Dettagli
Scarica Docx
Leggi di più
Our precious planet manifests countless spectacular events every day. The Auroras or Northern and Southern Lights are such examples and are among the most majestic cosmic splendors ever witnessed. A few hours after the night falls – and when the occasion is right – translucent clouds of lime green, purple, and golden colors can brighten up the entire polar skies. These glowing lights dance and flow constantly in the shapes of curtains, arcs, and rivers. At one moment, they are hardly perceptible. At the next moment, they shine vividly, forming breathtaking celestial panoramas.Auroras have been a theme in human history for millennia. In 1619, Italian astronomer and physicist Galileo Galilei coined the term “Aurora Borealis” after the Roman goddess of the dawn. Long before him, the Auroras had inspired a diverse collection of myths, legends, and arts. For some, the lights carry particular spiritual relevance even today. In 1790, English natural philosopher and scientist Henry Cavendish developed a method of making quantifiable observations of the Aurora.According to modern science, all Auroras begin with solar activity. As this NASA video explains, several billion tonnes of plasma are hurled out from the sun when a solar storm occurs. “When the solar storm reaches our planet, something strange happens. An invisible shield, the Earth’s magnetic field, deflects the storm. The magnetic fields couple together and create a funnel for the gas streams down on the daylight side of the pole. This is the daylight Aurora. The magnetic fields stretch further back and couple together. The magnetic rubber band breaks, and the gas from the solar storm streams along the magnetic lines towards the poles on the night side. This is the nighttime Aurora.”The foundation of the current understanding of the Aurora was first laid at the beginning of the 20th century, thanks to Norwegian scientist Kristian Birkeland. He made this terrella experiments, a very famous experiment. His incredible discoveries have been forever immortalized on the Norwegian 200-kroner banknote.
