Tokyo glows green by night, as seen in the
photography of International Space Station astronaut Dan Tani.
The
greenish light reflects the widespread use of mercury vapor lighting, as
opposed to the sodium vapor lighting that produces an orange-yellow light seen
in other nighttime cities. Newer areas near the shore of Tokyo bay contain more orange sodium
vapor lamps, but the majority of the urban area shines a cool blue-green.
Such a
top-down view also reveals the city layout, with ribbons of light radiating outward
from the city center following streets and railways. The regularly spaced
lights along one of the westward-trailing ribbons are probably train stations
lining a transit route, possibly the Chuo Line of Japan Railway.
— NASA and SPACE.com Staff
Credit: NASA
Return each weekday for a new SPACE.com Image of the Day.
| 
