Researchers may have discovered the earliest known record of an aurora. The reference to a "five-colored light" in the northern sky is nestled in the scrolls of the ancient Bamboo Annals, a chronicle of Chinese history written in the 4th century BCE. The event probably occurred around 1000 BCE during the Zhou Dynasty, per LiveScience. Although the Bamboo Annals have already been studied in depth, the aurora reference was previously mistranslated as referring to a comet, according to a research team led by scientist Hisashi Hayakawa of Japan’s Nagoya University.
Until now, the earliest known reference to an aurora appeared on cuneiform tablets from ancient Assyria, about 300 years after the Chinese observation. Also known as the northern lights, the colorful phenomena are usually associated with northern latitudes. Stargazers today would have little if any hope of observing aurora at mid-level latitudes of China; However, as LiveScience explains, 3000 years ago, "Earth's north magnetic pole inclined toward the Eurasian continents, at about 15 degrees closer to central China than it does today." That difference means ancient people as far south as Beijing—and on the land that is now New York City—could certainly have witnessed spectacular auroral events.
NASA says the light shows are a result of disturbances in Earth’s magnetic field caused by solar flares and coronal ejections from the sun, a "living, breathing ball of gas." While Earth's atmosphere shields the planet from most solar particles, larger disturbances can create magnetic storms, causing atmospheric elements to glow; oxygen creates a red and green effects, while nitrogen is purple and blue. According to Hayakawa and fellow researchers, studying ancient auroras is not simply a matter of historical trivia; such findings are useful for helping scientists "model long-term patterns of space weather and solar activity." (Read more aurora borealis stories.)