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Science Blog ZINC PROJECTS

Toronto at night ... from space

Date: 24-Feb-08
Author: Andrew Yee

While the nighttime view of Toronto is a spectacle for visitors and residents, the amount of light that spills upward has brightened the night sky so much that unaided eyes can easily see only bright objects from within the city. As the surrounding cities expand, this kind of wasted light -- called light pollution -- also affects increasingly larger areas.

Nightscape of Toronto as seen from Centre Island. Serious light pollution in the Greater Toronto Area limits naked eye observing of only bright stars and planets in the night sky. Here, communications satellite Iridium 75 produced a flare over the Downtown Toronto skyline on 2 September 2007. Courtesy: Andrew Yee
(Click on image for larger version)

How far does city light radiate upward? An astronaut of Expedition 16 on the International Space Station took this image (shown below) of the Greater Toronto Area and neighbouring cities on 20 January 2008 at 5:25 am EST (1025 UTC), when the orbital outpost passed over an area to the southwest of Corning, New York at an altitude of 337 km. The astronaut pointed the camera toward the western end of Lake Ontario to capture the image.

The large expanse of glow is from Toronto and its immediate neighbour Mississauga. The image covers as far west (left side) as Hamilton and as far east as Oshawa. At the very center of the image is Downtown Toronto. A long straight line of light that extends far from Downtown Toronto is Yonge Street, which is the longest street in the world according to the Guinness Book of Records.

Click on the image to see a larger version. Click here for an annotated version.

Courtesy: Image Science and Analysis Laboratory, NASA Johnson Space Center