A Conversation for Absorption and Emission Lines

When first switched on

Post 1


in the evening, what explains the muted purple colour of street lighting, which persists (fading out gradually) for four or five minutes as the bulb warms up to yellow/orange? Is a different agency at work here? I was surprised as a kid to notice the streetlights didn't go straight to orange - they had to warm up from magenta/purple first.

When first switched on

Post 2

Traveller in Time Reporting Bugs -o-o- Broken the chain of Pliny -o-o- Hired

Traveller in Time smiley - tit playing with lights
"Exactly as you suggest, it is warming up. The Sodium needs to be evaporated before it can be used as ionised gas. During the preheating the lights show a reddish orange colour, not unlike an oven. "

Key: Complain about this post

Write an Entry

"The Hitchhiker's Guide to the Galaxy is a wholly remarkable book. It has been compiled and recompiled many times and under many different editorships. It contains contributions from countless numbers of travellers and researchers."

Write an entry
Read more