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

Star Stuff & Cecilia Payne

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If this quote really is from Cecilia Payne, then she had the right idea—at least for a female astronomer in the 1920s. Women in science back then faced an uphill battle to get recognized for any discoveries they made, and Payne was no different.

What’s so special about Payne, you might ask? Well, she wasn’t just one of the many “unsung heroes” of modern science. She was the one who figured out what stars are made of.

Yeah, that’s right. She sent a probe to the sun, collected a jar of star stuff, and brought it back to her laboratory…

Um, no, not really. It wasn’t that easy.

In fact, it was very difficult. She had far too many roadblocks than were fair. But she wasn’t out for money or recognition. She was just in it for the science. And science was what she got…

Continue reading

The Balmer Thermometer

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How hot would you say this star is? Take a wild guess.

Well…sorry, but I’m going to stop you for a moment just to make sure we’re all using Kelvins. The Kelvin scale is like the Celsius scale, except water freezes at 273 K instead of 0℃. 0 K is absolute zero, which is purely theoretical and doesn’t exist.

Now can you guess this star’s temperature?

I’ll give you another hint. This is a real photograph, so it’s impossible for this star to be any star other than our sun. How hot do you think our sun is?

Okay…I’ll tell you. It’s about 5800 K, which—for those of you unfamiliar with Kelvins—is about 5527℃. Kinda crazy, huh?

Next question. How do we know this? I mean, it’s not like we stuck a thermometer in the sun’s surface and actually measured it, right? Continue reading

Stars and Radiation

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Stars are hot.

Really hot. Hot enough to have energy to spare for their planets. If our star wasn’t hot, we couldn’t live on Earth. And our star isn’t even particularly hot for a star. It’s a middle-aged star of low mass, so it’s relatively cool compared to other stars.

You might also notice that stars aren’t all the same color. There are redder stars and bluer stars and more whitish stars.

We know stars are hot. They’re also bright. And they’re different colors. But how does that all translate to radiation—and how can we see it? Continue reading

Atoms and Radiation

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Everything we know about space comes from radiation.

Now wait just a moment here. That statement explains how astronomy is such a successful field of science—it’s based entirely on the information we can glean from radiation, after all. But how does that make sense?

I mean, it’s one thing to study radiation. It’s quite another thing to study matter, the “stuff” in the universe. How does one have anything to do with the other?

Well…that’s where atoms come in. Radiation does, in fact, have a lot to do with the “stuff” it comes from. And if it weren’t for that basic principle, astronomy as a science wouldn’t work.

Thankfully for astronomers, it does. So what’s the secret, then? What does radiation have to do with matter? Continue reading

Infrared & High-Energy Astronomy

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You probably recognize this image. You see something like it whenever you look up at the sky. Some days are clearer than others—some, you might even see a completely blue sky—but regardless, you know that this is an image of our atmosphere.

But do you know just how much your atmosphere does for you?

We’ll talk about how it protects you from space rocks later on. For now, consider the energy from our own sun. The sun doesn’t just send visible light our way—it operates in all wavelengths of the electromagnetic spectrum.

Some of those wavelengths are harmful, like gamma rays, X-rays, and ultraviolet radiation. Others, like infrared radiation, microwaves, and radio waves, are perfectly fine.

The atmosphere doesn’t really pick and choose which wavelengths get through to the surface. It blocks out some radiation it doesn’t need to. At least it protects us from the harmful wavelengths.

But that’s bad news for astronomers, because those wavelengths still contain useful information about the universe.

So how to we capture and analyze them? Continue reading

Radio Astronomy: Advantages

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Whoa…what’s this thing?

It’s a radio telescope, the largest in the world. It’s so huge that a normal support system can’t support its weight. So it’s basically suspended between three mountaintops. It’s 300 m across, which is 1000 feet. It’s huge.

This is the kind of construction endeavor that radio astronomers must try if they want to get much detail from radio waves. The radio wavelengths of the electromagnetic spectrum are really, really weak. You need huge telescopes to collect enough.

But, as ever, astronomers face the same basic problem: money.

Huge telescopes are expensive. It’s unfortunate for astronomers, but true—just think of the cost of labor of basically burying a whole valley under a radio dish.

So why bother? Continue reading

Radio Astronomy: Limitations

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Astronomy is a labor of love, and radio astronomy is no different.

As I covered in my last post, radio astronomy deals with the longest wavelengths of the electromagnetic spectrum (a spectrum that includes visible light). Radio waves are not sound waves. They’re radiation just like visible light, infrared, and ultraviolet.

I’ll prove to you that radio waves can’t be sound waves. We get them from space—that’s why there’s such a thing as radio astronomy. But there’s no sound in space. Why? Sound requires something to pass through, and space is a vacuum.

So, we’ve established that radio waves are just another form of electromagnetic radiation. And astronomers love to collect any form of electromagnetic radiation. We can’t touch the stars ourselves, so it’s our only chance at learning about the cosmos.

Why? Because just about everything in the sky emits electromagnetic radiation.

Everything except black holes and a couple other things…but those are topics for another day.

But electromagnetic radiation isn’t easy to collect. And radio waves are especially hard. Continue reading

The Spectrum of Light

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Does this look familiar?

People think of rainbows as a symbol of happiness and fortune. There are even myths that leprechauns hide gold at the end of a rainbow. That’s more of a tease than good fortune, if you ask me, because it’s impossible to reach the end of a rainbow.

That’s right. Impossible.

Some people wonder if rainbows look the same from the back. The answer’s no. They don’t. You wouldn’t see a rainbow if you were standing behind it.

Whoa…why would that be? Continue reading