什么是化学痕迹?它们危险吗?

什么是化学痕迹?它们危险吗?

The persistent high-altitude contrails are more than stripes in the stratosphere. They are the stuff of conspiracy theories on par with Area 51, the Roswell UFO crash and who shot JFK.

持续的高空尾迹不仅仅是平流层的条纹。这些都是阴谋论的内容，与51区、罗斯韦尔UFO坠毁事件和刺杀肯尼迪事件一样。

The trails coming out of planes are harmless and normal, say scientists. (Photo: Vaclav Volrab/Shutterstock)

The chemtrail conspiracy theory claims that some contrails are chemical, biological or otherwise toxic elements sprayed at high altitudes by government agencies — of some sort — for the purpose of — well, something not good.

“化学痕迹阴谋论”声称，一些飞机尾迹是政府机构在高空喷洒的化学、生物或其他有毒物质，其目的是——嗯，是不好的。

Normal jet airliner exhaust contrails quickly dissipate, the conspiracy theory holds. Chemtrails — which are loaded with toxic heavy metals and heaven knows what else — linger in the sky for hours.

阴谋论认为，普通喷气式飞机的尾气尾迹会很快消散。含有有毒重金属和天知道还有什么其他物质的化学物质会在空中停留数小时。

The theory has no scientific basis, writes Grant Petty, a professor of atmospheric science and the University of Wisconsin-Madison.

威斯康辛大学麦迪逊分校的大气科学教授格兰特•佩蒂写道，这一理论没有科学依据。

“The lifetime and behavior of contrails depend on the environmental conditions in which they form,” Petty writes. “Growing contrails result when the humidity at high altitudes is at or above the saturation point with respect to ice. So when condensation is injected in the atmosphere at those altitudes, the microscopic particles of ice don’t simply evaporate, they persist and even grow, and they are spread by the winds into broader patches of cirrus cloud.”

佩蒂写道:“尾迹的寿命和行为取决于它们形成的环境条件。”“当高海拔地区的湿度达到或超过冰的饱和点时，就会产生越来越多的尾迹。因此，当这些高度的大气中注入冷凝物时，微小的冰粒不仅会蒸发，还会持续存在，甚至会增长，它们会被风吹散成更大范围的卷云。”

If persistent contrails are more common, Petty suggests, it is because there is more high-altitude airliner traffic and the stratospheric humidity is higher because of the moisture left by the contrails of all that traffic.

佩蒂认为，如果持续的飞机尾迹更常见，那是因为高空航班的流量更多，而平流层的湿度也更高，因为飞机尾迹所留下的水分。

The researchers were also shown four images that are often identified as chemtrails. All of them said they were just ordinary contrails, and they gave peer-reviewed citations to support their claims.

研究人员还看到了四幅通常被认为是化学痕迹的图像。他们都说这些只是普通的轨迹，并给出了经过同行评审的引文来支持他们的说法。

“We wanted to establish a scientific record on the topic of secret atmospheric spraying programs for the benefit of those in the public who haven't made up their minds," said study co-author Steven Davis of University of California Irvine, in a statement. "The experts we surveyed resoundingly rejected contrail photographs and test results as evidence of a large-scale atmospheric conspiracy."

加州大学欧文分校的史蒂文·戴维斯是这项研究的共同作者，他在一份声明中说:“我们想建立一个关于秘密大气喷洒计划的科学记录，以造福那些还没有下定决心的公众。”“我们调查的专家成功地驳斥了航迹照片和测试结果，认为它们是大规模大气阴谋的证据。”

The researchers say the goal of their study isn't to try to change the minds of those convinced chemtrails exist "these individuals usually only reject counter-evidence as further proof of their theories." Instead, they say they just wanted to offer objective science for a basis of discussion.

研究人员表示，他们的研究目的并不是试图改变那些坚信化学实验存在的人的想法，“这些人通常只是拒绝将反证据作为他们理论的进一步证据。”相反，他们说他们只是想提供客观科学作为讨论的基础。