[meteorite-list] Just Another Question

Sat May 31 13:18:01 EDT 2008

"From the International Space station (One of the lowest satellites): 
11,412 mph (7,091 Km/h)"

Oops: to get out of Earth orbit and become a "meteoroid" that should 
have been:

>From the International Space station (One of the lowest satellites):
7,091 mph (11,412 Km/h)

Best wishes,
Doug

-----Original Message-----
From: mexicodoug at aim.com
To: Meteorite-list at meteoritecentral.com
Sent: Sat, 31 May 2008 12:05 pm
Subject: Re: [meteorite-list] Just Another Question

Al M. wrote: 

"I don't think it would be possible for an astronaut to throw an 
object, rock or otherwise out of the orbit of the Earth." 

Hi Al, Pete, Friends and Listees, 

Haven't kept with this thread, but I thought I'd add this info for the 
throwing arm of the astronaut to create an artificial meteorite from 
some favorite heights. 

I noticed Dr. Grossman mentioned the need for extraordinary evidence 
(i.e., claims by necessity must be treated with skepicism, until at 
least someone can show you a piece of it). 

Here are some of the "physics": the minimum speeds the clever Astronaut 
would have TO THROW any object to gain an independent orbit from Earth: 

>From the International Space station (One of the lowest satellites): 
11,412 mph (7,091 Km/h) 

>From a GPS satellite (nearly the highest): 
3,692 mph (5,941 Km/h) 

He has to be clever as he needs to throw it exactly in his direction of 
motion to make the satellite's speed additive and also away from the 
Moon so that doesn't add significant additional speed required. I just 
used the 11.2 km/s value at Earth's surface which fails to take into 
consideration the air resistance (this is only partly why expecting 
material to survive the shear force going up through Earth's atmosphere 
is an Extra-ordinary claim). Not a problem - these are the right 
answers for space. 

The best baseball players on Earth have been clocked at around 100.9 
mph. 
The best Jai-alai ball has been levered at about 188 mph. 
These speeds are taken over a very short distance from the throwing arm 
on Earth, so would be nearly the same in space. 

BTW, if an astronaut on the Moon wanted to "throw" something out of 
Lunar orbit, he would need to throw at 5,315 mph (8,554 Km/h) which 
would leave it barely moseying away from a Lunar orbit, but he would 
need it to end up at a minumum of over 3,220 mph (5,188 Km/h) more to 
then escape Earth. 

Throwing things at these speeds is of course hypothetical given the 
capabilities. 

Back to the original question Earth meteorite possible? to comment: 
These same capabilities need to be taken into consideration with 
regards to the mass integrity of any Earth ejecta. Assuming an object 
can hit Earth fast enough to impart sufficient velocity at cratering 
which will survive the trip back up and more importantly an order of 
magnitude more to rip it from Earth's gravitational grasp, is like 
assuming you can find a Nolan Ryan to pitch a ball at about 12,000 mph. 
It is also a possibility that no physical Nolan Ryan exists. 

Earth meteorites don't have a chance due to this reason, unless you 
make one modifying assumption: That the original impactor causing them 
creates a transient vacuum behind it long and straight enough for 
backspauled material to find its way out. THAT is an extraordinary 
claim unless we are talking major planet smasher and vapor condensation 
in space just to make sure the ejecta aren't too small or just plasma 
or molecules! Ojo, this means the cloud MUST condense in outer space 
while it is moving away at these speeds. That just adds another degree 
of complexity. Not impossible, of course. The jury is still out. I'd 
repost a recent answer about 6 months ago I made talking about the 
atmospheric dynamics required for Earth meteorites to happen but I'm 
not good at maintaning these old met-list links as some others :( 

Best wishes, 
Doug 

-----Original Message----- 
From: AL Mitterling <almitt at kconline.com> 
To: Meteorite-list at meteoritecentral.com 
Sent: Fri, 30 May 2008 7:51 pm 
Subject: Re: [meteorite-list] Just Another Question 

Hi Pete,  

I don't think it would be possible for an astronaut to throw an object, 
rock or otherwise out of the orbit of the Earth. (lets not talk about 
the Hassablat that got away) Seems like that would be possible but if 
you think about it, both the astronaut and the rock are in orbit around 
the Sun. Even a hard throw towards the Sun would only start the rock 
moving back and forth in roughly the same orbit the Earth is in. You 
might have better luck with trying to reduce it's energy (a retro so to 
speak throw) so it would loose energy and fall into a tighter orbit 
towards the sun. You have to think about the actual speed the Earth is 
traveling around the Sun. Any throw would most likely not be able to 
leave the Earth/Moon orbit. Even if an astronaut was well away from the 
Earth Moon system in order for the astronaut to not drop directly into 
the Sun he would have to have an orbit around the Sun. So even throwing 
objects without major gravity near by would even be difficult. It's why 
objects in the inner solar system have a harder time coming out 
(gaining energy) than objects have loosing energy and going in towards 
the inner planets and Sun.  

Jeff Grossman wrote: to be called a meteorite, an object had to escape 
the dominant gravitational influence of its parent body. In this case, 
we would say that a terrestrial (Earth) meteorite would be an object 
ejected from earth by natural causes (i.e., by impact), which entered 
an orbit around the sun and later was re-accreted (fell as a meteoroid, 
became a meteor and then meteorite when it survived passage) by and to 
the earth.  

Jeff states: Nothing like this has ever been found. Its distinguishing 
properties might be a fusion crust, evidence for cosmic-ray exposure in 
space, and lithology that is completely exotic for its find location. 
Without an exposure history (or being an observed fall) it would be a 
very tough sell.  

Hope that helps. All my best!  

--AL Mitterling  

Pete Shugar wrote:  

> So if an object were to be taken into orbit and given excape velosity 
 > from earth's gravitational well such that it was not in orbit around 
 > earth, but in orbit around the sun and at a later time reentered > 
earth's gravity well, passed thru the atmosphere and survived to > 
impact the earth, it would not be a meteorite simply because it was > 
not ejected fron terra firma by natural means? Granted that man made > 
debri isn't classed as a meteorite but non man made material > 
shouldn't be penalized because an astronaught decided to impart > 
excape velosity to a rock,puting it into orbit around the sun.  
> I say material surviving to impact from any source (excluding man > 
made) would and should be called a meteorite.  
> Pete  

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