Space launches, and more specifically morning space launches, are causing spectacular bright clouds to appear in new areas, according to recent research published in the journal Earth and Space Science.
About 80 kilometers The highest clouds in the Earth’s atmosphere float above the ground. calls clouds noctilucentesmesospheric or polar mesospheric, these aggregations of crystallized water vapor are high enough to reflect sunlight, even after the Sun has set or even before it has risen.
Due to their position in the upper atmosphere, when present at the right time, noctilucent (meaning “glow at night”) clouds shine with an otherworldly brilliance. They can make the sky at dusk or dawn resemble the surface of the ocean on a bright day: ripples of silvery light between patches of darkness.
“You see them from 30 minutes to an hour and a half after sunset or before sunrise,” he said. Cora Randallan atmospheric scientist at the University of Colorado, Boulder, and one of the researchers on the new study, on a video call with Gizmodo. “And that’s because they’re very wispy, they’re very thin clouds. you can only see hers when the sunlight scatters on its and it’s dark where you’re standing.”
LEmissions from rocket launches, which pump cloud fuel (i.e., water vapor) directly into the mesosphere, are probably doing make these unique formations more common. Launches taking place at the Kennedy Space Center in Cape Canaveral, Florida, could be correlated with the formation of noctilucent clouds thousands of miles away and days later.
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Noctilucent clouds are generally invisible because they most commonly form over the poles and occur during each hemisphere’s respective summer; the season of noctilucent is from mid-May to August in the north and from mid-November to February in the south. The poles never darken during the summer, so noctilucent clouds tend to be blotted out by the ever-present sunlight.
But in recent decades, more noctilucent clouds have been observed in the so-called “mid-latitudes,” far from the poles, as far south as California and Colorado. “We had noticed that they were getting brighter and more frequent basically over the last 50 years or so,” Randall said. Scientists hypothesized that climate change or solar cycles were to blame.
For the new study, Randall and his co-investigators amassed cloud data between 2007 and 2021, collected by NASA’s Aeronomy of Ice in the Mesosphere (AIM) satellite. They focused their attention on northern latitudes between 56 and 60 degrees (a narrow band bordered by Bergen, Norway, to the north, and Edinburgh, Scotland, to the south), since the mid-latitude data were more reliable. What they found was that the clouds did not seem to follow any apparent trend.
Instead, they noted that mid-latitude noctilucent clouds are super variable, showing up a lot at some times but not at others. Surprisingly, that year-to-year variability strongly tracks the frequency of morning rocket launches, according to data from NASA’s Aeronomy of Ice in the Mesosphere (AIM) satellite.
The researchers also observed that, in the morning, atmospheric winds rapidly carried particles in the mesosphere poleward, which aligned with the observed relationship between rockets ynubes noctilucentes. Theory says that the water vapor from the emissions of rocket launch is blown north by winds at areas of the upper atmosphere that are cool enough for bright clouds to form.
Los case studies Earlier studies have linked noctilucent clouds to emissions from the space shuttle launch. However, this is the first research to show that even much smaller rockets seem to have an effect. “The shuttle, of course, is huge compared to some of these other transport vehicles,” said Michael Stevens, an astrophysicist at the Naval Research Laboratory and co-author of the recent paper. “Sothe fact that all the smaller vehicles are contributing, and not only contributing, but in a way driving variability from year to year, It was kind of a surprise. We didn’t expect that,” she said.
Though it’s probably not just the rockets. Other factors are likely to continue to influence the appearance of noctilucent clouds. Climate change, Randall specified, almost certainly continues to play a role, even if the data set she and her colleagues analyzed didn’t pick up a clear signal. “There is no doubt in my mind that anthropogenic activities are affecting the clouds. It’s really more of a question of to what extent quantitatively,” she explained.
Interestingly, it is thought that there is a relationship between volcanic eruptions and mesospheric clouds for more than a century. The first known recorded case of a noctilucent cloud sighting was in 1885, two years later of the Krakatoa eruption.
But having a clearer picture of the influence of rocket launches could offer a clearer picture of all the ways we humans are changing our planet. Besides being beautifulTo the eye, noctilucent clouds don’t have much of a known impact here on Earth. Instead, its importance is as a potential indicator of man-made change.
The mesosphere and the clouds that appear within it are very sensitive to small changes. If we better understand the impact of, say, rockets, we can use that knowledge to accurately assess the effects of larger atmospheric disturbances, such as massive greenhouse gas emissions, both Randall and Stevens said.
Noctilucent cloud research is also, in essence, a basic expression of human curiosity. “The fact that they have become more and more frequent at the end of the 20th century and in the 21st century has aroused the interest of many scientists. We would like to know why this is happening,” Stevens said. For decades, it has been a mystery. Now, it’s a little less than one. If you look up at the sky at dusk or dawn and see a sea of bright sky, you know that a rocket could have formed the clouds.