A rarely seen spectacle surprised residents and scientists of the Argentine Antarctic base Belgrano II in the early hours of this Tuesday: an aurora australis colored the sky of the region in different shades of green . The phenomenon was shared on the social networks of the Ministry of Defense of the Nation.
At the Belgrano II Joint Antarctic Base, Austral Auroras were observed, a phenomenon visible near the South Pole in the form of luminescence that appears in the extended night sky of our southernmost base.✨❄️ pic.twitter.com/GMAMqPOQ1h
— Ministry of Defense (@MindefArg) July 17, 2023
The auroras form at the poles of the planet, both in the northern and southern hemispheres, and their names vary depending on the location. The auroras australis, which can be seen in Argentina, Australia and New Zealand, receive this name because austral means "of the southern hemisphere."
The northern lights, on the other hand, can be seen in the northern hemisphere and that is why they are called this way, since borealis means "from the north."
Both phenomena are caused by charged particles, mainly electrons, that are emitted by the Sun and headed towards the Earth. When they interact with the Earth's magnetic field, they collide with atoms and molecules in the Earth's atmosphere, such as oxygen and nitrogen, and these explosions generate the emission of light in different colors.
"The solar storm particles are drifted towards the north or south given the characteristics of the Earth's magnetic field. The auroras borealis or australis can occur during the day or night, but they are seen at night because they have a luminosity faint and are better reflected in the dark," Bernardo Eylenstein, an engineer specializing in space weather, a researcher at the La Plata Observatory and part of the team that studies magnetic observations from the Trelew Observatory, explained to Télam.
Colors
Auroras can be green, blue, pink, fuchsia and orange, and this varies according to the composition of the gases in the atmosphere and the height at which they interact.
"It is a phenomenon that we commonly see in countries like Norway, Siberia or Canada because the North Pole is more populated than the South Pole. At the South Pole there are kilometers and kilometers of water between Antarctica and the continent, which is why the possibility of seeing them is lower," Eylenstein added.
In addition, these astronomical phenomena are more difficult to observe near the lights of cities and large metropolitan areas, due to so-called "light pollution."
In the southern hemisphere, the aurora australis can be seen on certain occasions in Ushuaia from the Argentine mainland, or from the city of Punta Arenas, in Chile. "The sun has an activity cycle that lasts 11 years. When that cycle is at its peak, that is when the phenomenon is greatest and can be seen from Ushuaia," explained the specialist.
The Belgrano II Base
The base where the images were taken was founded on February 5, 1979 to continue the scientific research that was being carried out at the old Belgrano Base, erected in 1955 and deactivated in 1980.
Today it constitutes the southernmost permanent base of the Argentine Republic, located 1,300 km from the South Pole, and is characterized by having four months of polar night and four months of day.
The same astronomical phenomenon, which ends up being a visual spectacle for those who can contemplate it, had been recorded in the same Antarctic region last May.
The probabilities of auroras, both boreal and southern, can be consulted on the NOAA (National Oceanic and Atmospheric Administration) website of the United States.
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