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Ask Dr. Universe Technology, Engineering, Math
University Communications Network > Ask Dr. Universe > Technology, Engineering, Math

Dr. Universe: How many peas would fit in the sun? -Keegan, 8

Our sun is so massive, you could fit more than one million earths inside of it. To find out how many peas would fit inside the biggest object in our solar system, I decided to ask my friend and mathematician Kimberly Vincent at Washington State University. Vincent and her students said that to figure out how much of something can fit inside the sun, we need to know the volume of the sun. The volume is how much space something takes up. Read More ...

Dr. Universe: Why do gadgets need batteries? How do they work? -Shereen and Jasmine, 8, Florida

Dear Shereen and Jasmine, Batteries can power up all kinds of gadgets. To find out how batteries work, I decided to visit my friend and materials engineer Min-Kyu Song. He makes batteries in his lab at Washington State University. As you might know, materials are made up of atoms—and atoms have tiny parts called electrons. If you’ve ever felt a spark when you touched a doorknob, you’ve felt electrons making the jump from your body to the door. Read More ...

Dear Dr. Universe: What do planets have inside? -Rhianna, 10, Calif.

Dear Rhianna,

Each planet is a little different on the inside. And what’s inside a planet can shape what’s on the outside, too. That’s what I found out from my friend Steve Reidel, a geologist at Washington State University.

“Well, there’s the rocky planets,” he said. “Then there are the big, gas giants.”

Rocky planets, like Earth, are wrapped in a thick crust. Beneath Earth’s crust is the mantle. The mantle is quite solid, but it actually behaves more like a fluid. It flows and deforms. It’s similar to Silly Putty, but a really strong version of Silly Putty. It’s about 1,800 miles thick. It is also the main source of Earth’s volcanoes.

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Dr. Universe: I have a ginormous question for you. How come non-biodegradables take like a million, billion, zillion years to decay? -Madeline C., age 8

Dear Madeline,

You’re right. It can take a really long time for some things to decay.

If we buried an apple peel in the backyard it might only take a few weeks to break down into the soil. But if we buried a plastic water bottle, it would probably still be there hundreds of years from now.

Read More ...