Retrograde and prograde motion

High school (ages 12+)
Space & Astronomy

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/retrograde-and-prograde-motion

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. What is prograde motion?Prograde motion is when a planet, moon, or other object moves in the same direction as its primary’s rotation, usually counterclockwise when seen from above the north pole.
2. What is retrograde motion?Retrograde motion is when an object moves in the opposite direction to its primary’s rotation, either in orbit or in the way it spins.

Primary Object: The central celestial body around which another object orbits or rotates.
Inertial Frame of Reference: A coordinate system in which Newton's first law of motion holds true; used for consistent measurement of motion.
Protoplanetary Disk: A rotating disk of dense gas and dust surrounding a newly formed star, from which planets form.
Gravitational Capture: The process by which a celestial body moving past another body is drawn into orbit by its gravity.