Asteroid impact a greater threat than we thought
6 May 2014 by Evoluted New Media
On the 6th of August 1945 the World’s eyes were violently opened to the reality of nuclear war. As ‘little boy’ – an American uranium-gun type warhead – detonated over the Japanese city of Hiroshima the fear of future nuclear war became imprinted on the psyche of humanity. Since 1996 however the Comprehensive Nuclear-Test-Ban Treaty Organisation has aimed to stop all testing of nuclear weaponry…and they have been remarkably successful. By utilising a huge monitoring system – which will, when complete, consist of 337 facilities across the globe – not even the merest of nuclear whispers can happen without them knowing about it. So sensitive is their equipment in fact it isn’t just nuclear explosions they pick up. Indeed between 2000 and 2013 their sensors twitched feverishly on no less than 26 separate times...yet not one of these events was due to a nuclear explosion. No, to understand what exactly it was which set the system off you have to look at another of humanity’s imprinted fears. Asteroid impact. Recent data released by the CTBTO suggest 26 asteroids ranging in energy from 1-600 kilotons have hit the Earth. To get your energetic bearings, ‘little-boy’, the infamous Hiroshima bomb was 15 kilotons. Yet other than perhaps the impact in Chelyabinsk, Russia last year, most of the world has remained blissfully unaware of these celestial intruders. Now, a US group known as the B612 Foundation who campaign for space protection say the new figures from the CTBTO perfectly highlight the hidden danger of asteroid strikes. Worryingly, Dr Ed Lu – former astronaut and CEO of the foundation – thinks the only thing preventing a catastrophic impact from a ‘city-killer’ sized asteroid has been ‘blind luck’. Blind luck. Not something you really want to hear when an expert talks of something best described as a ‘city-killer’. Yet it would seem that destruction isn’t the only by-product of an asteroid strike. Amazingly enough, recent work published in Geology suggests that this most violent of events can, on occasion, be preservative. A team from Brown University in the US have discovered plant material thought to be around 10 million years old preserved in glass formed by asteroid strike. The ‘impact glasses’ studied come from the Argentinian lowland areas known as the Pampas and the team say the remains look very similar to the grass that still grows there today. They think that when the asteroid slammed into the ground the rock melted and was thrown clear of the crater – and it was this molten rock spray that trapped surrounding organic material. Yet surely this organic material would be vaporised almost instantly on contact with molten rock? Not so say the team who conducted experiments in an attempt to recreate the event. In fact they say the incredible temperatures were actually key – indeed it was only at temperatures above 1500oC that features of leaves could be conserved. They suggest that the sublimation at the edge of the plant would have created a layer of insulting steam, allowing the interior to be preserved. Incredible to think a capsule in time which could give us remarkable insights into the delicate past of the Earth was formed by one of its most violent events. https://www.youtube.com/watch?v=X_1F2psGfCA
