Science Tutor: Sunrise vs. Copernicus

It’s not what you don’t know that will trip you up, its what you don’t know that isn’t so.

Did  the sun rise today?

No, it did not!

After all, tsunrise.jpghe sun does not revolve around the earth, so how could it rise or set? What actually happened is that the earth rose against the sun. Try using that phrase instead of ‘sunrise’ and you might get some funny looks… When you think about the way our speech patterns reflect the world we see, instead of the world we know, its no wonder that people get confused.ptolemaic-system.png

In the Middle Ages, people assumed the sun moved around the earth. They had perfectly good eyes, and they could tell! People believed this way since ancient Egypt, when Ptolemy drew a GEOCENTRIC map of the solar system: the earth is in the center.


HeliocentricThen came the Enlightenment. In 1543, the Polish scientist Nicolaus Copernicus studied the stars and proved that the sun was the center: his map is HELIOCENTRIC. Because people were starting to use their minds! Hurray for the new age!



aris.jpgBut, Copernicus  was not the first to figure out that ‘sunrise’ and ‘sunset’ are gigantic optical illusions. Many years ago – 23 centuries! – Aristarchus from the Greek island of Samos discovered the same thing. We know that Aristarchus lived at about the same time as two of our other scientific heroes, Archimedes and Eratosthenes, and that he was 20 to 30 years older than them. We know that his greatest work has been lost in the mists of time. We know a little about this work because Archimedes mentions it in a work called The Sand Reckoner.


Knowledge. What goes around, comes around.



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