Wow! The northern lights over Vegas. In your News item (and thanks for the links to the photos -- spectacular!), you wrote that the phenomenon of the aurora borealis is similar to that of neon lights. Can you go into a little more detail about the science of it?
More than happy to. Thanks for asking.
Yesterday, we reviewed the history and science of neon lights, for which Las Vegas was known for decades (though not as much any longer).
Earlier this month, due to the peak of an 11-year cycle of coronal mass ejections, otherwise known as solar storms, the northern lights were quite visible over the darker parts of the northern Las Vegas Valley, much farther south (by 1,800 miles or so) than normal.
The aurora and neon lights are similar in that both produce light through the excitation of atoms. And having seen the northern lights in all their glory in northern Alaska, we can tell you that excited atoms emit amazingly colorful and active lights, veritable shimmering, pulsating, and dancing overhead curtains, arcs, ribbons, spirals, and ripples of green, red, and blue/violet.
The process begins with energetic particles from the sun, usually ejected during solar flares, that travel en masse as solar winds. The particles are guided by Earth's magnetic field, or magnetosphere, toward the regions surrounding the North (aurora borealis) and South (aurora australis) poles. As the anxious ions enter the upper atmosphere, they collide with oxygen and nitrogen atoms and are "excited" by the encounters, which releases energy in the form of light.
Green is the most common color, produced by oxygen at an altitude of about 60 miles. Red can appear either at higher or altitudes, while blue/violet is usually seen at the lower end of the altitude range below 60 miles and closer to the horizon.
Again, as we saw in yesterday's QoD, with neon lights, an electric current passes through low-pressure noble gases (neon, argon, helium) inside glass tubes. The electricity as the energy source excites the electrons in the gas atoms, creating the distinctive lights.
Thus, both involve a partially ionized gas, where free electrons and ions interact to produce light under electrical influence — neon lights via applied voltage, auroras via geomagnetic fields attracting solar particles.
Essentially, neon lights are a miniaturized human-engineered version of the natural "neon sign" that the auroras represent on a planetary scale. Cool, huh!
