A region of sky around the Orion Nebula. As well as the Orion Nebula and the stars within it, the Sword of Orion includes the open cluster NGC 1981, the diffuse nebula NGC 1977, and the double star Iota Orionis.
科学参考收录了60776条科技类词条，基本涵盖了常见科技类参考文献及英语词汇的翻译，是科学学习和研究的有利工具。