--- title: "Earth & Space Vocabulary" description: "Use technical vocabulary for Earth's motion and the wider universe — rotation, revolution, axis, tilt, orbit, light year, gravitational force, atmosphere, lunar phases, waxing, waning, solstice, equin" canonical: https://lightmysky.com/learn/science/earth-and-space-vocabulary-mt_LQt4vnKeB4 source: https://lightmysky.com/learn/science/earth-and-space-vocabulary-mt_LQt4vnKeB4.md retrieved: 2026-10-19 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Earth & Space Vocabulary Use technical vocabulary for Earth's motion and the wider universe — rotation, revolution, axis, tilt, orbit, light year, gravitational force, atmosphere, lunar phases, waxing, waning, solstice, equinox, eclipse — and apply these when explaining day and night, the seasons, and the Moon's phases Subject: Science · Area: Space Systems & Earth's History · Ages 8 to 11 Page: https://lightmysky.com/learn/science/earth-and-space-vocabulary-mt_LQt4vnKeB4 ## Ready when they can - Use 'rotation' and 'revolution' correctly to describe Earth's two distinct types of movement and explain what each causes - Use 'waxing' and 'waning' to describe the Moon's phases and explain what causes them - Apply 'solstice' and 'equinox' correctly when explaining why seasons exist and why day length varies ## Lesson: Earth and space vocabulary Earth is always spinning around an imaginary line through its middle, called its axis. This spin is called rotation. One full rotation takes about 24 hours, which is one day. Rotation is why we get day and night: the side of Earth facing the Sun has daylight, and the side facing away has night. At the same time, Earth is also traveling all the way around the Sun on a path called an orbit. This trip is called revolution. One full revolution takes about 365 days, which is one year. Rotation is a quick spin, but revolution is a much longer journey. *(drawing: A rotation is quick: about 1 day. A revolution is a much longer journey: about 365 days, one whole year.)* Earth's axis is not straight up and down. It leans, or tilts. Because of this tilt, some places get more direct sunlight at different times of the year, which causes the seasons. A solstice is the day with the longest or shortest daylight of the year. An equinox is a day when daytime and nighttime are almost exactly equal. **Example.** Maya watches the Moon every night for a month. First she sees a thin sliver of light. Each night the lit part grows a little bigger, which astronomers call waxing. After the Moon is fully lit, the lit part starts shrinking each night instead, which is called waning. These changing shapes are the Moon's phases, caused by seeing different amounts of its sunlit side as it orbits Earth. **Tip.** Two more words are worth knowing. Gravitational force is the pull that keeps Earth orbiting the Sun and keeps our atmosphere, the layer of air around Earth, from drifting off into space. And when the Moon, Earth, and Sun line up just right, we get an eclipse. **Recap.** Rotation spins Earth to make day and night, revolution carries Earth around the Sun to make a year, and the Moon's waxing and waning come from watching its sunlit side change. ## Practice 8 questions on this page, each with its working shown. ## Needs first - [Naming the Planets](https://lightmysky.com/learn/science/naming-the-planets-mt_EHuU1ZeUFA) ## Opens up - [Phases of the Moon](https://lightmysky.com/learn/science/phases-of-the-moon-mt_4V-vYhFUcm) - [Why We Have Seasons](https://lightmysky.com/learn/science/why-we-have-seasons-mt_lFiDFPkVmH) - [Earth's rotation and day/night](https://lightmysky.com/learn/science/earths-rotation-and-day-night-mt_q15w--Fb5H) - [Galaxies and the universe](https://lightmysky.com/learn/science/galaxies-and-the-universe-mt_v9uYnIY5-B)