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In reply to the discussion: Regarding the meteor crash in Russia... [View all]JackRiddler
(24,979 posts)88. Do some research first, at least.
Quote: "What could be more rare than a meteor crashing?"
Meteorites are not "rare."
Big ones could be called that from the limited perspective of humans stuck in short-term thinking patterns, but on an astronomical time scale, big ones are also common.
Cornell astronomy site:
http://curious.astro.cornell.edu/question.php?number=470
It's a bit hard to tell exactly how many meteorites hit Earth each year. Most meteors that you see in the sky are caused by pea-sized pieces of rock and there's a lot of stuff this size in the solar system that Earth can run into! We can estimate the number of meteorites per year by carefully monitering the meteorites per day in one area, for example by using an all-sky camera to image the meteors visible in a given location, and then assume that all areas get roughly the same number of meteorites and add up the total.
Another way to tell how many meteorites hit Earth each year is to look at the number of meteorites found in dry regions where there isn't much vegtation or erosion (like deserts), where you expect to be able to find most of the meteorites that fell. We can get an estimate of how long ago the meteorite fell to Earth by looking at how it's been weathered, or altered by Earth's atmosphere and the local climate. Then we can plot how many meteorites fell at that region per year.
However, I can still find a lot of different estimates for how much stuff hits Earth each year, partly because different studies look at different size ranges, and all the procedures have errors. Estimates for the mass of material that falls on Earth each year range from 37,000-78,000 tons. Most of this mass would come from dust-sized particles.
A study done in 1996 (looking at the number of meteorites found in deserts over time) calculated that for objects in the 10 gram to 1 kilogram size range, 2900-7300 kilograms per year hit Earth. However, unlike the number above this does not include the small dust particles. They also estimate between 36 and 166 meteorites larger than 10 grams fall to Earth per million square kilometers per year. Over the whole surface area of Earth, that translates to 18,000 to 84,000 meteorites bigger than 10 grams per year. But most meteorites are too small to actually fall all the way to the surface. (This study was led by P. A. Bland and was published in Monthly Notices of the Royal Astronomical Society.)
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Like the time Rex Heflin was on the job inspecting highway signs in 1965 with his Polaroid?
Octafish
Feb 2013
#6
Well, if Mr. Heflin had thrown a Frisbee into the air, it would need to be about 30-feet across.
Octafish
Feb 2013
#14
I find it odd that often those that express faith in an almighty have such a hard time believing
rhett o rick
Feb 2013
#39
And so amazing that they designed their ships to meet earth sci fi imaginations.
alphafemale
Feb 2013
#56
When I first saw the photo a few years ago, I also noticed the dust (or whatever) under the saucer.
BlueJazz
Feb 2013
#77
Generally, what we see in terms of deployed aircraft are at least 10 years behind latest technology
stevenleser
Feb 2013
#171
Thank you, PCIntern. The subject has been ridiculed and is considered, by many, taboo.
Octafish
Feb 2013
#16
Ah the Roswell aliens. They aren't in New Mexico, that's what they want you to think.
Kalidurga
Feb 2013
#62
Poof...there went any credibility you may have had on this or any other subject....
OldDem2012
Feb 2013
#30
Credibility with the "I'll believe anything" crowd is the least of my concerns...
SidDithers
Feb 2013
#37
I can't wait for you to tell us that Betty and Barney Hill were on the grassy knoll...
SidDithers
Feb 2013
#119
'"As for Oswald, I don't know if he was a hero in all this or not."-Octafish to DU
zappaman
Feb 2013
#142
He wasn't convicted of anything - only accused by J Edgar Hoover and Allen Dulles.
Octafish
Feb 2013
#159
I'll give you an answer just as soon as the CIA and FBI come clean with what they've covered up.
Octafish
Feb 2013
#180
"Those interested in laughing about the assassination of President Kennedy, please don't."
zappaman
Feb 2013
#183
What "meteor?" I stand with Thomas Jefferson. Rocks don't fall out of the sky.
Jackpine Radical
Feb 2013
#38
Only a disinformationist would post that, in order to confuse the issue, zappaman.
Octafish
Feb 2013
#188
No, I do not. But so far there is no evidence that UFOs have visited earth. So.....
Logical
Feb 2013
#141
You UFO believers crack me up. No proof (scientific proof, read about it) and now with.....
Logical
Feb 2013
#129
That letter sounds kind to me. I will gladly compare Klass expertise and background to Friedman. n-t
Logical
Feb 2013
#146
There's a big difference between them. Your guy worked to silence discussion.
Octafish
Feb 2013
#163
Amazing, wow, it amazes me how little evidence there is for this crap. Thanks for link! n-t
Logical
Feb 2013
#151
That always cracked me up. You fly across the universe but forgot to turn off the running lights. nt
Logical
Feb 2013
#158
Right...just another way to avoid answering any questions ever directed to you....
zappaman
Feb 2013
#185
Yup. Edgar Cayce's story was not explainable by anything in this dimension.
joeunderdog
Feb 2013
#182
AND, since more and more Scientists adhere to the theory of Life itself came to Earth
Amonester
Feb 2013
#106
Not nearly as funny as the debunkers who can post nothing but cheap shots and ridicule.
Octafish
Feb 2013
#120
Rough test, considering usable and discernible evidence of meteors would pre-date
TheKentuckian
Feb 2013
#140
Why is it that the only people who see Bigfoots just happen to have a camera that doesn't focus?
underpants
Feb 2013
#153
When those hawt alien women arrive for mating season, you are so NOT getting an invite...
Blue_Tires
Feb 2013
#177