National Aeronautics and Space Administrion

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Sunday, January 12, 2020

How Copernicus moved the SunBy Dan Falk Astronomy August 2019 pp. 45-51



To many Copernicus was a misunderstood man, but he was a great person I beleive. He inspired so may great minds and continues to inspire them to this day.

The astronomers ideas forced humanity to consider our planet a ball of rock circling the fiery Sun and not the center of the universe.

Frombork's fortified red-brick cathedral complex is every bit as majestic as nearby Melbork Castle, and it has an added bonus for astronomy enthusiasts: Here, Nicholas Copernicus turned the universe upside down.

Within Frombork's massive walls, the astronomer settled down to write his treatise describing a heliocentric (Sun-centered) cosmos, the eventually published as De revolutionibus orbium coelestium (On the Revolutions of Heavonly Spheres) in 1543. To this day the great thinker rest just beneath the cathedral floors.

In some ways he was radical: His theory forced us to think of the Earth as a ball of rock whizzing though the space -- a shocking idea at the time. But in other ways, he was conservative, imagining the planets moving in perfectly circular orbits, just as the ancient Greeks had believed some 14 centuries earlier. On the Revolutions was, in some respects, a "tweaking" of the Almagest, the books-length treatise on the structures of the cosmos written by the Greek thinker Ptolemy in the second century.

We also perhaps think of Copernicus too narrowly. His astronomical work certainly dominated the final decades of his life, so we remember him as an astronomer and mathematician. But he was also a churchman, a doctor, and economic theorist.

A NATIONAL TREASURE

Though his first language was German, he was the subject of the King of Poland. And today, Poland understandably celebrates him as one of its own.

Every city in Poland seems to claim some connection to Copernicus, and statues and memorials abound. There's a salt sculptor of the astronomer and even some of the Wifi passwords are Copernicus at local taverns and other places.

In the capitol, Warsaw, an enormous statue of the astronomer stands in the city center while a science center-- which includes a planetarium called the Centrum Nauki Kopernik -- is just a few blocks east, overlooking the Vistula River.

When he went to collect the rents from the tenant farmers he treated them fairly. If they were elderly, he lowered the rent. Or if they didn't have children to help them on the farm, he would do something to help them out like giving them a horse... So it seems to me like he was a remarkably decent person.

Dava Sobel "A More Perfect Heavon: How Copernicus Revolutionized the Cosmos"

CHANGING THE HEAVENS

Planets, in the heavens, must surely move in perfect circles -- an idea that Copernicus seemed to endorse. But he also believed each planet should move at a constant speed along those circles. In Ptolemy's system, the planets moved at a constant speed, only relative to an imaginary point: the equant. To Copernicus this seemingly arbitrary construction was at odds with the spirit of Plato's vision.

Ptolemy was a mathematician, astronomer and geographer who lived 100-170 A.D. He lived in Alexandria in the Roman Province of Egypt.

Copernicus was half right; the planets do revolve around the Sun, but their orbits are elliptical, and they speed up and slow down as they orbit, as German astronomers and mathematician Johannas Kepler would eventually show.

The period of each planet's orbit gets progressively longer as one proceeds outward away from the Sun.

Truly indeed the Sun, as if seated upon a royal throne, governs his family his family of planets as they circle about him.

But in Copernicus' scheme, our entire planet is sweeping out a huge circle of every year. And still the stars do not shift; there is no annual parallax. The only explanation is that Copernicus' scheme, the so called "fixed stars" must be farther away than anyone had imagined. The universe had become a much bigger place. (It wasn't until the 1830 that astronomers could detect nearby stars tiny annual parallax.)

Galileo was tried for heresy and placed under house arrest. Some of his writings, along with Copernicus' books, were banned.

According to legend, Copernicus was presented with a copy of the published book as he lay on his deathbed; he is believed to have died of a stroke soon afterward.

Earth feels perfectly still beneath our feet; to see that it is not so requires an extraordinary leap of fate of the imagination. I was feeling of awe at this larger -- and all the more amazing universe that he gave us.

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