Tag Archives: Solar system

The Lost Planet of Vulcan

For nearly two hundred years, Newton’s laws of motion worked pretty well. Then, a French scientist named Urbain Le Verrier came along and messed it all up.

He calculated Mercury’s orbit using Newton’s laws and waited until it orbited the sun again in 1848, awaiting confirmation of his calculations. Mercury didn’t behave as expected. Its orbit was off by a fraction of a degree, enough to perturb exacting astronomers. Le Verrier went in search of what could’ve caused his calculations to go awry, and seized upon a dramatic possibility.

What about an unknown planet? If a small planet existed between the sun and Mercury, it would explain the deviation in his calculations. Le Verrier called the unknown planet Vulcan, and set about trying to find it.

Only Le Verrier never could find it, and neither could the many other astronomers who looked.

The mystery was finally solved decades later by Albert Einstein’s General Theory of Relativity. It showed that Newton’s laws were wrong, and the mass of objects warped space in a way that brought objects together, rather than an object itself attracting other objects. It also perfectly explained the shape of Mercury’s orbit without needing to postulate a planet no one could find.

Einstein’s theory remains unchallenged to this day, and even NASA telescopes can’t find Vulcan. It seems to have existed only in our imaginations.

I found out about Vulcan today in an excellent class I’m taking. It’s called Puzzles, Problems and Paradoxes and you can sign up here. It’s online every Wednesday at 11:10am Central through UT-Austin.

For more on science, check out these posts:

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Photo: “False Color View of Mercury” by NASA Goddard Photo and Video is licensed under CC BY 2.0