Col. Chris Hadfield, the twitter astronaut star that entertains us with his videos of daily routines in space, made an interesting observation from the orbit. Even though it's 23 years since the fall of Berlin Wall (or as I Berliner Mauer), the division between west and east Berlin is still materialized in the form of different street lamps used in each part. Whereas in the former East Berlin there are sodium-vapour lamps that emit rather yellowish light, the western part uses fluorescent lamps (gas lamps and mercury arc lamps) whose colour is more white.
Interesting fact: Berlin with its nearly 44 000 gas lamps owns currently more than 50% of all of the worlds remaining stock of 80 000. However, the city wants to get rid off them as it plans to become carbon neutral by 2050.
