CELPIP Reading Part 3 Practice Test: Dark-Sky Preserves In Canadian National Parks

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On a clear, moonless night in the backcountry of Jasper National Park, the sky is crowded with so many stars that even familiar constellations can be hard to pick out. Nights like this are increasingly rare, which is why the park was named a dark-sky preserve in 2011. A dark-sky preserve is an area where artificial light is carefully managed so that the natural night environment is protected. In Canada, the designation is granted by the Royal Astronomical Society of Canada, an organization run largely by volunteers, which launched the program in 1999. Contrary to what many visitors expect, the status does not mean that every light must be switched off. Instead, outdoor lighting must be kept to a minimum, shielded so that it points downward, and used only where it is truly needed. Two years after Jasper, Wood Buffalo National Park, which straddles the border between Alberta and the Northwest Territories, became the largest dark-sky preserve on the planet.

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The threat these preserves face is light pollution, and its most visible form is skyglow, the dome of brightness that hangs over towns and cities at night. Skyglow occurs when light escaping upward is scattered by molecules and tiny particles in the air. Because blue light scatters more easily than other colours, the switch to white LED street lights, though it saves energy, has in some places made skyglow worse. Researchers estimate that the Milky Way can no longer be seen from the homes of most North Americans. The effects go well beyond astronomy. Migrating birds, which use the stars to navigate, can become disoriented by brightly lit buildings, and countless insects die circling street lamps. In humans, bright light at night can reduce the production of melatonin, the hormone that helps regulate sleep.

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Protecting the darkness in a busy national park takes deliberate effort. In Jasper, many fixtures at campgrounds and park facilities have been replaced with shielded lights that give off a warm, amber glow, which has less impact on the night sky. Staff also encourage visitors to use flashlights with red lenses. Human eyes need twenty to thirty minutes to adjust fully to darkness, and a single burst of white light can undo that process in seconds, whereas red light preserves night vision. Park officials point out that the benefits are not only for stargazers: many of the park’s animals, from bats to owls, hunt and travel under cover of night.

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Darkness has also become a valuable economic asset. Each October, the Jasper Dark Sky Festival brings astronomers, scientists and musicians to the town for talks, concerts and guided stargazing sessions. Because the festival takes place after the busy summer season, it fills hotel rooms and restaurant tables at a time when business would normally be slow. The town also has a small planetarium, where powerful telescopes let visitors view planets and distant galaxies. Astro-tourism brings its own challenges, however. On popular viewing nights, the headlights of arriving cars can spoil the view, so guides ask drivers to switch to parking lights as they approach observation sites.