nebulosity

1.You can still see the gas or nebulosity in big telescopes and the right filters.

用大望远度的滤色，你也可以看到那些气体或星云状物。

2.Researchers had known the cluster was encountering a gas cloud, because off striking nebulosity that envelopes the cluster?

研究员知道云就是气体云接触，由于冲击星云包裹了云？