In 2018, new aurora-like discoveries swept the world. From 2015 to 2016, citizen scientists reported 30 cases of purple ribbons in the sky with green fence structures underneath. Now called “STEVE” (i.e. the enhanced speed of intense heat emission), this phenomenon is still new to scientists who are trying to understand all its details. What they know is that STEVE is not an ordinary aurora-some people think it is not an aurora at all-and new discoveries about the formation of stripes in the structure have allowed scientists to solve this problem even further.
“Usually in physics, we build understanding and then test extreme situations or test situations in different environments,” explains space scientist Elizabeth MacDonald at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. . “STEVE is different from the usual aurora, but it is made of light and driven by the aurora system. When these tiny pinstripes are discovered, we may be learning how to produce a fundamental new thing about green aurora.”
These “tiny little stripes” are very small dot-like features in STEVE’s green fence.In a new paper AGU progress, The researchers shared the latest findings in these areas. They believe that the fringes may be moving light spots-the light spots in the image have become longer due to camera blur. The tip of the stripes in one image will align with the end of the tail in the next image, which helps scientists make this speculation. However, there are still many questions to be answered-determining whether the green light is a point or a line is another clue to help scientists find the cause of the green light.
Joshua Semmert, a professor at Boston University and the first author of the paper, said: “I’m not sure about this phenomenon.” “You have other sequences that look like a tubular structure that persists between images. And it doesn’t seem to be a mobile point source, so we’re not sure yet.”
STEVE as a whole is still something that scientists are still trying to mark. Scientists tend to divide the optical features in the sky into two categories: airglow and aurora. When airglow occurs at night, the atoms in the atmosphere will recombine and release some of their stored energy in the form of light, resulting in bright colors. By studying the patterns of airglow, scientists can learn more about the atmosphere, the ionosphere. On the other hand, to be classified as aurora, light must be released by electron bombardment. These features are formed in different ways, but also different in appearance-airglow occurs throughout the earth, while aurora forms in a wide ring around the earth’s magnetic poles.
Semit said: “Generally speaking, Steve does not seem to fit any of these categories very well.” “The source of emissions comes from a mechanism that we don’t fully understand.”
The purple emission of STEVE may be the result of ions moving at supersonic speed. The green emission seems to be related to the vortex, as you can see in a river, its flow rate is slower than other surrounding water. The green features also move slower than the structures in the purple emission, and scientists speculate that they may be caused by space particles (charged particles and the brewing of a magnetic field called plasma) at these heights.
“We know that this kind of turbulence will happen. Some people’s entire career is based on studying turbulence in ionospheric plasma formed by very fast flows.” Semit said. “Evidence usually comes from radar measurements. We never have optical signals.” Semeter suggested that when it comes to the appearance of STEVE, the flow in these conditions is so extreme that we can actually see them in the atmosphere.
MacDonald said: “This article is the tip of the iceberg in the new area of these small parts of the picket fence. Some things we do in physics are trying to weaken our understanding,” MacDonald said. . “This article identifies the altitude range and some techniques that we can use to identify these features, and then we can better resolve them in other observations.”
In order to determine the altitude range and determine these characteristics, scientists extensively use photos and videos taken by citizen scientists.
MacDonald said: “Citizen scientists are the ones who have caught the attention of Steve’s phenomena. Their photos usually take longer than our traditional scientific observations.” “Citizen scientists don’t fall into the mode that scientists enter. The way they do things. It’s different. They can move the camera at will and make any exposure they want.” However, in order to make new discoveries about the points in STEVE, the photographer actually took a shorter exposure photo to capture the action.
In order to obtain these photos, citizen scientists spent several hours in the cold in the middle of the night, waiting for the aurora (or hopefully STEVE) to appear. Although the data can indicate whether aurora will appear, the STEVE indicator has not been identified. However, in any case, the Aurora Chaser will appear and take pictures.
Photographer and co-author of the paper Neil Zeller (Neil Zeller) said that he did not initially intend to become a citizen scientist. Zeller explained: “This is just for its beauty.” Zeller has been involved in the discovery of STEVE from the very beginning. He showed MacDonald a photo of STEVE that he had taken, triggering the first study of the phenomenon. He is now a co-author of the paper.
Zeller said when contributing to this research: “It’s an honor, it is true.” “I tend to take a step back from the scientists who are doing this work. I am there because of its beauty. And capture these phenomena in the sky.”
This article also makes use of another valuable citizen scientist contribution-a volunteer database of STEVE observations. Michael Hunnekuhl, another author of the paper, maintains the database and has contributed to STEVE’s discoveries in the past. Hunnekuhl noticed that the stripes in the photo were independent of the scientist who wrote the paper, so his detailed recording and triangulation techniques were crucial to this research.
Zeller and other citizen scientists plan to continue to take and examine these photos to capture the beauty of the Earth’s atmosphere. MacDonald, Semeter and other scientists will continue to study them to discover more about Information about this new phenomenon.
Steve on the fence
Courtesy of NASA’s Goddard Space Flight Center
Citation: Citizen scientists chasing the aurora help discover the new feature of STEVE (November 13, 2020), which will be available from https://phys.org/news/2020-11-aurora-chasing-citizen on November 13, 2020 -scientists-feature-steve search. html
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