An aurora australis, the southern version of the phenomenon, seen from the International Space Station in 2010.
Auroras paints the sky around the dust when the sun is particularly active, which shoots very charged particles in the Earth's atmosphere. Scientists once thought that the magnificent events were mirror images, but to their surprise, the screens in the north (aurora borealis) and south (aurora australis) do not exactly match.
Since scientists realized that these two celestial screens are not aligned, they have tried to solve why. Now, a team of researchers believes that he has found the reason – asymmetry in the magnetic tail of the Earth. But the strange thing is that asymmetry is caused by the exact inverse of what the scientists expected.
"The reason why it is exciting is that we have previously thought that system asymmetry enters the magnetosphere through a mechanism called tail reconnection," Anders Ohma, Ph.D. candidate at the University of Bergen in Norway and the main author of the new study , said in a statement published by the magazine. "What this article shows is that it is possible that it is the opposite". [Northern Lights Photos: The Amazing Auroras on Earth]
Everything is reduced to the magnetic tail of the Earth, which is created by the interactions between our planet and the sun. These interactions begin with the magnetic field of the Earth, which scientists believe emerges from the wombs that rotate through the core of the Earth and generate electrical charge. Magnetic fields: from refrigerators to planets, we create lines of invisible magnetic fields between the north and south poles that can govern the behavior of the material around them.
But the magnetic field of the Earth is not the only one there is, the sun also has one, which affects the constant flow of highly charged plasma particles that emit in all directions. The magnetic field embedded in this current, called the solar wind, interferes with the earth it produces, places it on the side of the Earth's light and makes it stretch towards the distant surface of the sun, in the form of a tail.
The magnetic field lines pass through the twisted field, and they are not fixed in place: they break and reform in dramatic events called reconnections. This phenomenon in the tail is what the scientists had thought could not attack the northern and southern Aurores. (It is the queue that matters for the aurora because this is the side of the magnetic field that is in the dark, and the auroras are only visible at night).
Instead of that, the team behind the current investigation realized that the magnetic field of the solar wind does not always align with accuracy with the Earth. When it is biased, it introduces an asymmetry between the north and south poles in the magnetic field of the Earth, which, in turn, causes the mismatch between the auroras of the north and the south.
In this way, the researchers collected simultaneous infrared observations far away from the lights of the north and the south and observed the degree of appearance of the two auroras. They then added data on reconnections to the magnetic tail of the Earth. But when they compared the two sets of measures, they saw exactly the opposite of what they had expected to see – instead of these dramatic reconnections increasing the aurora's asymmetry, the auroras once again coincided.
Understanding auroras is not vital, since auroras are just symptoms of how the sun affects the Earth through a set of phenomena called space time. But space weather can interfere with navigation and communication satellites and even network the electrical networks. And scientists are still trying to figure out exactly how space weather works and how to predict it better. Auroras are just the prettiest phenomenon to start cracking.
The research is described in an article published last month in the Journal of Geofhysical Research: Space Physics.