< p >你看到一位年长的飞机航迹云及其阴影。你也可以看到一些新的飞机,甚至一些年长的人。< / p > < p >尾迹不一定是连续的。例如,航迹云出现在下图水平似乎神奇地出现在图像的左端。< / p > < p > < img src = " https://web.archive.org/web/20150913071323if_/http: / / science-edu.larc.nasa.gov /专科学校/图片/ contrail5.jpg”alt = "形象的轨迹似乎突然在半夜天空”> < / p > < p >你看到在你的形象,但在这种情况下的轨迹问题似乎是垂直的。航迹云停止约1/3的图片。鉴于轨迹变得厚随着高度的增加,变得非常分散顶部附近,我怀疑航迹云停在哪里最年轻的航迹云的一部分。这意味着飞机飞离你的位置(即。图中,向地平线可见)。航迹云停在这一点上,因为飞机进入干燥的地区,稳定的空气。航迹云的持续秒到几个小时,这取决于当地的大气状况。< / p > < p >航迹云下面的黑带呢?航迹云体积阴影。 You were in just the right place to see it. Notice that while the contrail is twisted and not quite straight, that dark band is straight. If you look closely, you can see that it doesn't end at the horizon. It appears to extend into the water. It's a shadow, a volumetric shadow to be precise. The next two links are to images that show exactly this effect. These images appear to be copyrighted, so I'm going to leave them as links rather than embed them.
Link to image portraying a jet chasing it's volumetric shadow
Link to another image of a contrail and its volumetric shadow
Finally, this is a very striking example of the volumetric shadow from a contrail, in this case the launch of STS-98. This image is from Wikipedia, so it's fair use. In other images (you can search for them) taken from other angles, the shadow isn't nearly as striking, sometimes even non-existent.
