electromagnetic spectrum
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The Starlight We Can’t See
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,…
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Stars and Proper Motion
Recognize this constellation? Well, at the time stamp of about 2000 AD (CE), I think you will. It’s one of the most famous constellations in the night sky. Well, technically, it’s not a constellation at all. It’s an asterism — a…
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Energy Flow from the Sun’s Core
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…
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Our Sun: The Chromosphere
This diagram is a tiny bit misleading. Here, it looks like the chromosphere is the visible surface of the sun, with the photosphere just below. Really, we never see the chromosphere. If you ever look through a solar telescope at…
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The Doppler Effect
Have you ever heard the ice cream truck? When I was little, I remember hearing the ice cream truck all the time. Just the sound of the opening notes of “Pop Goes the Weasel” were enough to propel me to…
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Star Stuff & Cecilia Payne
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…
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Types of Stars
Meet the sun: a G2 class star towards the middle of its lifespan. Wait a second…G2? What does that even mean? It’s all part of a way astronomers break down the billions of stars in the sky and organize them…
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The Balmer Thermometer
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…
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The Atomic Spectrum
Astronomers know that if white light passes through a prism and is bent, it’s separated out into its component colors — the colors of the rainbow. Astronomers also know that when light interacts with atoms, the building blocks of the…
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Stars and Radiation
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…
