The Perseids
The 2023 Perseid Meteor Shower that peaked on August 12/13. With current sensitive digital cameras and fast wide-angle lenses, it is possible to reveal meteors and their colors in real-time video. I was at Maine Stargazing & Photography Retreat with my family and the participants who came from across the country to join our week-long workshop under one of the darkest skies in the New England (https://babaktafreshi.com/workshop). The speakers in the video are my colleagues Richard Nugent and Bruce Berger of Boston astronomy club (https://www.atmob.org).
The green color in meteors is caused by oxygen in Earth's atmosphere. When a meteoroid rips through the atmosphere, air in its path becomes so hot that oxygen molecules briefly lose one of their electrons. They recombine very rapidly, emitting green photons as a side-effect. A similar process makes the green color of aurora. A fringe of yellow in the light is due to meteor itself. When a sodium-rich meteoroid cuts through the atmosphere, hot sodium vapors glow yellow like a sodium discharge lamp.
Most visible meteors are caused by particles that range in size from about a small pebble to a grain of sand and weigh less than one to two grams. A meteor’s brilliant flash of light is caused not by mass but by high kinetic energy generated by speed. Brighter meteors known as fireball are produced by larger objects (tennis-ball-size or larger) and may reach the ground in the form of a small rock depending on its composition (ice, metal, or mineral).