What physical requirement must an oxygen atom meet at higher altitudes to produce the red auroral color?
Answer
It must remain in its excited state for a relatively long time (about 100 milliseconds)
For oxygen to emit red light, the atom needs a relatively quiet transition window, requiring it to remain excited for about 100 milliseconds before emitting a photon, rather than losing energy through collisional heat.

#Videos
What causes the Northern Lights?
Related Questions
What is the ultimate driver causing the stunning light displays near Earth's poles?What charged particles primarily constitute the solar wind ejected from the Sun?What structure forms a protective bubble around Earth, deflecting the majority of incoming solar wind particles?What feature of the magnetosphere guides solar wind particles toward the polar regions?Which two gases are primarily responsible for generating the visible light when struck by solar particles?When an excited atmospheric atom relaxes, what particle is emitted to create visible light?What is the most common auroral color observed by the human eye, and which gas is responsible for it?What is the typical altitude range, in miles, where auroral collisions occur?During very active solar storms, what color light is usually observed resulting from the excitation of nitrogen molecules?How do the auroral ovals generally behave during periods of low solar activity?What physical requirement must an oxygen atom meet at higher altitudes to produce the red auroral color?