Mercury, Venus, Mars, Jupiter, and Saturn are easily visible to the naked eye, and that was especially so in antiquity when no light pollution existed. Those planets, then, were studied even by the Babylonians thousands of years before Christ. Distant Uranus was discovered by Hershel in 1781. The planet behaved oddly though, leading Johann Galle to the discovery of Neptune in 1846. All the planets are named after Greek and Roman deities, taking their names from their primary features. Mercury, for example, revolves around the sun in just 88 days, so it was named after the speedy messenger god. Bright Venus was named after the god of beauty, while blood-red Mars was named after the god of war. Gigantic Jupiter, king of the planets, was named after the king of the gods. Saturn, slow to move through the sky, was named after the god of agriculture. Distant, ephemeral Uranus was named after the god of the heavens, and Neptune appears in a deep blue color, so it was named after the ocean god.