Tunguska-Sized Asteroids Impacts Not So Common 24
JoeGee writes "MSNBC.com is reporting that a new study aided by data from U.S. Military satellites is causing scientists to revise the frequency of Tunguska-like impacts downward. Military satellites used to detect rocket launches and/or nuclear flashes are also good at monitoring the frequency of flashes in the atmosphere caused by ten meter to one meter sized objects burning up in our atmosphere. The study has concluded that Earth encounters much less interplanetary debris than was previously thought, and Tunguska-scale events only occur on average of once every millenium."
Variable (Score:5, Insightful)
Let's just say... (Score:3, Funny)
"Peiser said the study was valuable in another way because it helped show the U.S. military can detect the difference between a nuclear explosion and a meteor that sets off a flash similar to it -- a capability he said could help governments avoid mistaking a meteor blast for a nuclear weapon.
It would probably be good to have this capability to keep some guy with a key in a silo from pushing the panic button and obliterating us all....
Huh? (Score:4, Interesting)
Re:Huh? (Score:2)
If you look out into space and a ratio(lets say L:B) of little asteroids to big asteroids and if you make the assumption that for an individual asteroid its size does not effect its chances of hitting a planet then:
X/Y=L/B => XB=YL => Y=XB/L
Now if you want to get fancy and remove the above assumption then it wouldn't be all that difficult to run a monte carlo simulation where you initialize a solar system with different populations of asteroids and apply the laws of gravity to simulate a few million years and use the output statistics to replace the above ratios. Hmmm maybe I should write up a grant proposal and see if anyone would pay for that cluster I've always wanted
Re:Huh? (Score:5, Insightful)
| \ Legend:
| \ \ = Observed meteor data (small sizes)
| \ or
F | \ Telescope observations (large sizes)
R | . . = Interpolated data
E | . * = Tunguska sized
Q |
U | *
E |
N |
C |
Y | \
| \
| \
+-----------------
0 S I Z E
According to the article there is a good coorilation between the
meteor data for the small sizes and the telescope observations
for the large sizes, therefore they assume that the graph is a
resonable model of the sizes of the interplanetary debris.
Therefore they feel that the interpolated data between the
two data sets is fairly accurate.
I cant believe that I am drawing ascii art graphs on slashdot.
I need to get out more. (Actually I am going to the premere of the
new Bond film this evening so I am getting out, just not enough)
Re:Huh? (Score:2)
Well.... (Score:1)
Re:Well.... (Score:2)
Re:Well.... (Score:1)
I wasnt sure what "Tunguska" was or meant, so....
well, anyway, I was more convinced of the Antimatter posibility than anything else
where there was a given amount of antimatter in a field of some sort (plasma/magnetic/etc) and when it came into contact with the earth's more dense atmoshpere, the field was destroyed, bringing the antimatter into contact with regular ol' matter,
KABOOM
besides, the calculations i have heard about say that the object exploded some distance about the earth, which, yes, could have happened if there was fusion of hydrogen, but, the other effects of the Tunguska situation do not seem to go along with the comet theory
(thats just the
Re:Well.... (Score:3, Informative)
The problem is we don't know, and scientists are still debating it.
Other Tunguska theories (Score:2)
Proponents of this theory describe how near the very center of the explosion the trees were unburnt. They say that the gas squirted out from the underground deposit under such high pressure, over a number of days, that an ice dome formed around the hole -- just like your can of canned air gets cold. This ice protected the most central trees.
The explosion is said to be right over a natural gas field. The region of Siberia has huge natural gas reserves [geocities.com].
Bah! (Score:2)
Based on hypothesis... (Score:3, Insightful)
The rate of objects entering the atmosphere in the 10 years observation period is representative of the average rate of the 1000 years period of the conclusion
The rate is constant (no asteroids or comets storms like the Leonids [slashdot.org] shooting stars storm we just observed)
The sampling (300 meteors) is statistically significant
The extrapolation/interpolation to bigger size meteors is valid.
This is definitely not a sig.
In related news... (Score:1)
Come on, if it was any different, there would be records of unexplained explosions all over history books, not to mention that at least some of the holes would still be visible.