[meteorite-list] Iranian Fireball Was Of Geophysical Origin

Mail actions: [ respond to this message ] [ mail a new topic ]
Contemporary messages sorted: [ by date ] [ by thread ] [ by subject ] [ by author ]

From: Charles Viau <cviau_at_meteoritecentral.com>
Date: Thu Apr 22 10:31:22 2004
Message-ID: <002001c3f255$c7894570$1800a8c0_at_chupa>

This is a multi-part message in MIME format.

------=_NextPart_000_0021_01C3F22B.DEB33D70
Content-Type: text/plain;
 charset="us-ascii"
Content-Transfer-Encoding: 7bit

The 'bit of a stretch" comment in the same context as " just like we
have Martian meteorites" is intentional. The gravitational forces on
the Earth are higher, and there is a dense atmosphere related to Mars.
It takes a much bigger impactor on earth to eject material at escape
velocity than it would on Mars. Therefore, the amount of available
material that could possibly find it's way back to Earth would be much
less and should be rather rare. Who knows: as rare as a Venusian
meteorite? No one has every classified one but you can bet your helmet
that they are here somewhere. We only know that Mars and Lunar materials
are here because we have been to those places and analyzed the chemical
and geological properties of rocks, which were mostly basalts.

The angle of impact would not be that important with an impactor like
Chixilub, Sudbury, Vredfort, Chesapeake and probably Manicouagan.
The size of these bodies would eject material even on a zenith
trajectory. They would also punch such a vacuum hole in the atmosphere
that it would suck out great quantities of molten matter that would go
into earth orbit and most likely reenter the atmosphere producing
tektites.

The point here is that it does not require an extreme amount of physics
to understand that there are pieces of this entire solar system all over
the place. We just have to look at all of the impact craters that we can
see in our neighborhood to understand that every planet has probably
traded material with every other over the course of the last 4 billion
years.

CharlyV

-----Original Message-----
From: meteorite-list-admin_at_meteoritecentral.com
[mailto:meteorite-list-admin_at_meteoritecentral.com] On Behalf Of
MexicoDoug_at_aol.com
Sent: Friday, February 13, 2004 11:13 AM
To: meteorite-list_at_meteoritecentral.com
Subject: Re: [meteorite-list] Iranian Fireball Was Of Geophysical Origin

This topic was discussed a few weeks ago on the list, and it seems
pretty convincing that Earth parented meteorites are elusive for good
scientific reasoning - it seems that if conditions to produce them
happened, that the material would be glass or a split planet Earth (a la
did the moon come from Earth question we had recently).

While it may be possible (though statistically highly improbable), it is
important not to say it is "a bit of a stretch", "just like we have
Martian meteorites here".

Those statements taken together are misleading, to say the least.

It is important to recognize that Earth and Mars are so different
regarding atmospheric density (over 100X) / viscosity and to a much
lesser degree gravity, that such an analogy is not based on astronomy
and physics, but rather wishful thinking, with a general ignoring of
scientific principles - i.e. a solution (Earth parented meteorites exist
because I can think it and there are Martian meteorites here) looking
for a problem (Why no one has ever confirmed an Earth parented
meteorite).

Extending that logic, I would ask where the Solar parented meteorites
are at, and while we are at it the Jovian parented and Venusian
parented meteorites as well. The conditions on Mars simply do not lend
themselves for comparison to Earth. Venus is a better comparison for
Earth. Perhaps someone could work out the physics to show what sort of
impactor on Earth is capable of causings something besides glass and
giving it escape velocity.

Without doing the physics, it is clear it would have to be a kilometer
plus sized impactor imparting in an instant to a kilometer plus sized
Earth rock escape velocity plus frictional loss velocity, which further
does not explode with that velocity at sea level as it makes its way
through the exponientially most dense part of the atmosphere (i.e. a
"reverse meteorite") at a right or obtuse angle to the impact (which
tends to create a velocity vector landing back on Earth). While this
might sound "plausible", for an impactor to produce a kilometer plus
sized rock with such a velocity seems nearly impossible, knowing the
characteristics of Earth surface features.

To actually achieve the above, either ground zero has to become liquid
or plasma eventually producing glasses, for which there is some evidence
in tektites, or Earth must be split like a nut, for which the Moon was
presented as evidence in such a hypothethised impact around 4.5 billion
years ago....

So that would leave a scenario of a gigantic impactor hitting near the
base of a Mount Everest made of solid iron or other high tensile type
structure, incoming at a low entry angle, and propelling the peak into
outer space.

In the case of Mars objects over 10 meters (but probably in the realm
500 km) can impact whole much more readily and produce "reverse
meteorites" with the initial velocities potentially conducive to this
event which can escape more readily as gravity (and hence resulting
escape velocities) is less than 40% Earth's. Furthermore Mars is closer
to the Asteroid belt and is expected to have more flux of such potential
impacts.

Saludos
Doug Dawn
Mexico

En un mensaje con fecha 02/13/2004 8:21:52 AM Mexico Standard Time,
cviau_at_beld.net escribe:

and bit of a stretch.. but plausible: Just like we have
Martian meteorites here on earth, so would we not have some of the
ejecta from our terrestrial impacts also in orbit around the Sun

------=_NextPart_000_0021_01C3F22B.DEB33D70
Content-Type: text/html;
 charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

<html xmlns:o=3D"urn:schemas-microsoft-com:office:office" =
xmlns:w=3D"urn:schemas-microsoft-com:office:word" =
xmlns:st1=3D"urn:schemas-microsoft-com:office:smarttags" =
xmlns=3D"http://www.w3.org/TR/REC-html40">

<head>
<META HTTP-EQUIV=3D"Content-Type" CONTENT=3D"text/html; =
charset=3Dus-ascii">

<meta name=3DProgId content=3DWord.Document>
<meta name=3DGenerator content=3D"Microsoft Word 10">
<meta name=3DOriginator content=3D"Microsoft Word 10">
<link rel=3DFile-List href=3D"cid:filelist.xml_at_01C3F22B.DB7CA380">
<o:SmartTagType =
namespaceuri=3D"urn:schemas-microsoft-com:office:smarttags"
name=3D"City"/>
<o:SmartTagType =
namespaceuri=3D"urn:schemas-microsoft-com:office:smarttags"
name=3D"place"/>

<style>

</style>

</head>

<body lang=3DEN-US link=3Dblue vlink=3Dpurple =
style=3D'tab-interval:.5in'>

<div class=3DSection1>

The
‘bit of a stretch” comment in the same context as
” just like we have Martian meteorites” is
intentional.  The =
gravitational
forces on the Earth are higher, and there is a dense atmosphere related =
to
Mars. It takes a much bigger impactor on =
earth to
eject material at escape velocity than it would on Mars. Therefore, the =
amount
of available material that could possibly find it’s
way back to Earth would be much less and should be rather rare.  Who knows: as rare as a Venusian meteorite?   No one has every =
classified one
but you can bet your helmet that they are here somewhere. We only know =
that
Mars and Lunar materials are here because we have been to those places =
and
analyzed the chemical and geological properties of rocks, which were =
mostly
basalts.<o:p></o:p>

<o:p> </o:p>

The angle of impact would not be that important with =
an impactor like Chixilub, <st1:City><st1:place>Sudbury</st1:p=
lace></st1:City>, Vredfort, <st1:City><st1:place>Chesapeake</st=
1:place></st1:City> and
probably Manicouagan.<o:p></o:p>

The size of these bodies would eject material even on =
a
zenith trajectory.  They =
would also punch
such a vacuum hole in the atmosphere that it would suck out great =
quantities of
molten matter that would go into earth orbit and =
 most likely reenter the =
atmosphere
producing tektites.<o:p></o:p>

<o:p> </o:p>

The point here is that it does not require an extreme =
amount
of physics to understand that there are pieces of this entire solar =
system all
over the place. We just have to look at all of the impact craters that =
we can
see in our neighborhood to understand that every planet has probably =
traded
material with every other over the course of the last 4 billion =
years.<o:p></o:p>

<o:p> </o:p>

CharlyV<o:p></o:p>

<o:p> </o:p>

-----Original =
Message----- 
From: =
meteorite-list-admin_at_meteoritecentral.com
[mailto:meteorite-list-admin_at_meteoritecentral.com] On Behalf Of MexicoDoug_at_aol.com 
Sent: Friday, February =
13, 2004
11:13 AM 
To:
meteorite-list_at_meteoritecentral.com 
Subject: Re: =
[meteorite-list]
Iranian Fireball Was Of Geophysical Origin

<o:p> </o:p>

This topic was discussed a =
few weeks
ago on the list, and it seems pretty convincing that Earth parented =
meteorites
are elusive for good scientific reasoning - it seems that if conditions =
to
produce them happened, that the material would be glass or a split =
planet Earth
(a la did the moon come from Earth question we had recently).  
 
While it may be possible (though statistically highly improbable), it is
important not to say it is "a bit of a stretch", "just =
like we
have Martian meteorites here". 
 
Those statements taken together are misleading, to say the least. 
 
It is important to recognize that Earth and Mars are so different =
regarding
atmospheric density (over 100X) / viscosity and to a much lesser degree
gravity, that such an analogy is not based on astronomy and physics, but =
rather
wishful thinking, with a general ignoring of scientific principles - =
i.e. a
solution (Earth parented meteorites exist because I can think it and =
there are
Martian meteorites here) looking for a problem (Why no one has ever =
confirmed
an Earth parented meteorite). 
 
Extending that logic, I would ask where the Solar parented meteorites =
are at,
and while we are at it the Jovian parented  and Venusian parented
meteorites as well.  The conditions on Mars simply do not lend =
themselves
for comparison to Earth.  Venus is a better comparison for =
Earth. 
Perhaps someone could work out the physics to show what sort of impactor =
on
Earth is capable of causings something besides glass and giving it =
escape
velocity. 
 
Without doing the physics, it is clear it would have to be a kilometer =
plus
sized impactor imparting in an instant to a kilometer plus sized Earth =
rock
escape velocity plus frictional loss velocity, which further does not =
explode
with that velocity at sea level as it makes its way through the =
exponientially
most dense part of the atmosphere (i.e. a "reverse meteorite") =
at a
right or obtuse angle to the impact (which tends to create a velocity =
vector
landing back on Earth).  While this might sound =
"plausible", for
an impactor to produce a kilometer plus sized rock with such a velocity =
seems
nearly impossible, knowing the characteristics of Earth surface =
features. 
 
To actually achieve the above, either ground zero has to become liquid =
or
plasma eventually producing glasses, for which there is some evidence in
tektites, or Earth must be split like a nut, for which the Moon was =
presented
as evidence in such a hypothethised impact around 4.5 billion years =
ago.... 
 
So that would leave a scenario of a gigantic impactor hitting near the =
base of
a Mount Everest made of solid iron or other high tensile type structure,
incoming at a low entry angle, and propelling the peak into outer =
space. 
 
In the case of Mars objects over 10 meters (but probably in the realm =
500 km)
can impact whole much more readily and produce "reverse =
meteorites"
with the initial velocities potentially conducive to this event which =
can
escape more readily as gravity (and hence resulting escape velocities) =
is less
than 40% Earth's.  Furthermore Mars is closer to the Asteroid belt =
and is
expected to have more flux of such potential impacts. 
 
Saludos 
Doug Dawn 
Mexico 
 
En un mensaje con fecha 02/13/2004 8:21:52 AM Mexico Standard Time,
cviau_at_beld.net escribe: 
 
<![if !supportLineBreakNewLine]> 
<![endif]><o:p></o:p>

and bit of a stretch.. but
plausible:  Just like we have 
Martian meteorites here on earth, so would we not have some of the 
ejecta from our terrestrial impacts also in orbit around the =
Sun<o:p></o:p>

<o:p> </o:p></fo=
nt>

</div>

</body>

</html>

------=_NextPart_000_0021_01C3F22B.DEB33D70--
Received on Fri 13 Feb 2004 12:21:07 PM PST

This message: [ Message body ]
Next message: nelson oakes: "[meteorite-list] NWA1836, "Twisted Sister", Achondrite (cumulate eucrite, monomict)"
Previous message: Adam Hupe: "[meteorite-list] Ad - Weekly Rare Material Special"
In reply to: MexicoDoug_at_aol.com: "[meteorite-list] Iranian Fireball Was Of Geophysical Origin"

Mail actions: [ respond to this message ] [ mail a new topic ]
Contemporary messages sorted: [ by date ] [ by thread ] [ by subject ] [ by author ]

StumbleUpon

del.icio.us

Yahoo MyWeb