Auroras

• Researchers have revealed global observations of auroras associated with carbon dioxide using satellites.

ABOUT AURORAS

• Auroras are caused by interaction of charged particles (electrons and protons) of solar wind with atoms of upper atmosphere i.e. ionosphere.
• In the Northern Hemisphere, the phenomenon is called the northern lights (aurora borealis), while in the Southern Hemisphere, it’s called the southern lights (aurora australis).
• The usually observed green and red auroras happen between 100 kilometres and 250 kilometres above the surface of the planet due to an excited state of atomic oxygen.

CO₂ AURORAS

• When charged particles crash into planet’s atmosphere, they interact with many different atoms and molecules including Carbon dioxide.
  • While the gas is known for acting as a greenhouse gas due to its presence in the lowest part of the atmosphere, trace parts of carbon dioxide also exist in the atmosphere at the edge of space.
• When CO₂ molecules about 90 km above Earth become excited during an aurora, they emit infrared radiation.
• This leads to more infrared radiation than is typically observed in the planet’s atmosphere.