This is an I-Hard podcast, guaranteed human.

Picture the solar system.

Likely, you have put the sun at the center motionless in your mind with the planets whizzing all around it.

Or maybe you've seen that viral video that breaks the common view and shows the sun in motion through the galaxy. But isn't the

galaxy moving to? What's the right way to think about all this to assemble a mental universe?

How fast are we going? And does that question

even make sense? A new study raises some interesting puzzles. Today, we're going to dig into

all of that and help you make sense of it. Welcome to Daniel and Kelly's extraordinary

universe in motion.

Hello, I'm Kelly Wienersmith. I study parasites and space, and it doesn't matter what I am moving relative to. I am always moving pretty slow.

Hi, I'm Daniel. I'm a particle physicist, and I'm particularly interested in our cosmic context. So, Daniel, cosmic context. Yes.

What in your mind would be the coolest spot for us to be in the universe if we could know?

Like, should we be in the center?

Should we be at the edge?

If we could be anywhere you wanted us to be, where would we be?

Wow, that's a crazy question.

And I can't believe nobody's ever asked me that before. And I have never thought about that before. You know, if the universe is infinite, then there are no places, really. They're all the same. So then the question is only interesting if the universe is not infinite. And even if the universe is finite and closed, there's still no special places.

So the most interesting thing would be if the universe is finite and has an edge, in which case, being near the edge would be amazing because the edge would have to be different in some way from other kinds of space.

It would be like a different kind of Lego brick

that makes up the universe. And different is always fascinating. Because like at the edge, for example,

momentum wouldn't be conserved. You know, for example, like when you throw a ball against a wall,

the ball bounces back, but also the wall gets pushed back a little bit, even if the wall is

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