Friday, March 17, 2017 2:29 PM
7.3 Dating Planetary Surfaces
• The age of thesesurfaces is not necessarily theage ofthe planet as a whole.
Geologically activeobjectscan have planetweatheringwhicherasesevidenceof
Counting the Craters
• Works becausethe rateat whichimpactshave occurred in thesolar systemhas
• Crater counts can onlytellus the time since thesurfaceexperienced a major
• Measure the ageof individual rocks.
○ Using the propertiesofnatural radioactivity.
fifty0fifty thatdecaywilloccur for any of thenuclei
• Radioactive elements withhalf-liveswe have determinedcanprovide accurate
• The decay ofradioactivenuclei generallyreleases en