[meteorite-list] Michigan Meteorite

From: Graham Ensor <graham.ensor_at_meteoritecentral.com>
Date: Sat, 20 Jan 2018 11:41:19 +0000
Message-ID: <CAJkn+kbsCTmEWXUg4C8nrm9zOgtX=tbOtAWJ2HxKgs9AEQ9MrA_at_mail.gmail.com>

Hi Greg,

Great thing to do with your daughter...sorry you did not find
anything...I'd say it's still worth going back and having another go...wish
I was as close.

To answer a few questions... The larger pieces would probably bury
themselves more but nearly all meteorites loose all there energy from space
during the hot flight to about 20km above ground and then freefall...so
they do not have a great speed when they hit the ground...the smaller
pieces are even skewed by the winds from the main line of the meteors
direction. If the ground is hard or is a frozen lake then these smaller
pieces would not penetrate far at all and may well bounce or sit on the
surface to be seen.....deeper snow would be a problem and as with the
Chelyabinsk fall they would leave a small hole to look for if the snow had
stopped falling or drifting....many were found like that in Russia.

They are usually cold when they land and do not retain heat from the hot
flight which is stripped away in the plasma ball...the insides would still
be very cold and the air temps up at 20km are also very cold during the
freefall stage. If they sat for a while on hard snow or ice they may well
sink over time as the sun heats the black body up.

Hope that helps.

Graham

On Fri, Jan 19, 2018 at 5:27 PM, Sam Sabba via Meteorite-list <
meteorite-list at meteoritecentral.com> wrote:

> Hello all!
>
> I sent a post in a few days ago but I think I caused confusion by sending
> it via my other email address that was not the one I registered with.
> Let's see if this works better.
>
> My 7 year old daughter begged me to take her meteorite hunting after I
> picked her up form school this past Wednesday. My first reaction was to
> say no given the long odds, the cold, and the fact that she would miss a
> practice. She persisted, and then I realized I was being a fool and only
> thinking of the effort and poor odds involved, and not of the journey and
> wonderful scientific lesson itself! So we drove the 1 hour (easy compared
> to the travel time for the rest of you I see) and hunted a collection of
> Hamburg athletic fields. We did not find anything, but had a good time in
> the process. I see now that of course several pieces have been found
> (congrats to those that have found some).
> I am completely new to this, and I wanted to ask a few questions to
> satisfy my curiosity as well as my daughter's. Now that the professionals
> are in town, we will not be bothering to try again. :)
> During our search, we had expected that any pieces would have gone down
> into the ground at least a little bit. I however see that several of the
> pieces that have been found were just laying in the snow on top of a frozen
> lake. Is it normal for pieces of a meteorite to not land with enough force
> to break through ice or even frozen soil? Would they normally at least
> break through *unfrozen* soil, such as on a lawn or athletic field?
> Also, given the approximately 2 inches of snow we had on the ground here,
> would heat be produced from the meteorite itself or from it's impact that
> would have melted snow around it in any meaningful way?
> My daughter is probably doing her show-and-tell presentation at school as
> I type this (using a regular rock we found to represent the potential
> meteorite) so it is too late to provide her details for that, but we are
> both still curious.
> Thank you and good luck to those who will still be looking!
>
> Greg
>
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Received on Sat 20 Jan 2018 06:41:19 AM PST