ScienceAugust 16, 2026
exosphere
EK-soh-sfihr
Definition
The outermost layer of a planet's atmosphere, where gases are so sparse that particles can escape into space.
Etymology
Derived from the Greek 'exo' meaning 'outside' and 'sphere'. It was coined to describe the 'outer sphere' of the atmosphere.
In the news
The article mentions the exosphere in the context of studying the chemical response of lunar regolith to lander instruments, noting that sensors will help characterize the lunar exosphere at the surface.
Space Coast launch schedule:
Read the full article ↗Orlando Sentinel