Hi there, welcome back to the fort.
My friend Sam the Bat is here today.
Yeah, Squeaks came to visit me in the observatory and told me all about the volcanoes in Hawaii that you guys talked about.
And I thought, since we're on the topic, I'd come down and join in.
After all, as an astronomer or someone who studies space, I know quite a bit about volcanoes, since scientists have found them on other planets.
To that end, I have a science quiz question for you, Jessi.
I love science questions.
Okay, go ahead, ask away.
What is the name of the biggest volcano ever?
Hmm, that's a really good question, Sam.
Mauna Loa in Hawaii is the biggest volcano on Earth, but...
You asked me the name of the biggest volcano ever, and that would have to be Olympus Mons on Mars.
Drat.
I thought I'd trick you with that one.
Ta-da!
You'll have to get up pretty early to trick me with a science question.
But I am impressed that you know about this giant volcano.
What else do you know about it?
Well, like you said, the biggest volcano scientists know about right now isn't on Earth.
It's on Mars.
Mars is the fourth planet from the sun and our neighbor in the solar system.
Olympus Mons is really big.
It's 100 times bigger than the biggest volcano on Earth.
It's so big that you could fit the main islands of Hawaii inside the base.
Right you are, Sam.
It's huge.
It's taller than even the tallest of Earth's mountains.
Do you know why?
Oh, sure.
It's because...
All right, you got me.
I don't know why.
Why is Olympus Mons so much taller than the volcanoes on Earth?
It's a good question to wonder about Sam, because there's a lot to learn about Earth and Mars when we look for the answer.
The reason has partly to do with what's called plate tectonics.
When Squeaks and I were talking about volcanoes in Hawaii, we talked about how Earth has layers.
We said that if we could take a closer look at Earth's topmost layer, called the crust, we would see that it's made of large, odd-shaped pieces called plates.
These plates are always moving.
Although, they move so slowly that we can't even feel it, even though we're standing on top of them.
Plate tectonics is the idea that these plates cause lots of changes on Earth, like the formation of mountains, earthquakes and volcanoes.
Sometimes, a plate moves over a very hot place in the Earth's middle layer, the mantle.
In the mantle.
It's so hot that the rock down there is melted like an ice cube can turn into liquid water, but way hotter.
And that melted rock can bubble up from below.
As the plate moves over the hot spot, the rock slowly oozes up and leaves a trail.
Before, Squeaks and I talked about how that trail of melted rock became the islands of Hawaii.
But all that happens because the plates of the Earth are moving.
Eventually, the plate moves far enough from the hotspot to drag the volcano away from where the magma can get through the surface.
Everything cools down and the volcano stops erupting.
Whoa, that's really interesting.
But what does it have to do with Olympus Mons?
Well, like Earth, Mars has layers, and its outermost layer is its crust.
Unlike Earth, though, this crust isn't broken up into plates.
It's more like one giant piece and it doesn't move.
A long time ago, a hotspot formed under where Olympus Mons is now.
But because Mars doesn't have plates that are moving.
The melted rock that bubbled up didn't form a trail.
All of the molten rock that ever came out of Olympus Mons is piled up around one spot.
Since there's no moving plate to drag the volcano away from the hot spot.
This volcano has been growing taller for at least 115 million years.
That's older than a lot of the dinosaurs.
And some scientists say it could be even older.
Super old and super tall?
This volcano has everything.
Is Olympus Mons still erupting?
Well, we don't actually know.
Some scientists think that it is active and might have last erupted about two million years ago.
So it might get even bigger?
That's awesome.
It would be considering.
It's already about 26 kilometers high, which is close to three times higher than Earth's highest mountain, Mount Everest.
Whoa, that would be amazing to see.
I'd like to take a vacation to Mars to explore Olympus Mons.
Can you imagine how great that hike would be?
It would be out of this world.
The very top of Olympus Mons pokes all the way through Mars' atmosphere.
If you could walk all the way up to its peak, you'd be in outer space.
That settles it.
I'm going to go get Squeaks so we can imagine what it would be like to take that vacation to Mars.
Thanks for helping me today, Sam, and thank you for joining us today.
If you want to keep learning and having fun with Sam, me and all our other friends, be sure to hit the subscribe button and we'll see you next time on SciShow Kids.
See ya.
