The Starlight We Can’t See

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Find yourself a dark, unpolluted night sky on a clear night free of clouds, and you are very likely to look up into the heavens and see a sight quite like this. It’s what we see of the Milky Way, our galaxy.

When I’m at an astronomy event with a sky like the one above, I find it absolutely incredible. Do you notice how the stars don’t all look the same?

A couple are startlingly bright, there are numerous stars that are somewhat dimmer, and if you look really hard, you notice that even the dark night background is sprinkled with stars so faint they can barely be seen.

But what if I told you that you’re not even seeing the half of it? 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

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