Thank you Hive account@agcrypt for your query. I agree with your comment to some extent; but you must realise that it is not just the spinning that causes a centripetal force (the force acting towards the centre = gravity), but mass also plays a huge part. For a light object to have the same gravity as a much heavier object, it must be spinning much quicker. The Earth is huge and extremely heavy. Hopefully this helps you out in some way or another!