Warning: Missing argument 3 for write(), called in /www/wwwroot/biwei1.cn/incs/robot.php on line 68 and defined in /www/wwwroot/biwei1.cn/incs/data.php on line 487 Jupiter 'shepherds' the asteroid belt, preventing the asteroids from falling into the sun or accelerating into a new planet. Credit: Petr Scheirich