For the earth to change its direction of rotation instanteaneouslu would be impossible, since it would need an infinite amount of ebergy to achieve it. Even for it to happen over a very long period would require a very great deal of energy - far more than humankind can produce. Supposing that something of the sort did happen, there would be devastating consequences. The earth has a circumference of around 24,000 miles, and rotates once in just under 24 hours (23h 56m actually). That means that at the equator, the change of rotation would mean that everything standing on the surface would suddenly find the surface moving westwards relative to it at 2,000 mph - or roughly Mach 3, Those things which were relatively well-attached to the surface would be bombarded with those less well-attached, at roughly this speed. The seas are not well-atached, so there would be waves travelling at 2,000 mph or so, inundating vast areas of what is now land. There would be enormous frictional forces within the earth, unless all of it started spinning the wrong way at the same time. The risk would be that fritction within the earth would cause at best major seismic and volcanic activity, at worst total re-melting of the crust. One way or another, all life on earth, except perhaps some very primitive unicelled organisms, would be killed off. Contrary to what someone else has said, satellites would continue to orbit - but geostationary satellites wouldn't be geostationary any more. They would pass over any given point on the equator twice per day now. Telecommunications would be greatly disrupted, and your satellite TV wouldn't work. Then again, your TV would be gone, and you would be dead, so never mind.