For a long time, those of us who think of ourselves as reality-based have snickered at the conspiracy theorists who argue that contrails–those wispy streams of ice and pollution particles in the sky left behind by jet aircraft–actually are signs of a clandestine government effort to modify the weather.

But now, as it turns out, maybe we shouldn’t have been quite so dismissive. While there’s still no evidence that contrails are part of an insidious cabal, a new study published in International Journal of Climatology and detailed in this press release, reveals that they actually can influence temperatures on the ground and local weather patterns.

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Pennsylvania State University geography professor Andrew M. Carleton and graduate student Jase Bernhardt studied April data from two weather stations, one in the South and the other in the Midwest, and also located contrails using satellite imagery. Then they compared the daily temperature at sites with contrails above them with similar data from places where there weren’t any of the  man-made clouds in the sky. Otherwise, the sites were basically similar in terms of land use, cover, soil moisture and air-mass conditions.

The researchers found that contrails somehow depress the difference between daytime and nighttime temperatures, typically decreasing the maximum and raising the minimum. In the South, the reduction in the temperature range was 6 degrees Fahrenheit, while in the Midwest it amounted to five degrees.

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Oddly, the research has a connection to another focal point of conspiracy theorists–the 9-11 attacks. A previous study done in the three days following the even, when commercial jets were grounded, suggested that the absence of contrails had an effect upon weather. But it took the longer recent study to show that the effect could be observed over a longer period as well.

All in all, this revelation about contrails may even compel us to reconsider other possibilities, such as the existence of the chupacabra, and whether the top-secret Area 51 test range in Nevada is actually a hospitality center for extraterrestrials.