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How Did the Planets in Our Solar System Get Their Names?

-- Candice | October 22, 2021

Question:

I saw someone say that Jupiter was named because it’s the biggest planet but that doesn’t make sense because we didn’t even look at Jupiter through a telescope until Galileo. Neil Degrasse Tyson says in one of the episodes of Cosmos that Saturn was named because it moves slowest against the background of “fixed” stars, I’ve heard Mercury is named because it’s fastest in the sky (though isn’t it only visible to the naked eye during transit? Were people looking at the Sun? I know Newton and Galileo both did, through telescopes no less, but were the ancient Babylonians/Egyptians/Greeks?), Venus is named because it’s the brightest non-luminary, and Mars because its red color is apparent in the night sky and the red was associated with the blood spilled in war. Those all seem like reasonable explanations but the Jupiter one has me questioning whether we actually know any of these as a matter of historical record of some sort or if these are just hypotheses as to the origin of the names?

-- Candice

Answer:

As you suggested for a couple of planets, all of the planets, except for Earth, were named after Greek and Roman gods and godesses. There is a nice explanation of the naming history for the planets on Cool Cosmos.

-- Jeff Mangum

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