On the Two Dangers From Space Friday 2-15-13

The most amazing coincidence happened Friday 2-15-13:  this planet was menaced by two different bodies approaching it from two different directions,  at two wildly-different speeds.  One hit us,  the bigger,  more dangerous one,  did not (quite). Update 2-16-13:  fireball without blast seen over North Carolina Friday night for a third one!  Update 3-6-13:  asteroid 2013ET will pass by about 2.5 lunar radii on Saturday 3-9-13;  having been discovered just days earlier.  This one is football-field size,  which would have been a huge threat as an impact.  The short warning (few days) is a little ominous,  don't you think?  Effective deflection may take years to accomplish.  We may not know in time to do anything but duck and cover,  when one of these finally hits us.  Too bad there is no warning network.

Asteroid 2012DA14 flew by on the predicted path at the predicted speed and at the appointed time,  without hitting us.  All was just as predicted for the early afternoon of that day,  central time.  It was discovered last year,  so we had several months warning to track it and determine that it would miss,  as it did.

Asteroid 2012DA14 was an object about half the size of a high school football field.  Had it struck us,  the explosive yield would have been similar to a multi-megaton nuclear weapon,  causing total destruction over an area hundreds to perhaps a thousand miles in dimension,  a very serious event indeed. 

The meteor that damaged Chelyabinsk in Russia earlier in the morning central time,  was about the size of a city bus,  and was not observed before it struck.  Its explosive yield was in the tens-of-kilotons equivalent,  similar to the bombs dropped on Hiroshima and Nagasaki long ago. 

That explosion took place low in the atmosphere,  but not down on the ground,  when the meteor broke up explosively.  The shock wave that it trailed,  plus the shock wave from the explosive breakup,  are what did the damage.  Many separate pieces are already known to have rained down.

News reports by Friday evening fortunately list no dead,  but upwards of 1000 injured,  mostly by flying glass.  Apparently,  one factory suffered a roof collapse.  This could have been very much worse. 

All of the experts agree:  sooner or later,  one of the bigger ones is going to hit the Earth.  If it is big enough,  it does not have to hit a city,  or even the ground at all,  to kill millions of people.  The really large ones cause blast,  fire,  debris fallout,  and all sorts of pollution effects,  that are entirely global (which is exactly what is thought to have killed-off the dinosaurs long ago).

On paper,  there are at least three ways (and perhaps many more) that we might deflect such a threat,  but only if we have enough warning to reach it in time.  In practice,  we have absolutely nothing but an underfunded effort to find and track as many of these things as possible. 

There is not one single funded effort anywhere in the world to try out any of these theoretical means of deflection.   Nor does any country on the planet possess a spaceflight capability that could reach one of these things in time to do any good,  not even the US. 

The probability that we will be wiped out by such an impact in the next few years is pretty close to zero,  but in the next couple of centuries,  pretty large.  But that is only probability:  it could happen tomorrow,  or two-or-more centuries hence.  All we really know is that sooner or later it will happen,  and the consequences are pretty much unthinkable,  far worse than a general nuclear war. 

I cannot think of a better rationale for a government space program than developing the high-energy space travel and asteroid deflection technologies required to protect us,  against the time this disaster actually looms.  (A side benefit of such a capability is the ability to make far faster exploration voyages to places like Mars.) See also the post "On Asteroid Defense and a Good Reason for Having National Space Programs" dated 4-21-09.  Nothing has changed since I wrote that one,  except the Russians got "hit" by a small one. 

Back to the coincidence of two unconnected events happening on the same day:  both dangers from space.   I think that somebody (God,  Mother Nature,  whatever you might believe) is trying to tell us something.  It might be wise to listen.

Footnote:  the UN is looking at the problem of how to warn the world if somebody somewhere spots one of these threats coming at our Earth.  Right now,  there is not even a way to reliably pass the word "duck and cover".  

Update 3-6-13:  there are 3 comets headed our way,  too.  One should be putting on a show to see about sundown a few days from now,  no threat of impact.  There's another like that in November.  And in October,  there's another one that could possibly impact Mars.  We really do live in a shooting gallery. We just didn't know that until recently.