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These Rocks Are Older Than the Sun
These Rocks Are Older Than the Sun
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0:00
If you’ve learned anything from our Rocks Box videos,
0:02
it’s that rocks tell us a lot about our planet.
0:04
But a select few rocks teach us about a place much farther away: space!
0:10
Meteorites are a treasure trove of information about the solar system and beyond.
0:15
They can help us decode how the planets formed
0:19
and provide tantalising clues about life elsewhere in the cosmos.
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But meteorites are pretty rare, and the big,
0:26
important ones that get studied for decades are even rarer.
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So we’re gonna take a look at four of the heavyweights,
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space rocks that changed the way we see the universe.
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[♪ INTRO]
0:41
First up is the Krasnojarsk meteorite, a rock that helped European scientists
0:45
realize that meteorites came from space in the first place.
0:49
That wasn’t always stuff we knew.
0:51
There are records dating back centuries of Chinese and Egyptian scholars
0:55
talking about metallic objects falling from the sky,
0:58
but it took far longer for the Western scientific community
1:01
to get that celestial memo.
1:03
Why’d it take so long for Europeans to get the message?
1:05
Well, it starts with Aristotle.
1:08
Now obviously people had been seeing rocks fall to the Earth
1:12
since as long as there had been people.
1:14
But back in 350 BCE, Aristotle believed that space was filled with
1:19
a substance called aether, leaving no room for anything else.
1:23
As a result, he thought that anything that fell to earth
1:26
must have started out on Earth.
1:28
He called them ‘exhalations’.
1:30
I guess maybe he was a fan of breathing exercises.
1:34
It wasn’t until the enlightenment, toward the end of the 18th Century,
1:37
that this ancient idea was finally debunked.
1:40
In the 1770s, an assistant to the German naturalist Peter Pallas
1:44
was travelling through Siberia documenting rocks and fossils,
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when locals directed him towards an awesome specimen:
1:52
a nearly 800 kilogram lump of metal embedded with glassy green minerals.
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We now call it the Krasnojarsk meteorite,
2:00
but it wasn’t called that right away, because nobody knew that it was from space.
2:04
All they knew was that it was an extremely cool rock.
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Pallas had the rock hauled back to Europe,
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where he published a scholarly description of it.
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But he never imagined it had come from space.
2:16
Twenty years later, Pallas’ descriptions fell into
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the lap of another German scientist, Ernst Chladni.
2:22
Based on Pallas’s descriptions, as well as eyewitness accounts
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of bright objects streaking through the sky,
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he proposed an extraterrestrial origin for the meteorites.
2:32
He claimed that they were the debris from catastrophic collisions in outer space.
2:36
Of course, nobody at home believed him, because everyone knew
2:40
that there was nothing out there in space besides the moon.
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But through the start of the 1800s,
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evidence started to accumulate in Chladni’s favor.
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Several more meteor falls were witnessed,
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and new mineralogical and chemical analyses revealed that rocks like
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Pallas’s Siberian specimen were completely unlike anything found on Earth.
3:01
Chladni was vindicated and Aristotle’s stubborn idea was put to rest.
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The Krasnojarsk meteorite is a type of meteorite called a pallasite,
3:10
named after Peter Pallas himself.
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They contain both iron and rocky crystals,
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and we think that they form when an asteroid fuses with the minerals of
3:19
a planetary embryo, and that resultant fusion-thing gets hurled back out into space.
3:25
So meteorites like this are even a window into the interior of our own planet,
3:30
where our drills and pickaxes will never reach.
3:33
But our next famous meteorite is a window into
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the beginning of something much bigger: our solar system.
3:39
The Allende meteorite fell to Earth in 1969,
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where it broke apart over Chihuahua, Mexico.
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More than two tons of rock were immediately recovered,
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and thanks in part to its lucky timing,
3:51
it became the most studied meteorite in history.
3:54
In 1969, labs on Earth were poised to receive the
3:58
first Apollo rock samples from the moon.
4:00
Scientists and instruments were already geared up to study extraterrestrial rocks,
4:04
and so in a way, Allende became a test subject for those approaches too.
4:08
Geochemists have measured its oxygen isotopes, its trace elements,
4:12
and superheavy elements, to understand where it formed and how.
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It’s been examined using electron microscopes,
4:19
x-rays and CT scans to help understand its mineralogical makeup.
4:23
And all of this testing helped us understand how meteorites form,
4:27
and how they change when exposed to different environments.
4:30
And with the Allende meteorite, it also revealed things that we never expected.
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Allende is a type of meteorite known as a carbonaceous chondrite.
4:39
These meteorites are usually made up of tiny round grains called chondrules,
4:43
as well as larger, irregular shaped white inclusions.
4:47
The chondrules date from a time in the early solar system
4:50
when things were really messy.
4:52
They’re basically frozen spherical droplets of silicate minerals,
4:56
which had been flash-melted when planets collided.
4:59
Those minerals were then thrown out into space where they instantly
5:02
cooled and solidified, and then gradually accreted together again.
5:07
However, there is a brand-new paper that came out in June of 2026,
5:11
while we were working on this video,
5:13
that may call this hypothesis into question.
5:15
The new paper suggests that the chondrules and matrix all formed together
5:19
at the same time in one chondritic reservoir,
5:22
meaning that they could form without a planetary collision.
5:25
Regardless of which hypothesis wins,
5:27
we know that these remarkable asteroids are also incredibly ancient.
5:32
The light coloured inclusions inside Allende are rich in aluminum,
5:36
and contain minerals that only could have formed
5:38
at extremely high temperatures close to the sun.
5:41
Together, these inclusions and the chondrules are some of
5:45
the oldest solid matter in the solar system.
5:48
Dating to 4.566 billion years ago, the chondrite assembled under
5:52
the rays of a newly ignited star, likely before any other planets had formed.
5:57
But there’s more.
5:59
Looking even more closely at the Allende meteorite,
6:02
researchers have found tiny grains that predate our sun.
6:06
Nanodiamonds and presolar graphite grit inside this Mexican rock
6:12
can be traced right back to the explosive death of stars
6:16
before our solar system was a glimmer in the universe’s eye.
6:20
The Allende meteorite is indeed older than the planet it ended up landing on.
6:25
Allende may be the most popular meteorite of its kind, but it’s far from the only one.
6:29
Number three on our list is the Murchison meteorite,
6:32
another carbonaceous chondrite, which also fell in 1969, but this time in Australia.
6:38
It’s a popular year for meteorites.
6:39
Like Allende, it also contains presolar grains,
6:42
and some researchers think that they are around 7 billion years old.
6:47
If so, they would steal the prize for the oldest material on Earth.
6:51
But the rest of the meteorite is made up of a dusty matrix
6:54
which dates to around the beginning of the solar system,
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and scientists discovered something entirely
7:00
unexpected inside of it: organic matter.
7:03
Yes, organic. As in, carbon-based.
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As in, the stuff living things are made of.
7:08
The meteorite contains amino acids, sugars, hydrocarbons, and alcohols.
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Even some of the nucleobases which are the encoding language of DNA.
7:18
In all, there are tens of thousands of different
7:21
organic molecules hiding inside Murchison.
7:24
In fact, there’s so much organic stuff in this rock,
7:27
it had a noticeable smell that some have compared to compost or brussels sprouts.
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These organic molecules are the building blocks of life,
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made by life since life began.
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But as far as we know, there isn’t any other life in the solar system.
7:41
So what’s going on with Murchison?
7:44
Well, even if we call it organic chemistry,
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life isn’t the only thing that can make these molecules happen.
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It’s thought that the smaller, simpler molecules were created
7:53
thanks to the chance chemical reactions in the interstellar medium early on
7:57
in the solar system’s history, when there was more stuff around to combine.
8:02
These early creations then accreted along with the rocky components of
8:06
Murchison, and then were further altered by UV radiation in the meteorite itself.
8:11
Over its long history, the asteroid that gave birth to Murchison
8:14
was also permeated with water at several points,
8:17
caused by radioactive heating melting ice crystals inside its structure.
8:22
This liquid water helped to create even more organic molecules.
8:26
Studying Murchison, and theorizing about its formation in the lifeless
8:30
early solar system, has shown us that the
8:32
building blocks of life are not unique to living things.
8:36
This has helped us question our theories about the origin of life,
8:40
and raised the possibility that some of the very first organic chemistry
8:44
actually originated among the stars, rather than here on Earth.
8:48
Which brings us to our fourth and final meteorite.
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Did you know it was coming? I did.
8:53
Because some people believe that it contains evidence of real extraterrestrial life.
8:58
Found in the Allan Hills region of Antarctica in 1984,
9:01
ALH84001 is a Martian meteorite.
9:05
Formed by volcanic lava more than 4 billion years ago,
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it was ejected after an impact 16 million years ago,
9:11
and arrived on Earth around 13,000 years ago,
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to sit on the white Antarctic ice until explorers wandered by and picked it up.
9:20
What a legacy.
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You know, if I was gonna be a rock, that’s the one I’d wanna be.
9:24
But its biggest moment came in 1996,
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when a controversial paper was published claiming it contained microfossils.
9:32
Electron microscope images show a tiny track of magnetite disks,
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that looked a lot like trails that bacterial decomposers
9:40
leave behind as they navigate.
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Additionally, chemical analysis revealed that the meteorite
9:45
contained a specific kind of organic molecule called
9:48
polycyclic aromatic hydrocarbons, which on Earth
9:51
are produced by decaying organic matter.
9:54
Almost immediately, people were swept up
9:56
in the excitement of discovering life on Mars.
10:00
Then-president Bill Clinton even made an announcement about the discovery.
10:04
I was at summer camp.
10:05
I was so mad I couldn’t blog about it.
10:07
So that’s where we’re at.
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But a lot of the scientific world was more skeptical.
10:11
For one thing, the worm-like shape that seemed so convincing is
10:15
basic enough that non-biological processes can make it too.
10:19
So the resemblance to earthly microbes is probably a coincidence.
10:23
Also, those polycyclic aromatic hydrocarbons are formed by life,
10:27
but not only by life.
10:28
They’re also found in things like car exhaust and interstellar gas clouds.
10:32
It also seems like it was heavily altered by water-rock interactions while on Mars,
10:38
which could be the source of both the organic molecules and the magnetite.
10:42
There’s also a good chance it got some good old Earthly contamination,
10:46
after the rock spent 13,000 years out in the open on the Antarctic ice surface.
10:51
Today, most researchers agree that ALH84001 does not contain evidence of
10:57
life on Mars, but it does still contain lots of information about the red planet.
11:02
The minerals inside the meteorite reveal the presence of liquid water,
11:06
and specifically water that was at a low temperature
11:09
and of a neutral or weakly alkaline pH.
11:12
Not only that, but it contains clay minerals,
11:14
which are thought to have been important catalysts for
11:17
early biochemical reactions on Earth,
11:20
meaning that they could have performed the same role on Mars.
11:23
So even if it’s not proof of life on Mars, this meteorite is still pretty far out.
11:28
These meteorites are just a few of the tens of thousands that have been
11:32
found on Earth, and which continue to rain down on our planet every day.
11:36
They’ve helped transform what we know about life, the universe and everything.
11:41
And Rocks Box subscribers will receive a piece of this legacy
11:44
when they get these pieces of a meteorite from Northwest Africa.
11:47
We’ve been running the Rocks Box subscription for more than two years now,
11:50
and the feedback from our subscribers has been amazing.
11:53
And luckily for those of you who’ve been waiting for more subscriptions to open up
11:57
(there are not that many because of course we
11:59
actually have to source these things),
12:01
but we now have room in the Rocks Box for new people to join.
12:04
Whether you’re a seasoned rock hound or just starting out your collection,
12:08
SciShow Rocks Box might be just the monthly treat that you need.
12:12
Or maybe you’ve got a friend who’s mineral-curious,
12:14
or a relative who is just impossible to shop for.
12:17
If so, head over to Complexly.store/rocks to check it out.
12:20
We also sell some fan favorite minerals as one-offs.
12:24
Plus, there are accessories like this jeweler’s loupe
12:27
so that you can get more up close and personal with your rocks.
12:30
There’s a whole lot more as well.
12:31
That’s Complexly.store/rocks.
12:34
Thanks for watching!
12:36
[♪ OUTRO]
