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Squeaks and I have been reading all of the great questions you’ve sent us.
Some are about animals, the weather, our bodies, and even about physics.
You’re all so smart and so curious, and we love getting these questions!
We noticed that lots of you want to know where the Earth came from, and that’s a good question,
with a really cool answer:
It came from a huge cloud in space!
[Squeaks squeaks]
That’s true, Squeaks.
The Earth formed billions of years ago, so we don’t have any pictures or videos to
see it happening!
But we can figure out what happened based on some clues.
You might already know that the Sun is a star, and that Earth is a planet moving around the
Sun, as well as Mars, and Venus, and a bunch of others — 8 planets in all.
Together, the Sun and everything moving around it make up our solar system.
By learning about the solar system, and by looking at what’s happening around other
stars where planets are first forming now, scientists can get a pretty good idea of where
the Sun and planets like Earth came from.
And it all started out as a giant cloud of dust and gas all floating together in space.
Scientists think that more than 4 billion years ago, that enormous cloud got a really
strong shock.
We don’t know exactly what caused it, but it could be that a nearby star exploded.
Whatever it was, that far away explosion shook the whole dust cloud, and as the cloud shook,
all of the dust and gas inside began to move closer together.
Some of the dust and gas in the center squished together, and as more and more dust and gas
got squished inside it, the middle of the cloud become very big, very thick, and very,
very hot.
Can you think of what’s in the middle of our solar system that’s very hot?
[Squeaks squeaks!]
That’s right, it’s the Sun.
The dust at the center of the cloud got squished together so much that it started burning up,
and it became our star, the Sun!
Even back then, the Sun was so big, and so heavy, that it was able to pull things closer
to it just by being there.
This was because of a force called gravity: the same thing that pulls you back down to
the ground when you jump.
A force is anything that’s a push or a pull.
Like, if I pull on Squeaks' arm, I'm putting a force on him!
Gravity is a force just like that.
It pulls little things, like us, close to big things, like the Earth, almost like a
magnet.
It’s always there, pulling us to the ground and keeping things on Earth from floating
into space.
And billions of years ago, gravity also pulled what was left of the cloud of dust and gas
towards the Sun.
The dust and gas slowly began to swirl in a circle around the Sun.
It looked a bit like a big disk, or a flat circle.
[Squeaks squeaks]
It was starting to look a lot more like our Solar System.
But the planets were still missing!
Over time, everything in the disk moved into different rings around the Sun.
And then, the dust and gases in the rings began to clump together.
Because something was pulling on them.
[Squeaks squeaks]
You got it!
Gravity was pulling everything together.
The clumps of dust and gases started to get bigger … and bigger … until eight of these
clumps basically became baby planets.
Over thousands of years, the baby planets gathered more and more material with their
gravity, until they became the eight planets of our solar system.
And today, each planet still moves around the Sun, just like when it was a young, growing
planet.
[Squeaks squeaks]
It is amazing how much the Earth has changed since then!
Everything around us used to just be pieces of dust floating around in space, and now
it’s this huge, amazing planet, with all kinds of incredible things living on it.
Including us!
There’s always more to learn about the planet we call home, and about space, where all of
the other planets are.
Maybe tonight we can get a closer look at some of them through our telescope!
Thanks for joining us, and for sending such great questions!
If you have more questions about the Earth, or space, or anything at all, we’d love
to hear them!
Ask a grownup to help you leave a comment below, or send us an email at kids@scishow.com.
We’ll see you next time, here at the Fort!
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