Short definition:  Planetary geology is a science discipline that focuses on the geology of solid-surface celestial bodies, such as planets and their moons, asteroids and meteorites. It is also known as space geology, astrogeology or exogeology.

Detailed definition: Planetary geology is a relatively new discipline, having appeared in the 1960s. Some topics that planetary geology is concerned with are: studying and analysing the composition of celestial bodies to better understand their origins and history; determining the properties and processes in the internal structure of astronomical objects, such as their volcanism, impact craters and fluvial processes; classifying exoplanets based on their geology and composition. Planetary geology is closely linked with the Earth’s geology, and many planetary geology studies are conducted by comparing the geology of the celestial body with the Earth’s geology. One of the main aims of these studies is trying to figure out whether other planets are capable of supporting life.

Etymology: Even though the prefix -geo comes from Ancient Greek γῆ (gê, “earth”) and is mostly associated with topics related to the Earth, planetary geology is named as such for historical and convenience reasons.

Sample sentence(s): Planetary geology researchers at Harvard contribute to robotic space missions to other planets.

Translations:

French: Géologie planétaire

German: Astrogeologie

Italian: Esogeologia

Polish: Geologia planetarna

Swedish: Astrogeologi

Links to Videos/Articles:

Byrne, P. K. (2021). Planetary Geology. In Elsevier eBooks (pp. 37–51). https://doi.org/10.1016/b978-0-08-102908-4.00125-9

TAWNIA VANDERWOOD. (2019, August 20). Meet a Planetary Geologist [Video]. YouTube. https://youtu.be/POMlppgXgM4

Space junkyard...

Short Definition:
A probe is a smaller spacecraft meant to explore the space, but will return to a space station upon return from the exploration.

Detailed Definition:
A probe's role is to study other planets and moons, perform scientific observations and gather data about the universe. It's an unmanned spacecraft that can be remotely controlled and monitored during its mission. Some famous probes include Voyager, Pioneer and Galileo probes.

Etymology:
From latin proba - meaning "proof"

Sample Sentence(s):
Voyager 2 probe was launched in 1977.

Translations:

French:
sonde

German:
Sonde

Polish:
Sonda

Swedish:
sond

Links to Videos/Articles:
https://www.nasa.gov/content/goddard/parker-solar-probe
https://www.space.com/40437-parker-solar-probe.html