- [Cory] What you're looking at are tiny bits of rock and metal under a device called
an electron microprobe. The samples came from
a rooftop in Brooklyn but they might have traveled
quite a ways to get there. Possibly from outer space. We're at NASA trying to figure out whether they really are tiny meteorites. Because if so, they
could help unlock secrets you really wouldn't believe. (soft music) - So earlier this year we set out to find a micrometeorite of our own. We wandered around a roof
with a powerful magnet. We spent hours in front of a microscope. We got advice from a
Norwegian jazz guitarist who also happens to be the world's foremost micrometeorite hunter. You know what, just watch the other video. We'll put a link to it at the end. Anyways, the end result was this image. It's our best sample. The one most likely to
have come from space. But, the image alone isn't conclusive. We wanted to find out what it takes to positively ID a meteorite. And what scientist can learn from it. So we headed to NASA's Johnson
Space Center in Houston where, well, we met this guy. - You take a bee's head, right You glue the bee's head to a carbon disk. Just look at the bee's head,
and kids love this, right. You see the eyes and
the hairs are all moving around like this 'cause they hard jump and they swirl around. - [Cory] Mike Zolensky is a
space scientist at Johnson. He's walking us through
the electron microprobe. It uses a stream of electrons the way a microscope uses photons. Particles bounce off your
sample and hit a sensor, returning a wonderfully detailed image of tiny rocks or anything
else you put in there. - I used to have a bee's
head just for tours. And believe me, adults love it too. I mean, everyone loves
looking at the bee's head. - Oh, yeah, it's amazing. Mike works within NASA's
astromaterials research and exploration science division. It's a very nondescript
building at Johnson but inside is maybe the
ultimate cabinet of curios. Materials from the moon and Mars. Dust from comets. Flecks of asteroids. Atoms from the sun. We're interested in the 60 to 100 tons of material from outer space
that lands on Earth each day. Most of it lands unnoticed
but every now and again a big meteor lights up the
sky and experts like Mike, mobilize to collect samples from it. It all sounds pretty Indiana Jones-y. - It's really fun, usually. It's sometimes a gun and
it's not fun, you know. - [Cory] Does that happen? - Yeah, sure, but it's okay. It's a long story, long story. - Mike's job is to wring
every detail possible out of the samples that cross his desk. Some are big like these
two that he showed us. Samples that landed in
Australia and Morocco. But our samples are only a
couple hundred micrometers wide. We brought a few along with us. Our best candidate, plus
a few bonus options. And one sample from our expert in Norway. To the naked eye they're almost invisible. In our microscope, you can
start to see some shape and texture but in the
electron microprobe. Wow. We visited Houston to
answer a simple question. Did any of our samples
actually come from space? And to figure that out,
we looked at two things. The shape of the rocks
and the chemical elements present on their surface. The electron microprobe can measure both. We started with shape. - [Mike] So here's one of the samples that you found in, I
guess Brooklyn, right? - This was a rooftop in Brooklyn, yeah. - Yeah, wow. These are all spheres, so they definitely were melted in the atmosphere. - The idea is that as a tiny object speeds through the air, it melts
and globs into a little ball. But that can happen to
Earthly materials, too. Like bits of industrial pollution. - The question there is, is
it extraterrestrial sample or could it be from, say,
a coal fired power plant? - The material makeup of our
samples were less encouraging. IDing a meteorite often
means finding elements that are rare on Earth's
surface but common in space. Things like palladium, platinum, uranium. But sample after sample, we
saw very Earthly elements. Iron, oxygen, silicon. - So, this second particle
again, we see the same pattern. These little flattened
crystals on the outside. Which, again, are magnetite. Over here are iron oxide. But it's probably
terrestrial contamination. Our sample from Norway
was much more exotic. - These have these little dendritic, like little fern shaped crystals of something else on the outside. - [Cory] Mike says that
crystalline structure is usually the mark of
a voyage all the way from space to the Earth's surface. But what really tipped the scales? The probe readout showed lots of magnesium mixed with a little silica. - That's telling us
this is another mineral called olivine which is
the most common mineral in the solar system, probably. This is in almost every kind of meteorite and micrometeorite I can think of. So this is almost pretty much nails this as being a micrometeorite. - Olivine is quite common here on Earth but it's largely found inside the planet. Olivine can reach the
surface via volcanic activity but it's presence still makes
you take a sample like this seriously and after 30
years in the business, Mike can spot olivine from a mile away. - It's so common, I just
recognize it instantly now, you know, it's like an old friend. Really old friend, four
and a half billion years, that's a really old friend, right? - So, where does that leave our samples? What came of all those
hours spent searching? Not much. Mike says you'd have to
look inside the samples to be sure but nothing seemed conclusive. We basically found magnetic dirt. Hunting down tiny rocks from space is laborious and frustrating. But for NASA each verified sample truly is a diamond in the rough. Because if you know what to look for and you find it, the whole
galaxy opens up to you. - [Mike] We've found meteorites like this that contain liquid
water droplets in salt. So those were our first samples
of extraterrestrial oceans. Where were those
environments, we don't know. We need to find that out but
now we're learning about, you know, what kind,
what were the first steps towards, perhaps, life. First steps towards organized cells, those were present perhaps
in these meteorites. - [Cory] Other samples hold
clues that could change our understanding of the solar system. Samples like this one. - So this is a rock
that is from an asteroid that is from the inner solar system and heated up, melted, it contains, the composition suggests it formed in the inner solar system but it contains bits of rock from the outer solar system. And the question is, how'd
those get mixed together? - [Cory] One theory, the planets weren't always in the position they are now. - So the models have Venus
and Neptune swapping places. Saturn and Jupiter moved
in pretty far and stopped, then moved back out again and there's a chance that we can date that process by studying this rock
and other rocks like it. - NASA has other samples still of very old cosmic dust. Little motes of material that can teach us about the earliest days
of the solar system. Some samples arrived via comets which contain dust from the farthest edges of the solar system and dump some of it along the Earth's path. And once in a while, even
rarer samples turn up. Dust from outside the solar system. From before it. - [Mike] The galaxy is turning
and we're part of that. And as the galaxy spins
around like a pinwheel there's a rain shower of interstellar dust passing through our solar system. They're usually really tiny and they're pretty rare but that happens. - Space is a paradox. It's vast and almost completely empty. Yet at the same time it's
teeming with material. We can study some things
with telescopes and probes. Other times, we're stuck with models. Mathematical guesses that tell us, this is probably happening
somewhere, out there. Except sometimes, if we're lucky, actual physical evidence from out there, happens to land at our feet. And then one little speck like this one can change everything. - You can find grains that prove that supernovas happen the
way we think they do or don't. There are grains from Wolf-Rayet stars and red giant stars that tell us about the process of star formation and death. It's pretty amazing that
you can test all those, apparently, strange wacky
theories us physicists have by looking at little microscopic
grains of meteorites, but it's true. - Hey everyone, if you wanna find out how to collect your own micrometeorites be sure to check out part one down here. And as always, thanks for watching.
