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Ask Dr. Universe Earth and Sky
University Communications Network > Ask Dr. Universe > Earth and Sky

What makes fluffy snow turn into crunchy, slippery, icy snow? — Penelope, 11, New York state

Dear Penelope,

I love the feel of freshly fallen, fluffy snow. But then it turns crunchy and wet. That feels yucky under my paws.

I asked my friend Jaitun Patel why that happens. She’s a data scientist at Washington State University’s AgWeatherNet. She makes sure weather stations put out reliable data.

She told me that fluffy snow turns crunchy because of how falling snowflakes land then melt and refreeze.

Snow forms when water vapor freezes way up in the clouds. That makes ice crystals called snowflakes.

Snowflakes look different depending on the conditions when they form. Some look star-shaped. They have lacy or … » More …

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What is a white hole? — Darwin, 11, British Columbia, Canada and Rubal, 9, Australia

Dear Darwin and Rubal,

Before I read your question, I had never heard of a white hole.

So, I scampered over to my friend Vivienne Baldassare to find out more. She’s an astrophysicist at Washington State University.

She told me that, so far, white holes are just an idea. It’s what happens if you take math about black holes and work it backwards.

“White holes are really the mathematical inverse of a black hole,” Baldassare said. “But we have no reason to think they exist right now.”

A black hole is an area in space that has gobs of gravity.

We’re familiar … » More …

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What creates icebergs? — Kenton, 8, Washington state

Dear Kenton,

When I think about the Arctic, I picture frigid waters filled with narwhals, polar bears and icebergs.

I asked my friend Von Walden how those icebergs got there. He’s a polar scientist at Washington State University.

He told me a glacier is a huge mass of ice on land. But glaciers don’t just sit there. They move. A glacier is like a slow-moving river of ice. It’s made of heavy, compacted snow. It flows over the land because of its own weight.

An iceberg is a broken-off piece of a glacier.

To be an iceberg, that broken-off chunk must be … » More …

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Why does the Earth have lava in the middle? – Nora, 6, Florida

Dear Nora,

I live near a few volcanoes. One of them—Mount St. Helens—is bubbling with molten material that will probably gush out as lava someday.

I asked my friend Johannes Hämmerli about lava. He’s an earth scientist at Washington State University.

He told me Earth is mostly solid.

“The very center of Earth is a solid metal ball,” Hämmerli said. “Outside that ball, there’s a thick shell we think is liquid. And the rest of Earth—if you go through the mantle and crust—is pretty much solid.”

Earth formed when a cloud of dust in space collapsed. The elements inside the cloud squished … » More …

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How was the Earth made? — Penny, 8, Washington state

Dear Penny,

Blue oceans, green forests, a cozy blanket of oxygen. Our planet is a super comfy home. It’s hard to imagine there was ever a time it didn’t exist.

I asked my friend Julie Ménard how Earth formed. She’s a planetary scientist at Washington State University.

She told me it started with the Big Bang. That was nearly 14 billion years ago.

“The Big Bang is not an explosion,” Ménard said. “It’s an expansion. Everything in our universe today was in a tiny spot—smaller than the eye can see. Eventually, the pressure and density got so high that it started to expand.”

… » More …

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Where does all the snow go after winter? – Bobo, 7, Washington state

Dear Bobo,

There’s nothing more magical than sparkly flakes gently falling on a fluffy blanket of snow. But it’s a temporary kind of magic. When it warms up, the snow disappears.

I asked my friend Jennifer Adam what’s going on. She’s a water scientist at Washington State University.

She told me snow is frozen water. When temperatures rise, it melts. The solid frozen water turns back into liquid water.

That melted-snow water works just like rain water. It soaks into the ground. It fills up the spaces between bits of underground soil and rock. That’s the water that plants slurp up with their … » More …

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How do scientists know the mass and size of planets? – Lucy, 10, Illinois

Dear Lucy,

When I go to the veterinarian, they measure how big I am. They use a scale to check my weight. They find my length and height with a measuring tape.

But nobody can put a planet on a scale. Or wrap a measuring tape around it.

I asked my friend Katie Cooper about it. She’s a geologist at Washington State University. She studies our planet and other planets, too.

She told me we send satellites to orbit our solar system. When a satellite swoops around a planet, it snaps pics and takes measurements. Those images and measurements help scientists estimate the … » More …

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How many volcanoes are in the world? – Garrett, 10, Maryland

Dear Garrett,

On very clear days, I can see five volcanoes from my campus. They’re Rainier, Hood, Adams, St. Helens and Baker. That’s…a lot.

I asked my friend Katie Cooper about it. She’s a geophysicist at Washington State University.

Students walk down a pathway at WSU Vancouver with a red brick academic building visible to the left and St Helens shown at the end of the path

Check out the view of Mt. St. Helens from the … » More …

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Can humans live in space for a month? – Maya, 11, Seattle

Dear Maya,

I mostly keep all four paws on the ground. It’s hard to imagine living out in space.

I asked my friend Erica Crespi about it. She’s a biologist at Washington State University. She  studies how animals tolerate stressors faced in the environment—including how humans can live and thrive in space.

Crespi told me that Valeri Vladimirovich Polyakov lived on the Mir Space Station for 437 days and 18 hours in the 1990s. So far, that’s the record for living in space.

Polyakov’s job was to test the effects of a long space flight—like maybe a trip to Mars. He handled … » More …

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Why can we sometimes see the moon during the day? – Eli, 7, Texas

Dear Eli,

I love to go for a walk with my dog roommate. Sometimes we see the moon in the sky—even though it’s daytime.

I asked my friend Michael Allen why that happens. He’s an astronomer at Washington State University.

He told me that we have to ask “what is a day” to answer your question.

“The sun lights up the earth,” Allen said. “Since the earth is a round ball, only half of the ball can ever be lit up at any one time.”

The side of the earth that the sun shines on experiences day. The side that faces away from … » More …

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What would happen if you put a baseball-sized piece of neutron star on the Earth? Would it fall to the core of the Earth and become part of the core or pass through the Earth? – MacKenzie, 12, Louisiana

Dear MacKenzie,

A neutron star is what’s left after a massive star runs out of fuel and explodes as a supernova.

I asked my friend Matthew Duez about it. He’s an astrophysicist at Washington State University.

He told me that a neutron star is the densest known object in the universe. Its mass is like the sun’s mass. But a neutron star is the size of a city.

When something is dense, it has lots of stuff—or mass—crammed into a small space.

Imagine if we took all the humans on the planet and squished them together. We mash and squash them until they fit … » More …

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What is a supernova? – Grady, 7, Oklahoma

Dear Grady,

I was exploding with excitement to ask my friend Guy Worthey about supernovas. He’s an astronomer at Washington State University.

He told me a supernova is a very energetic explosion in space.

There are different kinds of supernovas. One kind—called a type II supernova—happens when a really big star dies.

“Why would a star bother to blow up?” Worthey said. “It seems dramatic. Human beings don’t blow up when they die.”

But humans don’t have cores that do nuclear fusion. Deep inside a star, protons and neutrons bang together and make new chemical elements. That nuclear fusion is why stars shine.

… » More …

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Why do glow-in-the-dark things light up when it’s dark? – Haygarth, 5, United Kingdom

Dear Haygarth,

I love glow-in-the-dark stickers. I leave them next to a sunny window for a little while. Then turn off the lights and watch them glow.

I asked my friend Hergen Eilers how those stickers work. He’s a physicist at Washington State University.

He told me that glow-in-the-dark things use a type of phosphorescence. That means they absorb energy—like light—and then glow. A material that can do that is called a phosphor.

Glowing in the dark works because of electrons.

Everything in the universe is made of atoms. That includes you, me, whatever you’re reading this note on—and glow-in-the-dark stickers.

All those … » More …

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What's the weirdest thing found on Mars? – Remmi, 8, Texas

Dear Remmi,

Mars is about 140 million miles from our cozy planet. A human mission to that cold, rocky neighbor would mean being away from Earth for about 3 years. But the things those explorers would see and learn would be mind-blowing.

I asked my friend Katie Cooper about that. She’s a scientist at Washington State University. She studies how geology and physics work on Earth and other places in space.

She told me the weirdest thing on Mars is a ginormous volcano.

“Olympus Mons is the largest volcano in the solar system,” Cooper said. “It dwarfs Earth’s volcanoes! Its massive size helps … » More …

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What are protons made of? – Dean, 11, Utah

Dear Dean,

There’s a pencil lying on my desk right now. It’s not much to look at, but what if I could zoom way in and see the protons and other itty-bitty stuff inside it?

My friend Ryan Corbin told me it would be like looking at a bubbling soup of fundamental particles. He’s a quantum physicist at Washington State University.

He told me that protons—along with neutrons—form the nucleus in the middle of an atom.

“Atoms make up all the stuff that we see,” Corbin said. “An atom has neutrons and protons in its nucleus. Protons have a positive electric charge. Neutrons … » More …

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What makes snow sparkle? – Hillary’s 1st graders, Washington State

Dear 1st graders,

I love bright, snowy days. That’s when you’ll find me building snowcats, throwing snowballs and watching the sun sparkle on the freshly fallen snow.

I asked my friend Von Walden why that sparkle happens. He’s an atmospheric scientist at Washington State University. Some of his research takes place near the North Pole and the South Pole.

He told me that snow sparkles because of the way snowflakes interact with the sun.

It turns out snowflakes are ice crystals. On Earth, snowflakes are hexagonal. That means they’re crystals with six sides.

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What caused the first mass extinction on Earth? – Aayush, 10, New Jersey

Dear Aayush,

It’s sad when living things go extinct. That means they’re gone forever. I think about extinct unicorns all. the. time.

My friend Jodi Rosso told me that a mass extinction is when a huge number of species die out all at once. She teaches earth science at Washington State University.

“There are periods when a whole lot of animals and plants die off in a short time,” Rosso said. “When we say a short time, we mean less than 2 million years. From a human perspective, that's forever. But in geologic time, that's short.”

Groups of living things are always expanding or shrinking their numbers. Scientists think there are as many as 10 million species on Earth right now. Between 100 and 10,000 of them go extinct every year.

A mass extinction is when big percentage of all species die off.

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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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Does the sun orbit anything? – Kingston, 11, Illinois

Dear Kingston,

When we think about orbits, we usually picture the Earth zooming around the sun. But does the sun just sit there? Or is it on its own journey?

I asked my friend Guy Worthey. He’s a space scientist at Washington State University.

He told me that an orbit happens because the gravity from something big pulls on a moving object. The sun has lots of gravity because it’s ginormous compared to Earth. So, that gravity pulls on the Earth and holds us in orbit.

But our sun isn’t the only star. It’s one of many, many stars in the Milky … » More …

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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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Recently there was an online news article that mentioned cold magma that was flowing on the land. What is cold magma? – Matt, 7, Illinois

Dear Matt,

When I think about volcanoes, I picture molten magma deep inside the Earth. Or burning hot lava pouring down the side of a mountain. But you’re right that there have been news reports that mention cold lava.

I talked about what that could be with my friend Katie Cooper. She’s a geologist at Washington State University.

She told me the news may be using “cold lava” to describe a lahar. That’s a mix of water and rocky debris that sometimes whooshes down the side of a volcano. It's also called a debris flow or a volcanic mud flow.

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What safety measures can we take during extreme weather conditions? – Zadok, 8, Kenya

Dear Zadok,

When I was a kitten, a tornado tore through the neighborhood I was visiting. It got eerily quiet outside. Then the sky turned green. My littermates and I climbed into an empty bathtub to stay safe. After that, it got super loud.

I talked about extreme weather with Nathan Santo Domingo. He’s a weather scientist at Washington State University.

He told me that how to prepare depends on where you live. Different places have different kinds of extreme weather.

“Keep an eye on the forecast and know what's coming your way,” Santo Domingo said. “Be smart about what happens in your area.”

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Why do we need the sun? – Samai, 9, Ohio

Dear Samai ,

Right now, the sun is shining through my window. It feels warm on my muzzle.

I talked about the sun with Guy Worthey. He’s a professor of astronomy and physics at Washington State University.

He told me that our lives depend on the sun.

“The sun keeps you warm and powers everything,” Worthey said. “Without it, Earth would be a frozen nightmare.”

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Why do we have to go to sleep at night, but the other side of the world is having morning? – Braelyn, 12, Ohio

Dear Braelyn,

If I drew a straight line through the Earth to the opposite side of the planet from me, I’d hit a place called Port-aux-Français. That’s an island near Antarctica. Mostly scientists live there.

Right now, it’s 12 PM, or noon, on Friday for me. But those scientists are probably snoozing in their beds. For them, it’s after 12 AM, or midnight, on Saturday. They’re already living in my tomorrow. Weird!

I talked about why that is with my friend David Luftig. He’s a science librarian at Washington State University. Science librarians are experts in two things: science and helping people find information for research and learning.

He told me it’s all because of Earth’s rotation. As the Earth rotates, or spins, the sun shines on one part of the Earth at a time.

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How did one comet kill all the dinosaurs? If crocodiles, snakes and birds came from dinosaurs, did it actually kill all of them? — Mya, 11.4, Virginia

Dear Mya,

It’s hard to imagine that one space rock wiped out the dinosaurs. But it did more than that. It killed 75% of the plants and animals on Earth. Me-OW.

I talked about that with my friend Barry Walker. He teaches geology classes about Earth’s history at Washington State University.

Walker told me that we call a space rock that hits Earth a meteorite. The meteorite that took out the dinosaurs set off changes on Earth. Those changes lasted for thousands of years. That’s how it killed so many things.

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Besides telescopes and spaceships, how do we really know that there are other planets? – Ia, 12, Montana

Dear Ia,

I looked through a high-power telescope for the first time in college. I couldn’t believe how many stars I saw. It’s hard to imagine all the planets orbiting all those stars.

I talked about how we know those planets are out there with my friend Jose Vazquez. He’s an astronomer at Washington State University.

He told me that scientists look for planets outside our solar system using a number of instruments—like a photometer. That's a tool that attaches to a telescope and measures light.

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How does it rain? — Gabby, 10, Ohio

Like most cats, I don’t love wet fur. I check a weather app every morning to see if I need an umbrella. But how rain happens was a mystery to me.

So, I talked about rain with my friend Nathan Santo Domingo. He’s a field meteorologist with AgWeatherNet of Washington State University. That’s a weather tool for farmers, gardeners and other people in Washington.

“The first thing to remember is that Earth's surface is 71% water,” Santo Domingo said. “We also have a giant orb in the sky—the sun—that’s feeding energy into the atmosphere and reaching down to Earth's surface.”

The sun’s energy changes the water in the oceans, rivers and lakes. The water changes from a liquid to a gas called water vapor. That water vapor floats up into the bubble of gas that surrounds Earth—called the atmosphere.

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How did our planet get to be the one with breathable air? – Jacob, 11, Idaho

Dear Jacob,

When I wake up from a cat nap, I stretch and take a deep breath. It feels good to fill my lungs with oxygen.

But that wasn’t always possible on Earth.

I talked about this with my friend Sean Long. He’s a geologist at Washington State University.

“The cool thing is the answer has to do with life,” Long said. “Early life forms on Earth gave us all the oxygen. They were single-celled bacteria.”

Our planet is about 4.5 billion years old. There’s been life on Earth for 3.5 billion years. The first life forms were made of just one cell. They were bacteria and their cousins called archaea.

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What happens if you get sucked up by a black hole? – Amari, 10, North Carolina

Dear Amari,

I was fascinated by black holes as a kitten. I liked them because they were scary. But they’re also far away so I knew I was safe.

I talked about this with my friend Vivienne Baldassare. She’s an astronomer at Washington State University.

Baldassare told me a black hole is an area in space with lots of gravity. That’s the same force that pulls your body toward the Earth.

“If we want to send a spacecraft somewhere else in the solar system, it has to travel fast enough to escape the gravity of Earth—so the rocket doesn't just fall back down to Earth,” she said. “A black hole is a place where that escape speed is the speed of light. Nothing can move faster than the speed of light. So, nothing can escape from inside the black hole.”

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How does evolution work? – Aubree, 10, Kentucky

Dear Aubree,

When I thought about evolution, I always pictured big changes that happened over long time periods—like how birds evolved from dinosaurs.

But then I talked with my friend Jeremiah Busch. He’s a biologist at Washington State University. He told me evolution is happening all the time.

“As soon as you see that evolution is occurring around us, it changes the way you think about the world,” Busch said.

There are a few ways evolution happens. These include mutation, gene flow, genetic drift and natural selection.

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Did dinosaurs eat humans? – Brileigh, 10, North Carolina

Dear Brileigh,

If you looked inside a T. rex mouth, you’d see some 12-inch teeth. That’s longer than my tail!

I asked my friend Aaron Blackwell if dinosaurs used those big chompers on humans. He’s an anthropologist who studies human biology at Washington State University. He told me dinosaurs and humans didn’t live at the same time.

“Dinosaurs died out 65 million years ago—before there were even primates,” Blackwell said. “So, they could never have eaten a human or even a monkey.”

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What causes the oceans to rise? – Ash, 11, Kentucky

Dear Ash,

There are two ways to answer your question. One looks at why the ocean rises and falls every day. The other explores what’s causing sea level to rise over time.

I talked about both with my friend Jonathan Robinson. He’s the Beach Watchers coordinator at Washington State University Snohomish County Extension.

If you’re at the beach during high tide, the beach looks smaller because the water comes up higher onto the beach. The tides are what make that happen, Robinson told me.

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How do gems form underground? – Jett, 11, Kansas

Dear Jett,

When I was a kitten, I loved collecting rocks and gems. So, I was very excited to talk about your question with my friend Johannes Haemmerli. He studies minerals in the School of the Environment at Washington State University.

Minerals are solids that form from non-living elements in nature. They have a very specific structure for how those elements are arranged. Haemmerli told me that nearly all gems are minerals or sometimes mixtures of minerals.

You’re right that gems form underground. A diamond forms when the element carbon is buried nearly 100 miles deep inside the Earth. It’s super-hot and there’s tons of pressure down there. Eventually the pressure pushes the carbon atoms together to form the mineral we call diamond. Above ground, where there is much less pressure, the same carbon can come together and form a mineral we call graphite. That’s the “lead” of your pencil.

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How did life begin? Kelsey, 10, Texas

Dear Kelsey,

The universe is a big place. Thinking about how we fit into it is part of what makes humans (and cats like me) special.

I talked about your question with my friend Afshin Khan who studied astrobiology and environmental science at Washington State University. Astrobiologists explore how life began. They also look for signs of life outside Earth.

Khan told me your question is a huge mystery.

“We have very good ideas about what could have happened,” she said. “In different labs around the world, we’ve gotten very close to simulating some of those conditions. But simulations can only get so … » 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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Dr. Universe: How come some rocks are easy to break and some are hard? - Natalie, 10, Russellville, Kentucky

Dear Natalie,

If you draw with a pencil, you can tell how soft the graphite inside is. Pieces of graphite break off to leave the pencil mark. But can you imagine drawing with a diamond? Diamonds and graphite are both what you might call rocks. How come they’re so different?

To find out, I talked to my friend Katie Cooper, a geologist and associate professor in the Washington State University School of the Environment. Geologists often study how different types of rocks and minerals form—and that’s the secret to whether they’re easy or hard to break.

Rocks are made of minerals, and minerals are made of elements, which are substances made of a single type of atom. You can get to know the Earth’s elements by looking at a Periodic Table.

Some minerals are made of a single element, like diamond and graphite, which are both made of carbon. Others are a mix, like limestone, which is made of calcium and carbon.

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Dr. Universe: Why does the sky turn darker in winter? - Alex, 6, Cincinnati

Dear Alex,

As winter gets underway here in North America, you may notice we don’t feel the sun’s rays for quite as many hours as we did in fall and summer.

To find out why this happens, I talked with my friend Vivienne Baldassare, an astronomer at Washington State University.

She said the reason we get fewer hours of daylight in the winter has to do with how Earth rotates. As our planet goes around the sun, it is always rotating. This rotation is also why we have day and night.

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Dr. Universe: How do worms help protect the dirt? -Fisher, 7, Palouse, WA

Dear Fisher,

Worms can help the soil in a few different ways. One helpful thing worms do is move around different materials, such as leaves and grasses, and make holes in the soil. That’s what I found out from my friend Lynne Carpenter-Boggs, a soil scientist at Washington State University, who was happy to help with your question. Lynne Carpenter-Boggs “Worms are actually very strong,” Carpenter-Boggs said. “They can break through soil and make holes that allow air, water and plant roots to follow those channels.” Read More ...

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: How were Saturn’s rings made? -Amelia, 9, Washington State

We still don’t know exactly how the rings around Saturn formed, but scientists who study Saturn’s rings have come up with a couple of ideas. One common theory many scientists agree upon is that Saturn’s rings are made from the little leftover pieces of what used to be a moon. My friend David Atkinson is really curious about the solar system and told me more about it. He is a graduate of Washington State University and now works at the NASA Jet Propulsion Laboratory. He also worked on the Cassini-Huygens space research mission which helped us learn more about Saturn, Saturn’s large moon Titan, and the entire Saturn system. Read More ...

Dr. Universe: Why does oil on the street look like a rainbow? -Jorgos, 10, Bothell, WA

When it rains, sometimes we can see oil on the street rise to the top of puddles and spread out into a rainbow of colors. One of the main reasons we see color is because of light, said my friend Cigdem Capan, a physics instructor at Washington State University. She reminded me that when our eyes sense colors, we can trace those colors back to different wavelengths of light. Perhaps you can make some waves in the air with your hand. Make small, tight waves. Now make a big, wide waves. Read More ...

Dr. Universe: Can a shadow make a shadow? – Aven, 7, Palouse, WA

Dear Aven, When we look around our world, we can find all kinds of shadows. One way we can explore the answer to your shadow question is with a little experiment. My friend Anya Rasmussen, a physics professor at Washington State University, told me all about it. First, you will need to cast your shadow on a wall. Rasmussen reminded me shadows form when an object—such as your body— blocks light and keeps the rays from reaching a surface—like a wall. Read More ...

Dr. Universe: Why do we have seasons? -Bella, 9, North Carolina

Dear Bella,

It turns out seasons can be quite different depending on where you live. But no matter where you live, the reason for the seasons has to do with the way the Earth rotates.

To find out exactly why we have seasons, I talked to my friend Vivienne Baldassare, a physics and astronomy professor at Washington State University.

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Dr. Universe: How many black holes are in the galaxy and the universe? -Krisha, 9, New Jersey

Dear Krisha, While we can’t see black holes with our eyes, astronomers have figured out how to spot these objects in our universe. One astronomer who is really curious about understanding black holes is my friend Sukanta Bose, a researcher at Washington State University. First, he told me there are different kinds of black holes. Supermassive black holes can be millions to billions of times the mass of the Sun. We have a supermassive black hole in our own Milky Way galaxy called Sagittarius A*, which is pronounced as Sagittarius A-star. Read More ...

What is a tornado made of? - Alice, 6, Ames, Iowa

Dear Alice,

Have you ever felt a warm wind blow by you, followed by a cold gust of air? You can’t see it, but you can sense it on your skin. Invisible to you, winds mix together.

Usually, these winds are harmless. But under the right conditions, they can also be the main ingredients for a tornado.

To learn more, I chatted with Jon Contezac, Craig Oswald, and Joe Zagrodnik, a team of Washington State University scientists who are very curious about the weather.

To make a tornado, they explained, you need two big things: rising air and rotating air.

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What is a sinkhole? What causes one? - Kathrine, 12, Calgary, Canada

Dear Kathrine,

Sinkholes can be scary to think about. They don’t happen too often, but when they do, they can take people by surprise. The solid ground disappears, and a hole suddenly appears.

It might seem like sinkholes appear out of nowhere. But they actually need specific conditions to form.

To have a sinkhole, you first must have a cave.

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Where does the universe end? - Oriah, 8, Pullman

Dear Oriah,

When you look up at the night sky, it can feel like the universe is a big blanket of stars above you. But unlike a blanket, the universe doesn’t have corners and edges. Far beyond what humans can see, the universe keeps going. As far as humans know, it never stops.

When I saw your question, I went straight to my friend Michael Allen to learn more. He is a Senior Instructor of Physics and Astronomy at Washington State University.

The universe is bigger than the biggest thing you’ve ever seen. It’s bigger than the biggest thing this cat can imagine. It’s so big that even your question has more than one very big answer.

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Dr. Universe: Why does the wind blow? -Odin, 7, Mt. Vernon, Wash.

Dear Odin,

When the wind blows, it can do all kinds of things. It can help pick up tiny seeds and carry them away, so plants and flowers can grow in new places. It can push a big sailboat across an ocean. We can even harness the wind to make clean energy to power our homes and schools.

That’s what I found out from my friend Gordon Taub, an engineer at Washington State University. He is very curious about wind energy and told me more about why the wind blows.

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Dr. Universe: How do trees help the air? – Ella, 12

Take a big, deep breath. As you inhale and exhale, you can probably feel the air taking up space in your lungs. The air we breathe is made up of a few different things. It includes gases such as nitrogen, oxygen, and carbon dioxide—just to name a few. Animals breathe in oxygen and breathe out carbon dioxide. But in the plant world, it’s the opposite. Trees, plants, and even algae in the ocean, take in carbon dioxide from the air and, using the energy of the sun, transform it into the oxygen we all breathe. Read More ...

Dr. Universe: What are shooting stars made of? – Erin, 11, Arkansas

If you are anything like me, you probably like watching for shooting stars in the night sky. A shooting star, or a meteor, is usually a small rock that falls into Earth’s atmosphere. When I went to visit my friend Michael Allen, a senior instructor of astronomy and physics at Washington State University, he told me a lot of shooting stars are no bigger than a pencil eraser. Read More ...

Dr. Universe: What can I do to help stop ocean pollution? -Hailey, 10

It’s great to hear you want to help our oceans. After all, they do a lot for us. Life in the ocean provides much of the oxygen we breathe and is also a source of food for many animals, including humans. One of the most important things we can do to prevent more pollution is to keep our garbage, especially plastic, out of the ocean. That’s what I found out from my friend Richelle Tanner, a marine biologist and researcher at Washington State University. While a lot of plastic ends up in the ocean, it actually started under the Earth’s surface in the form of oil, leftovers of plants and animals that died long ago. Read More ...

How do volcanoes erupt? –Miles, 10, Tampa, FL

Wherever we find a volcano on the surface of our planet, we can find the source of an eruption beneath it. That’s what I found out from my friend John Wolff, a volcanologist at Washington State University. Our planet is home to all kinds of volcanoes that erupt in different ways. Some eruptions are quiet and continuous, with a slow flow of lava. Other volcanoes erupt explosively and can spew ash and lava hundreds of feet up into the sky. All of this lava has its start underground in the form of something called magma. Wolff said that scientists used to think there were large pools of hot liquid beneath volcanoes. Now we know it isn’t quite that simple. Magma is not really a liquid, but rather a kind of sludge or slurry. It helps to think of it kind of like honey. Read More ...

Dr. Universe: How do earthquakes happen? -Aescli E., 10, Utah

We’ve had a lot of earthquakes on our planet this year. Maybe you’ve learned about them from the news or felt one shaking up your own neighborhood. First, it is important to know a bit about the Earth’s outer layer, or crust. The crust is made of seven big pieces called “plates.” They are about 60 miles thick and sort of float on the molten rock beneath them. That’s what I found out from my friend Sean Long, a geology professor at Washington State University who knows a lot about earthquakes. Read More ...

Hello Dr. Universe: I was wondering, how does an eclipse happen? - Susan, 13, San Francisco, CA

Dear Susan,

It just so happens the Great American Eclipse is coming up on Aug. 21, 2017. This solar eclipse will be the only one visible from across the lower 48 states in nearly a hundred years. When it happens, parts of the country will experience darkness for a couple minutes during the day.

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What do astronauts eat in space? –Rhemi, 12, St. Louis, Mo.

Dear Rhemi,

Astronauts eat all kinds of different foods up in space. The food is often similar to what we have here on Earth. But in space, there's very little gravity. There’s very limited refrigeration, too. On the International Space Station, the refrigerator is only about half the size of a microwave. That means scientists who prepare and package astronaut food have to do it in ways that take up very little room and don’t need to be kept cold.

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Dear Dr. Universe: When will the next major earthquake be? Earthquakes really interest me and I want to know so I can be prepared when the next major quake happens. - Carmen, 11, Chowchilla, Calif.

Dear Carmen,

Our planet’s surface is constantly on the move. Sometimes this movement really shakes things up.

The Earth’s crust is made up 14 major pieces and dozens of smaller ones, called plates, that move in super slow motion. Earthquakes can happen when these plates suddenly slip past each other. They send out waves of energy that make the ground shake.

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Dear Dr. Universe: What causes lightning? -Monica, 10, Costa Rica

And while we’re at it, let’s answer these questions:
When lightning strikes the ocean, what happens to the fish? –Olivia, 12, Manchester, UK
Why is lightning attracted to metal objects? –Grant, 11, Pullman, Wash.
Why does lightning sometimes just happen in clouds? –Leo, 11, Cayman Islands
 
Dear Monica, Olivia, Grant, and Leo:
While you are probably not in the middle of an electrical storm right now, there are more than 1,000 happening at any given moment on our planet. They happen on Saturn, Venus, and Jupiter, too.  

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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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Dear Dr. Universe: What exactly is climate change? How does it affect the way we live? –Pranav, 10, Melbourne, Fla.

Dear Pranav,

If you’re anything like me, one of the first things you'll do in the morning is check the weather. Sometimes it’s rainy and I’ll put on my rubber boots. Other days it’s really sunny and I’ll grab my sunglasses. When we look at the patterns of these weather conditions over a long time—sometimes over hundreds of years—we can learn about a place’s climate.

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Hello! My name is Daiwik and my question is "Why are stars in space? Why are they needed? Can they be made on Earth?" No one I know knows the answer to this. Can you find out for me?- Thanks, Daiwik P.S. You're awesome!

Dear Daiwik,

If you are anything like me, you like watching the night sky. The stars we see are a lot like our nearest star, the sun. They are just much farther away. That makes stars look like small twinkly things instead of a big, furious thing like our sun.

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Dear Dr. Universe: I was just wondering if there are any volcanoes on any other planets? Danny, 10, Kenmore, WA

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Dear Danny,

The answer to your question takes us out into our solar system and deep below the surfaces of other moons and planets.

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What is the Kuiper Belt? -Zaara A., 7, Deep Bay, Australia 

Dear Zaara,

You might say the Kuiper Belt is the frozen frontier of our solar system. Out beyond Neptune’s chilly orbit, this saucer-shaped region is home to Pluto, billions of comets, and other icy worlds.

“The Kuiper Belt is really the edge of knowledge,” said my friend and astronomy professor Guy Worthey when we met up in the Washington State University planetarium.

“Out there it’s a little dim,” Worthey said. “We are pretty far from the Sun.”

In fact, it’s about 3 billion miles away. Even at the speed of a jet airplane, it would take more than 680 years to travel from Earth … » More …

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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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Dr. Universe: What materials would you use to make a rocket -Freya, Scotland

Dear Freya,

Whether it’s a model rocket you build in the backyard or one that launches a space shuttle, there are lots of materials you could use. So, when I saw your question I grabbed my lab coat and safety goggles, and zoomed over to my friend Jake Leachman’s lab. He’s a rocket scientist and engineer at Washington State University.

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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 ...