· Get a Cloudy Nights T-Shirt · Submit a Review / Article Click here if you are having trouble logging into the forums Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User You are not logged in. [Login] Entrance · Main Index · Search · New user · Who's Online FAQ · Calendar Speciality Forums >> Space Rocks Previous   Index   Next   Threaded   Pages: 1 Dick Lipke professor emeritus Reged: 02/20/07 Loc: Marine City,Mich. Meteorites age?       #2634711 - 09/10/08 11:21 AM Edit   Reply   Quote Quick Reply   With all the analyzeing of a found specimen to prove the authenticity of a meteorite why do you seldom see the approximate age of the meteorite itself.Holding a meteorites in your hand is humbling enough,but to hold something that may older than our solar system is some thing else.I have searched both The Meteoritical Society and the Encylopedia of Meteorits but never see any reference to the age. Post Extras:       Glassthrower Vendor - Galactic Stone & Ironworks Reged: 04/07/05 Loc: Oort Cloud 9 Re: Meteorites age? [Re: Dick Lipke]       #2634755 - 09/10/08 11:42 AM Edit   Reply   Quote Quick Reply   Dating meteorites is difficult for a number of reasons, and accurate numbers have only became available in the last 3 or 4 decades. First, meteorites were formed inside their parent body and existed in a whole state for a period of time. During this time, material near the surface of the parent body (which presumably had little or no atmosphere) was exposed to harsh cosmic rays - this cosmic radiation causes a different breakdown of elements than what meteorites experience on Earth. (Earth's dense atmosphere absorbs the cosmic rays before they reach the surface) ...also, material deep down inside the meteorite parent body was shielded from cosmic rays by the layer of surface material over it. At this stage, cosmic rays are breaking down key isotopes into decay products at varying rates that are dependent on exposure. Geological forces such as intense heating and/or compression can also alter the equation and apparent age to some degree. Then, the parent body broke apart (likely a collision with another large body) and the inside portions became exposed to cosmic radiation for the first time. With this violent rearrangement of the source material, the resulting meteorites would exhibit different age results, depending on which method of dating was employed. Different scientists running the same methods would get different results because of human error or unforseen analytical flaws in the methodology. Depending on the meteorite type (iron, chondrite, pallasite, eucrite, etc), a ballpark age to give when asked is about 4.5 billion years. Generally, the bulk of the constituents that make up meteorites were formed in the solar nebula along with the planets themselves. Some material, like CAI's (Calcium Aluminum Inclusions) are thought to be some of the first solid material to condense out of the fledgling solar nebula - predating the Earth. Rarely, interstellar dust particles (microscopic) are found on/within meteorites and these wayward particles may be much much older than anything we know - these may predate our own sun. Regards and clear skies, MikeG PS - Cosmic Debris by Burke has a wealth of information on the long interesting history of dating meteorites accurately. Post Extras:       charlie g sage Reged: 10/05/07 Re: Meteorites age? [Re: Glassthrower]       #2713339 - 10/22/08 09:47 PM Edit   Reply   Quote Quick Reply   Hello all, my understanding is that our Sun is 'middle aged'...about 4.5 billion years old. Our Sun has another 4.5-5.0 billion years to exhaust it's hydrogen to helium fussion reactions. After this , our Sun will become 'a red giant star'. My question to Mike G, and to all CN folks is: 1) All elements above hydrogen and helium 'had to be forged in a star...or above iron...in the nova explosion nuclear chemistry of the violent super-nova process at a stars end point of a 'brief moment of Iron core'. 2) So where, when do elements 'above iron'...enter into our star system? How are 'meteorites' with elemental content above helium in our solar system? The fate of our Sun is very predictable...where are all these 'higher on the periodic-table elements'...from? 3) To say 'these elements are from earlier stars' is sloppy talk. Why do we know our Suns age, we know our Suns future life-cycle progression...yet all these 'higher elements above helium' are part of our planet materials...and content of meteorites. Stars in our Milky Way 'super-nova exploded enough for our earth/our rocky planets/and meteors which on earth capture we call meteorites???!! There is no sense of scale in this picture, was our Milky Way 'cranking out several generations of stars that 'super-nova exploded' to make enough 'dust'for our Sun to then form? This can not be! Our Sun is Hydrogen, 10% helium...where are the 'higher elements' from? And what time scale? Please respond, 'Glass thrower', and CN folks? charlie guevara NJ,US Post Extras:       edwincjones Close Enough Reged: 04/10/04 Re: Meteorites age? [Re: charlie g]       #2713799 - 10/23/08 06:42 AM Edit   Reply   Quote Quick Reply   meteorites from the Moon and Mars should be younger Post Extras:       Glassthrower Vendor - Galactic Stone & Ironworks Reged: 04/07/05 Loc: Oort Cloud 9 Re: Meteorites age? [Re: edwincjones]       #2714665 - 10/23/08 04:32 PM Edit   Reply   Quote Quick Reply   Indeed, Martian meteorites, especially shergottites, have much in common with Earthly rocks that result from magma action. They are "semi volcanic" in nature and much younger than most common chondrites which hail from the asteroid belt. Post Extras:       bob71741 scholastic sledgehammer Reged: 02/16/08 Re: Meteorites age? [Re: Glassthrower]       #2715006 - 10/23/08 07:42 PM Edit   Reply   Quote Quick Reply   William Cassidy's book, Meteorites, Ice, And Antarctica (isbn: 0521258723) offers some insight into meteorite age, and the differences between Martian, Lunar, and asteroidal meteorites. He discusses the collection of some 10K meteorites in 14 years in Antarctica. If you can get hold of a copy, its a very good read; a little pricey for $50 hard cover or $37 e-book, but it should be available in most college libraries and some major public libraries. Post Extras:       Dick Lipke professor emeritus Reged: 02/20/07 Loc: Marine City,Mich. Re: Meteorites age? [Re: bob71741]       #2927507 - 02/14/09 02:40 PM Edit   Reply   Quote Quick Reply   http://www.newscientist.com/article/mg20126934.700-apollo-17-rock-helps-date-moon.html Post Extras:       Pages: 1 Previous   Index   Next   Threaded   Extra information 0 registered and 3 anonymous users are browsing this forum. 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