Date: November 19, 2010
Title: Gifts from the Sky
Podcaster: Sandy Antunes
Organization: Project Calliope LLC – http://projectcalliope.com
Description: Need a gift for an astronomer? Wonder what different meteorites fall to Earth? Combine the two in our little cafe!
Bio: Sandy looks at the science and the people in today’s 9-5 pro astronomy world. Born in the heart of a dying star (as we were all), Alex draws from his research, writing, and game design work to bring you the joy of science twice a week at Science20.com/skyday— and to launch the first personal science/music satellite via http://ProjectCalliope.com.
Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by Harold Levene and Sue Freier in honor of the 19th Birthday of their astro-geek daughter, Bev.
[Emma the waitress] Dr. Antunes, table for one?
[Sandy the diner] Yes please, ah, thanks for the menu. Hmm… I think I’m ready to order. I’d like the steak, rare, with the caesar salad.
[Emma] Okay. Would you like a meteorite to go with that?
[Sandy] … excuse me?
[Emma] I said, would you like a meteorite to go with that?
[Sandy] As in, a chunk of rock or metal from space that entered the Earth’s atmosphere and was found in or near the crater it left?
[Emma] Exactly. One of our specialities.
[Sandy] Umm… what meteorite goes with steak?
[Emma] Well, I’d recomment an iron or stony meteors.
[Sandy] Stony are called chrondrites, yes? And chondrites are the most common falls, the common stony meteorites, correct?
[Emma] Yes. Stony meteors are believed to come from the asteroid belt. Most are a few dollars per gram, for the most common kinds.
[Sandy] Any with carbon, as in, a carbonaceous chondrite?
[Emma] Such as a 1969 Murchison Australian? We have some, but they’re over $100 per gram.
[Sandy] Why so pricey?
[Emma] Well, they’re rare. And since carbon is a building block for life, they’re considered more interesting by some people.
[Sandy] In that case, simple iron sounds appealing…
[Emma] Oh, good choice! They do make up fewer than one tenth of fragments, but they’re very popular.
[Sandy] How about a mix, a stony iron meteorite? I’m told they form from the interior of asteroids or from complex asteroids, since they’re from the boundary between the asteroid’s stony crust and its iron core.
[Emma] Well, I’m afraid all we have today are just iron or stony. But if you check again next week, sometimes we have some in stock, usually few dollars a gram.
[Sandy] I see. So do all meteors come from the asteroid belt, then?
[Emma] No, some come from planets. In fact, we may have a planetary achondrite available. Should I go check with the meteor steward?
[Sandy] What, pray tell, is a planetary achondrites?
[Emma] Well, they’re thought to come from the crusts of other planets or even the moon. They are usually pricey. We have some fragments of Mars basalt, for perhaps $ 100 a piece. Very tiny, but very special.
[Sandy] Wait, so we have pieces of Mars _on_ Earth?
[Emma] Well, yeah. Active solar system, you know.
[Sandy] Huh, I didn’t know. A different question– I see you list both Finds and Falls, what do those terms mean?
[Emma] If the meteorite’s reentry and impact was seen, it’s called a Fall. If the fragments were found later, it’s a Find. I mean, like you found something.
[Sandy] Hmm… that makes sense. So you list some iron Finds but almost all the stony chondrites are ‘Falls’. Is this because it’s hard to tell a rock from space from a rock from Earth, if you don’t actually see it fall?
[Emma] Exactly. So most stony meteorites are Falls, not finds. That’s one reason there’s many iron fragments available, even though most meteorites aren’t iron.
[Sandy] Ah, that also explains some of the years you offer here. I see you have a Canyon Diablo from Arizona, 1981, with the actual impact estimated to be from 20,000 to 40,000 years ago.
[Emma] Right, no one to spot that one, at least no one who could tell us about it.
[Sandy] Do you have anything more recent, then? Perhaps a fresh recent Sikhote-Alin from Russia?
[Emma] Oh, that’s a good choice in iron. Yes, it was witnessed falling in 1947 and it’s priced very affordably.
[Sandy] What is ‘affordable’?
[Emma] We consider ‘affordable’ as less than $1 a gram. In fact, we recommend you research the fragments a bit before buying.
[Sandy] So, overall, you’re saying I can get pieces of 4.5 billion year old space rock, of various types, for just a few dollars a gram?
[Emma] Yeah! Bear in mind these are rocks.
[Sandy] Ah, right, heavy. Let me estimate.. a cube one centimeter on each side, about a half inch, if made of rock, that would be about 4 to 6 grams.
[Emma] Yes, so from a reputable non-eBay dealer, you can get a nice, verified specimum for around $20.
[Sandy] That’s the price of a decent bottle of wine. That sounds like a wonderful present for an astronomy fan, I would think.
[Emma] Most definitely. You think about it and I’ll come back to take your order.
[Sandy] Much obliged. [pause] And I’d like to say I’m much obliged to my co-host, Emma, for this month’s podcast. I do collect meteorite fragments, primarily purchased from Eric Twelker at meteoritemarket.com. Their website is also where this podcast got the bulk of its information. As for myself, you can read my work at ProjectCalliope.com, including links to my twice-weekly space science blogs. See you next month! I’m Dr. Sandy Antunes, the daytime astronomer, signing off from 365 Days of Astronomy.
End of podcast:
365 Days of Astronomy
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