Question #eb034
1 Answer
The same way that a rotating figure skater can slow down just by spreading out their arms.
Explanation:
If you have ever watched Olympic figure skating I am sure you have seen a skater spinning in one spot and when the pull their arms in their rotation speeds up. The reverse is true when the skater puts their arms out (they slow down). In physics terms it is called conservation of momentum.
Since the Earth is spinning, any redistribution of mass will affect the rate of spin that same as the figure skater moving their arms. You may have read how the massive earth quake Japan in 2011 actually shortened the length of the day by 2 milliseconds (aprox.).
In the case of El Nino we have a large amount of warm water being pushed to the eastern part of the Pacific, over running the cold water. This redistribution of mass will lengthen the day by as much as a millisecond. The reverse is also true of a La Nina.
Don't worry too much about it, as the ocean is fluid the effects of both El Nino and La Nina on the rotational speed of the Earth are only temporary.
