Book 8, Question 6
Why Do the Moon and Planets Follow the Same Path Across the Sky?
The Moon and planets follow the same path because they all travel in a flat plane around the Sun! The planets orbit the Sun in a flat, pancake-shaped sheet. From Earth, that sheet looks like one curved line across the sky, called the ecliptic.
More fun facts
- The Sun's yearly path across our sky is very close to the paths of the planets and the Moon.
- The Moon's orbit is tilted only about 5 degrees from the Sun's path, so the Moon also travels through the zodiac constellations.
- Isaac Newton realized that the Moon circling Earth and an apple falling from a tree follow the same basic rules.
- Johannes Kepler found a rule for planets: a line from the Sun to a planet sweeps out the same amount of space in the same amount of time.
- People all around the world take turns seeing the Moon each day, just as we all see the same Sun over 24 hours.
Sources: NASA, NASA Science, NASA Science
Questions kids ask
What is the ecliptic?
It is the path the Sun seems to follow across our sky over a year.