The stars and planets are made from the same chemical bricks and mortar . There is nothing so exotic as unobtanium , a plot contrivance of the film " avatar . "

恒星和行星都是相同化学物质构成的，宇宙中并不存在unobtanium这种奇异的物质，这只是电影《阿凡达》中的一种构想而已。