Hey there, Smarty Pants, trusty narrator here, back with another episode of Smarty Q, where your questions take us from the biggest thing imaginable all the way down to stinky feet. Let's get smarting.

Question one comes from my smarty friend Charlie in Park City, Utah, who wants to know,

how big is the universe?

Fentastic question, Charlie, and the answer is really, really big.

Scientists believe the universe is about 93 billion light years across.

What does that mean?

A light year is how far light travels in one of our years.

Light is the fastest thing we know. It's about 186,000 miles per second. Even at that speed,

it takes billions of years to cross the universe. And here's the wild part. That's just the observable

universe, the part we can see. There may be

more universe well beyond that, that we can't see yet. So essentially, the universe is so big,

even scientists don't know if it has an edge. Okay, question two. Nico and Willem want to know

how does a combustion engine work? Wow, what a great engineering question. A combustion engine

works by using tiny explosions to make things move. Here's the simple version. First, air and fuel

go into a metal tube called a cylinder. Then, a piston, a moving metal plug, sits inside the cylinder.

The piston squeezes the air and fuel together. A spark plug

creates a spark. Boom. A small explosion happens. That explosion pushes the piston down. The

piston turns a crankshaft and the crank shaft turns the wheels. This happens hundreds or

thousands of times per minute, which is what makes cars move smoothly instead of jumping around.

Pretty cool, right?

Okay, on to question three.

This is an interesting one from Smarty Pants Ethan and his Smarty Mom Carly in Brooklyn, New York.

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