Distances Between Stars

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When you look up into the sky on a clear night away from the glare of the city, you see trillions upon trillions of stars.

Thousands of years ago, the classical astronomers saw the same thing you do today—except perhaps a little different, due to the ever-changing cosmos. And, like you, they weren’t satisfied with just looking. They wanted to know what was out there.

For hundreds of years, they developed model after model to explain why the stars seemed to orbit the Earth and why certain objects in the sky—which they named planetsseemed to wander backwards from time to time.

Tycho Brahe, an astronomer known mainly for what he got wrong, dismissed the idea of the Earth orbiting the sun because he could detect no parallax between the stars.

If he had been able to measure parallax, he might have realized that the universe was much larger than any of his fellow classical astronomers imagined.

So what is parallax…and how can it help us measure the distances between stars? Continue reading

Solar Weather

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When you hear the word “weather,” you probably think of clouds and lightning bolts and rainstorms. Maybe, if you live in particularly high elevation or latitude, you think snowstorms or even blizzards.

We humans are used to these weather patterns. They’re the norm here on Earth. But would you be surprised to hear that the sun has weather of its own?

The sun doesn’t have clouds. Electricity doesn’t crackle through its atmosphere and build up as lightning. Its surface sits comfortably at about 5800 K, which is 9980°F and 5526°C—so it doesn’t even get close to cold enough for rain or snow.

So what kind of weather does the sun have? Continue reading

The Sun’s Magnetic Show

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Do you recognize the name Galileo Galilei?

Galileo was the classical astronomer who made the drawing above. I have little idea what his writing actually says—it’s in Latin—but it’s clear enough what this early diagram is all about.

It’s a drawing of his observations of the sun.

And it’s proof, discovered way back in Galileo’s time but not accepted until much later, that the sun actually rotates.

How do we know that? Continue reading

Spots on the Sun

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Have you ever looked at the sun, and seen something like this?

Now, before you decide to look at it right now and see what you see, it’s my responsibility as an amateur astronomer to remind you of the safety risks. Focusing your eyes on the sun is dangerous—there’s a reason our eyes automatically flinch away.

How dangerous, you ask? Dangerous enough to burn and even scar your retinas, permanently damaging or even destroying your vision.

Yes, I’m serious.

Now, all this is not to turn you off solar observing entirely. There are safe—and cheap—ways to look at the sun, and see its spots.

But what exactly are sunspots?

Continue reading

The Solar Neutrino

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Ever heard of a neutrino?

Well, I guess now you have. But what exactly is a neutrino?

Don’t worry, they’re not harmful. They’re passing through you this very second and you’ll never notice them, not in your whole life. They’ll never hurt you because they just don’t interact with matter—including you—in the way you’d expect.

I’ll bet now you’re wondering where they even come from.

Well, as the diagram illustrates, they come from the sun. They’re kind of a side-effect of the nuclear reaction that powers the sun, and they radiate out from the sun in droves. But that’s not even the coolest bit.

We know how many neutrinos should come from the sun if our theories about its power generation are right. So if we can count them, we can prove those theories correct.

That’s when we encounter a bit of a problem. We can’t actually detect neutrinos.

So how the heck do we count them? Continue reading

From the Core to the Surface of the Sun

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Ask any climate scientist how we should power our world without fossil fuels, and they’re bound to tell you about wind and solar power.

You might be surprised to know that both of these come from the sun. Solar panels collect the sun’s energy directly, but we wouldn’t even have wind if not for the sun.

Why? Because in order to move, you need energy. And not just you. I’m talking about every speck of material on Planet Earth that shifts an inch. It’s because it has energy.

That energy can come from a lot of places. Earth is still a dynamic world with a hot interior, but it’s not hot enough to sustain all the life and other movement on its surface. A lot of our planet’s energy comes from the sun.

But here’s the big question. How the heck does it get here? Continue reading

The Proton-Proton Chain

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Take a wild guess: how much energy do you think the sun generates?

Think about it. It definitely generates enough energy to power a world.

Humans depend on the photosynthesis of plants, which converts sunlight into energy. And that’s not all. Without energy from the sun, our atmosphere would behave very differently, and so would our oceans.

Everything that moves on Planet Earth does so because it has energy. And a lot of that energy comes from the sun. It doesn’t even stop there—obviously, the sun has plenty of energy to spare, if the recent influx of solar power means anything.

The sun is incredibly powerful. And it’s powerful enough to keep generating that kind of massive energy supply for billions of years.

So where does it get all its energy? Continue reading

Our Sun: Helioseismology

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We can’t see below the surface of the sun.

That makes sense, really. We can’t see below the surface of the Earth, either—we have to get creative if we want to find out what goes on below the crust.

In the sun’s case, we can’t see below its photosphere because the gases within are so dense, light can’t escape. And we depend on light to see anything.

So…if we can’t see inside the sun, how do we study it? Continue reading

Our Sun: The Corona

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When we observe our sun’s corona, we discover something odd.

It’s really, really hot.

But…wait a second. How is that odd? Shouldn’t the sun be hot?

Well…yes. It should, and it is. Its surface temperature is almost ten thousand degrees Fahrenheit, and its core is many times hotter. But there’s a basic law of physics that says energy flows from hotter regions to cooler regions.

The core and photosphere (the visible surface) follow this rule. Even the chromosphere, the lower atmosphere, does as it’s told. But the corona is made up of gases that are hotter than the chromosphere.

What’s up with that? Continue reading