Aurora is ranked as one of the most beautiful natural wonders of a planet on a global magnetic field, and space weather experts are getting closer to understanding one of the mysteries of the phenomenon. You see, when an aurora illuminates the sky in the North Peninsula through the Arctic, the same pattern should erupts into the sky in the southern hemisphere above the Antarctic. But scientists have noticed that the two did not coincide after comparing the simultaneous images of the northern and southern aurors in 2009.
Why would they expect them to be symmetrical in the first place?
How Aurors work
The aurora is a visible reminder of the epic interaction between the magnetic field of the sun and the global magnetic field on Earth, aka magnetosphere. The sun constantly pumps huge quantities of energy particles, such as protons, helium cores and traces of heavy ions. Together, these particles are released into the interplanetary space, washed over planets like a sunny wind.
Other solar phenomena, such as coronal mass ejections (or CMEs), erupt, exploding magnetized clouds of these particles in space at high speed. The solar wind, solar missiles and CME, as well as the effects they have on our planet, are collectively known as "space time". Complete this space time can have strong effects on our planet – and our technology – after meeting the magnetosphere on our planet.
One such effect is a geomagnetic storm. This can happen if the magnetic field of the sun communicates with the magnetosphere in a certain way by injecting the magnetosphere with solar particles that create an aurora. Aurora develops when these particles follow the magnetic field of our planet on the columns, raining through the atmosphere. Depending on what atmospheric gases struck, a nice colorful lighting will appear.
Now, let's retreat and imagine these bar magnetics diagrams, with North (N) and South (S) poles printed at each end. The lines of the magnetic field they create will reveal the symmetrical loops connecting the north and south columns. This is excessive reproduction of the magnetic field of our planet, but physics is the same.
Next, let's put the simplified magnetic field on our planet in a constant stream of particles from the sun. This stream, i.e. the solar wind carries the solar magnetic field – known as the interplanetary magnetic field (or the IMF) – creating pressure on the magnetosphere of our planet, keeping it back. The side of our magnetosphere will be compressed, while the night side of the magnetosphere becomes elongated, such as the stretched drop of water. If the solar wind is stable, there will not be much to happen; the inflow of particles would flow unevenly over the magnetosphere on Earth. However, we know that the time of the universe is something but stable.
While the sun is rotating, washes the winds at different speeds over our local space neighborhood, and eruptions like rockets and CME can create very dramatic and dynamic changes in the interplanetary space. If the magnetic conditions are right, the sun can throw a bubble of magnetized particles on the Earth, which will be injected into the layers of the magnetosphere (imagining the layers of the magnetosphere as layers of garlic skin is not far from its true structure). These particles are then returned to the tail of the magnetosphere (appropriately referred to as the "magnet"), where they are stored while the magnet does not pass through the re-connection events, releasing the pressure and forcing the stored solar particles to flow along the lines of the magnetic field to the Earth's atmosphere. Magnetic relaying is a phenomenon in which the magnetic fields are forced together, attached as resilient, then re-connected, releasing energy, together with large abrupt particles.
All things are equal, and remembering our simple bar-magnet diagram described earlier, the field lines leading to the North and South columns on Earth should look the same, and equal amounts of particles should fall in identical patterns over the Arctic and Antarctic. And this is where two new and complementary studies come in, published in the Journal of Geophysical Research: Space Physics and Annales Geophysicae.
In 2009, space weather experts compared aurora models that broke out during a geomagnetic storm. What they saw was confusing; the templates created were in different locations and had different forms than predicted. At that time they assumed that this asymmetry was caused by the complexity of re-connection events in the magnetotal, sending different amounts of charged particles to the North and South columns, thereby creating disagreement. However, these new studies show that asymmetry can actually be caused by the orientation of the IMF embedded in the currents of the solar wind first encountered by the magnetosphere of our planet – something that the researchers call "asymmetric geospatiality".
Confused? The American Geophysical Union produced a great video explaining this:
We can imagine the magnetic field of the sun as a series of randomly oriented lines, washing over the Earth, like shallow waves, to wash through stones on the beach. If they have a north-south magnetic orientation that corresponds to the north-south magnetosphere orientation, they will be connected to the Earth's magnetic field and will move backward, merging with the magnetotal along with the solar wind particles they contain. In this case, the magnet will appear symmetrically, and all generated aurors will be symmetrical. Templates are the same!
But what if the magnetic field of the sun is oriented east-west relative to the north-south field of the Earth? According to these new studies, this can cause the magnet to become distorted and asymmetrically. As you can probably guess, this will have an effect on the produced aurors, which will direct the sunspots into an asymmetric pattern and create asymmetric aurors. Templates do not match!
Over time, since more and more energy is released by re-connecting to the magnet, it will spread and these airs will slowly return to their symmetrical form. This is counterintuitive. Spaceflight experts once assumed that asymmetry was once caused with magnetic re-connection. In reality, it seems that re-linking releases magnetic pressure to restore symmetry sympathizers.