Asteroid size danger chart

I have promoted this article with Asteroid size danger from regular contributor Goat Guy.

There certainly have been a lot of detection events in the military surveillance satellite record, both public and secret. I’m not terribly surprised at the 1 in 15 years for “megaton class” impactors: ⅘ of the world is ocean, far from eyes that might catch a glimpse of such a bolide. Of the remaining ⅕, more than ¾ of it is essentially “beyond the horizon” of people who might be able to report it, especially if at the lower end of the explosive-energy release spectrum.

So… Let’s do a little simple math. The impact energy will be directly related to d³ (third power of diameter). Let’s say Chelyabinsk was 500 kT or better, 0.5 MT (not metric ton, but megaton):

----------------------------------------------
meter      megaton      megaton     kilometer
diameter   kinetic E    airburst    crater
----------------------------------------------
2          0.001        0.001        0  daily, around world
3.3        0.002        0.002        0  trivial
4          0.004        0.004        0  very small
5          0.008        0.008        0  small
6.5        0.017        0.017        0  notable
8          0.032        0.032        0  notable
10         0.063        0.063        0  scary, but safe
13         0.14         0.14         0  window breaker
16         0.26         0.26         0
20         0.5          0.5          0  Chelyabinsk
25         1.0          1.0          0
----------------------------------------------
33         2.2          1.5          0.7  town killer
40         4.0          2.0          0.9  suburb killer
50         7.8          2.8          1.3  city killer
65         17           4            1.8  Tunguska
80         32           6            2.2  
100        63           8            2.8  metro region killer
125        122          11           4    State disruption
160        256          16           5    Country disruption
200        500          22           6
250        977          31           7    SubContinent disruption
----------------------------------------------
330        2,246        47           10   Civilization threat
400        4,000        63           12   Civilization challenge
500        7,813        88           15   Civilization disruption
650        17,164       131          19   Extinction threat
800        32,000       179          24   Extinction challenge
----------------------------------------------
1,000      62,500       250          30   Climate change
1,250      122,070      349          37   Climate oveturn
1,600      256,000      506          48   Regional extinction
2,000      500,000      707          59   
----------------------------------------------
2,500      976,563      988          74   Extinction event
3,300      2,246,063    1,499        98
4,000      4,000,000    2,000        119
----------------------------------------------
5,000      7,812,500    2,795        149  Apocalyptic Extinction Event
6,500      17,164,063   4,143        193  Sterilization threat
8,000      32,000,000   5,657        238
10,000     62,500,000   7,906        298  Planetary sterilization

CLEARLY we don’t want to be anywhere near the bottom of the list. Too much bad shite happening down there. The above calculations are my own, based on scope-and-consequence models from around the Net. The assessments of “damage” are also my own. Goat’s scale.

Well there’s your Friday Fodder.

GoatGuy

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