Questions asked by Nooran A.

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• Regolith is sampled on mars and he concentration of potassium-40 is 120 ppm. In a crater, potassium-40 is only 12 ppm. If the half life of potassium-40 is 1.2 billion years, how long ago was this crater formed?
  
• . If a planet’s closest distance to the Sun is 1.00 AU, and its furthest distance from the sun is 9.00 AU, what would its orbital period be?