There can be no doubt that the computer revolution has touched virtually every person in the country in some way or other.
Nor can there be any doubt that it has brought tremendous improvements in productivity and efficiency. 46)Indeed, there are many tasks undertaken by computers that could not be done without them, and we have reached the point that the benefits of computerization are taken for granted.
Having accepted that computers are here to stay, what is the downside 47)The most obvious answer is that because of increased efficiency, less people are needed and the loss of jobs, particularly in the service industries, has been enormous, with more job losses yet to come.
However, on a more insidious note, many users have not realized how computers have introduced vulnerability to their business. If computers are soon a boon, how do we cope when something goes wrong
Computers have many uses, varying from pure accounting or back-of
For years, astronomers straggled to calculate the age of the universe. Estimates ranged from 10 to 20 billion years old, a frustratingly large spread. But that was before the launch of the Hubble Space Telescope, named after the astronomer whose discovery 70 years ago began the quest to learn the universe’s age.
Edwin Hubble found that the galaxies (星系) within the universe are speeding away from each other at a rate proportional to their distance. That expansion rate----the Hubble constant (常数)----is the key to calculating the age and size of the universe. But pinning down the constant requires precise measurements of the distances to far-flung galaxies.
In May, a team led by Wendy Freeman of the Carnegie Institution, of Washington, D. C., announced the result of eight years of Hubble measurements: The universe is expanding at a rate of 21 kilometers per million light-years. That translates to an age of approximately 12 billion years for the universe. simila
A. Estimates of the universe’s age range from 10 to 20 billion years old, a frustratingly large spread.
B. The quest to learn the universe’s age began 70 years ago by a famous astronomer named Edwin Hubble.
C. The galaxies in the universe stand still, relative to each other.
D. The new number of the universe’s age is not quite the last value.
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