SCIENCE LAB SPECIAL : SKY GHOSTS

 

Atmosphere Fireworks : Extraterrestrial metals may fuel ghosts in the sky :

In June 2019, scientists in Spain started to search the skies above the Mediterranean Sea for a ghost, a transient luminous event that appears briefly at high altitude.

'' Seeing a ghost is really difficult,'' said Maria Passas-Varo, a researcher at the Institute of  Astrophysics at Andalusia in Spain.

A few months later, they caught one with a specialized camera : a green spirit flickering at the crown of jellyfish-shaped maelstrom of fuchsia lightning 50 miles [ 80 kilometers ] above the sea.

In a study published in the journal Nature Communications, Dr. Passas-Vaso and her colleagues revealed that the ghost's pale emerald complexion came, in part, from excited oxygen, similar to the green glow of auroras.

But the main contributor was another element of iron. That was a surprise because the metal was ultimately being delivered from space.

''There are layers of metal that dance,'' in and above thunderstorms, Dr. Passas-Varo said.

'' The metallic traces are interesting, but I'll caution that this was only 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 ghosts are iron-fueled, he added, we need '' to see the results from multiple ghosts.'' [ Robin George Andrews ]