div class=ts-pagebuttonPage 1button div class=ts-image amp-img class=ts-thumb alt=Page 1: GRAVITY Earths gravity field changes from place to place src=https:reader031vdocumentsnetreader031viewer20220224086216dcac55ab2b00f3537aa5html5thumbnails1jpg width=142 height=106 layout=responsive amp-img divdiv