Astronomy in French: Names of the Planets, Sun and Moon
Astronomy is one of the most inspiring areas of science, and French vocabulary for planets and celestial bodies appears everywhere from documentaries to museum exhibitions, news reports, and school science resources. Many of the terms come directly from Latin or Greek, which means they often look familiar to English speakers. Understanding these connections helps you memorise the words more easily and talk confidently about the solar system in French.
1. Core Vocabulary: The Planets and Key Celestial Bodies
(from Course – French for Science)
Mercury — le Mercure
Venus — la Vénus
Earth — la Terre
Mars — le Mars
Jupiter — le Jupiter
Saturn — la Saturne
Uranus — l’Uranus
Neptune — le Neptune
sun — le soleil
moon — la lune
2. Etymology & Memory Tips
Most of the planet names come directly from Roman mythology, just like in English. The French forms are therefore very familiar — you mostly need to notice the gender and capitalisation.
le Mercure — Mercury
From the Roman god Mercurius.
Also the name of the element mercury (le mercure).
Memory tip: The spelling is almost identical; in French, planets are usually masculine unless ending in -e.
la Vénus — Venus
Named after the Roman goddess of love.
Memory tip: French assigns feminine gender to Venus, matching the goddess herself.
la Terre — Earth
From Latin terra (earth, land).
Used both as a planet and the ground beneath your feet.
Memory tip: Capital T when referring to the planet; lowercase when referring to soil or ground.
le Mars — Mars
From Mars, the Roman god of war.
Memory tip: Same spelling as the chocolate bar — an easy hook.
le Jupiter — Jupiter
From the Roman god Jupiter, king of the gods.
Memory tip: Identical spelling. Always capitalised for the planet.
la Saturne — Saturn
From the Roman god Saturnus.
Memory tip: The –e ending often indicates feminine nouns in French → la Saturne.
l’Uranus — Uranus
From Greek Ouranos (sky).
Memory tip: Starts with a vowel → l’Uranus, making pronunciation smoother.
le Neptune — Neptune
From the Roman god of the sea.
Memory tip: Think of the trident → Neptune; the French word is identical.
le soleil — the sun
A unique French-derived word (not from a god).
Memory tip: Related to “solar” → solaire.
la lune — the moon
From Latin luna — also basis for lunar, lunatic, lunation.
Memory tip: The English adjective lunar keeps the same root.
3. Sentence Builder: Talking About Planets and Space
La planète ______ est…
The planet ______ is…
- La planète Mars est très froide.
- La planète Jupiter est immense.
- La planète Vénus est très chaude.
On observe ______ avec…
We observe ______ using…
- On observe le soleil avec un télescope spécialisé.
- On peut observer la lune à l’œil nu.
Cette planète a…
This planet has…
- Cette planète a des anneaux. (Saturne)
- Cette planète a beaucoup de lunes. (Jupiter)
Il y a ______ dans notre système solaire.
There are ______ in our solar system.
- Il y a huit planètes dans notre système solaire.
- Il y a des comètes et des astéroïdes.
4. More Astronomy Vocabulary
Building on the core list, these words can help build richer sentences:
une planète — a planet
une étoile — a star
un satellite — a satellite
une galaxie — a galaxy
un télescope — a telescope
l’univers — the universe
l’orbite — orbit
tourner autour de — to orbit
Examples:
- La Terre tourne autour du soleil.
- La lune est le satellite naturel de la Terre.
- Jupiter possède des dizaines de lunes.
5. Grammar Notes: Capital Letters and Gender
1. Capitalisation
Planets: capital letter (Mars, Jupiter, Neptune).
Earth:
- La Terre = planet
- la terre = soil/ground
2. Gender
French planets vary in gender:
- Most ending in -e are feminine (la Terre, la Vénus, la Saturne).
- Others are masculine (le Jupiter, le Mars, le Mercure, le Neptune).
- l’Uranus avoids gender marking in speech, but is masculine in grammar.
6. Practice: Build Your Own Sentences
Try completing these:
1. La planète ______ est ______.
2. Cette planète a ______.
3. On observe ______ avec ______.
4. Ma planète préférée est ______ parce que ______.
Example:
Ma planète préférée est la Neptune parce que j’aime sa couleur bleue.
