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Tunguska-Sized Asteroids Impacts Not So Common

Posted by timothy on from the sigh-of-relief dept.

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."

3 of 24 comments (clear)

  1. Variable by Henry+V+.009 · · Score: 5, Insightful

    This information is only as good as the time period we've been collecting it for. Meteor frequency is quite variable, therefore one decade's (or less) observation may not be of much value.

  2. Re:Huh? by fava · · 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)

  3. Based on hypothesis... by Mazzaroth · · Score: 3, Insightful
    The conclusion of the analysis is valid if the following hypothesis (somewhat related, i know) are considered as true:

    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 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.