Particles discharged from the sun travel 93 million miles (around 150 million km) toward Earth before they are drawn irresistibly toward the magnetic north and south poles. As the particles pass through the Earth’s magnetic shield, they mingle with atoms and molecules of oxygen, nitrogen and other elements that result in the dazzling display of lights in the sky. … Typically, when the particles collide with oxygen, yellow and green are produced. Interactions with nitrogen produce red, violet, and occasionally blue colors. The type of collision also makes a difference to the colors that appear in the sky: atomic nitrogen causes blue displays, while molecular nitrogen results in purple. The colors are also affected by altitude. The green lights typically in areas appear up to 150 miles (241 km) high, red above 150 miles; blue usually appears at up to 60 miles (96.5 km); and purple and violet above 60 miles. These lights may manifest as a static band of light, or, when the solar flares are particularly strong, as a dancing curtain of ever-changing color.