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Educational Product Teachers Grades 5-12. National Aeronautics and Space Administration. Exploring Meteorite Mysteries Slide Set with Script. NOBLESVILLE FALL. - PowerPoint PPT Presentation
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National Aeronautics and
Space Administration
Educational Product
Teachers Grades 5-12
Exploring Meteorite Mysteries
Slide Set with Script
Just after riding bikes Brian and Brodie were
standing talking on Brodie's lawn. Suddenly they heard a low-pitched whistling sound and Brian
saw an object spinning through the air past
Brodie.
The object, which looked like a rock, landed with a thud on the ground near them. The boys picked up
the rock and found it slightly warm. They looked around, but couldn't find anyone who might have
thrown it.
A scientist from Purdue University confirmed that
the rock really was a meteorite.
13 year old Brodie Spaulding and 9 year old Brian Kinzie
August 31, 1991Noblesville, Indiana
It is a typical stony meteorite, gray inside and covered It is a typical stony meteorite, gray inside and covered with a dark crustwith a dark crust
About 30,000 small meteorites like Noblesville fall on About 30,000 small meteorites like Noblesville fall on Earth each year, but only a few are foundEarth each year, but only a few are found
BRIANBRIAN
ANDAND
BRODIE’SBRODIE’S
ROCKROCK
NowNowknown known as theas the
NoblesvilNoblesvillele
MeteoritMeteoritee
Large meteorite falls are rare, Large meteorite falls are rare, about one every ten or twenty about one every ten or twenty
years over the whole Earth years over the whole Earth
One of the most spectacular One of the most spectacular occurred in 1947, in the occurred in 1947, in the
Sikhote-Alin mountains of Sikhote-Alin mountains of eastern Russia eastern Russia
February 12, the calm was February 12, the calm was shattered by a bright meteor, shattered by a bright meteor,
visible for more than 300 visible for more than 300 kilometerskilometers
After it streaked over the After it streaked over the horizon, great explosions roared horizon, great explosions roared
and echoed from the hills, so and echoed from the hills, so loud they were heard 100 loud they were heard 100
kilometers awaykilometers away
It must have been larger It must have been larger before it hit the Earth, because before it hit the Earth, because
some of it vaporized in the some of it vaporized in the atmosphere and on impactatmosphere and on impact
Some of the Some of the meteorites were meteorites were
embedded in trees!embedded in trees!
The Sikhote-Alin The Sikhote-Alin meteorite was meteorite was
probably a piece probably a piece broken off an broken off an
asteroidasteroid
Clearings in the Clearings in the thick forest were thick forest were
blasted open by the blasted open by the impactimpact
There were 106 There were 106 craters and holes in craters and holes in the forest where the the forest where the
meteorites had meteorites had landedlanded
This is one This is one fragment of the fragment of the
Sikhote-Alin Sikhote-Alin meteoritemeteorite
It is about 15 cm It is about 15 cm acrossacross
The photograph The photograph shows the original shows the original meteorite surface, meteorite surface, melted into thumb-melted into thumb-print shapes during print shapes during
its flight through its flight through our atmosphereour atmosphere
Larger meteorites Larger meteorites are extremely rare, are extremely rare,
but make but make enormous craters enormous craters when they hit the when they hit the
EarthEarth
It was formed It was formed about 50,000 years about 50,000 years ago when a large ago when a large iron meteorite hit iron meteorite hit
the Earththe Earth
Scientists Scientists estimate that the estimate that the
meteorite weighed meteorite weighed one million tonsone million tons
Meteor Crater in Arizona is Meteor Crater in Arizona is over one kilometer across and over one kilometer across and
150 meters deep150 meters deep
Many meteorites have Many meteorites have been found in deserts, been found in deserts,
where the heat and where the heat and dryness have kept them dryness have kept them
from rusting awayfrom rusting away
When meteorites are When meteorites are discovered, they are discovered, they are
called findscalled finds
Over 2,000 meteorite Over 2,000 meteorite finds have been made finds have been made
around the worldaround the worldSome of these meteorites were Some of these meteorites were on Earth for hundreds of on Earth for hundreds of
thousands of years before being thousands of years before being foundfound
The best collecting The best collecting place in the world is place in the world is
Antarctica, where Antarctica, where meteorites fell on meteorites fell on the ice and were the ice and were preserved in itpreserved in it
Here scientists Here scientists have found a have found a
meteorite, and have meteorite, and have taken pictures to taken pictures to
document their finddocument their find
Each sample is Each sample is photographed, given photographed, given
a number, and a number, and carefully packaged.carefully packaged.
Meteorites Meteorites collected by U.S. collected by U.S.
expeditions in expeditions in Antarctica are sent Antarctica are sent to this clean lab at to this clean lab at
NASA's Johnson NASA's Johnson Space Center in Space Center in Houston, TexasHouston, Texas
There they are There they are described, described,
classified, and classified, and distributed to distributed to
researchers around researchers around the world for studythe world for study
Although people have Although people have seen meteorites fall seen meteorites fall
since the earliest since the earliest times, it was only times, it was only about 1800 when about 1800 when scientists finally scientists finally
became convinced that became convinced that rocks really did fall rocks really did fall
from the skyfrom the sky
Since then, we've Since then, we've discovered that most discovered that most meteorites come from meteorites come from the asteroid belt, the the asteroid belt, the
area of the solar area of the solar system between the system between the orbits of Mars and orbits of Mars and
Jupiter where many Jupiter where many asteroids orbit the sunasteroids orbit the sun
Asteroids are small Asteroids are small planets, fragments of planets, fragments of rock and iron left over rock and iron left over
from the formation of the from the formation of the solar system or the solar system or the breakup of larger breakup of larger
fragmentsfragments
Many asteroids Many asteroids probably look like Ida, probably look like Ida,
the asteroid in this the asteroid in this picture taken by the picture taken by the Galileo spacecraft in Galileo spacecraft in
19931993
Ida is about 30 Ida is about 30 kilometers long, is made kilometers long, is made
of rock, and has many of rock, and has many craterscraters
Comets are small bodies Comets are small bodies made of rock, dust and made of rock, dust and
ice, formed in the distant ice, formed in the distant reaches of the solar reaches of the solar
systemsystem
Then solar radiation Then solar radiation heats the comet's surface, heats the comet's surface, causing part of the ice to causing part of the ice to
boil off into space and boil off into space and carry some of the dust carry some of the dust
with itwith it
When this happens the When this happens the comet can develop a "tail" comet can develop a "tail"
millions of kilometers millions of kilometers long, and leave a dust long, and leave a dust
trail behind in solar orbittrail behind in solar orbit
Very few asteroid pieces get the chance to travel that farVery few asteroid pieces get the chance to travel that far
Most asteroids never do, and spend eternity in space, Most asteroids never do, and spend eternity in space, quietly orbiting the Sunquietly orbiting the Sun
Larger Larger meteoritemeteorite
s s don't don't come come from from
comets comets but from but from asteroidsasteroids
It's a It's a long way long way from the from the asteroid asteroid belt to belt to
the Earththe Earth
Every now and again the Every now and again the orbits of asteroids cross and orbits of asteroids cross and
their quiet times endtheir quiet times end
Then the asteroids collide Then the asteroids collide and shatter, and the pieces and shatter, and the pieces
fly into different orbits around fly into different orbits around the sun the sun
Some of these pieces orbit Some of these pieces orbit closer and closer to the suncloser and closer to the sun
Eventually some of their Eventually some of their orbits cross the Earth's orbit, orbits cross the Earth's orbit, and the piece of asteroid can and the piece of asteroid can
hit the Earthhit the Earth
We see this moving We see this moving flame as a meteor flame as a meteor crossing the sky crossing the sky
If the asteroid fragment If the asteroid fragment is big enough, fist-sized is big enough, fist-sized or so, it won't burn up or so, it won't burn up
completely and will fall to completely and will fall to the Earth as a meteorite the Earth as a meteorite
These small meteorites These small meteorites do not explode or make do not explode or make craters when they hit craters when they hit
They just hit like an They just hit like an extra large hailstone or a extra large hailstone or a rock thrown from across rock thrown from across
the streetthe street
Stony meteorites are Stony meteorites are commonly made of commonly made of
familiar minerals like familiar minerals like plagioclase, pyroxene, plagioclase, pyroxene,
and olivineand olivine
Scientists believe that Scientists believe that they were formed in the they were formed in the outer parts of asteroidsouter parts of asteroids
The two main types of The two main types of stony meteorites are stony meteorites are
chondrites and chondrites and achondritesachondrites
Stony meteorites look a Stony meteorites look a lot like Earth rocks, and lot like Earth rocks, and are often not recognized are often not recognized
as meteoritesas meteorites
Iron meteorites Iron meteorites probably formed in the probably formed in the
cores of asteroidscores of asteroids
Inside, many iron Inside, many iron meteorites are made of meteorites are made of
criss-crossing criss-crossing intergrown crystals of intergrown crystals of
two iron-nickel mineralstwo iron-nickel minerals
The sizes and shapes of The sizes and shapes of the crystals suggest that the crystals suggest that
they cooled down so they cooled down so slowly, a few degrees slowly, a few degrees
each million years, that each million years, that they must have been they must have been inside large asteroidsinside large asteroids
The two types of crystals in The two types of crystals in this sample are several this sample are several
centimeters widecentimeters wide
Some meteorites are Some meteorites are mixtures of iron and mixtures of iron and
fragments of rockfragments of rock
They are called stony-They are called stony-iron meteoritesiron meteorites
This sample, like the This sample, like the one in the Meteorite one in the Meteorite
Sample Disk, formed at Sample Disk, formed at the boundary between the boundary between the metal core and the the metal core and the
rocky mantle of an rocky mantle of an asteroidasteroid
The story of meteorites The story of meteorites begins 4.6 billion years begins 4.6 billion years
agoago
The solar system began The solar system began as a spinning cloud of gas as a spinning cloud of gas and dust, called the solar and dust, called the solar nebula, which collapsed nebula, which collapsed under its own weight to under its own weight to form a new star, our Sunform a new star, our Sun
As the solar nebula spun As the solar nebula spun and churned, dust grains and churned, dust grains stuck together to form stuck together to form
dustballs, and huge bolts dustballs, and huge bolts of lightning melted them of lightning melted them
into small spheresinto small spheres
These solidified into rocky These solidified into rocky balls called chondrulesballs called chondrules
This diagram shows an This diagram shows an undifferentiated stony asteroid which undifferentiated stony asteroid which was heated enough for the inside to was heated enough for the inside to
meltmelt
In an asteroid the densest material is In an asteroid the densest material is iron metal, shown as black dots, which iron metal, shown as black dots, which
sinks toward the centersinks toward the center
The lightest minerals, silicates called The lightest minerals, silicates called feldspar, float toward the surface feldspar, float toward the surface
The remaining material solidifies to The remaining material solidifies to form the minerals olivine and form the minerals olivine and
pyroxene, which stay in the middlepyroxene, which stay in the middle
The Earth and Moon differentiated The Earth and Moon differentiated just this wayjust this way
Early in the solar Early in the solar system's history, about system's history, about
4.4 billion years ago, the 4.4 billion years ago, the Earth's surface was a Earth's surface was a violent, lifeless placeviolent, lifeless place
Primitive meteorites, Primitive meteorites, called carbonaceous called carbonaceous chondrites, may have chondrites, may have
brought water and brought water and carbon into this carbon into this
inhospitable world, and inhospitable world, and so helped set the stage so helped set the stage
for lifefor life
It was covered with active It was covered with active volcanoes and hot lava flows, volcanoes and hot lava flows,
as in this photoas in this photo
The dinosaurs were The dinosaurs were killed 65 million years killed 65 million years
ago after a huge ago after a huge meteorite hit the Earthmeteorite hit the Earth
The explosion caused The explosion caused great storms and great storms and
waves, and the sky was waves, and the sky was dark for months with dark for months with
dust and ashdust and ash
The dinosaurs, along The dinosaurs, along with many other with many other
animals and plants, animals and plants, were probably killed by were probably killed by
the climate changes the climate changes that followed the that followed the
explosionexplosion
Meteorites have also had Meteorites have also had devastating effects on life...devastating effects on life...
In 1993 a comet was In 1993 a comet was discovered heading for discovered heading for
JupiterJupiter
That planet's immense That planet's immense gravity had torn the gravity had torn the
comet into more than 20 comet into more than 20 fragments, which were fragments, which were
lined up and heading for lined up and heading for Jupiter at over 60 Jupiter at over 60
km/secondkm/second
In the summer of 1994 In the summer of 1994 one fragment after one fragment after
another smashed into another smashed into the planet, producing the planet, producing
huge explosionshuge explosions
We saw, from a safe We saw, from a safe distance, the kind of distance, the kind of
massive impacts that have massive impacts that have scarred all of the planets, scarred all of the planets,
including Earthincluding Earth
Today, we look to Today, we look to the future, toward the future, toward space missions to space missions to the asteroids, and the asteroids, and
eventually to eventually to human travel to human travel to
other planetsother planets
Guided by the Guided by the meteorites that fall meteorites that fall to Earth, we might to Earth, we might mine the asteroids mine the asteroids for oxygen, water for oxygen, water
or metalor metal
We might also search them for We might also search them for more clues to our origins, as we more clues to our origins, as we
continue to explore the solar continue to explore the solar systemsystem
One day humans One day humans will explore the will explore the
surface of Mars and surface of Mars and other worlds other worlds
farther still from farther still from EarthEarth
In order to stay In order to stay for long periods, we for long periods, we will have to learn to will have to learn to "live off the land," "live off the land,"
just like the just like the pioneers of oldpioneers of old
Resources from Resources from the planets and the planets and asteroids may asteroids may
provide the key to provide the key to humanity's humanity's
exploration across exploration across the solar systemthe solar system
The Moon is covered The Moon is covered
with craters in a wide with craters in a wide
range of sizesrange of sizes
You can see a few of You can see a few of
the largest with your the largest with your
naked eyes, and many naked eyes, and many
more with binocularsmore with binoculars
The planet Mercury, The planet Mercury, as seen by the as seen by the
Mariner 10 spacecraft, Mariner 10 spacecraft, is also covered with is also covered with
craterscraters
Mercury has Mercury has essentially no essentially no
atmosphere, and its atmosphere, and its cratered surface looks cratered surface looks much like that of the much like that of the
MoonMoon
Venus Venus has a thick has a thick atmospheratmospher
e which e which destroys destroys
many many impacting impacting
bodies bodies before before
they reach they reach the surfacethe surface
The colors in this picture were made by a computer, to The colors in this picture were made by a computer, to make it easier to pick out the craters and other featuresmake it easier to pick out the craters and other features
We We cannot cannot see the see the
surface of surface of Venus Venus
directly, directly, since the since the atmospheatmosphere is filled re is filled with thick with thick
cloudsclouds
The surface of Venus has craters tooThe surface of Venus has craters too
Impact craters Impact craters are also visible are also visible on the planet on the planet
MarsMars
The thin The thin martian martian
atmosphere does atmosphere does not do much to not do much to
slow an slow an impacting body impacting body
from spacefrom space
This photo, taken This photo, taken by the Viking by the Viking
spacecraft, shows a spacecraft, shows a relatively fresh relatively fresh crater on the crater on the
martian northern martian northern plainsplains
If craters are so If craters are so common in the solar common in the solar
system, why are system, why are they so rare on they so rare on
Earth?Earth?
The The Earth’s Earth’s
surface is surface is constantly constantly
being being changed changed
by erosionby erosion
Water, Water, ice, wind, ice, wind, and plate and plate tectonics tectonics
have have destroyed destroyed
most of the most of the craters craters
that Earth that Earth once hadonce had
Only relatively young or quite large craters Only relatively young or quite large craters exist on Earth todayexist on Earth today
The craters of some The craters of some impacts can still be impacts can still be seen, often as round seen, often as round lakes like the twin lakes like the twin
Clearwater Lakes in Clearwater Lakes in CanadaCanada
These two craters, 32 These two craters, 32 and 22 km across, are and 22 km across, are both 290 million years both 290 million years
oldold
Manicouagan Manicouagan crater in Canada is crater in Canada is a ring-shaped lake a ring-shaped lake
nearly 70 km nearly 70 km acrossacross
In the 212 million In the 212 million years since it was years since it was formed, the crater formed, the crater has been deeply has been deeply
erodederoded
Some craters have Some craters have been almost been almost
completely eroded completely eroded awayaway
Spider Crater in Spider Crater in Australia, 13 km Australia, 13 km
across, is over 600 across, is over 600 million years oldmillion years old
It is barely It is barely recognizable as an recognizable as an impact structureimpact structure
Chondrules are the Chondrules are the primitive building primitive building blocks of the solar blocks of the solar
systemsystem
The largest The largest chondrule in this chondrule in this
picture is less than 1 picture is less than 1 cm acrosscm across
Most chondrules Most chondrules are so small that it is are so small that it is
difficult to learn difficult to learn much about them much about them
without a microscopewithout a microscope
In the early solar nebula In the early solar nebula chondrules came together chondrules came together to form larger and larger to form larger and larger masses, this process is masses, this process is
called accretion called accretion
In most meteorites, In most meteorites, though, the chondrules though, the chondrules have been partially or have been partially or totally destroyed by totally destroyed by
metamorphism metamorphism
To destroy chondrules To destroy chondrules takes a lot of pressure and takes a lot of pressure and cooking time, so much that cooking time, so much that these meteorites could not these meteorites could not have been formed as small have been formed as small rocks floating in the solar rocks floating in the solar
nebulanebula
In some chondrites the In some chondrites the chondrules are chondrules are
separated by patches of separated by patches of iron metal iron metal
Different types of Different types of chondrite meteorites chondrite meteorites
have different amounts have different amounts of metal and have been of metal and have been
heated to varying heated to varying degreesdegrees
Chondrites are called Chondrites are called primitive because they primitive because they formed early in solar formed early in solar system history and system history and
haven't changed since haven't changed since thenthen
Carbonaceous Carbonaceous chondrite chondrite
meteorites are meteorites are black because they black because they contain carbon, like contain carbon, like soot or pencil leadsoot or pencil lead
They also contain They also contain water, complex water, complex
carbon compounds carbon compounds and mineral grains and mineral grains even older than the even older than the
solar system - solar system - pieces of dust that pieces of dust that formed long ago formed long ago
around far distant around far distant starsstars
Action on an Action on an asteroid may not end asteroid may not end with differentiationwith differentiation
The lava hardens to The lava hardens to a rock called basalta rock called basalt
Some basalts from Some basalts from asteroids fall to Earth asteroids fall to Earth
as meteoritesas meteorites
Some asteroids got so hot Some asteroids got so hot that they melted inside and that they melted inside and
spewed lava onto their spewed lava onto their surfaces, just like this lava surfaces, just like this lava
flow on Earthflow on Earth
Achondrites are a Achondrites are a class of stony class of stony
meteorites, so named meteorites, so named because they do not because they do not contain chondrulescontain chondrules
They look like They look like igneous (lava) rocks igneous (lava) rocks
on Earthon Earth
These achondrites These achondrites formed during formed during
volcanic eruptions on volcanic eruptions on planets or asteroidsplanets or asteroids
This is a meteorite This is a meteorite which was found a few which was found a few years ago in Antarcticayears ago in Antarctica
Scientific studies have Scientific studies have proven that this proven that this
meteorite and a few meteorite and a few others like it are from the others like it are from the Moon, not from asteroidsMoon, not from asteroids
They were blasted off They were blasted off the Moon by other the Moon by other
meteorite impacts there, meteorite impacts there, and quickly traveled the and quickly traveled the short distance from the short distance from the
Moon to the EarthMoon to the Earth
This meteorite, found This meteorite, found in Antarctica, contains in Antarctica, contains
traces of Martian traces of Martian atmosphereatmosphere
The Martian The Martian atmosphere gas is in atmosphere gas is in
black veins and black veins and pockets of glass, which pockets of glass, which you can see on this cut you can see on this cut
surfacesurface
The glass probably The glass probably formed when another formed when another
meteorite hit Mars and meteorite hit Mars and partly melted these partly melted these
rocksrocks
The frozen continent of The frozen continent of Antarctica has proven to Antarctica has proven to
be the best place on Earth be the best place on Earth to find meteoritesto find meteorites
The meteorites fall onto The meteorites fall onto glacial ice and are carried glacial ice and are carried
along until the glacier along until the glacier encounters a mountain encounters a mountain range or other barrierrange or other barrier
The ice then stops and The ice then stops and eventually evaporates, eventually evaporates, leaving the meteorites leaving the meteorites
behindbehind
Meteorite collecting Meteorite collecting trips to Antarctica trips to Antarctica
are not easyare not easy
Teams live in polar Teams live in polar tents far from their tents far from their
permanent bases for permanent bases for months at a timemonths at a time
In bad weather In bad weather team members may team members may be confined to their be confined to their
tents for days, but on tents for days, but on good days they are good days they are
out finding out finding meteoritesmeteorites
They travel by They travel by helicopter and helicopter and
snowmobilesnowmobile
Meteorites Meteorites collected in collected in
Antarctica by U.S. Antarctica by U.S. expeditions are expeditions are brought to this brought to this
special clean lab at special clean lab at the NASA Johnson the NASA Johnson Space Center in Space Center in
Houston, Texas for Houston, Texas for initial studyinitial study
Experienced Experienced curators describe curators describe and classify themand classify them
The meteorites are kept in The meteorites are kept in glove boxes filled with nitrogen glove boxes filled with nitrogen gas to keep them from rusting gas to keep them from rusting
or otherwise changingor otherwise changing
The curators The curators are responsible are responsible for distributing for distributing
meteorite meteorite samples to samples to scientists scientists
around the around the worldworld
Here a piece Here a piece of a small of a small
meteorite is meteorite is being chipped being chipped
off for scientific off for scientific studystudy
The meteorites are The meteorites are examined with many examined with many sophisticated toolssophisticated tools
One of them is the One of them is the scanning electron scanning electron
microscopemicroscope
This microscope can This microscope can take pictures with take pictures with
magnifications of over magnifications of over 100,000 times and 100,000 times and
determine the chemical determine the chemical compositions of bits of compositions of bits of material too small to be material too small to be
seen with the naked seen with the naked eyeeye
Computers are used Computers are used everywhere in everywhere in
scientific laboratoriesscientific laboratories
Some are used to Some are used to control instruments control instruments and some to collect and some to collect
datadata
Scientists also use Scientists also use computers to create computers to create
the diagrams and the diagrams and write the reports that write the reports that
tell others of their tell others of their resultsresults
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