Relative age means older or younger, not an exact number of years. A small crater can be younger than a large one if it cuts the larger crater’s rim. Size alone does not give the order. Examine the overlap and distinguish observed features from the model’s deliberately simple circles.
Space · Discover & try
What can overlapping craters tell us?
Reading level 3 of 5 · IndependentChange
Word help
Rim
The raised edge around a crater.
Relative age
Whether one event occurred before or after another.
Ejecta
Material thrown out from an impact site.
Watch · Try · Explain
See how it works
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Real NASA image plus a separate original overlap model; the drawing does not simulate crater physics or numerical ages.
What to look for
- Distinguish real image from original model.
- Find an interrupted rim.
- Avoid using crater size as an age clock.
Explain what you noticed
In a different diagram, crater Q cuts across crater R’s rim. Which event happened later?
Keep this idea: A crater that cuts an older crater’s rim formed later, while erosion can hide evidence.
Follow the sources
- NASA Space Place — What Is an Impact Crater?
- NASA Space Place — Why Does the Moon Have Craters?
- NASA — Korolev Basin on the Far Side of the Moon
Source material checked 2026-10-28. Explanations and activities by Nepedia. Source links do not imply endorsement.
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