A killer asteroid streaking
towards earth at 67,000 miles an hour
[explosion and drums]
Giant chimney like towers scorching hot
rising from the bottom of the ocean floor
[ music ]
a young man epic sea voyage that shook the foundation of the world.
[explosions and Music]
An expedition back through time into the heart of human ancestry
Of all the discoveries in the history of science
Few have the power to compel...
Or the potential for controversy,
Than those concerning how life on earth began
How species evolved
Why some species survied
And others become extinct
[rumbling and panicked roars]
These are the greatest discoveries in the origin in evolution of life
[music climaxes]
[Theme Music of piano and violin]
[Bill Nye} Life is a game of chance
The odds of surviving or facing extinction are always changing
Now some changes are gradual; the result of a slow process of nature
Others, happen in a blink
Like the one that caused the extinction of the ancient Dinosaurs
[Music]
In 1980, a Geologist named Walter Alvarez
was studying rock strata in mountains North of Rome
When he came across something curious.
a thin ancient layer of clay
(Scientist) So this clay layer here
marks the boundary between two
different geological periods. [music]
(Bill Nye) The layer of clay marked what is
known in geology as the KT boundary.
A dramatic turning point in the history
of the earth about 65 million years ago.
When the ancient dinosaurs mysteriously vanished.
For Alverez, here was the moment of discovery.
analyzing samples from the KT boundary
he found the clay contained
extremely high levels of aridium.
an element rarer on earth but abundant in space.
When similar levels of aridium where found
around the world Alverez began
wonder what could have caused it to blanket the
earth.
The answer he concluded was the impact from an asteroid of gigantic proportions
Over six miles across
Taller than Mount Everest
Moving at a speed of 67,000 Miles an hour
[Boom]
Doctor Elisabetta Pierazzo is a research scientist at the Planetary Science Institute
In Tuson Arizona
(Bill Nye) So how much energy did this thing have?
[Elisabetta] an energy that is about a hundred million megatons
of TNT
This is about 10 times the worldwide
nuclear arsenal at the peak of the Cold War
[Bill Nye] Ten times the worlds Nuclear Arsenal
when it was really big
[Elisabetta] yes
[Bill Nye] All in one place?
[Elisabetta] all in one point released in...
a second. So that was a humongous amount of energy
That was delivered to the Earth
[dramatic music plays]
[Bill Nye] The devastation was colossal
[Dinosaur screeches]
A cloud of vaporized rock and debris mushroomed into the air
blocking the Sun
scorching fireballs blasted across the face of the Earth
The air became chocked with poisonous gas and soot
nearly half of all life forms on earth
perished in the Apocalypse
including the ancient Dinosaurs
The only piece of the puzzle missing from Alvereze's story was proof of the asteroid
if it was as big as he said it was
then it must have left quite a crater
finally Geologist found one that just happened to be sixty five million years old
the Chicsalu Crater
an immense hole
1,200 miles wide
buried under a thick layer of sediment at the bottom of the Gulf of Mexico
off the coast of the Yucatan Peninsula
[Elisabetta] yes so, the complexity increases with the magnitude
of the impact event.
Because the Chicsalu crater is under water
this is a good place to get a sense of what happened
when the asteroid hit.
this is meteor crater Arizona
50,000 years ago...
A meteorite about the size of a house
streaked out the sky and slammed into the Earth
it triggered an explosion greater than twenty million tons of TNT
And created this.
A crater five hundred fifty feet deep
and three quarters of a mile across
room enough for twenty football fields
and more than 2 million spectators
[Bill Nye] Impressive, isn't it?
But remember, the asteroid that caused the "KT" Event
was the size of Mount Everest
so to visualize the crater that it made we need something a lot bigger
Like the Grand Canyon!
this is the South Rim.
from here to the other side is 16 Miles.
but even that's not big enough.
the Asteroid that caused the "KT" Extinction
blasted a Crater 8 times as large
one hundred twenty five miles across
from here to the gaming tables in Las Vegas
And when the Asteroid hit it went deep as well
It's a long climb from here to the bottom of the Canyon
about a mile and a quarter.
but according to Walter Alveraz, the Asteroid made a crater that was a staggering 20 miles deep upon impact
then quickly filled in.
How do Scientist know all this?
the Evidence has come from a variety of sources
Seismec studies revealed the enormous ring like shape of the Crater
Thousands of core samples uncovered rocks
with traces of having been altered by an high-impact collision
And computer modeling that calculated the explosion it would have taken to create
the Chicsalu Crater.
But Walter Alvarez's discovery of what caused the extinction of the ancient Dinosaurs
is not without contraversy
his Asteroid scenario is at the center of an ongoing debate.
with opposing Scientist offering their own theories.
One theory argues that intense volcanic eruptions poisoned the Earth's atmosphere
and killed the ancient Dinosaurs before the "KT" Event ever occurred.