1. 河外星系：external furnace ==> 外置炉膛,炉外燃烧室 | external galaxy ==> 河外星系 | external gas injection ==> 外部注气
external galaxy的意思
1. The thick disk of the Milky Way Galaxy is of great importance to study structure and evolution of our Galaxy and external galaxies as well.
银河系厚盘的发现，对于研究银河系以至星系的结构和演化具有重要意义。
2. Scrutiny of variable stars in M81 (aka NGC 3031) has yielded one of the best determined distances for an external galaxy -- 11.8 million light-years.
科学家对M81 的变星进行的探测活动，最终使他们确定了一个银河外星系距地球最准确的距离之一——118亿光年。
3. Embody in modern culture: And the image, map, international indicate (water-saving sign, energy conservation sign etc.) a network, the photograph, the common sense living in the homeland, humorous flash photograph, q expression, physics circuit diagram, chemistry experiment pursue the science personage, national treasure, the celebrity well-known saying, the fine arts work, the external galaxy, modern military affairs weapon, means of transportation, life prompt, scientific knowledge, propagate law, advertisement etc..
还体现在现代文化：网络图像、地图、国际标志，科学人物、国宝图片、国内生活常识、幽默flash图片、q表情、物理线路图、化学实验图、名人名言、美术作品、河外星系、现代军事武器、交通工具、生活提示、科学知识，和宣传法律、广告等。
4. As a galaxy of the most courageous of the three heroes, you have to eliminate external threats.
作为银河系最勇敢的3名英雄之一，你必须消灭外来的威胁。