terrestrial bulls eye was 65 million years ago at Chicxulub on the Yucatan Peninsular. Luckily, there was no civilisation about to destroy, but it was a bad day for T Rex and its dinosaur cousins, along with 80% of the plant and animal species on the planet. The death of the dinosaurs resulting at least partially from the impact on the Yucatan had the benefit of allowing tiny mammals and ultimately us to exploit the ecological niches vacated by these most successful of animals (in terms of the longevity of their reign).

At the identical time although, it's a sobering thought to feel that mass extinctions caused by incoming asteroids occur, on average, just about every 100 million years, and the next one will wipe out mankind. It is not a question of if, it is a question of when it will happen. Unlike T Rex although, the very good news is that we can stay clear of such an unpleasant visitor from space, even with our present technologies. Or rather we can make sure that such a possible impactor avoids us.

Worldwide, apart from the United States and NASA, most governments have not taken the problem of asteroid impacts seriously sufficient. Commendably NASA has surveyed huge parts of the solar method, specifically in the vicinity of Earth for Near Earth Objects (NEOs) and Potentially Hazardous Asteroids (PHAs) (those which directly cross the Earth's orbit around the Sun). Such objects routinely pass between the Earth and the Moon, even between the Earth and some of our geo-stationary satellites. Full details of NEOs and PHAs discovered are obtainable here:

So what can we do if an NEO or PHA is detected and has our name on it? If the asteroid is composed of a loose barely gravitationally-bound conglomerate of ice and rock the nuclear choice of blowing it to smithereens with a detonation would replace 1 difficulty with a host of them, we would then face the prospect of a number of smaller fragments reigning down on the Earth causing most likely as much destruction.

One of the most considered scientific methods of removing the threat once one of these killer inbound asteroids has been located is not a Bruce Willis-style detonation at all, but concerns making use of the pressure of sunlight.

Light is composed of particles called photons, and like any particles, photons from the Sun create pressure - albeit especially little pressure. Focus the photons utilizing mirrors into an intense beam, obtain the asteroid early enough, and only a miniscule change of the object's trajectory by photon pressure is required.

The Pasadena, California based Planetary Society (TPS), the largest public space interest group in the world, is now working with a team at the University of Glasgow in Scotland to study a new technique which uses this concentrated light to gently move an asteroid -- a project they call "Mirror Bees." The researchers in Scotland, under the leadership of Massimiliano Vasile, became interested in this approach when they discovered that Mirror Bees would function even more easily and effectively than each approach, apart from nuclear warheads (the difficulties with this option has already been discussed).

This new technique involves several modest spacecraft -- each carrying a mirror -- swarming around a hazardous asteroid. The spacecraft could precisely tilt their mirrors to focus sunlight onto a tiny spot on the asteroid, vaporizing the rock and metal, and creating a jet plume of super-heated gases and debris. Alternatively, the satellites could contain potent lasers pumped by sunlight, and the lasers could be utilized to vaporize the rock. The asteroid would become the fuel for its own rocket -- and slowly, the asteroid would move into a new trajectory.

Main questions still stay about this technique. For example, will the plume of superheated gases ejected from an asteroid dissipate, or will it block sunlight to the mirrors? Would the debris settle on the satellite mirrors? Can the asteroid's rotation be dealt with efficiently? Will the gas plumes be enough to deflect the asteroid?

TPS is stepping in to fund a series of laboratory experiments to answer these and other questions. Vasile's group is working with Ian Watson and the laser lab of the University of Glasgow's Mechanical Engineering Department to devise some ingenious tiny-scale experiments. TPS will be funding equipment, supplies, and a graduate student dedicated to working on the experiments. Only by means of these varieties of studies, as nicely as additional theoretical research, can the details of this technique be worked out and understood. If it pans out, it will be a rapid, effective, and safe choice to use against the asteroid that inevitably will come Earth's way.

It is comforting to know that this valuable investigation is being undertaken against one of the biggest threats against our civilisation. Until we commence seriously colonising space the human race still has all its eggs in 1 basket here on Earth. It would be foolish and irresponsible to ignore the risk, to be able to do something about it and but do absolutely nothing. T Rex had an excuse. With our intelligence and technology, we don't.