The True Brightness of Stars

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Have you ever looked up at the night sky and noticed that while relatively bright stars outline the constellations, there are numerous other stars that are almost too faint to see with the naked eye?

If you ever noticed this, you probably guessed that the brighter stars are literally brighter, and the fainter stars truly are fainter. Or maybe you guessed that they don’t vary in brightness that much, but fainter stars are much farther away.

But that’s not really true…or, at least, it’s not the whole answer.

So what’s the real reason why some stars appear to be brighter than others—and how can we tell how bright they really are? Continue reading

Precession

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We have a bit of a shorter post today—I thought precession warranted its own post, before I go on to talking about the ecliptic.

Precession is refers to the way Earth wobbles around on its axis, a bit like a top. This motion is caused by the sun and moon’s gravity tugging on the planet, and is key to understanding how many ancient cultures viewed the sky.

So what is precession, exactly? Continue reading