Scientists identify ghost element in storm – 12/17/2023 – Science

In June 2019, scientists in Spain went in search of “ghosts” haunting the skies over the Mediterranean Sea. They had only been discovered in May of that year. What were? The only way to know was to register one of them.

But this would prove to be a very complex task. These “ghosts” are difficult to see with the naked eye and appear for an instant at a great distance from the ground.

“Seeing one of them is really difficult,” said María Passas-Varo, a researcher at the Institute of Astrophysics of Andalusia in Spain.

On September 21, 2019, however, they captured one with a specialized camera: a green spirit atop a jellyfish-shaped swirl of fuchsia-colored lightning 50 miles above the sea. And, after carefully untangling the various frequencies of light emitted by the ghost, scientists revealed its composition.

In a study published last Tuesday (12) in the journal Nature Communications, Passas-Varo and his colleagues revealed that the ghost’s emerald color is the result, in part, of oxygen, similar to the green glow of the auroras; nitrogen also plays a role.

The main culprit, however, was another element: iron. This came as a surprise because the metal was being delivered from space.

Better understanding ghosts and other lightning-like phenomena could help scientists interpret the chemistry and physics of Earth’s upper atmosphere.

“There are layers of metals that dance” within and above the storms, Passas-Varo said.

Ghosts are a type of transient luminous event (TLE) that were first described by scientists in 1989. TLEs can include blue jets, which shoot upward from storm clouds, as well as upper atmospheric lightning. dyed red that can have various shapes, such as carrots and jellyfish, and are known as sprite.

TLEs are like fireworks, according to Passas-Varo. And little is definitively known about them — especially ghosts, the first of which was observed over a sprite storm in Oklahoma in May 2019.

To capture their own ghost, the team aimed a spectrographic camera — which can use light to determine chemistry — high into the atmosphere from an observation post in Castellgalí, Spain. All they could do was wait for storms of sprites to appear, cross their fingers, and hope that at least one sprite was briefly decorated with a ghost, and that their camera was pointed in the right place.

Finally, they found one.

“It was a matter of luck,” said Passas-Varo.

This one was powered primarily by extraterrestrial iron, not atmospheric oxygen. The camera also revealed the presence of nickel, sodium and silicon. The complex chemical soup responsible for this ghost even added an orange tinge to its green glow.

All of these elements often come from micrometeoroids and dust particles from deep space that are almost constantly plunging into the upper atmosphere. This means that ghosts could effectively be seen as interplanetary visitors.

Still, some researchers said not too many conclusions should be drawn from the new paper’s findings.

“The metallic traces are interesting, but this was just a single event,” said Chris Vagasky, a lightning researcher at the University of Wisconsin-Madison who was not involved in the new work. To see if all the ghosts are iron-fueled hauntings, he said “it would be good to see results from multiple ghosts.”

He has no doubt that the search for ghosts and other TLEs will continue — in large part because these ghosts are intrinsically fascinating.

“It’s really amazing to think that there is so much more going on during a thunderstorm than what you can see or hear,” Vagasky said.