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Posted on 09/09/2009 9:48:17 PM PDT by neverdem
The number of car-to-house-sized meteoroids whizzing through the Earth’s neighborhood is about 10 times higher than Earth-based telescopic surveys suggest, a new study reveals.
That finding, reported online August 28 and in an upcoming Journal of Geophysical Research–Planets, comes from analyses of recently declassified data on infrasonic waves in the atmosphere detected between November 1960 and April 1972. The network of instruments collecting the data was originally designed to detect low-frequency sound waves produced by aboveground nuclear tests, says Elizabeth Silber, a planetary physicist at the University of Western Ontario in London, Canada.
But during the 13-year period, the instruments also detected infrasonic waves produced by 13 meteoroids. Such waves are generated in prodigious amounts as extraterrestrial objects blaze through the upper atmosphere, where many shatter before reaching the Earth’s surface (SN: 7/19/03, p. 36). The waves can travel thousands of kilometers because they aren’t effectively damped by the atmosphere...
(Excerpt) Read more at sciencenews.org ...
Something to look forward to, I suppose...
We should do the same thing to these asteroids that French farmers due to snails invading their vegetable gardens - devour them all.
There is enough platinum group metals in an average-sized asteroid to equal in worth the entire annual global output. That is a lot of money. Intriguingly, we have the technology to do this NOW!
I say, let’s go get those space rocks before they get us!
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FReepmail me if you want on or off my health and science ping list.
Ping
We know Jupiter was hit by the Shoemaker-Levy comet, then a second major collision (making a earth-sized hole in its upper atmosphere) about 12 years later. Saturn's rings got plugged by a large “something” earlier this year - large enough to create a long dust plume of material pulled from the ring. So figure 1 planet-busting collision in Saturn or Jupiter every five years. We know that many have hit!
Earth seems largely missed though - the AZ Meteor Crater was about 50,000 years ago - and I know of none more recently than that.
So - how large a hole (megaton bomb range ??) do these “car-sized rocks” make?
Why would we not see 100 to 300 “recent” craters from these speckling the surface - if they really were as frequent as this article implies?
Why would we not see 100 to 300 “recent” craters from these speckling the surface - if they really were as frequent as this article implies?
Oh I absolutely grant those: The most recent being 50,000 years ago though.
But, if these car-sized collisions are causing the sonic booms (the atmospheric vibrations talked about in the article above) as frequently as indicated, where are the “house” and “apartment building” collisions that would cause craters over the last 49,000 years?
Would erosion, glciers, water impact “splashes”, and Arctic-Antarctic impacts being that that many medium-sized holes?
Hiroshima and Nagasaki blasts destroyed those cities with 12 kiloton nuclear airbursts. But a Hiroshima-sized nuclear wepon at 5000 feet made no discernible crater in the ground - it was still basically flat just 1 year later - what sized meteoroid can flatten a city (or cause equal damage) but leave no trace in the geological record?
A nuclear blast causes tremendous secondary EMP damage over large areas - Does a comet/asteroid impact cause EMP from its plasma release, even
1908 Tunguska.
Berringer Crater:
“The object that excavated the crater was a nickel-iron meteorite about 50 meters (54 yards) across, which impacted the plain at a speed of several kilometers per second.”
My car is a LOT smaller than 150 ft.
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Speculation: the population of asteroids per unit volume is sparser inside the orbit of Mars?? (Plus, also remember that the gravity well of the big gas giants extends a lot further than the puny rocky inner planets.)
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