Space Weather and Earth's Aurora

Aurora are colorful lights in the nighttime sky primarily appearing in Earth's polar regions. But what causes them? The culprit behind aurora is our own Sun and the solar plasma that is ejected during a magnetic event like a flare or a coronal mass ejection. This plasma travels outward along with the solar wind and when it encounters Earth's magnetic field, it travels down the field lines that connect at the poles. Atoms in the plasma interact with atoms in Earth's upper atmosphere. This reaction produces the colorful lights we call aurora.