From the brains behind brains on, this is the Moment of Um.

Answering those questions that make you go, um, um, um, moment of um, um, comes to you from APM Studios. I'm Ruby Guthrie.

Um.

The sun is the center of our solar system. And here's what we know for sure about it. We know it's a star.

We know it's a sphere.

We know it's huge.

It alone contains 99.8% of the total mass in the solar system.

And one million Earths could fit inside it.

But here's one question that's been burning in listener

Adya's mind. Namaste. My name is Adya and I'm from La Crescent, Minnesota. My question is,

why does the sun stay in one place? Can't it move around like Earth? That's a really good question. The thing is,

it's hard for us to sense how much the sun is actually moving. I'm Brittany Kami. I'm a scientist

who studies the universe and I work on building detectors to be able to see out in the universe.

In our solar system, our sun is in the center of it, and we're all going around

it the same way in a racetrack, then all the cars go around the same center. It's similar

with the sun, is that the sun is going slowly around the center of our galaxy, but it's so

slow that we don't notice it on Earth.

Music but it's so slow that we don't notice it on Earth. So we're on Earth, and Earth is going around the Sun, and we looked out, and we realized

these tiny little dots were moving around, and those tiny little dots were other planets,

and then we were able to put together the picture that all these planets were connected

in our solar system.

When we continue to look up and look out, then we made really, really, really precise measurements

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