♪
Clues, clues, lookin’ for clues…
Oh!
It’s you!
Hi!
You were probably expecting Jessi, right?
Well, she and Squeaks will be back next time,
but right now they're off doing a bit of detective
work in Yucatán,, Mexico!
You might say they’ve flown south for the
winter.
And of course I approve of that!
Very bird-like of them.
You see, we teamed up because we got curious
about one of the greatest mysteries of all
time:
What happened to the dinosaurs?
If you know me, you know that I loooove dinosaurs.
And a long time ago — around 65 million
years! — the dinosaurs were large and in
charge.
They had ruled the Earth for over 160 million
years.
And then, something strange happened, not
just to dinosaurs, but to over half the Earth's
species.
That means a type of living thing, like oak
trees, or cuckoo birds like me, or humans
like you.
All at once, about 65 million years ago, a
bunch of different species just went extinct
— they were completely wiped out!
That’s because something big happened, causing
huge changes on Earth.
Changes in the weather, changes in the oceans
… changes that made it harder for dinosaurs
and other living things to find food and survive.
Sure sounds mysterious!
Most species will go extinct sometime, but
what I wanna know is: What happened?
What caused so many species – from tiny
ocean creatures to big land reptiles like
T-rex and Triceratops – to all go extinct
at the same time?
Scientists don’t know for sure, but they
have a few different guesses.
Some scientists think it happened because
of a giant rock moving through space, called
an asteroid, that crashed into the Earth.
As it happens, that’s just what Jessi and
Squeaks went to Mexico to learn more about!
And Jessi’s giving us a call right now!
How’s your vacation, Jessi?
Jessi: Terrific, Dino!
Squeaks and I are here at the Yucatán Peninsula
in Mexico, and we’re learning so much!
We learned that 65 million years ago, an asteroid
blasted in from outer space and landed right
here!
This asteroid was enormous — it was 12 kilometers
wide, so big that it would take hours just
to walk from one side to the other.
And when it landed, the explosion left an
even bigger crater — a big bowl-shaped dent
in the Earth.
It’s called the Chicxulub crater, and it’s
about 150 kilometers wide.
The explosion sent lots of rocks and other
debris raining down on anything nearby.
And it sent billions of tons of soot into
the air!
Soot is the dusty stuff that’s left over
when something burns up,
Dino: That's one powerful explosion!
Jessi: It sure was!
It made the whole world really hot for a few
days.
And it started fires, giant waves, and huge,
strong winds; and it shook the Earth, in a
super powerful earthquake!
Dino: Thanks for the hot tips, Jessi.
Enjoy the rest of your trip!
Now, some scientists think that the explosion
from the asteroid sent so much soot into the
air that it blocked out the Sun.
For a while, it was really dark outside, even
during the day!
And without sunshine, it started to get cold,
which meant some of the living things that
were used to warmer weather couldn’t survive.
There was another problem, too: plants need
sunlight to live, so a lot of the plants back
then died.
Without plants, the animals that ate plants
didn't have enough food, and without enough
plant-eaters, the animals that ate meat went
hungry too.
That’s why some scientists think the asteroid
was what caused the dinosaurs to go extinct!
But other scientists think there may have
been another cause, and that even before that
asteroid crashed into the Earth, disaster
was in the air for the dinosaurs.
And they think the culprit was ... volcanoes!
Because right around the time that the dinosaurs
went extinct, one of the biggest volcanic
eruptions in history was underway, in the
area of the world that’s now India.
For close to a million years, eruptions sent
rocks and dust and soot onto the land and
into the air.
Just like with the asteroid impact, all this
stuff in the air would have blocked out the
Sun, making the Earth cooler and darker.
So we don’t know for sure what darkened
the skies and wiped out all those species
— it could have been the asteroid, or it
could have been the volcanoes, or both!
We have so many clues, but the true culprit
is going to remain a mystery... for now.
Either way, the dinosaurs were pretty unlucky!
A lot of things went very wrong for them,
all at the same time.
But even though life was hard, some types
of plants and animals were able to find food
and shelter while the Earth was changing,
and they survived!
Whatever happened all those years ago, life
on Earth goes on, and we’re all here, solving
mysteries together!
Do you have any big mysteries you’re wondering
about?
Ask a grownup to help you and leave a comment
below, or send us an email at kids@scishow.com.
And if you want to join us next time, hit
that subscribe button!
