- And now, here's my friend, Astronomer Amy Mainzer!

- Thanks, Jet!

In "Ready Jet Go!

", our friend Jet Propulsion is from the planet Bortron 7, but Bortron 7 isn't a real place.

We made it up using our imagination.

It's science fiction.

One the other hand, science facts are different from science fiction.

Facts are real, and we accept them because they're supported by evidence that we can see in real life.

So what do science facts tell us about planets in other solar systems that are not our own?

We know that in our solar system, our planets go around our home star, the Sun.

But are there other solar systems out there?

Well, in real life, astronomers have now found lots of planets going around other stars.

In fact, here's four planets that are going around another star.

Astronomers have been watching them with a telescope for years.

Now, we've had to blot out the star in the middle so that you can see the other planets because they're a lot fainter than the star.

But look at them go.

We now know that the universe is full of planets.

In fact, when you look up at the night sky, many of the stars you see probably have planets of their very own.

Now most of these stars that you see in the night sky with your eyes are like our Sun.

They're big and yellow-white.

Planet Earth is covered with green plants that love our sun's yellow-white light, but not all stars are like our sun.

Some are a lot smaller and redder.

We call these Red Dwarf Stars.

Our Milky Way Galaxy is full of Red Dwarf Stars, and scientists have even found planets that go around them.

Just like Jet's made-up home world, Bortron 7, in "Ready, Jet, Go!"

Can you imagine what it would be like to be on a planet orbiting a Red Dwarf Star?

Scientists think that the sky might look pretty different.

It could be orange, or even red.

And the plants might be purple and black instead of green, but we don't know for sure yet because these planets still look like tiny dots in our telescopes.

We can't see them close up.

So we have to use our imagination to figure out what they might be like.

Imagination's really important in science.

Scientists use our imaginations to help inspire us to make new discoveries, like finding planets in other solar systems.

Even though the planets we found so far just look like tiny dots in our telescopes, we do know for sure that some are small and rocky, like the Earth or Mars, and others are a lot bigger.

Giant blobs of gas like Jupiter or Neptune.

And who knows, maybe there's a planet out there with kids on it that are looking back at us.

Now that's fun to imagine!

But for all the other planets out there that we found, Earth is still my favorite.

After all, we've got donuts.

Mmm.

Mmm.

That's good.

- Thanks, Amy!

You can make your own science discoveries with "Ready Jet Go!"

games on the PBS Kids Games app.

Start playing today!