Imagine you're a dinosaur,
let's say an Alamosaurus, around 66 million years ago. The sun has set and you're
minding your own business, just lumbering around an
area that will eventually be called Austin, Texas, when
something glowing in the sky catches your eye. You're not too concerned,
but you keep an eye on that weird glowing star
for a couple of hours anyway. The thing is, that star
keeps getting brighter, but it doesn't seem to be
moving, so you forget about it. Then out of nowhere,
around 60 hours later, you feel the thunderous boom
of a supersonic shock wave. That thing you hoped might
be a routine shooting star is actually an asteroid
around 6 miles wide-- 6 miles wide. Before you can even think
"what the hell was that?" the thing you thought was
a star 60 hours ago plunges 18 miles into the Earth,
and you die immediately. Today we're going
to do a step by step breakdown of the asteroid
that wiped out the dinosaurs. But before we get started,
now is a great time to subscribe to our
channel, "Weird History." Leave a comment and let us know
what you think about this video or tell us what weird
phenomenon or person you'd like us to cover next. Now, onto the disastrous event
which some scientists say nearly demolished Earth before
it even really had a chance to make it as a planet. The Chicxulub asteroid slammed
onto the coast of Mexico and killed just about
everything on Earth. The first thing Earth felt
before the Chicxulub asteroid struck was its
violent shock wave. Because the air in
front of the asteroid was compressed and
unbelievably hot, it blasted a hole through
the Earth's atmosphere, causing the mother
of all shock waves. Naturally, ground zero absorbed
the asteroid shock wave first with a sudden spike
in air pressure, which ruptured lungs and other
internal organs of every living creature within a
1500 mile radius. But that wasn't even
the worst of it. Not long after you, the
leaf-eating Alamosaurus died from the
pulverizing shock wave, the 6-mile wide asteroid plunged
onto the shore of what we now refer to as the Yucatan
Peninsula, which is about 200 miles west of Cancun. Immediately after the
asteroid-- which, by the way, vaporized upon impact-- smashed into the rim
of the Gulf of Mexico, the Earth rebounded
from the impact and the peak of
its crust briefly rose higher than Mount Everest
before it broke apart and fell back to sea level. The energy produced from
the impact of the explosion was equivalent to 100
trillion tons of TNT, roughly 7 billion
times as powerful as the Hiroshima atomic bomb. But the blast didn't
look like the kind of atomic explosion you're
familiar with-- you know, the all too-familiar
mushroom cloud. Instead, the impact looked more
like a rooster tail made up of molten material. A lot of the molten debris
was several times hotter than the surface of the sun,
and it set fire to everything within 1,000 miles. What molten debris? Good question. Once the asteroid
hit Earth, the force kicked back 25 trillion
metric tons of rock ash and shot debris into
the Earth's atmosphere. An inverted cone of
liquefied molten rock shot up into the sky. The heat turned the molten
rock into little red hot beads of glass. Scientists call them
tektites, and after they reached the peak of
their trajectory, they began falling
back down to Earth at 100 to 200 miles per hour. Jan Smit, a retired professor
of sedimentary geology from Vrije Universiteit
in the Netherlands, who is considered the
world expert on tektites, studied the North
Dakota fossil site and says the fish got it
the worst from the tektites found there. "Paddlefish swim
through the water with their mouths open,
gaping, and in this net, they catch tiny
particles, food particles, in their gill rakers, and then
they swallow, like a whale shark or a baleen whale. They also caught tektites. That by itself is
an amazing fact. That means that the first
direct victims of the impact are these accumulations
of fishes." Smit also noted
that the buried body of a Triceratops and a
duck-billed hadrosaur proves beyond a doubt
that dinosaurs were still alive at the time of impact. It's theorized that it
rained the very same tektites for nearly an hour,
and set everything that came in contact with on fire. While the tektites were busy
setting fire to the Earth, the heaving ocean turned
into a towering tsunami tearing up coastlines,
sometimes peeling up hundreds of feet of rock,
pushing debris inland, and then sucking it back
out into deep water. Less than 10 minutes
after impact, a 30-foot wave
pounced on what we now know as fossil site North
Dakota, nicknamed Tanis after the lost
ancient Egyptian city. The wave threw thousands
of fish onto a sandbar, trapping them as
the water receded. They struggled to
breathe, but their gills were clogged with tektites,
essentially suffocating them. Approximately 20 minutes
after the asteroid's impact, a second wave reached
North Dakota's fossil site, burying the beached fish under a
pile of gravel, sand, and dirt. The massive disruption created
a fossilized graveyard. The fossils show fish
topped on top of each other with scorched tree trunks,
insects, part of a Triceratops, and mammals. The lucky dinosaurs died upon
the impact of the asteroid. The dinosaurs that lived had
a rough couple of months. Debris from both the asteroid's
impact in the Western Hemisphere and volcanic activity
in the Eastern Hemisphere blocked out the sun's light. The plants that survived
impact died from lack of light. Without any vegetation,
surviving herbivores succumbed to starvation, and
the carnivores quickly followed. Scientists have hypothesized
the mass extinction eliminated 75% of all
species and wiped out 99.9999% of all
living organisms. For many years after,
the Earth was toxic. Due to the asteroid's
heat and impact, many minerals vaporized and
released dangerous gases into the atmosphere,
including greenhouse gases, such as carbon dioxide,
carbon monoxide, and methane. One of the more immediately
damaging effects, however, was from sulfur. Sulfur was introduced
into the water cycle, creating sulfuric acid and
causing subsequent acid rain. About 45 minutes after impact,
a thunderous blast of wind would tear through ground
zero at 600 miles an hour, blasting debris everywhere
and leveling anything that might still be standing. The sound of the
explosion would arrive at the same time,
around 105 decibels, about as loud as if you were
standing underneath the rotors of a Huey helicopter. For the first few
hours, there would have been close to total darkness. But soon after that, the
sky would begin to lighten. For anyone or
anything out of range of the direct effects of
the asteroid explosion, one would be treated to
the sight of dark skies and a display of shooting
stars created by the impact debris raining back on Earth. They wouldn't have looked quite
like regular shooting stars or meteors though. Meteors burn up at higher
speeds and get hotter. These shooting stars would have
been re-entering the atmosphere at lower altitudes,
traveling slower and emitting infrared radiation. The best guess is that
the atmosphere would have been some sort of red glow. After the red glow, the
sky would darken as ash and debris swirling
around the globe created a creeping twilight. During the following weeks,
months, and maybe even years, the skies were probably
somewhere between twilight and a very cloudy day. Once the dust
literally settled, one of the more distinctive
clues that the asteroid left us was a thick
layer of clay packed with iridium, a metal
rare on Earth but common in asteroids and comets. This layer is known as
the K-T or K-Pg boundary, marking the end of
the Cretaceous Period, and the beginning of the
Tertiary Period, or Paleogene. Walter Alvarez, the
UC Berkeley professor who, along with his father,
Nobelist Luis Alvarez of UC Berkeley, were the
first to recognize the significance
of iridium that was found in the same 66
million-year-old rock layers around the world. They proposed that a
comet or asteroid impact was responsible for
both the iridium at the K-T boundary and
the mass extinction. While most scientists agree that
the effects of the Chicxulub asteroid killed off the
non-aerial dinosaurs, some scientists still claim
volcanic eruptions wiped them out rather than the asteroid. New evidence suggests
both may have contributed to the mass extinction. While the Chicxulub
asteroid smashed into Earth, it triggered earthquakes
with magnitudes as high as 11 on the Richter
scale, strong enough to be felt on the opposite
side of the globe. The theory is that the
asteroid's impact may have led to volcanic eruptions in India. Nearly 200,000
square miles of lava spread across the region
known as the Deccan Traps. This would have released
disruptive toxic gases into the atmosphere and
generated enough ash to block out sunlight for years. While most accounts focus on the
crazy violence and destruction from those first
few minutes to days after the impact of
the Chicxulub asteroid, it was the long-term
environmental effects that ultimately wiped out most
dinosaurs and much of the rest of the life on Earth. The lack of sun caused
by the dust cloud meant photosynthesis would
have been incredibly reduced. The soot and ash would
have taken months to filter out of the
atmosphere, and when it did, the rain would have
fallen as acidic mud. Further massive fires would have
produced huge amounts of toxins that temporarily destroyed
the planet's protective ozone layer. Then there was the carbon
footprint of the impact itself, which released an estimated
10,000 billion tons of carbon dioxide, 100 billion
tons of carbon monoxide, and another 100 billion tons
of methane in one fell swoop. Scientists still debate
many of the details, which are derived from computer models
and field studies of the debris layer, knowledge of
extinction rates, fossils and microfossils,
and many other clues. But one thing just about
every one of them agree on is the fact that the Chicxulub
asteroid landed just off of Mexico and tore it up. How do you think
it all went down? What would you do
if NASA spotted another 6-mile-wide asteroid
hurtling towards Earth? Share your thoughts
in the comments below. And while you're at it, check
out some of these other videos from our Weird History.
