lightn.光；光线；灯；打火机；领悟；浅色；天窗adj.轻的；浅色的；明亮的；轻松的；容易的；清淡的v.点燃；变亮；照亮adv.清楚地；轻便地lightmetern.照度计

1. Stars emit light which contains only certain characteristic wavelengths.
   恒星发出的光只含有特定的波长。
2. Fighting gravitational clumping would take a wavelength of a few dozen light-years.
   为了对抗重力造成的聚集，这些粒子的波长可能会长达好几十光年的距离。