Hi, I'm Celine Shaw from King Edward's in
Edgbaston and I'm here for a week on work
experience. I've chosen this Allende meteorite,
a small, fragment, for the Object of the Month.
It was the largest carbonaceous chondrite
ever found on Earth, roughly the size of a
car, and it was spotted, a giant fireball,
falling over the Mexican state of Chihuahua
on the 8th of February 1969.
As it exploded it into scattered into thousands
of fusion-crusted individuals. As you can
see there's the fusion crust here, it's got
like
a glossy finish and this would have formed
because as the fireball was falling it was
falling at great speeds, say about 10 miles
per second and this would have produced a
lot of heat and melted the exterior.
As it exploded it was dispersed over quite
a large area and there was an extensive search
for all the pieces. It was actually described
as the most studied meteorite in all of history.
It was important for research purposes because
of its rarity as it accounts for less than
5% of all the chondrites on Earth. And also
inside there's lots of calcium-rich inclusions
which are among the oldest objects in the
Solar System. Unlike other chondrites it doesn't
include any iron or nickel so it's unusual
from that aspect.
This chondrite would have formed in the Solar
System a few million years ago and it would
have been formed by the accumulation of dust
and grit particles all clumping together and,
as you can see, in the internal structure
-- as it's been cut and polished it's more
visible -- there's some dark chondrules and
also some white-coloured calcium and magnesium
rich inclusions. Also there's some smaller,
millimetre-sized, chondrules which are only
found in meteorites and not in Earth rocks.
