Well, when we jumped into WWII, we threw off the Nazi Axis, why can't the Chinese throw off the Earth's axis by jumping? For those humor impaired, the foregoing is a JOKE!   JUST a JOKE!

Having re thought the foregoing posts, simply put my point was and is this: If E=mC^2, what one is saying is that mass converts to energy and releases an incredible amount of energy. Energy can convert to mass (as in atomic fussion) with a tremendous release of energy as well as a consumption of energy. Either way WORK is being done. There is motion. There is HEAT being released. According to the 2nd Law of Thermodynamic there is no such thing as a perfect machine. During ANY energy exchange, ANY, some heat is lost to the universe in a random fashion which increases the entropy of the system(s) and the whole. It is a wholly logical conclusion therefore, that ANY work done results in an overall loss of matter as heat. That loss would be in the inverse proportion of C^2 and virtually unmeasureable except by statistical means, at the scale we live. Metaphysics? I think not.