@keyframes ex3_anim {
0% { background-position: 0; }
100% { background-position: 560px; }
}
#terre {
background-image: url('images/terre.jpg');
/* On utilise une image mappée de la Terre de 560x280 */
border-radius:140px;
width: 280px;
height: 280px;
margin:auto;
box-shadow: 0 0 50px black inset;
animation : ex3_anim 20s infinite linear;
}
<div id="terre"></div>