PHYSICS 20A Lecture Notes - Lecture 4: Tidal Locking, Orbital Period, Merriam-Webster
Document Summary
We see the moon from sunlight reflected off its surface: origin of the light is from nuclear fusion inside the sun"s core, we do not see the light that the moon generates it does emit light. Phases: half of the moon"s surface is always illuminated by sunlight, phases depend on how much of that illuminated half is visible to us, those phases are: Waxing crescent: moonlight appears to begin growing. First quarter: half of the illuminated moon is visible (waxing) Waxing gibbous: moonlight appears to finish growing. Full moon: the entire illuminated half is visible. Waning gibbous: moonlight appears to begin shrinking. Third quarter: half of the illuminated moon is visible (waning) Waning crescent: moonlight appears to finish shrinking. Wane to decrease in size, extent, or degree (merriam webster) Wax to increase in size, numbers, strength, prosperity, or intensity (mw) Crescent less than half of the moonlit face is visible. Gibbous more than half of the moonlit face is visible.
