Earth & SkyGreek → English
Planetesimal
/ˌplænɪˈtɛsɪməl/noun
One of the small solid bodies that clump together to build planets in a young star system.
The Greek roots
πλανήτης
planḗtēs
wanderer
Literally: “an infinitesimal planet”
Follow a root:πλανήτης6 words
The story of the word
A hybrid, and openly so: Greek at the front, and a tail borrowed wholesale from infinitesimal, which is Latin. Thomas Chamberlin and Forest Moulton coined it in the early 1900s for their theory that the planets grew by accretion from countless small bodies. Their mechanism for making those bodies, a near-collision with a passing star, is long dead. The accretion picture they attached the word to is now the standard account.
- How it travelled
- Ancient Greek → scientific coinage → English
- First recorded
- early 1900s
The same roots elsewhere
Other languages reached for exactly the same Greek pieces.
Same family
planetplanetoidprotoplanet
In a sentence
Simulations start with a swarm of planetesimals and let gravity do the rest.