Sometimes you see they've broken apart.
This is parts of a chondrule that broke.
Chondrules the early solar system these meteorites that are landing
on us are made out of tremendous amounts of chondrules.
Almost like like little b b's in space a very very strange thing.
I could show you pictures of chondrites all day long
it's not as satisfying as seeing them in real life.
If you get a chance go see some of these things.
Here's a beautiful one from the American
Museum of Natural History in New York City.
Go there.
Check this one out.
You can see it's been sliced open.
This is a slice of one of the most famous carbonaceous chondrites,
we'll talk about that in a minute, and it's called the Allende chondrite.
And they get their names based on where they fell on the Earth.
And you can tell this one's different.
You see the chondrules, all over the place, nice round globules.
You see there's some beautiful big splotches
of calcium aluminum inclusions in through here but
mostly you'll see chondrules but what you also
see, is between, in between the chondrules, is
this black stuff that's called the, the matrix
the stuff that holds the chondrules together so
it's not that everything is chondrules, there's is
glue in between, and what is this glue?
Well.
In the previous chondrites we were looking at, it was just more of the same
sort of material that the chondrites are made out of, the sort of rocky material.
But in carbonaceous chondrites, the, the matrix in through here is carbon.
In forms like, like graphite, just pure carbon.
Carbon now, when I say carbon, you should suddenly
sit up and think woo, this is really interesting.
Carbon of course, is one of the key components
of organic matter of life of all these things.
We're looking for where stores of this carbon could have been.
Certainly could've been wherever these things, these carbonation chondrites
were forming and eventually falling down to the Earth.
Here's another carbonaceous chondrite.
These are just I find these spectacular.
These dark matrix of carbon and then just full
of all of these Chondrules in the middle of there.
So what is going on with chondrites?
We find them all over the place in the meteorites that we find on the Earth.
We think of them as the very first
primitive things that were made, in the solar system,
a, after the calcium aluminum inclusions, or perhaps
at the same time as the calcium aluminum inclusions.
And yet when we think about the accretion of things in the solar system
we think about the way, things start to stick together and get bigger and bigger.
It doesn't make chondrules, it doesn't make little millimeter sized b b's that
makes maybe big dust bunnies or something
or irregular globs not chondrules not chondrules.
Why chondrules?
Well you can study chondrules for your entire
life and what you would find is that you
can figure out things like chondrules were heated
to very high temperatures, and then cooled very quickly.
You'd find that they come in a range of sizes,
but that any individual meteorite, they tend to be all kind
of the same size, the range is not very big,
but the tend to be all sort of the same size.
There are a million different little aspects of chondrules that you need to
understand if you're going to put this sort of together where they came from.
I'll give you a couple different ideas, this is still unsettled,
it's not one of these things where no one has any
idea where chondrites came from, it's that there are too many
ideas and nobody has settled on yet what the story is.
There are some ideas that material is starting to grow and
shock waves came in through the big nebula of gas and dust
and those shock waves quickly shock heated this stuff it formed into
these little blobs and then cooled back down as the chocolate went.
There are other ideas that they were formed by, by material
being pulled close to the sun and then being ejected away from
the sun and heated up to very high temperatures very briefly
and just pulled close and then cooling as it was ejected away.
Other ideas that these, all these little chondrules were sort of sorted together
into similar sized balls by eddies and
currents that were flowing in through there.
There have been ideas that the chondrils were
melted by lightning that occurred inside the nebula.
None of these things is really certain.
It's an area of extremely active research,
and extremely detailed research that I'm, I'm sort
of sad that we don't have time to get into in, in the gory detail here.
What the key point really to take home is that there was some process that was seems
to have been fairly ubiquitous in the early
solar system that led to chondrules being strewn everywhere.
And by everywhere, I would point out that I really mean everywhere.
Pieces of chondrules have been found in the dust from
comets, there have been, has been one fly by of
a comet where the dust was collected brought back to
the Earth and that dust was analyzed, pieces of chondrules.
Chondrules, they are everywhere.
In the next lecture we'll talk about the other source of meteorites that we find.
