So one of our readers asked us this question the other day: If the Solar system revolves around the galaxy, does it mean that future human beings are going to observe other nebulas in different zones of the sky?


Short answer: Yeah!

Long answer: … except the galactic orbit takes about 250 million years, so the last time the earth was on the other side of the galaxy was when the dinosaurs were doing whatever it is they do. I wouldn’t count on humans surviving that long.

But if you want a different sky, you don’t have to wait that long! There are different nebulae and stuff popping up all the time – supernova are bright and leave remnants in the sky that have been observed and recorded for centuries by Chinese astronomers, Europeans, and possibly even Native Americans!

On timescales a little bit longer than human lifetimes, the constellations shift! The stars in the visible constellations are all at different distances, have different brightnesses, and are moving relative to the earth and each other, changing constellations over thousands of years! For example:

My favorite fact though, is that Polaris wasn’t always the north star! Due to the motion of stars and the precession of earth’s axis, the star Thuban (alpha Draconis in the constellation Draco) was the closest to the pole around the time the pyramids were built. The northern shaft in the Great Pyramid may therefore point toward Thuban’s position in the sky at the time the pyramid was built, allowing astronomers to calculate the age of the pyramids with significant precision! If confirmed, this bit of astronomy can inform modern archaeology and Egyptology! Of course, there’s an obvious way to challenge this interpretation – over thousands of years, pretty much any line of site will have a star on it. Maybe Thuban is a coincidence?


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Last Update: September 1, 2016

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