Aurora pillar dance

Polar auroras, such as dancing pillars, are atmospheric phenomena caused by the interaction of solar wind with Earth's magnetic field, forming colorful curtains in the night sky at high latitudes.

About this subject

Aurora borealis and aurora australis are luminous displays occurring in polar regions, typically between 65° and 72° latitude. The phenomenon happens when charged particles from the solar wind collide with gases in the upper atmosphere, exciting oxygen and nitrogen molecules. This excitation releases visible light in green, red, and purple, forming shapes like curtains, arcs, and occasionally vertical pillars that appear to dance in the sky. The pillar shape occurs when the magnetic field line is aligned with the observer's line of sight, creating elongated beams.

Aurora intensity and frequency vary with the 11-year solar cycle, being most active during solar maximum. Popular viewing destinations include Tromsø in Norway, Yellowknife in Canada, and Antarctica. Auroras are extremely rare in Brazil, but intense geomagnetic storms in 1859 and 2024 produced reddish displays at low latitudes. Culturally, auroras inspire myths: Inuit legends depict them as spirits of the dead playing; Norse mythology saw them as reflections from Valkyrie shields.

Beyond aesthetics, auroras have scientific value. They help study Earth's magnetosphere and space weather, which can affect satellites and power grids. The term 'aurora' was coined by Galileo Galilei in 1619, honoring the Roman goddess of dawn, and 'borealis' refers to the north wind. Although the image is a studio still life, its title evokes the dynamic beauty of these natural light pillars.

Frequently Asked Questions

What causes the different colors in auroras?

Colors depend on the type of gas and altitude. Oxygen emits green light (up to 240 km) and red (above 240 km). Nitrogen produces blue and purple. Green is the most common.

Can auroras be seen in Brazil?

Yes, but extremely rare. During very strong geomagnetic storms, such as in May 2024, reddish auroras were recorded in southern and southeastern states, though brief and faint.

What is the best time to see auroras?

Between September and March in the northern hemisphere (aurora borealis) and March to September in the southern hemisphere (aurora australis). Dark, clear skies and high solar activity are essential.