a) Composite image of the jellyfish sprite (red). The slit projection is superimposed as a yellow line. b) Average (stacked) video frames of the bright background in the 10 s before and after the sprite time show a banded structure that we interpret as likely caused by modulation of the hydroxyl luminous air layer ( OH*) by gravity waves. Credit: Nature Communications (2023). DOI: 10.1038/s41467-023-42892-1
A team of astronomers from the Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía and Universitat Politécnica de Catalunya has captured spectroscopy data of a mesospheric green ghost for the first time.
In their article published in the journal Natural communications, the group describes their years-long effort to capture data that would explain the nature of atmospheric green ghosts and how they ultimately succeeded in achieving their goal. The editors of Nature also published a Research Update summary of the work carried out by the team.
Previous research has shown that during some thunderstorms, atmospheric phenomena called sprites appear above normal types of lightning. Previous research has also shown that sprites are electrical discharges, usually displayed as red-orange lightning in various forms, meaning it’s technically another type of lightning. They are known in the scientific community as transient light events (TLEs).
In 2019, a citizen scientist named Hank Schyma, while recording video of a TLE, discovered that he had also recorded a greenish glow at the top of a TLE. He posted his video to YouTube, where it caught the attention of professional sky watchers. Since then, amateur and professional videographers have managed to capture the “green ghosts”, as they are now called. Many had been captured on video before Schyma’s publication but had not been identified as anything new.
After speculation within the scientific community, the consensus was that the green ghosts were likely nothing more than excited oxygen atoms. Unconvinced, the team members of this new study set out to capture spectroscopic data of a green ghost, which would show which materials present in the atmosphere contributed to its creation.
Due to their rarity, it took researchers almost four years to achieve their goal. This happened on the night of September 21, 2019, as the team aimed their aircraft at a TLE over the Mediterranean Sea. And although the team was unable to capture photographic evidence of the green ghost, their equipment showed a glow in the green spectrum: it lasted for more than 500 milliseconds, much longer than a TLE.
They found traces of nickel, iron and nitrogen in addition to oxygen, suggesting that the green ghost resulted from the meteoric ablation of interplanetary dust particles moving at high speeds through the atmosphere.
More information:
María Passas-Varo et al, Spectroscopy of a mesospheric phantom reveals iron emissions, Natural communications (2023). DOI: 10.1038/s41467-023-42892-1
Where the “green ghost” lightning takes on its emerald hue, Nature (2023). DOI: 10.1038/d41586-023-03810-z
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Quote: Atmospheric green ghost spectroscopic data first captured (December 13, 2023) retrieved December 13, 2023 from
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