2025年9月2日
The Horsehead and Flame Nebulas
Image Credit & Copyright: Daniel Stern
Explanation: The Horsehead Nebula is one of the most famous nebulae on the sky. It is visible as the dark indentation to the orange emission nebula at the far right of the featured picture. The horse-head feature is dark because it is really an opaque dust cloud that lies in front of the bright emission nebula. Like clouds in Earth’s atmosphere, this cosmic cloud has assumed a recognizable shape by chance. After many thousands of years, the internal motions of the cloud will surely alter its appearance. The emission nebula‘s orange color is caused by electrons recombining with protons to form hydrogen atoms. Toward the lower left of the image is the Flame Nebula, an orange-tinged nebula that also contains intricate filaments of dark dust.
Tomorrow’s picture: star jet
马头星云与火焰星云
影像提供与版权: Daniel Stern
说明: 马头星云是天空中最著名的星云之一。在图片的最右侧，它是橙色发射星云中的一个黑暗凹陷。马头特征之所以显得黑暗，是因为它实际上是一片不透明的尘埃云，位于明亮的发射星云前方。就像地球大气层中的云一样，这片宇宙云偶然形成了一个可辨识的形状。经过数千年，云内的运动必然会改变其外观。发射星云的橙色是由电子与质子重组形成氢原子所致。在图像的左下方是火焰星云，这是一个略带橙色的星云，内含复杂的黑暗尘埃丝状结构。
明日的图片: star jet
