[单项选择]
Light Night, Dark Stars
Thousands of people around the globe step outside to gaze at their night sky. On a clear night, with no clouds, moonlight, or artificial lights to block the view, people can see more than 14,000 stars in the sky, says Dennis Ward, an astronomer with the University Corporation for Atmospheric Research (UCAR) in Boulder, Colo. But when people are surrounded by city lights, he says, they’re lucky to see 150 stars.
If you’ve ever driven toward a big city at night and seen its glow from a great distance, you’ve witnessed light pollution. It occurs when light from streetlights, office buildings, signs, and other sources streams into space and illuminates the night sky. This haze of light makes many stars invisible to people on Earth. Even at night, big cities like New York glow from light pollution, making stargazing difficult.
Dust and particles of pollution from factories and industries worsen the effects of
A. A haze of light is formed from artificial lights such as streetlights and building lights.
B. Lights from different sources in the city stream into space and illuminate the night sky.
C. The night sky is illuminated by the lights from big glowing cities in the night.
D. Stargazing becomes difficult because there is a layer of haze in the air.
