Expert: Patrick Weiler - 2/4/2012

Question
Howdy there

Today I read that the Moon is slipping away from Earth and as it does its angular momentum increases. But how does its AM increase with the distance between their centers increasing?

Answer
Hello Michael...and thank you for using AllExperts
You have asked a very good question! The answer lies with the law of "conservation of angular momentum" which states that angular momentum can neither be destroyed nor created. Due mainly to global tidal friction of its oceans, Earth's rotational velocity (angular momentum) is slowing. That decrease in angular momentum must be conserved, so it is transferred to the moon as an increase in angular momentum. Thus angular momentum of the Earth-Moon system is conserved.

Be sure and let me know if you have any further questions.

NOTE:
Earth's rotation is slowing by about 2 seconds per 100,000 years.