Cosmic Near-Miss

It was a gentle reminder about the perils of living on a precarious planet.

Last week, an asteroid the size of a 10-storey building missed Earth by a mere 70,000 kilometres — that’s less than twice the height of geostationary communications satellites.

Named 2009 DD45, the potential impactor was similar in size to a rock that exploded above Siberia in 1908 with the force of a thousand atomic bombs, flattening 80 million trees across a 2,000 square kilometres area. And, yes, it’s a seriously sobering thought that astronomers had detected its presence only two days earlier. Having said that — and barring a worst case scenario — there’s no real reason to panic.

Because while it’s true that in the past there have been several such collisions between our planet and large pieces of space debris, some of which have even caused global extinction level events, the situation and circumstances are vastly different today. Sixty-three million years ago when an asteroid is supposed to have wiped out the dinosaurs there were no humans around. Neither was their technology.

As a result, the cataclysmic occurrence could not be forecast or mitigated. The world was totally at the mercy of nature.

Fortunately, we have the science to deal with most such contingencies today. Since the early 1980s Earth- and space-based telescopes have been pressed into action by various agencies such as the Lowell Observatory Near-Earth-Object Search and Catalina Sky Survey to locate, monitor and catalogue the orbital dynamics of near-Earth objects which can pose a threat in the future.

Also, in 1998, NASA commenced its part of the worldwide “Spaceguard” effort, with the goal of discovering and tracking over 90 per cent of the near-Earth objects larger than one kilometre. To date over 60 per cent of the estimated 1,000 to 1,200 large near-Earth objects have already been discovered.

However, should a large impactor still come zeroing in on our planet we have the capability now — using nuclear weapons, for instance — to deflect or disintegrate it at a safe distance. Attaching rocket engines on its surface can also be used to gradually change its trajectory using aerobraking techniques over a period of time. And finally, there’s the statistics: life-threatening catastrophic collisions occur once in millions of years. But of course, if our names are written on that rock, we could be history. It’s probably the story of all life.

The Times of India

Posted in News

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