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What causes aurora?
Home » Astronomy » Observing with Your Eyes » What causes aurora?During vernal equinox, Earth’s magnetosphere (protective magnetic sheath) and magnetopause (the point of contact) are positioned correctly to interact with the Sun’s influencing interplanetary magnetic field (IMF)—and the plasma stream which flows past us as solar winds. This leaves the door wide open for one of the most awesome signs of Spring—aurora!
A coronal hole on the Sun’s surface increases the solar wind, as do events like flares or explosions called coronal mass ejections (CMEs). When the charged proton stream encounters Earth’s magnetic field, it ionizes the neutral oxygen and hydrogen in our atmosphere. The particles become excited and start to glow, just like an electric coil.
Aurora can happen at other times of the year as well— depending on the activity of the Sun. Check with wonderful sites like SpaceWeather.com or SOHO for solar activity. Be sure to visit the Geophysical Institute to sign up for aurora alerts and use their tools to help locate the position of the Earth’s auroral oval.
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