Two blue orbs of light hanging mysteriously in the Earth's atmosphere that were photographed by an astronaut aboard the International Space Station (ISS) have been shared by NASA's Earth Observatory.
The picture, which shows Earth at night as the ISS passes over Southeast Asia, also contains the two white-blue blobs of light: one over the Gulf of Thailand, and the other far on the horizon near the South China Sea.
Despite their mystical appearance, these two blobs of light are actually the result of two separate phenomena: lightning and the moon.
According to the picture's annotations by the NASA Earth Observatory, the Gulf of Thailand light is experiencing a lightning storm. Usually, lightning storms are covered with clouds and therefore not visible from the ISS, but this strike was visible through a gap in the clouds.
"In this case you could see the lightning because there was a gap in the cloud top. In addition to the regular cloud-to-ground lightning, there are also lightning [strikes] which don't reach the ground," Tero Mielonen, a senior scientist at the Atmospheric Research Centre of Eastern Finland of the Finnish Meteorological Institute, told Newsweek.
"Most of them remain within the cloud, but sometimes they have visible channels that extend out into the air around the cloud (also above), but do not reach the ground."
The second blue blob visible in the picture is the light of the moon viewed through the Earth's atmosphere. The scattering effect of the atmosphere, which is also the reason that the daytime sky appears blue, has caused the moonlight to appear the same color as the electrical storm occurring below, according to LiveScience.
According to Mielonen, large thunderstorms can also produce other kinds of electrical phenomena called transient luminous events, appearing high in the atmosphere and visible from space.
"The most common ones are sprites, which can appear directly above active thunderstorms, and they tend to happen at the same time as cloud-to-ground lightning. They can extend up to 100 kilometers from the cloud top, but they are faint, so they are not easy to see by eye. Blue jets also emerge from the cloud top, and they form narrow cones which fan out and disappear around 50 kilometers altitude," Mielonen said.
"Then there are elves, which are rapidly expanding disk-shaped regions of glowing that can be up to 500 kilometers across. They can appear above areas of cloud-to-ground lightning, but they only last less than a thousandth of a second."
Red sprites, another rare form of red lightning, were recently photographed at the European Southern Observatory's La Silla Observatory in Chile's Atacama Desert. These are caused by large-scale, low-temperature electrical discharges above thunderclouds, between 30 and 55 miles above the ground.
"A single lightning strike can contain from 100 million to 1 billion volts and billions of watts of energy," Mielonen said. "There are approximately 40 000 thunderstorms and 3 million flashes around the globe every day."
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Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
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Jess Thomson is a Newsweek Science Reporter based in London UK. Her focus is reporting on science, technology and healthcare. ... Read more
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