• Question: is it possible to move the world by our own accord?

    Asked by amcdonnell to Adam, Chris, Eleanor, Jessamyn, Sinead on 11 Nov 2013.
    • Photo: Eleanor Holmes

      Eleanor Holmes answered on 11 Nov 2013:


      But by so little that it makes no difference at all. There is a principle in physics called the conservation of momentum. The Earth is always spinning around it’s axis and in this spinning it has what is called angular momentum. If you spin around in a circle you also have angular momentum. The total angular momentum of a system must always be the same (this is the conservation principle) so if you spin around in a circle you are adding angular momentum to the system of you + the Earth. To keep the equation balanced the Earth must slow down or speed up in it’s spinning (depending on which way you spin) and you will have moved the world.

      Now the difference in the rotational speed of the Earth is going to be so incredibly tiny that it won’t make any difference at all. And we can’t rule out that as you spin you may make molecules in the air spin with opposite angular momentum which cancels your spinning out and results in even less change to the rotation of the Earth, but still, it’s a start.