In aurora emission, which description correctly matches the sequence of events?

In aurora emission, which description correctly matches the sequence of events?

• A. Ions capture electrons, emitting gamma rays
• B. Solar wind creates ions, after that ions capture electrons, releasing light
• C. Ions capture electrons, emitting X-rays
• D. Ions capture electrons, then solar wind creates ions

Answer: (B)

The event sequence tested here starts with energy from the Sun being carried into Earth’s near-space environment by the solar wind, which creates ions in the upper atmosphere. Those ions then capture electrons (recombine), and as the resulting excited states settle back down, photons are emitted. This produces the observable light of the aurora. So the description that solar wind provides the energy to form ions, followed by those ions capturing electrons and releasing light, matches what we see: light in the visible range from atmospheric gases like oxygen and nitrogen as they relax after being energized. Gamma rays or X-rays would require much higher energies than typical auroral processes, so those alternatives don’t fit the usual auroral emission.

The event sequence tested here starts with energy from the Sun being carried into Earth’s near-space environment by the solar wind, which creates ions in the upper atmosphere. Those ions then capture electrons (recombine), and as the resulting excited states settle back down, photons are emitted. This produces the observable light of the aurora.

So the description that solar wind provides the energy to form ions, followed by those ions capturing electrons and releasing light, matches what we see: light in the visible range from atmospheric gases like oxygen and nitrogen as they relax after being energized. Gamma rays or X-rays would require much higher energies than typical auroral processes, so those alternatives don’t fit the usual auroral emission.