How is aurora created?

How is aurora created?

• A. Cosmic rays strike atmosphere generating light
• B. Sunlight reflecting off ice crystals
• C. Solar flares heat Earth's atmosphere causing glow
• D. Solar wind turns atoms into ions, then the ions capture electrons, releasing energy as light

Answer: (D)

Auroras come from energetic charged particles from the Sun that are guided by Earth’s magnetic field toward the polar regions. These solar wind particles collide with atoms and molecules in the upper atmosphere, exciting them or ionizing them. When excited atoms relax or ions capture electrons, energy is released as photons, producing the visible glow. The different colors come from which gases are involved and at what altitudes—the green and red hues mainly from oxygen, and other colors from nitrogen. The key idea is that the energy source is the solar wind’s charged particles, and the light results from their interactions with atmospheric atoms, not from sunlight reflecting off ice crystals or simply heating the air.

Auroras come from energetic charged particles from the Sun that are guided by Earth’s magnetic field toward the polar regions. These solar wind particles collide with atoms and molecules in the upper atmosphere, exciting them or ionizing them. When excited atoms relax or ions capture electrons, energy is released as photons, producing the visible glow. The different colors come from which gases are involved and at what altitudes—the green and red hues mainly from oxygen, and other colors from nitrogen. The key idea is that the energy source is the solar wind’s charged particles, and the light results from their interactions with atmospheric atoms, not from sunlight reflecting off ice crystals or simply heating the air.