内容简介
WedontfeelthatwearespinningwhenwestandontheEarth.ButinfacttheEarthismovingveryfast.Thegroundattheequatorisspinningat1,600kilometer(1,000miles)perhour!Theequatorisanimaginaryline.ItisaroundthemiddleoftheEarth.TheEarthspins(rotates)aroundanimaginaryline.