GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2007-05 > 1179702370


From: "Nelda Percival" <>
Subject: Re: [DNA] Comet set fire to Northern Hemisphere 13000 years ago?
Date: Sun, 20 May 2007 18:06:10 -0500


Eric,
I wasn't being funny or sarcastic.. By what scientific reason could it not
be feasible?? I really would like to know.. It is thought that many near
planetary hits and actual hits have occurred over the history of the planet
Earth..

Are you saying it does not happen?


Look at:
http://seds.lpl.arizona.edu/nineplanets/nineplanets/meteorites.html

A very large number of meteoroids enter the Earth's atmosphere each day
amounting to more than a hundred tons of material. But they are almost all
very small, just a few milligrams each. Only the largest ones ever reach the
surface to become meteorites. The largest found meteorite (Hoba, in Namibia)
weighs 60 tons.

The average meteoroid enters the atmosphere at between 10 and 70 km/sec. But
all but the very largest are quickly decelerated to a few hundred km/hour by
atmospheric friction and hit the Earth's surface with very little fanfare.
However meteoroids larger than a few hundred tons are slowed very little;
only these large (and fortunately rare) ones make craters.

A good example of what happens when a small asteroid hits the Earth is
Barringer Crater (a.k.a. Meteor Crater) near Winslow, Arizona. It was formed
about 50,000 years ago by an iron meteor about 30-50 meters in diameter. The
crater is 1200 meters in diameter and 200 meters deep. About 120 impact
craters have been identified on the Earth, so far (see below).

A more recent impact occurred in 1908 in a remote uninhabited region of
western Siberia known as Tunguska. The impactor was about 60 meters in
diameter and probably consisting of many loosely bound pieces. In contrast
to the Barringer Crater event, the Tunguska object completely disintegrated
before hitting the ground and so no crater was formed. Nevertheless, all the
trees were flattened in an area 50 kilometers across. The sound of the
explosion was heard half-way around the world in London.

There are probably at least 1000 asteroids larger than 1 km in diameter that
cross the orbit of Earth. One of these hits the Earth about once in a
million years or so on the average. Larger ones are less numerous and
impacts are less frequent, but they do sometimes happen and with disastrous
consequences.

The impact of a comet or asteroid about the size of Hephaistos or SL9
hitting the Earth was probably responsible for the extinction of the
dinosaurs 65 million years ago. It left a 180 km crater now buried below the
jungle near Chicxulub in the Yucatan Peninsula (right).

Calculations based on the observed number of asteroids suggest that we
should expect about 3 craters 10 km or more across to be formed on the Earth
every million years. This is in good agreement with the geologic record. It
is more difficult to compute the frequency of larger impacts like Chicxulub
but once per 100 million years seems like a reasonable guess.

Then there is NASA's find just this last month...

http://science.nasa.gov/headlines/y2006/13jun_lunarsporadic.htm

A Meteoroid Hits the Moon
06.13.2006

June 13, 2006: There's a new crater on the Moon. It's about 14 meters wide,
3 meters deep and precisely one month, eleven days old.

NASA astronomers watched it form: "On May 2, 2006, a meteoroid hit the
Moon's Sea of Clouds (Mare Nubium) with 17 billion joules of kinetic
energythat's about the same as 4 tons of TNT," says Bill Cooke, the head of
NASA's Meteoroid Environment Office in Huntsville, AL. "The impact created a
bright fireball which we video-recorded using a 10-inch telescope."

Lunar impacts have been seen before--"stuff hits the Moon all the time,"
notes Cooke--but this is the best-ever recording of an explosion in
progress:

Now, I'm not saying that the subject " A Comet set fire to Northern
Hemisphere 13000 years ago?" did happen, that is up to the Scientist to
discover, I am just asking why you are so sure it did not happen??

That could really effect the development of the human race...




Nelda's websites -
http://freepages.folklore.rootsweb.com/~bonsteinandgilpin/




----Original Message Follows----
From: "Eric Olson" <>
Reply-To: ,
To: ,
Subject: Re: [DNA] Comet set fire to Northern Hemisphere 13000 years ago?
Date: Sun, 20 May 2007 15:36:07 -0700

Right!

And I just saw Elvis at the Mall...

Eric


> [Original Message]
> From: Nelda Percival <>
> To: <>
> Date: 5/20/2007 2:55:35 PM
> Subject: Re: [DNA] Comet set fire to Northern Hemisphere 13000 years ago?
>
> Hi Eric,
> Why is that LAUGHABLE? seems like it could have been an occurance!
>
> http://www.guardian.co.uk/science/story/0,,2083785,00.html?gusrc=rss
>
> Nelda
>
> Nelda's websites -
> http://freepages.folklore.rootsweb.com/~bonsteinandgilpin/
>
> _________________________________________________________________
> Like the way Microsoft Office Outlook works? Youll love Windows Live
> Hotmail.
>
http://imagine-windowslive.com/hotmail/?locale=en-us&ocid=TXT_TAGHM_migratio
n_HM_mini_outlook_0507
>





-------------------------------
To unsubscribe from the list, please send an email to
with the word 'unsubscribe' without the
quotes in the subject and the body of the message

_________________________________________________________________
PC Magazines 2007 editors choice for best Web mailaward-winning Windows
Live Hotmail.
http://imagine-windowslive.com/hotmail/?locale=en-us&ocid=TXT_TAGHM_migration_HM_mini_pcmag_0507

This thread: