Lesson 4 Earth, Our Only Home
Is It a Light Problem?
____ at this beautiful painting.
It was created by the famous Dutch artist ____ van Gogh in 1889.
In Van Gogh's time, almost everyone could look up and ____ a wonderful starry night sky.
Now, how many of us are as lucky ____ Van Gogh?
In ____ many people in today's world cannot enjoy a starry night sky.
____ is so because of light pollution.
Most of us are familiar
Most of us are familiar with ____ water, and land pollution.
We know that they are serious problems, and we are taking action to solve ____
But did you know ____ light can also cause pollution?
Light pollution―too much light in the ____ place at the wrong time―is almost everywhere around the world.
It can ____ serious effects on humans and wildlife.
According to a recent report, about 80% of the world's population lives under skies that are not dark ____ at night.
Especially in big cities, ____ often cannot see a starry night.
They can also suffer from sleep problems because the natural rhythm of day ____ night is disturbed by artificial light.
Wildlife is threatened
Wildlife is ____ by light pollution, too.
Birds that migrate or ____ at night find their way by natural light,
but ____ in big cities can cause them to wander off course.
Every year millions of birds ____ after hitting buildings that have bright lights.
Sea turtles cannot easily find a place to lay ____ since beaches are too bright at night.
Also, many baby sea turtles ____ because artificial light draws them away from the ocean.
Clearly, light pollution is ____ serious as other forms of pollution.
We have to find ways ____ solve the problem.
If we do not, we may see stars only in our dreams or ____