环状星云 meaning in English

ring nebula = annular nebula

Seyfert galaxies are energetic because they have a central black hole surrounded by a ring of gas
赛非星系能量巨大，因为在其中心有-一黑洞，黑洞周围则环绕着环状星云。
As matter is sucked from the ring into the hole , part of it is converted into energy , which is radiated into space
环状星云的物质在吸收到黑洞中去的过程中，一部分转化成了能量，而这一能量向宇宙空间辐射。
They would prefer the ring to behave less like a gas and more like a syrup - which is where the starbursts come in
他们比较喜欢的解释是环状星云的活动不大象气体活动，而更象糖浆的活动- -星群爆发正是在这种糖浆似的星云中生产的。
Theorists , however , have had trouble trying to establish how the matter in the ring loses enough of its orbital motion to fall into the hole in the first place
然而，理论工作者首先遇到的难题是无法确认环状星云的物质是如何偏离自己的轨道而掉进黑洞的。