Chronometer, a timepiece that is exceptionally accurate. Traditionally, the term refers to the marine chronometer, a rugged mechanical instrument used at sea to keep time for navigational purposes. By measuring the position of a celestial body (with a device called a sextant), and by knowing the exact time of the measurement, a navigator can determine a ship's longitude from published tables. The typical marine chronometer is mounted on suspension devices called gimbals to keep it in a horizontal position and to reduce the effect of vibrations from the ship.
You Might Also Like
Every November, the Leonid meteor shower fills the sky with "shooting stars." This year, the shower is expected to peak twice. Learn how Leonid and other meteor showers work.
The man who had some theories about relativity was also an eccentric who gleefully eschewed socks, dodged German military service and spurned social conventions.