20世纪70年代的反思
(原标题: Reflections on the 1970s)
2023-02-02
浏览次数: 13
20世纪70年代有时会被天文学家忽略。例如，猎户座中这组美丽的反射星云——NGC 1977、NGC 1975和NGC 1973——通常被忽视，因为附近的恒星托儿所（更出名的是猎户座星云）发出了大量的光芒。这些反射星云沿着猎户座的剑状星云被发现，就在明亮的猎户座星云复群的北部，它们也与大约1500光年远的猎户座巨大的分子云有关，但主要是星际尘埃反射炽热年轻恒星光线的蓝色特征。在这张清晰的彩色图像中，猎户座星云的一部分出现在图像中心的反射星云群的底部边缘。NGC 1977横跨中心下方的区域，与NGC 1973（右上）和NGC 1975（左上）隔着暗色区域，其中点缀着氢原子发出的微弱红色辐射。这些黑暗的区域合在一起，形成了一个流行的绰号——跑人星云。根据猎户座尘埃分子云的估计距离，这个奔跑的人大约有15光年宽。
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The 1970s are sometimes ignored by astronomers. For example, this beautiful grouping of reflection nebulae in Orion - NGC 1977, NGC 1975, and NGC 1973 - is usually overlooked in favor of the substantial glow from the nearby stellar nursery better known as the Orion Nebula. Found along Orion's sword just north of the bright Orion Nebula complex, these reflection nebulae are also associated with Orion's giant molecular cloud about 1,500 light-years away, but are dominated by the characteristic blue color of interstellar dust reflecting light from hot young stars. In this sharp color image a portion of the Orion Nebula appears along the bottom border with the cluster of reflection nebulae at picture center. NGC 1977 stretches across the field just below center, separated from NGC 1973 (above right) and NGC 1975 (above left) by dark regions laced with faint red emission from hydrogen atoms. Taken together, the dark regions suggest the popular moniker, the Running Man Nebula. At the estimated distance of Orion's dusty molecular cloud this running man would be about 15 light-years across.
© Daniel Stern