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# planetesimal

noun (a planetesimal, planetesimals)

«planetesimal» in the English dictionary: everyday — its meanings, how the lessons use it, and examples, each with its tree on Mova.

## Everyday

A planetesimal is a small solid lump of rock, dust or ice, from a few metres to a few kilometres across, that moved around a young star; scientists think many of them crashed and stuck together to build planets. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/P/planetesimal/#m1)

### In the lessons

In space science lessons it explains how the planets of our Solar System formed about 4.6 billion years ago; asteroids and comets are thought to be leftover planetesimals. Phrases: dust grows into planetesimals.

### Examples

- Planets formed from millions of planetesimals. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/P/planetesimal/#x1)
- A planetesimal is like a building block of a planet. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/P/planetesimal/#x2)
- Some asteroids may be leftover planetesimals. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/P/planetesimal/#x3)
- The planetesimals bumped and stuck together. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/P/planetesimal/#x4)
- Scientists study planetesimals to learn how Earth formed. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/P/planetesimal/#x5)
- Earth may have grown from planetesimals crashing together. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/P/planetesimal/#x6)

### Note

Countable. Say plan-uh-TES-im-ul. Built from «planet» and «infinitesimal» (very tiny). An advanced science word; «building blocks of planets» is a simple way to explain it.

## On Mova

- [Trees and pragmatics of «planetesimal» in the school dictionary](https://mova.elamur.ai/free/en/corpora/dictionaries/school/P/planetesimal/): every meaning and example parsed by Mova, with its dependency tree and frames.
- [«planetesimal» in the school dictionary](https://mova.elamur.ai/free/en/dictionaries/school/w/planetesimal.html) on Mova free.