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Why does meat brown on the grill?

Why does meat get brown on the grill?

– Christina, Seattle, Wash.

Dear Christina,

You know summer is just around the corner when the smell of barbecue is in the air. It’s a great question you ask and it leads us to the Meats Lab at Washington State University. That’s where I met up with my friend and animal scientist, Jan Busboom. » More …

How do turtles live so much longer than other animals?

How do turtles live so much longer than other animals?

-8th grader, Lewiston, Idaho

Dear Reader,

You’re right, turtles and tortoises live a lot longer than most other animals. If you were a turtle, you might live for more than 150 years. One giant Galápagos tortoise named Harriet even lived to be more than 170 years old, said my friend Donna Holmes. » More …

What does a planet have inside?

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.

Even deeper in our planet is the core. It’s made up of metals, like nickel and iron. In fact, at the center of Earth there may be a ball of solid nickel and iron. It’s a solid because of the intense pressure there. But the outer part of the core is under less pressure, so it’s likely more fluid.

You may have heard that Earth is like one big magnet. It’s the reason why our compasses point north. Scientists think that as Earth’s fluid interior swirls around with the spin of Earth, it helps generate the planet’s magnetic field.

Earth’s magnetism is also part of the reason we have the Northern Lights. When particles from the sun strike particles in our atmosphere near the Earth’s magnetic field, it can create colorful displays.

While we can see some of the ways deep earth shapes our planet, we can’t actually look inside it. The deepest scientists have ever explored is about 5 miles into the Earth. Since we can’t slice up a planet, scientists use different measurements to figure out what’s going on.

One way they do this is to look at waves that earthquakes produce. Scientists can use seismometers, machines to measure the shaking of the ground, to help measure the waves. Some of these waves only move through solids, like the inner core. Others move through solids and liquids, like the outer core and mantle. They can use this information from the wave measurements to put together a better picture of the planet’s composition.

Other rocky planets—Mercury, Mars, and Venus—likely have similar interiors to Earth’s. It appears Mercury has the biggest core, at least compared to its size.

Then there are the giant gas planets: Neptune, Saturn, Jupiter and Uranus.

Air is one gas we all know. We breathe it. Planes zip through it. Each of these planets in the outer solar system is surrounded by different gases. We couldn’t stand on them.

If we did travel through the center of a gas giant, we would probably find something pretty familiar to our own rocky planet on the inside.

Your friend,
Dr. Universe

 

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Correction: An earlier version of this article described the mantle as big slush ball of hot liquid magma and minerals. This has been updated to a more accurate description of the mantle.