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 This is how two colliding galaxies interact and merge into a single elliptical galaxy over a period spanning two billion years of evolution, in a simulation made by the Advanced Visualization Laboratory (AVL) at NCSA[source: ]