Good to know that after billions of years of evolution and billions of years of technology advancement, 'human' error is still a problem...
Kloooong: You did remember to turn the cloaking on before we departed Pluto?
Qaata: Oops! *quickly presses button*.
Capt. Smith: Yup.... Those chlorine gas bursts react beautifully in a sunset sky don't they.... DON;T they?
Isn't there weather conditions at sunset that produce green light flashes from the setting Sun? It would be informative to know the weather conditions, time of day and if there were any radar confirmations. Also, I believe that there were forest fires in Canada at the time; possibly the smoke from such may have produced a reaction with the light from the setting Sun? However, I do wish that "the green UFO" had appeared where I am ; so much better than what's on TV.
Ref: Wikipedia "Green Flashes". Pilots report that atmospheric conditions produce a green flash at either sunrise or sunset, especially if traveling westward at sunset. Such an event lasts approx. 2 seconds.