Science

NEOs, impact hazards and warnings.

So for my next super regular blog update..it has only been two and a half years..don’t judge me!  *cough*  I think I shall say something about the recent meteor strike in Russia, if you haven’t seen the footage you’re probably living under a rock (See it here on BBC.co.uk), and where some people have been asking why they weren’t warned of this impending arrival.  Astronomers when dealing with observing Near Earth Objects (NEOs) and their impact hazards have a scale named the Torino impact hazard scale which categorises the potential hazard an object is likely to have and what steps should be taken when certain factors apply, essentially kinetic energy and probable impact location if it will impact at all.  Here is the Torino scale:

torino_plot

 

As you can see quite a lot of the chart rates the objects as being a 0 on the scale, meaning there is little consequence if the object strikes the Earth or that it is unlikely to ever strike the Earth.  With increasing energy and likelihood of collision, a 1 is described as “A routine discovery ion which a pass near the Earth is predicted that poses no unusual threat of danger.  Current calculations show the chance of collision is extremely unlikely with no cause for public attention or public concern.  New telescopic observations very likely will lead to a re-assignment to Level 0.” going up to Level 10 which states “A collision is certain, capable of causing a global climatic catastrophe that may threaten the future of civilization as we know it, whether impacting land or ocean.  Such events occur on average once per 100,000 years, or less often.” which is pleasantly apocalyptic.

So chances are the public were never warned today as it was predicted to be a Level 0 event (assuming it was spotted incoming), with hazards like these setting off an alarm and telling everyone a meteor may strike near where they live is likely to cause a more dangerous hazard than not telling anyone except officials about it, until it is known for sure that it will cause destruction and on what scale. 

It is estimated that about 20,000 meteorites will arrive at the Earth each year, some will burn up completely, others will be solid enough to strike the Earth, some will be slowed and of such small size that they will float down to Earth harmlessly.  This is a topic I personally want to do more reading on as it’s fascinating, I will try and improve the blog as I go along (assuming I don’t take so long to get around to the next post).

Thanks to NASA for the image of the Torino scale, and you can see the text version here.  Also thanks to the OU for what knowledge I have on the subject.

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