(singing) Meteorite and meteor-wrong, how to tell a difference, this is that song,
meteor-wrong and meteorites
Knowledge from us will give you the sight
[laughing] Oh my God... [laughing continues, clapping, indistinct]
[intro]
Hey, we're gonna have a quiz at the end of this video,
so make sure you pay attention, and then at the end, you can vote either in the poll or let us know in the comments
below if you think we're talking about is a "meteor-right" or a "meteor-wrong."
We are here today with Jim Holstein
who's the collection manager of physical geology and meteorites. And today, we're gonna talk about meteorites and meteor-wrongs
- Hi, Emily. - Hi! - Ready to rock again? - I am ready to rock
J: So let's review what meteorites are, first of all-- E: okay. J: meteorites are from space,
obviously they come from mainly between the asteroid belt between Mars and Jupiter.
They fall pretty much every single day, but they mostly burn up in the atmosphere. The ones that reach the ground, we call meteorites.
- So it's meteoroid,
meteor,
meteorite.
We're gonna talk about the different kinds here. - Mhm. There's three different types of meteorites: stony
Stony iron and iron meteorites. Most common types are stony meteorites,
specifically the ordinary chondrites. -
E:What does it mean to be a chondrite?
J: Chondrites refer to the feature inside of these meteorites called chondrules.
These--these are these spherical inclusions that form in space as these meteorites were forming and they're captured by the meteorites
E: And so what's an achondritic meteorite? - That is without
chondrules. - There you go. - But! There's another big difference though
J: What's in the center of the earth? E: a core. - And then? - A mantle and then the crust? - Yes, so the earth is differentiated.
Okay, and meteorites--ordinary chondrite meteorites--are from bodies that are undifferentiated
So they don't have-- E: a core, a mantle, and a crust. - Yes. - So it's just like rocks all the way down
J: Yeah, what's that--what is a core made out of? E: nickel and iron. J: That's right.
All that material, that nickel iron material, is scattered throughout the body
So what we're doing today is figuring out how to tell the difference between a meteorite and a meteor-wrong. One is the mass
because it has a higher metal content in it.
E: So I pick it up and I'm like wow, this is heavier than I thought
it should be that might be clue
number one. J: Clue number one... E: that I have a meteorite. J: mhm
And when you flip it over and you look at the cut and polished surface
If you hold it just right to the light you'll see little flakes of metal inside of it
E: And that's the iron?J: and that's the iron nickel.
E: But there are other indications that you might have a meteorite that you can maybe tell from the outside
- So as these things are streaking into the atmosphere, it's going super fast
right, and when it hits the air molecules, it generates heat and that heat actually melts the outer surface.
So take another ordinary chondrite like this...
E: Yeah this one got burned up. J: that one got burned up and
what usually happens with these meteors as they're streaking through the atmosphere,
the atmospheric pressure builds up in the front surface of it and that actually causes them to explode.
E: Oh, wow
J: and then the smaller pieces that are still tumbling through the
atmosphere and those little pieces get a fusion crust, and that's what that black surface is called.
So when you flip it over to the interior surface, that's what it looked like in space
Is that greyish green material. E: So it got this while it was flying to the earth. J: Mhm.
E: And that's why it's also it's not completely smooth, but it kind of has smoothed edges.
J: it has smooth edges, rounded edges, and it creates different features that are also very common for meteorites and
the best example I have right here is another ordinary chondrite and this has these little indentations
in there, and that happens when you have heated air wallowing out pieces of the rock.
E: So it's like in a river where some of the water gets in the bank and it kind of starts to carve out the edges a little bit.
J: Yeah, exactly done, but it's being done by super hot air.
Typically these things are tumbling
as they're coming in, and so what happens sometimes with these things is that they don't tumble, they come traveling straight into the atmosphere
and what that ends up doing is it becomes bullet-shaped? E: Oh
J: And you'll see these features called flow lines. E: Okay. J: and you'll see little lines coming up the side so
Mass. Typically gonna have a fusion crust, and they might have these indentations on the surface caused by atmospheric entry
E: But you can't just base it off of like the black coloration because
This is a meteorite, but it doesn't have the same sort of crust
as this one. J: When it weathers for a long period of time it actually removes some of those telltale signs.
E: So the reason that it's kind of rusty colored is because it's been sitting on the surface of the earth. J: And then it becomes more
difficult to identify
what a meteorite is. E: should we mention what this one is too? This is a special achondritic meteorite. J: This particular one came from a
crust of a local planetary body. Can you guess where it is? E: The moon! It's a moon rock
I'm holding the moon! J: You are literally holding the moon. E:Wow!
This one feels more special than some of the other ones. J: It's really rare.
E: Really? J: Really, really. So next let's talk about the second group of meteorites, the iron meteorites.
E: These are the second most common? J: second most common, uh less than ten percent. E: This is very heavy
J: These are really dense objects. I mean, these are primarily nickel iron. And here's another one over here. I'm gonna pick up--
oh my god. To understand meteorites, we have to cut them open. So this is what we call an end cut.
It has most of the outer outer surface, but it also has a nice smooth interior.
E: You can see that different crust on these two
That one is a lot shinier and black and this one you can tell it's probably sitting on earth for a while. J: Exactly so that one is more weathered.
E: But this side has all these really interesting intricate patterns in it. J: Widmanstätten patterns. E: Is that what that word is? J: mhm
J: These were discovered in the mid-1800s by a scientist who
determined that
these types of meteorites have two types of alloys or two types of minerals: kamacite and taenite. And these are two different
nickel-iron ratios, and those are the actual crystals. And to bring that feature out, you have to cut the meteorite,
polish it really smoothly, and etch it with acid, and that brings out that feature. E: Wow...
E: It's so pretty! J: Mhm, and they come in different sizes, different widths, and it's a function of how long it took for this meteorite to
crystallize or solidify
E: So if you find one that has really big lines... J: ...it takes a long time for it to cool. E: Wow
J: And this last one is an example of a stony iron meteorite
E: This is the rarest of all meteorites. J: Not necessarily. E: Really?! J: So this is the rarest of the three broad categories:
stony, stony iron, iron,
but the rarest are achondritic meteorites, and other types of meteorites within the stony group itself are even rarer still
E: And what makes this special other than the fact that it's the prettiest? (laugh)
J: You can see it's it's heavy, right? E: Mhm. J: So it has nickel iron. But it also has these green crystals
J: And those are all living crystals. Yeah, and olivine--this type of olivine--is found in the mantle of planetary bodies.
So you have core material, then a mixing with mantle material, and this inter--this boundary zone
actually solidify as a meteorite when the body broke apart, and if you look at the outside fusion crust,
you can actually see pieces of the green crystal. E: Yeah!
E: Neat!
E: It's pretty even on the outside! J: Mhm. E: And on the inside
J: Aw! E: So now we've gone over the three major types of meteorites, and next we're going to look at some meteor-wrongs!
[buzzer sound]
J: So first one
E: This guy J: What do you think of that? E: I mean, it's pretty heavy. It's pretty dense. It's about as heavy as one of these
chondritic stony meteorites. J: It kind of has a darker crust on it,
you know, it looks like it's been weathered a little bit, but that's terrestrial rock called the concretion.
E: Really what's in it? J: So it's basically in the iron concretion
And so what you have is a nucleus, sometimes organic material, then you have sediments forming around it.
Next one is one we see a lot of here. E: Okay. Ooh
This is interesting. J: Yeah, what do you see in that one? E: Well it's kind of got a
darker crust, but it also has little crystals on the outside. J: Mhm, you can see the sparkle in the crystals.
E: They look like quartz crystals. J: And you're holding it. Like how's it feel? E: It's very light. J: It's very light.
E: I mean, it's still a rock it would hurt if I...threw it at somebody
J: Haha, and so this is a piece of terrestrial basalt.
This is a igneous rock,
a fine-grained igneous rock. Has very small crystals inside of there, and look at this guy. E: And the third guy
E: Oh E: This is way too light. J: And you can barely see any crystal growth on there too. The crystals are there, but they're very, very small.
But you see these deep, deep pits which are gases that were escaping from this material before it solidified
E: So this is a lava rock. J: So it's a lava rock essentially. E: What's this one? Ooh, this one is pretty dense.
J: It's pretty dense E: Pretty heavy, little-- J: So when it's dense, like that at that size, you know, there's a metal inside of there
E: Mhm. J: Well, let's
Try something here
E: Wow!
It's magnetic!
They stuck! J: Can you guess which mineral that is that's magnetic?
E: Magnetite? J: Magnetite, exactly. This is one I get a lot of. E: Yeah
J: And look at the outside, look at the inside. So this is manganese ore. People find these, they find them along train lines,
and so forth because you see them thrown away sometimes, and they end up
you know here because people will think they're a meteorite and rightfully so. It has a dark surface, the inside's metal
It's typically a little bit heavier. E: Okay. J: Ones we were looking at have been all natural, uh, nature formed, this one is man-made
E: This is surprisingly light. J: Surprisingly light, exactly. E: for how big it is and it's dropping--
J: And it's shedding all over the place. E: sand on the table. J: So this is runoff from industrial
manufacturing slag
Or as some people call it, clinkers.
And for me, this is the most common type of meteor-wrong that people bring in because they find these things
It looks like it's been heated up. It looks like something melted. As a child,
in fact, I would find pieces of this, and I would think that they were meteorites.
That was my first exposure to meteorites as a child finding these things. I think that's the meteorite
E: I bet you just had pockets full. J: Oh my god. My mother hated me. E: Oh, yeah. How many washing machines did you ruin?
J: That's why they would call them clinkers because they would clink around in the dryer.
E: Really? J: No. E: No, I'm so gullible. Alrighty. J: So those are the most common meteor-wrongs!
E: Okay. J: You know what time it is? E: Quiz time! J: Quiz time!
J: Here's specimen number one. E: Specimen number one. J: For you and the audience. E: Ooh, this is gonna be tricky
Okay. This one is pretty, pretty heavy
Um...
I can't tell if it's heavier than I thought it was going to be, but it's got a little bit of rust on the outside and
It's got some shiny metal bits
I'm gonna go with
This is not a meteorite
J: You're right. E: Really?! I got it right!
E: What is it? J: It's magnetite. It's the one you saw before. E: Oh, that's the tricky one. J: The one that nails stick to
E: Yeah, okay specimen number two
E: This one. Ooh.
Oh man, this one does have that really dark crust on the outside
It's kind of heavy but doesn't feel
super heavy, but
It also doesn't have the pitting on the outside
But it kind of looks like another one of the meteorites on the table
I'm gonna go with this is a meteorite.
J: Womp, womp, womp. E: Oh no! It's not a meteorite?
You've seen that one already. E: Really! J: That's the manganese ore. E: Oh, dang!
J: And if you look at it really closely, you'll see the manganese sticking out some places.
Ohh, like it's shiny. J: So lesson to be learned, look very, very closely. E: I was wrong.
Together: specimen number three
E: This guy...wow...
Oh jeez, this is lighter than I would have thought it was
It's got a nice crust on the outside. It's a little rusted
So like if it was a meteorite, maybe it landed and then was weathered
Uhmm...and it's kind of got
It looks a little bit like a chondritic meteorite. J: Ah. E: I'm gonna go with this is a meteorite. J: Yes. E: I got it! Nice!
J: And the last one. E: This last one, okay
Wow, this one's really light. This one is like kind of
Lighter than I would have thought. Well, this is confusing because like this part has really got that darker crust, and this is not as
crusty looking
It doesn't have those lines on it but it does have pits on the outside and it does look like an
achondritic meteorite with the shiny pieces of iron nickel in it. So I'm gonna go with this is a meteorite
J: It is a meteorite, a chondritic meteorite
E: Alright Jim so now that we've learned what is meteorite and what is not a meteorite
What--what should someone do if they think that they found a meteorite?
well
first of all
Don't necessarily trust the internet. You need to take it to someone who knows about geology, who knows about rocks and minerals and meteorites.
So take it to your local university, a local museum, and have someone identify it for you. E: Yeah, and they'll do that for educational purposes?
J: They usually do it for educational purposes. We, as a non-profit,
we don't value specimens or appraise specimens
but we do have ID day here in September where people can bring in their rocks, minerals, and
potential meteorites, and we'll identify it for you. E: That's so neat. Cool. Yay museums! J: Yay meteorites and? E: meteor-wrongs!
(outro)