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Ask Dr. Universe astronomy
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What causes the northern lights? Are there southern lights, too? – Sebastian, 10, Minnesota

Dear Sebastian,

For many people, seeing the northern lights is the ultimate bucket list item. Lately, experiencing them has gotten a whole lot easier.

I asked my friend Michael Allen about those dancing green and pink lights. He’s an astronomer at Washington State University.

He told me that, along with its light, the sun emits charged particles—mostly protons and electrons. Those particles freely stream into space. Then, some of them bump into Earth’s magnetic field.

Earth has a magnetic field because there’s molten iron in its core. As the liquid metal moves and flows, it makes a giant magnet. The magnet is strongest near Earth’s poles. It makes loops of magnetic energy around the planet that reach out into space.

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Why is the sun so hot? – Ziyonna, 11, Indiana

Dear Ziyonna,

What happens if you do a big jump? Your body goes up into the air. But then it comes back down again. The reason you don’t just keep going up, up, up is because the force of gravity pushes your body and the Earth together.

It turns out gravity is a big reason the sun is so hot. That’s what my friend Michael Allen told me. He’s an astronomer at Washington State University.

He said that, at first, the universe was like a thick soup of gas and dust. Then, gravity pushed some of the gas and dust together. That’s how stars … » More …

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How was the moon formed? - Barbara, 10, Texas

Dear Barbara,

Why do moon rocks taste better than Earth rocks? They’re a little meteor! In all seriousness, your question is something humans wondered about for a long time.

I talked to my friend Michael Allen, astronomy professor at WSU about how the moon formed. He told me we figured out the answer in 1972. That’s shortly after humans visited the moon for the first time.

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Dear Dr. Universe: How did people figure out how much a whole planet weighs? They could not have just put it on a scale! How did they do it? – Angel, 14, California

About 300 years ago during another pandemic, there was a person named Sir Isaac Newton who spent a lot of time at home thinking about the universe. He was thinking about how objects fall and started to wonder if the same force that made objects fall also kept the moon in its orbit. He called this force gravity. That’s what I found out from my friend Guy Worthey, an astronomer at Washington State University. Gravity plays a big part in the answer to your question, and we’ll explore that in just a moment. Read More ...

Dr. Universe: Are aliens real? -Lily, 10, New York City, NY Is there life on other planets? -Heidi, Cincinnati, OH 

Dear Lily and Heidi,

Well, we don’t know for certain. Looking up to the stars at night, I’ve often wondered if alien cats are out chasing alien mice or taking naps on other planets.

My imagination aside, your questions are like those scientists are asking, too. And it’s no wonder we are so curious.

With billions of planets in our galaxy, including small Earth-like worlds, the possibility of life out there is an exciting thought to many people. So, humans have set out to look for planets that might support life.

In fact, this month scientists announced the Kepler spacecraft’s discovery of … » More …

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What if gravity pulled up, instead of down? -Kyle, Cedar Lake, IN

Our universe would look so different, Kyle. You might not recognize it even if you could be here to see it. Unfortunately, there probably wouldn’t be a whole lot to see. I learned about this from Washington State University professor and physicist Matthew McCluskey, who studies the material world. He explained how gravity pulls together dust, gas, and little particles floating around space to make massive clumps of matter that form stars and planets. For example: planet Earth. Every particle in the Earth is pulling on you at this very moment--every single one. Read More ...