>>DENTON EBEL: The Earth is going around the Sun at about 30 kilometers per second.
We’re all moving really fast.
And just like a windshield of a car hitting bugs,
we hit rocks, space rocks.
Many of these are leftovers from comets dropping little breadcrumbs behind them.
And these paths, as we cross them, make meteor showers.
Meteorites are bigger rocks.
They come in through the atmosphere.
They’re going very, very fast.
And if they come to the Earth and they hit the Earth and we pick them up as a rock,
then they're a meteorite.
What do meteorites tell us?
They tell us about the formation of the solar system.
They tell us about planets.
Our only samples of other planets are meteorites.
And they tell us about the dynamic history of the solar system
through the craters left by impacting meteorites.
Through the samples in the Hall, we tell the stories about these topics.
For example, if you look at the section on the origins of the Solar System,
the Allende meteorite that was observed to fall in Mexico in 1969,
it turned out to be a very important rock
because it contains calcium-aluminum-rich inclusions
and they're big enough that we could do isotopic dating
and come up with an age of the oldest rocks formed in the Solar System,
which is 4567.8 thousand million years —
so, four-and-a-half-billion, roughly.
When planets grow big enough to melt, they differentiate into a core and a mantle, like
the Earth.
But we haven’t actually seen the deep interior of the Earth.
We can’t drill down to the core of the Earth.
So, we infer the Earth’s core by looking at the density of the Earth itself.
We know there must be a very dense core.
The study of meteorites fits in there because early, very early in the solar system,
little planetary bodies formed cores.
[IMPACT SOUND]
And in our planetary section of the Hall, pieces of those kinds of bodies—early
planets—are recorded in the iron meteorites.
And so, studying those rocks gives us evidence for what is actually deep in the Earth
that we can’t sample in any other way.
Asteroids are in the asteroid belt between roughly Mars and Jupiter.
But there are lots of asteroids that cross the Earth’s orbit,
and those are called near-Earth asteroids.
And one of the topics we explore in the Hall is, in fact,
the hazards that meteorites pose.
If we have big objects hit the Earth, large enough to make craters, then we start to think
about hazards.
If it lands in the ocean, it makes big waves.
[IMPACT SOUND]
If it lands on land, it throws up a lot of dust.
That’s not good.
There are a lot of people thinking about stopping asteroids from hitting the Earth.
But it’s a tricky business.
And knowing about the asteroids proves critical.
So, for example, if an asteroid reflects a lot of sunlight,
then the sunlight’s bouncing off of it, giving it energy and pushing it in one direction.
And so, when you talk about deflecting asteroids,
one way to do it might be to paint the asteroid with something reflective so the Sun pushes
on it harder.
And if you do that early enough, then you can deflect the rock.
So, the way that the rocks interact with light,
which goes by the term spectroscopy,
is really important.
Spectroscopy also gives you clues
to the minerals that are present on the surface of whatever rock you’re looking at.
For example, because we were in orbit around the asteroid Vesta for two years,
we have close-up spectroscopy.
We know how those rocks on Vesta reflect sunlight in different wavelengths.
And we can look at the meteorites in the case about Vesta,
and they have the same spectrum.
So, we can match Vesta to these rocks.
And one of the future and important aspects of meteorite science is, in fact,
connecting specific meteorites to specific asteroids.
Meteorites are samples sent to us by processes in the solar system over which we have no
control.
Sample return, we control.
[RUMBLING]
>>ANNOUNCER: And liftoff of OSIRUS-Rex—its seven-year mission: to boldly go to the asteroid
Bennu and back.
>>EBEL: Sample-return missions are really difficult.
They require a spacecraft to rendezvous with a target,
collect material from the surface of the target,
and bring it back to Earth.
So, one of the things that we’re going for with sample return
is that material that hasn’t been through that
very brutal process of entering the Earth’s atmosphere at high speed.
So when we return samples from a comet, samples of the solar wind,
samples from the darkest asteroids, which have the most carbon near the surface,
which is going to tell us about origin-of-life-type chemistry—these are the important things
and important targets for research.
So, if this thing formed in space, then why does the sulfur exist here…
The American Museum of Natural History is about science.
It’s about communicating science.
But it’s also about doing science.
And we have a great meteorite collection
that we study to understand what these rocks can tell us.
>>SAMUEL ALPERT: My research is focused on a group of meteorites called the ordinary
chondrites,
meteorites that are very primitive, and their component parts are unaltered
since they formed in the early Solar System.
When you’re cutting a meteorite, you always want to make sure that you’re minimizing
loss of the sample.
[WHIRRING SAW]
And so, everything we do in the cutting process and in the preparation process is to avoid that.
>>MARINA GEMMA: My research focuses on the spectral properties of meteorites.
If we can match the spectral properties of the meteorites we have here
with the spectral features of asteroids in the asteroid belt,
then we can determine the parent bodies that these meteorites came from.
>>KIM FENDRICH: I’m studying samples of comet dust collected by the NASA Stardust
mission and returned to Earth in 2006.
Comets are some of the most primitive remnants left over from the early stages
of solar system formation.
They can give us clues to the environmental conditions at the time,
and also help to answer some of those existential questions
like, how did the Sun and the planets come to be?
How did we get here?
>>EBEL: In the Museum, you can find meteorites not just in this hall,
but in the Hall of Planet Earth
and in the Hall of the Universe,
because meteorites give us clues to the formation of the Earth,
the deep interior of the Earth,
and also to the larger galaxy of which this Solar System is a part.