Author Topic: Meteorites  (Read 4223 times)

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Offline Dave Nelson

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Meteorites
« on: 12 November 2007, 11:22:01 AM »
 hi gang,

            another of my many interests is meteorite collecting.  its pretty cool to have a lump of space rock
 in your hand.  If it could speak, what stories could it tell of its millions of years of flight through space
before arriving on earth ??

   http://www.sydneystormcity.com/meteorites.htm

  Although I have had my collection listed on the "encyclopedia of meteorites"  www site for several years
I thought it was about time to also get them up on my own www site.
I am also seriously considering photographing my rock and mineral collection and putting it up on the www
as well.   that will be a huge challenge with over 300 specimens to photo and write out html pages for.

cheers
Dave N
Sydney


MB Edit: Dave - have moved this thread to ensure you get a wider audience for your pages.  It fits into this section of the forum.

but it has nothing to do with chasing ????   I was going nutz with it changing it listing all the time
« Last Edit: 27 November 2007, 02:35:49 AM by Jimmy Deguara »

Offline Mike

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Re: Meteorites
« Reply #1 on: 22 November 2007, 08:07:39 AM »
Cool!   Can you provide a list of the website links for us Dave that you have created?  An excellent topic and the mind boggles as to where these things have come from and from what planet, moon or asteroid they came from - could they in fact be part of our own planet that is still floating around in orbit with the rest of the matter in space????

Mike
Darwin, Northern Territory.
StormscapesDarwin.com
Lightning Research 2010/14

Offline Dave Nelson

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Re: Meteorites
« Reply #2 on: 27 November 2007, 01:05:19 AM »
Cool!   Can you provide a list of the website links for us Dave that you have created? 

Mike

Mike ... the link is included in the message :)     the other site "encyclopedia of meteorites" is a
registered site (not mine) and may not last hence why I created a page on my own site

Its a spin off of both my rock, mineral and fossil collecting as well as a variation of my astronomy interests
it never ceases to amaze me how many of my interests interact with each other   :)

cheers
Dave N

Offline Mike

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Re: Meteorites
« Reply #3 on: 27 November 2007, 05:58:17 AM »
Yep, I thought you may have had more....viewed your link, most interesting.

Could you tell me et al the largest meteorite that has been located thus far globally?

How do you know how old they are whether it's AD or BC when it's been flying around up there - carbon dating?  This is something that's always puzzled me, how can you tell the age of it when you don't know where its been or come from?

Is there a specific place on this wonderful planet that seems to have more remnants/rocks than any other and is there a reason for this?  Impact of a specific number of projectiles over the last million or so years?

Mike
Darwin, Northern Territory.
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Lightning Research 2010/14

Offline Dave Nelson

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Re: Meteorites
« Reply #4 on: 27 November 2007, 05:02:26 PM »

Hi Mike
 a few answers for you....

Could you tell me the largest meteorite that has been located thus far globally?

Namibia, SW africa  .... 60 tonnes  its still in the place it fell/discovered   too heavy to move
   its a nickel/ iron meteorite

How do you know how old they are whether it's AD or BC when it's been flying around up there - carbon dating?  This is something that's always puzzled me, how can you tell the age of it when you don't know where its been or come from?

Most meteorites  are in the 4 - 4.6 billion years old  .... part of the earliest solar system material.

there is a way to timed their arrival on earth ... I need to look back through my university geology study
notes,   it has to do with formation of radio isotopes by the bombardment of the rock by gamma rays in space
which stops once it enters the earth's protective atmosphere
( will dig up that info)

 ok several Q"s here .....  now  you will see some of mine have dates associated with them ....
dates are derived by several ways; a)..  the fall was witnessed  the easiest and most accurate (of course)
 b) ... its effects on the surrounding geology and that the ages of the various geological features have
already been worked out.

keep in mind that carbon dating is good only for ~ 6000 years


Is there a specific place on this wonderful planet that seems to have more remnants/rocks than any other and is there a reason for this?

Yes and Yes .....  The Antartic ice sheet is a great place to find meteorites.  The have been falling there for
countless millions of years ... buried in the ice and later brought back up to the surface with ongoing ice
movements.  The black - dark colour of the meteorites stands out so easily on the white ice.
the first confirmed meteorite from the planet Mars was found in Antartica.
   Places like deserts or the geologically stable Australian outback are also good places to look
 little to no vegetation light coloured ground rock again makes the dark meteorites stand out.

 Impact of a specific number of projectiles over the last million or so years?

ohhh gosh   it has dropped off substantially since the early life of the planets.  it was early in the solar system's
creationwhen the great meteorite bombardment occurred, when the gravity fields of the various planets
scooped up the masses of loose rock scattered throughout the system.
prob >90% of all the craters seen on the moon today occurred in that early period.
we dont see so many craters on earth for 2 main reasons 1) ... earth's atmosphere burns up many of the incoming rocks ... 2) ... the surface of the earth id geologically VERY active and this has destroyed many of the
craters.

 its estimated that ~ 200 tonnes of material falled to earth each day,  YES ... DAY.  most of that is the dust
 material remaining from the burnups in the atmosphere.

there's some info for ya   :)

cheers
Dave N


Offline Mike

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Re: Meteorites
« Reply #5 on: 28 November 2007, 04:33:40 AM »
Strewth, and that's just scratching the surface i bet!


The meteorite that hit in what's now Wolfe Creek crater, how big would that have been?

Is there a standard sized meteorite that astronomers dread hitting earth that would cause a disastrous impact - say, would it anything bigger than a house be devastating? 

I understand that there are litterally thousands of rocks orbiting our planet, with all the satellites orbiting as well why aren't more of them knocked out of the sky - surely they'd have to be susceptible to impacts?

You've got my interest here so I went to this site which answered a few things, very interesting stuff once you read about it all...The photo of the crater is from the Barringer Crater in Arizona, apparently it's 1.186km wide and the meteor was 'only' 30-40 metres in diameter!  So the 60 tonne Hoba meteor, what damage did that do?

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

Also found a photo of that Hoba meteor - that thing is huge!

http://search.live.com/results.aspx?mkt=en-au&q=namibia+meteorite&FORM=TBHT

Other members may like to input this topic, it gets more fascinating the more you delve into it!

Mike


« Last Edit: 28 November 2007, 04:57:02 AM by Mike »
Darwin, Northern Territory.
StormscapesDarwin.com
Lightning Research 2010/14