Earth & SkyGreek → English
Barycenter
/ˈbærɪsɛntər/noun
The common centre of mass around which two or more orbiting bodies actually turn.
The Greek roots
βαρύς
barýs
heavy, weighty
κέντρον
kéntron
sharp point, centre
Literally: “heavy point”
The story of the word
βαρύς, heavy, plus κέντρον, the spike a compass turns on. The Moon does not orbit the Earth: both orbit a barycentre about 4,700 kilometres from the Earth's centre, which is still inside the planet, roughly 1,700 kilometres under your feet. For Pluto and Charon that point lies out in the open between them, which is one reason the pair keeps getting called a double system.
- How it travelled
- Ancient Greek → scientific coinage → English
- First recorded
- 19th century
Same family
barometerbaritonebaryonisobarcentre
In a sentence
The wobble astronomers measure is the star moving around the barycentre it shares with its planets.
Mission planners quote arrival times relative to the solar system barycentre.