32亿像素的全球最大相机，即将上线｜科学60秒
极端海王星外天体的特别之处，一方面在于其轨道的距离跨度极大，呈一个极扁的椭圆形。以塞德娜为例，它的近日点为76 AU，远日点则为约936 ...
BBC Take Away English “随身英语”：Why friends are sometimes unreliable 为什么 ...
Could our personalities make us more likely to let our friends down? Find out in this programme ...