Aurora is one of the most beautiful natural miracles of life on the planet with a global magnetic field, and spacecraft experts are getting closer to understanding one of the mysterious phenomena. You see, when the aurora illuminates the sky of the northern hemisphere above the Arctic, the same pattern should it erupts in the sky of the South Pole over Antarctica. But scientists noticed that the two did not match after comparing simultaneous images of northern and southern aurora in 2009.
Why would we expect them to be symmetrical?
How Auroras works
Aurora is a visible reminder of the epoch interaction between the solar magnetic field and the global magnetic field of Earth, called the magnetosphere. The sun is continually pumping large amounts of energized particles, such as protons, helium cores and traces of heavy ions. Together, these particles are released into the interplanetary space, drawing over the planets as a solar wind.
Other solar phenomena, such as ejection of coronal masses (or CMEs), emerge, spraying the magnetized clouds of these particles into space at high speed. Solar wind, solar flares and CMEs, as well as the effects on our planet, are commonly referred to as "space time". All this space time can have powerful effects on our planet – and our technology – when it meets the magnetosphere of our planet.
One such effect is a geomagnetic storm. It may happen if the magnetic field of the Sun interacts with the magnetosphere in some way by injecting the magnetosphere with the solar particles generated by the aurora. Aurores are developing when these particles accompany the magnetic field of our planet to the poles, rain through the atmosphere. Depending on what atmospheric gases are knocking, a beautiful light will appear.
Now, let's move and imagine those chart diagrams of bar magnet, with the north (N) and the south (S) poles printed at each end. The line of magnetic fields that are created will be followed by symmetrical loops connecting the north and south poles. This is an exaggerated streamlining of the planet's magnetic field, but physics is the same.
Then put the simplified magnetic field of our planet into a steady flow of sun particle. This current, called the solar wind, carries a solar magnetic field – known as an interplanetary magnetic field (or IMF) – creating pressure on the planet's magnetosphere by wiping it back. The daily side of our magnetosphere will be squeezed, while the night side of the magnetosphere will be elongated, such as stretched water droplets. If the solar wind was stable, there would not have been much to do; the particle current flows evenly across Earth's magnetosphere. However, we know that space time is all but stable.
As the sun turns, it drains solar winds of different speeds across our local space, and eruptions such as rockets and CMEs can create dramatic and dynamic changes in the interstellar space. If the magnetic conditions are fine, the Sun can throw the bladder of magnetized particles on Earth that will be injected into the layers of magnetosphere (imagining the layers of magnetosphere like the skin layers of the arch is not far from its actual structure). These particles then return to the magnetosphere (called magnetotail) where they are stored until the magnetotail passes through reconnection events, releasing the pressure and forcing the stored solar particles to flow along the magnetic field line into Earth's atmosphere. Magnetic reconnection is a phenomenon where magnetic fields are forced together, elastic, then re-coupled, releasing energy, together with massive waves of particles.
When all the same, and recalling the simple magnetic field diagram described above, the line of fields leading to the north and south poles of the Earth should look the same, and equal amounts of particles should fall in identical samples on the Arctic and Antarctic. And there are two new and complementary studies, published in the journal Geophysical Research: Space Physics and Journal Annales Geophysicae.
In 2009, spacecraft experts compared aurora eruption patterns during a geomagnetic storm. What they saw was confusing; the created patterns were in different locations and had different shapes than anticipated. At that time, it was assumed that this asymmetry was caused by the complexity of the reconnection event in the magnetotight, by sending different amounts of charged particles to the north and south poles, thus creating mismatch. However, these new studies show that asymmetry can actually be caused by the orientation of the IMF embedded in the sun's wind power, which for the first time meets the magnetosphere of our planet – something researchers call "asymmetric geospasms".
Confused? The American Geophysical Union has produced an excellent video explaining the following:
We can imagine the sun's magnetic field as a series of randomly-oriented rows, and washing over the Earth like shallow waves would be washed over the pebble beach. If they have a North-South magnetic orientation that matches the North-South magnetosphere orientation, they will connect to Earth's magnetic field and move back, merging with magnetotail together with the solar windparts they contain. In this case, the magnetotail will look symmetrical, and each generated aurora will also be symmetrical. Samples matched!
But what if the Sun's magnetic field is oriented east-west in relation to the North-South ground? According to these new research, this can cause magnetotail to become involved and asymmetric. As you probably can guess, it will affect the aurora that is produced by casting solar particles in an asymmetric pattern and creating asymmetric aurora. Forms do not match!
Over time, as more and more energy is released through reconnection into magnetotool, it will turn off and these aurora slowly return to its symmetrical shape. This is the opposite. Experts for space time once assumed it was once an asymmetry induced using a magnetic reset. In reality, it seems that re-coupling releases magnetic pressure to restore auroras in symmetry.