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

用镜和适度的滤色镜，你也可以看到那些气或星云状物。

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

研究员知道云团就是气云，于冲击星云包裹了云团？