(meteorobs) Fw: Possible meteorite

Tue May 3 00:09:39 EDT 2005

Hola List, Linda,

I just wanted to respectfully clarify the  objection about meteorites being 
"the temperature of space" as the "real problem  here".  While withholding for 
the moment interpretations of the "boiling  lake", I just wanted to add that 
space has no temperature and the "temperature  of space" is really a 
meaningless concept in this situation.

Temperature  realistically considered, is a sort of a measure measurement of 
kinetic energy  at the molecular level.  Which means one needs to have a mass 
to have a  temperature, and then to check the energy flux through, for 
example, a standard  unit cross sectional area.

Even that alone will not determine  temperature, because then you need to 
look at heat capacity and mass (heat  accumulation potential) the like of the 
material, which gets complicated because  then you have to look at the 
equilibrium of energy efficiency: wavelengths of  energy absorbed and emmisivity.

So, in the case of a meteorite:

If you work out the math based based  on a few simplifying assumptions and 
reasonable, you will find that iron  meteorites that fall have a core 
temperature around 90 degrees C (194 F), which  is rather hot to touch, and the outside 
rind from ablation could easily briefly  reach over 100 C (212 F) degrees 
before quenching.

Whether the iron  meteoritic mass actually makes it to the surface of the 
earth at that  temperature is another question, though.  Because after the 
incandescent  portion of the flight depending on size, the freefall speed for irons 
reached is  about 400 miles per hour nearing sea level for a typical decent 
chunk.  And  when you blow on something it cools down - a surface phenomenon.  
So the  actually cooling of the meteoritic chunk does not happen in space, but 
rather in  the lower atmosphere of earth from wind.

If it is an iron meteorite and  reasonably big - say the size of a 
basketball, it most certainly will be warmer  than ambient as soon as ground 
equilibration begins (initially, from the dark  phase wind cooling, the surface, which 
started out hotter during ablation, may  be colder - this will depend on shape 
and mass).

If it were a stone  meteorite, due to the different characteristics stony 
concretions have than  iron-nickel, the temperature would be right around 0 C (32 
F), a big difference,  still from the implied frigid temperature of space.

Actually the earth  itself is not magic and our temperature should be right 
about freezing, or  perhaps 5 - 10 below C (20 to 30 F) due to very similar 
considerations despite  the magmatic activity of the core.  The planet is in a 
sort of thermal  equilibrium just like other fixed objects on skewers (axes) 
orbiting.  The  real extra 25 C (extra 45 F) is due mostly to the atmospheric 
greenhouse  effect.

Now back to the question of Linda.  Could a meteorite have  caused all that?  
My answer would be definitely no, but I woudn't even  think about the lake 
activity.  If such a bolide came in, a huge end-of-the  world 
thundering-smashing-puttering sound would definitely have been more  memorable than the the 
bubbling lake, caused by the more distant mass entering  with cosmic velocity.  If 
you worry about the lake "bubbling" as in boiling  would she not have found 
dead fish and other scalding traces?  Of course, a  heavy iron (or stone) 
hitting bottom certainly could release a lot of pent up  detrital gas from the 
sediments of the lake bed giving the impression of boiling  whether any boiling 
occured or not (and boiling could possibly occur with a  large iron base on the 
above comments).  But then where were the  thunderclaps?

PS The Mazapil, Mexico meteorite was documented to have fallen  sizzling.  
How sizzling it was is hard to confirm 125 years later, but it  is pretty well 
accepted it was hot or warm.  As was Cabin Creek.   Those are both metal.  As I 
posted here recently, an aquaintance picked up  a stone meteorite moments 
after it fell 25 feet from him.  Initially  it was normal to slightly warm to 
touch.

Hope this helps...Saludos,  Doug

En un mensaje con fecha 05/02/2005 1:06:30 PM Mexico Daylight Time,  
lunro.imo.usa at cox.net escribe:
Here is an interesting note sent to the  American Meteor Society. I could 
have dismissed this story outright but I  felt others had the right to 
express their views. I'll share any of your  comments with Linda.

Thanks!

Bob

----- Original Message  ----- 
Subject: Possible meteorite

I am not sure if what I  witnessed was a meteorite or something else. 
Perhaps your insight and  knowledge of meteorites will help answer my 
question.

In 1952, when I  was 8 years old, my family lived in a house on a hill 
overlooking Townline  Lake in Lakeview, Michigan.  I was sitting on the 
screened porch when I  heard a loud splash.  When I looked up, I saw a large 
round area of the  lake boiling.  I was frozen with fascination.  The boiling 
area  looked to be perfectly round.  It was approximately 50-75 yards from  
shore ( it's hard to judge distance across the water) and the round boiling  
area was approximately 30-40 feet wide.  The boiling circle drifted to  the 
left about 20-30 feet from where it had begun as if something was  drifting 
down to the bottom of the lake at an angle.  After watching it  for several 
minutes, the boiling slowly stopped.  After the boiling had  stopped, I ran 
to tell my mother about it.  Of course she didn't see  anything since the 
boiling had already stopped, but I think she did believe  me since I was not 
one to make things up.

Would a meteorite cause  water to boil like that if it fell into a lake? 
Would it have cooled off  enough to stop the water from boiling in only a few 
minutes?  Would a  meteorite cause the water to boil in a perfectly round 
pattern?  Could  a meteorite hitting earth be that large and not cause any 
destruction if it  fell into a lake?  I have always wondered what it might 
have been, and  now, 52 years later, I remember the incident like it was only 
yesterday and  am still perplexed by the incident.

Any information you might be able to  shed on the subject would be greatly 
appreciated.

Thank you for your  time.

Linda Johnstone

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