gas cloud

基本解释

The green gas cloud is now essentially a delayed, optical echo of the dead quasar.
绿色的气体云通常被看做是泯灭后的类星体的余烬，能用肉眼观察到。
Waiting for a gas cloud to stumble into their vicinity isn't a very efficient means of hunting.
守株待兔地等待气体云闯入其领地可不是有效率的捕猎方式。
But it's also possible that Jupiter formed directly from a collapsing gas cloud, with no underlying planet to do the vacuuming.
但木星也有可能是从一团坍缩的气体云直接形成来的，不需要行星前体做吸引气体的过程。

One shows the remains of a dying star four thousand light years away which has thrown off a cloud of glowing hydrogen gas.

Only if alpha were a smidgen smaller when the light passed through the gas cloud could such a pattern have been produced.
ECONOMIST: Fundamental physics
But this gas cloud, because it is so far away, about 40, 000 light years is still seeing the quasar, though we are not.
NPR: What Makes Our Solar System Special?
And so, what we believe in this case happened is there used to be an extremely luminous quasar right next to this gas cloud.
NPR: What Makes Our Solar System Special?