阅读理解

    You may think that light pollution isn't something extraordinarily important. You may believe that every other type of pollution has a larger impact on the environment that light pollution does. But light pollution is serious.

    Light pollution, or “sky glow”, is the glow you can see at night above cities and towns. Light pollution is a problem that has been accompanying man ever since he started his first fire some 15,000 years ago. Light pollution is the light that comes from streetlights, buildings, parking lots and any other source of light that is reflected or directed into the atmosphere.

    Urban light pollution means that one-fifth of the world's population can no longer see the Milky Way(银河) with the naked eye(肉眼). Many city kids, even if they did look through the orange smog above their heads, would probably see only a handful of stars. We have lost our view of the stars, and we have mucked up our  night-time environment as well. Astronomers are calling for the dark places on Earth to be preserved as national parks.

    Lots of people find the ever-brightening night annoying, and animals that are programmed to prefer the dark may avoid a brightened habitat. Sea turtles can get lost searching for a beach to lay eggs, and their hatchlings(孵化的幼仔)may confuse over-lit beachfront resorts(度假胜地) for the ocean horizon, wasting precious energy needed to find the sea and escape predators(食肉动物). Because their necks aren't yet long enough to see things far away, baby turtles rely on the mirror image of the moon to guide them to the sea, to begin their new life. A car may even hit a particular turtle, which was thinking the light from a nearby city was moonlight reflecting off the ocean waves. Birds that live in and around cities can die because of sky glow, too. The bright lights can blind them, leading to countless collisions with buildings and other tall structures.

    On an individual level, people can help reduce much sky glow by using lighting only when necessary. The stars above us are priceless heritage— for not only for astronomers but for all humans. More of our children should be able to look up at night and see the Milk Way.

原来室内的电灯正常发光，当把台灯的插头插入插座时(台灯的开关断开)，室内的灯全部熄灭，熔丝熔断，发生这一现象的原因是(　)