21世纪大学英语读写基础教程 Unit1-21世纪大学英语读写教程

Unit 1

Text A

Many people often turn a blind eye to the "ordinary" things in life. They are not aware of the existence and importance of the sun, water and air. In this text, the writer tells us how important the sun is to all living things on the earth and what would happen if the sun did not reappear the next morning.

Great Baee of Fire

Hugh Downs

In an interview following my 1965 voyage across the Pacific in a small sailboat, I was asked what power I had on that boat. "Atomic power," I told the reporter.
I wasn't kidding: The boat did have an auxiliary engine and a limited fuel supply; but its main power was its sails. The sails, of course, did nothing unless there was wind, but the wind would not blow if there were not a temperature difference that made cooler air move into the space vacated by the rising warm air.
And there would be no warmer air unless something heated it.
That something is an atomic furnace 93,000,000 miles away that pours its radiation constantly on the day side of the turning Earth. It heats the air, makes it rise, sucks in other air, makes it blow on the sails and causes the boat to be pushed. So every sailboat is powered by an atomic engine—the sun.

You Gotta Love It
Although the sun is very large compared to the Earth, it is one of myriad stars in a very large galaxy, which is one of myriad galaxies in a very large universe. But the sun is special to us because it is the closest star; it holds us in its gravitational grip. And its energy, raining down on the home planet, is utterly necessary for the maintenance of all life.
I've often thought that among the things humans have elected to worship over historic and prehistoric eras, the sun is the most appropriate visible object. Sun worshippers were not too far off the mark.
For life to continue here, the sun must keep on shining. Scientists say that if it died (unlikely in the extreme—it's good for another 5 billion years), in less than two weeks nothing would move on the Earth's surface. Nothing would remain alive.
This is easily seen when you think about how it gets cooler after the sun goes down, and is coolest just before it comes up the next morning. If it's 80 degrees Fahrenheit at sunset and goes down to 60 just before dawn, the only reason the temperature goes back up is that the sun reappears and starts warming things up again.

When Hell Freezes Over
Suppose it didn't do that.
In two days the temperature would go to 40, and then 20 (all water would start to turn into ice) and the next day zero, and then 20 below and 40 below, and so on.
In about 10 more days, when the temperature was close to absolute zero, the gases of the atmosphere (nitrogen and oxygen) would freeze, putting a light snow of solid nitrogen onto the ground, followed by a fine powder of oxygen.
The Earth would then have no liquid water, no atmosphere, and no life.
Perhaps these facts refute the foolish sage who once said the moon was more important than the sun, because the moon shines at night, when we need the light, while the sun shines in the daytime when we don't need it!