The wave-like greens weave and twist, with hints of pinks at their tips, dancing in the sky as an elegant and otherworldly celestial choreography. Sweeping and swaying, the lights then surge with a rhythmic energy that seems to echo the heartbeat of the universe.
“The green colours of the waves, like messages from a different world, filled me with awe. I felt so small at that spot of the North Pole. I felt so lonely despite the crowd. I felt a connection with the earth, the sun and the entire universe. It made me appreciate the beauty of the world and the vanity of life,” says Panayoti Bachkangi as the Greek doctor recalls his first encounter with the Northern Lights, also known as Aurora Borealis, in Tromso, Norway.
The formation of the awestruck Aurora begins with the interaction between the Earth’s magnetic field and particles from the sun.
Intense magnetic activity and high temperature on the surface of the sun continuously release charged electrical particles into space, forming the solar wind. When the solar wind reaches the earth, our planet’s magnetic field acts as a shield, deflecting most of these high-energy charged particles around the Earth. This creates a region around the earth called the magnetosphere.
As the solar wind particles arrive at the Earth’s magnetosphere, some are captured by the Earth’s magnetic field and guided towards the poles, creating a reservoir of particles. Over time, the magnetic field lines in the magnetosphere become stretched and distorted due to interactions with the solar wind, and eventually snap, releasing the accumulated charged solar particles into the Earth’s atmosphere. When they are released, they are funnelled down into the atmosphere around the magnetic poles, colliding with the atoms and molecules in the earth’s atmosphere, through a series of energy transfer activities, the excess energy stored in the earth’s particles finally releases energy as the light of the Aurora.
The stunning display of Aurora’s colours, including green, violet, pink, white, and blue, depends on the speed at which solar particles enter the atmosphere. Faster particles reach deeper towards the earth’s surface.
At heights of 200 kilometres and above, oxygen atoms emit red light. Since our eyes are not as sensitive to red light as cameras, the red colour may appear more vibrant in photographs than what we perceive with our naked eye. The dominant, most visible to the naked eye green light is emitted by oxygen atoms at around 100 kilometres in altitude. At lower altitudes, approximately 80 to 90 kilometres, nitrogen molecules emit blue and purplish-red light. In bright and intense Auroras, all colours can be present simultaneously in different parts of the sky.
Be it curtain-like, in bands, pen stretches or waves, the shape and movement of the Aurora are influenced by the solar wind’s speed and the changing magnetic field.
2024 anticipates the peak of the 11-year solar cycle, a period in which the Sun radiates an increased abundance of charged particles and energy. More intense, vivid and stunning Auroras might be seen at an increased frequency across the night sky.
The celestial dance of the lights, the “heavenly feast”, as the Norwegian poet Knut Hamsun described, may become an even more breathtaking spectacle, with senses captivated by the lights, hearts touched by the humbling vastness of the universe, and souls lost in the wonders of the cosmos.
