Current theory holds that planets are made from disks of gas and dust left over after star birth.
现有理论指出：行星是恒星诞生之后的残留物——碟状尘埃和气体的产物。
2
In theory, planetary dust could block out UV rays, but the dust was bound up in the creation of those young planets.
理论上行星星尘可以把紫外线挡在外面，可在这些年轻行星的形成过程中，星尘是挤成一团的。
3
Scientists know planets form out of the discs of material around young stars, but theory says the transition from dust disc to planetary system is rapid and few objects are caught during this phase.