New Scientist reported a recent asteroid strike to the upper atmosphere on the 8th of October above Indonesia (with no damage to anything on the ground). Pictures of the upper air dust trail have also been reported.The asteroid was relatively small (10m across) and resulted in a blast with the equivalence of 50 000 tonnes of TNT (that's just over 5 on the Richter scale - if it was below ground). NS describes it as "about three times more powerful than the atomic bomb that leveled Hiroshima" which sounds quite impressive.
Objects of about 30m in size can reach the ground and do damage. The interesting little detail is that there is a window of blindness for objects smaller than 100m across, which are too small to find and track. This implies that 30-100m is a size range that leaves us with a blind spot for surprise. This NS article seems to indicate that even if we were aware of an imminent impact we may still not have the time or technology to avoid the potential results.
Classifiying objects according to their threat was a good idea and resulted in the Torino Scale. 50m sized objects with a high probability of impact are classified as 8 on this scale and are red. A no. 8 Torino object is where the surprises lie. They are the Black Swan's of astronomy.
Some people are calling for a global asteroid defence agency. Maybe a virtual one would be better. This way people could work on it part-time and get scrambled together 'Hollywood style' if the threat is confirmed.
No comments:
Post a Comment