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