Meteorites and Meteor-wrongs

just after I came to Washington University in 1979 the first lunar meteorite was found a rock that was blasted off the surface of the Moon landed in Antarctica and was found and became the first piece of the moon that we had to study that hadn't been recovered on a space mission and somewhat remarkably over the last 30 years there have been about 75 of these rocks now found in various places around the earth and so I try to get my hands on all of them and I made a popular web page about lunar meteorites and almost immediately people started picking up rocks in their driveway and saying you know this looks like just like that rock on your website it's a long story after that most meteorites are pieces of asteroids it's only like one in a thousand that come from the moon and another one and a thousand come from Mars but all the rest are our pieces of asteroids there are a lot of people who want to collect pieces of the moon pieces of Mars every unusual meteorite the price of a meteorite depends on how rare the meteorite type is a lunar meteorite goes for much more than an ordinary chondrite another issue is whether there's a good story to go along with it if you go out in your garden and you find this it might be worth two dollars a gram if that same rock came through your roof it would be worth twenty dollars a gram it's it's just the story that goes along with it the ones are observed to fall are usually worth more than the ones that are found and then if it has a funny shape like the sakoda leans all have funny shapes those those go for more if there was a hole in this one it would be worth more than if there's no I mean it's stuff that's just in as a scientist I have to chuckle because some of these lunar meteorites to me oh that's a really unusual type of lunar meteorite and they often don't go for any more than the ones that I think it's just another so and so right well this is a good meteorite and this is a very typical example of what we call an ordinary chondrite notice how it's all rounded as it came through the atmosphere it broke apart but just like putting an ice cube and water the corners and the edges are the first things to soften as it comes through the atmosphere and and ablates away and this is all fusion crust where it's chipped off you can see through and it's you almost all meteorites when you chip them the fusion crust it's lighter on the inside if I had a magnet here a magnet would probably stick to this because there's iron nickel metal some of the things that are commonly mistaken for meteorites like these chunks of hematite are the same color on the inside as they are on the outside and that's that's a giveaway that it's not not a meteorite this particular one has all kinds of holes in it you just never see holes in the surface of a real of a real meteorite and another trick I always tell people is to get a white ceramic tile and turn it over to the unglazed side and try to make a chalk mark on it and piece of hematite is going to make a red a red streak and a meteorite just isn't going to do that I mean another one of the most common kinds of things that people send that are not meteorites but catch people's attention again I our pieces that look like this which I'm almost certain is a piece of slag some man-made product it's glassy it's the same on the inside as the outside shows these flow features and that's real common from something that got poured off a melting pot they'll pick up a magnet but them the metal is not finely dispersed you'll find it as great big blobs of metal in it and so again this is something that somebody set me caught their attention it's dense often people find these things with with metal detectors but meteor on well these two are both iron meteorites and this one's been sawn this is from Argentina it's a real common meteorite that you can buy pretty cheap on the internet called Campo del Cielo there's tons of this stuff this one is kind of one of my favorite it's one of thousands and thousands of pieces of a iron meteorite known as Sokoto lien that's a mountain range in Siberia West by Western Siberia and this is probably the biggest meteorite impact to have happened in historical times it happened in 1947 and this is what they call Sokoto lien shrapnel this thing burst and there are millions of pieces just splattered all over the place embedded in trees embedded in houses it's amazing nobody got killed but there weren't many people who lived there fellow I know who we got interested in meteorite collection decided to do it the right way he went back to the style of famous meteorite collector Harvey 9 and Jerr back in the early part of the century he put advertisements in local newspapers out in Missouri he got contacted by somebody a few years ago went out and take a piece off of it and I think this is part of the original piece and it turned out to be not only a meteorite it's a very rare type of meteorite known as a pallasite this is all pure pure metal with grains of the mineral olivine peppered in it like a brand bun with raisins I think I could kind of thing and this is only the 20th pallasite I believe it is that's been found in the United States the whole rock is about the size of a basketball and this is just a small piece it and so we analyzed the olivine and determine that it was of what we call main group pallasite and we're not set up well to analyze the metal so I got him in touch with the world's expert on analysis of metal and iron meteorites and they determined that this is a what we call up an anomalous main group pallasite meaning that it's it's different in detail than any of the others but it's pretty darn close to what most Paulo sites are like and so we have a bigger very nice polished section of this down in our Museum this was just part of the original one that we got to analyze but that that's kind of fun you

Channel: Washington University in St. Louis

Views: 206,896

Keywords: meteorites, Randy Korotev, wustl, wustlpa, lunar meteorites, space rocks, pallesite, WashU, Washington University in St. Louis

Id: VQO335Y3zXo

Length: 7min 5sec (425 seconds)

Published: Wed Nov 09 2011