The marvelous telephone and television network that has now enmeshed the whole world, making all men neighbors, cannot be extended into space. It will never be possible to converse with anyone on another planet. Even with today’s radio equipment, the messages will take minutes—sometimes hours—on their journey, because radio and light waves travel at the same limited speed of 186,000 miles a second.
Twenty years from now you will be able to listen to a friend on Mars, but the words you hear will have left his mouth at least three minutes earlier, and your reply will take a corresponding time to reach him. In such circumstances, an exchange of verbal messages is possible—but not a conversation.
To a culture which has come to take instantaneous communication for granted, as part of the very structure of civilized life, this "time barrier" may have a profound psychological impact. It will be a perpetual reminder of universal laws and limitations against which not all our technology can ever prevail. For it seems as certain as anything can be that no signal—still less any material object—can ever travel faster than light.
The velocity of light is the ultimate speed limit, being part of the very structure of space and time. Within the narrow confines of the solar system, it will not handicap us too severely. At the worst, these will amount to twenty hours—the time it takes a radio signal to span the orbit of Pluto, the outer-most planet.
It is when we move out beyond the confines of the solar system that we come face to lace with an altogether new order of cosmic reality. Even today, many otherwise educated men—like those savages who can count to three but lump together all numbers beyond four—cannot grasp the profound distinction between solar and stellar space. The first is the space enclosing our neighbouring worlds, the planets; the second is that which embraces those distant suns, the stars, and it is literally millions of times greater. There is no such abrupt change of scale in the terrestrial affairs.
Many conservative scientists, appalled by these cosmic gulfs, have denied that they can ever be crossed. Some people never learn; those who sixty years ago scoffed at the possibility of flight, and ten years ago laughed at the idea of travel to the planets, are now quite sure that the stars will always be beyond our reach. And again they are wrong, for they have failed to grasp the great lesson of our age—that if something is possible in theory, and no fundamental scientific laws oppose its realization, then sooner or later it will be achieved.
One day we shall discover a really efficient means of propelling our space vehicles. Every technical device is always developed to its limit and the ultimate speed for spaceships is the velocity of light. They will never reach that goal, but they will get very near it. And then the nearest star will be less than five years’ voyaging from the earth.
Confronted with the new order of cosmic reality, many educated men ______.

A:become ignorant savage again B:find the "time barrier" unbearable C:will not combine solar and stellar space D:cannot adapt to the abrupt change of scale

From the 18th through the mid-19th century, whale oil provided light to much of the Western world. At its peak, whaling employed 70,000 people and was the United States’ fifth-largest industry. The U. S. stood as the world’s foremost whale slayer. Producing millions of gallons of oil each year, the industry was widely seen as unassailable, with advocates scoffing at would-be illumination substitutes like. lard oil and camphene. Without whale oil, so the thinking went, the world would slide backward toward darkness.
By today’s standard, of course, slaughtering whales is considered barbaric. Two hundred years ago there was no environmental movement to speak of. But one wonders if the whalers, finding that each year they needed to go farther afield from Nantucket Island to kill massive sea mammals, ever asked themselves: what will happen when we run out of whales Such questions today constitute the cornerstone of the ever-louder logic of sustainability.
Climate alarmists and campaigning environmentalists argue that the industrialized countries of the world have made sizable withdrawals on nature’s fixed allowance, and unless we change our ways, and soon, we are doomed to an abrupt end. Take the recent proclamation from the United Nations Environment Program, which argued that governments should dramatically cut back on the use of resources. The mantra has become commonplace: our current way of living is selfish and unsustainable. We are wrecking the world. We are cutting down the rainforest. We are polluting the water. We are polluting the air. We are killing plants and animals, destroying the ozone layer, burning the world through our addiction to fossil fuels, and leaving a devastated planet for future generations. In other words, humanity is doomed.
It is a compelling story, no doubt. It is also fundamentally wrong, and the consequences are severe. Tragically, exaggerated environmental worries—and the willingness of so many to believe them—could ultimately prevent us from finding smarter ways to actually help our planet and ensure the health of the environment for future generations.
Because, our fears notwithstanding, we actually get smarter. Although Westerners were once reliant on whale oil for lighting, we never actually ran out of whales. Why High demand and rising prices for whale oil spurred a search for and investment in the 19th-century version of alternative energy. First, kerosene from petroleum replaced whale oil. We didn’t run out of kerosene, either: electricity supplanted, it because it was a superior way to light our planet.
For generations, we have consistently underestimated our capacity for innovation. There was a time when we worried that all of London would be covered with horse manure because of the increasing use of horse-drawn carriages. Thanks to the invention of the car, London has 7 million inhabitants today. Dung disaster averted.
In fact, would-be catastrophes have regularly been pushed aside throughout human history, and so often because of innovation and technological development. We never just continue to do the same old thing. We innovate and avoid the anticipated problems.
From the last sentence of the second paragraph we learn that

A:people have stopped disputing the practice of whale killing. B:the number of whales has risen despite mass slaughter. C:modern society is more alert to the sustainability of nature. D:environmentalists have brought whale killing to an abrupt end.

The marvelous telephone and television network that has now enmeshed the whole world, making all men neighbors, cannot be extended into space. It will never be possible to converse with anyone on another planet. Even with today’s radio equipment, the messages will take minutes—sometimes hours—on their journey, because radio and light waves travel at the same limited speed of 186, 000 miles a second.
Twenty years from now you will be able to listen to a friend on Mars, but the words you hear will have left his mouth at least three minutes earlier, and your reply will take a corresponding time to reach him. In such circumstances, an exchange of verbal messages is possible—but not a conversation.
To a culture which has come to take instantaneous communication for granted, as part of the very structure of civilized life, this "time barrier" may have a profound psychological impact. It will be a perpetual reminder of universal laws and limitations against which not all our technology can ever prevail. For it seems as certain as anything can be that no signal--still less any material object—can ever travel faster than light.
The velocity of light is the ultimate speed limit, being part of the very, structure of space and time. Within the narrow confines of the solar system, it will not handicap us too severely. At the worst, these will amount to twenty hours—the time it takes a radio signal to span the orbit of Pluto, the outer-most planet.
It is when we move out beyond the confines of the solar system that we come face to face with an altogether new order of cosmic reality. Even today, many otherwise educated men—like those savages who can count to three but lump together all numbers beyond four—cannot grasp the profound distinction between solar and stellar space. The first is the space enclosing our neighboring worlds, the planets; the second is that which embraces those distant suns, the stars, and it is literally millions of times greater. There is no such abrupt change of scale in the terrestrial affairs.
Many conservative scientists, appalled by these cosmic gulfs, have denied that they can ever be crossed. Some people never learn ; those who sixty years ago scoffed at the possibility of flight, and ten years ago laughed at the idea of travel to the planets, are now quite sure that the stars will always be beyond our reach. And again they are wrong, for they have failed to grasp the great lesson of our age— that if something is possible in theory, and no fundamental scientific laws oppose its realization, then sooner or later it will be achieved.
One day we shall discover a really efficient means of propelling our space vehicles. Every technical device is always developed to its limit and the ultimate speed for spaceships is the velocity of light. They will never reach that goal, but they will get very near it. And then the nearest star will be less than five years voyaging from the earth.
Confronted with the new order of cosmic reality, many educated men______.

A:become ignorant savage again B:find the " time harrier" unbearable C:will not combine solar and stellar space D:cannot adapt to the abrupt change of scale

The marvelous telephone and television network that has now enmeshed the whole world, making all men neighbors, cannot be extended into space. It will never be possible to converse with anyone on another planet. Even with today’s radio equipment, the messages will take minutes--sometimes hours--on their journey, because radio and light waves travel at the same limited speed of 186, 000 miles a second.
Twenty years from now you will be able to listen to a friend on Mars, but the words you hear will have left his mouth at least three minutes earlier, and your reply will take a corresponding time to reach him. In such circumstances, an exchange of verbal messages is possible--but not a conversation.
To a culture which has come to take instantaneous communication for granted, as part of the very structure of civilized life, this "time barrier" may have a profound psychological impact. It will be a perpetual reminder of universal laws and limitations against which not all our technology can ever prevail. For it seems as certain as anything can be that no signal--still less any material object--can ever travel faster than light.
The velocity of light is the ultimate speed limit, being part of the very structure of space and time. Within the narrow confines of the solar system, it will not handicap us too severely. At the worst, these will amount to twenty hours--the time it takes a radio signal to span the orbit of Pluto, the outer most planet.
It is when we move out beyond the confines of the solar system that we come face to face with an altogether new group of cosmic reality. Even today, many otherwise educated men--like those savages who can count to three but lump together all numbers beyond four--cannot grasp the profound distinction between solar and stellar space. The first is the space enclosing our neighboring worlds, the planets, the second is that which embraces those distant suns, the stars, and it is literally millions of times greater. There is not such abrupt change of scale in the terrestrial affairs.
Many conservative scientists, shocked by these cosmic gulfs, have denied that they can ever be crossed. Some people never learn, those who sixty years ago laughed at the possibility of flight, and ten years ago laughed at the idea of travel to the planets, are now quite sure that the stars will always be beyond our reach. And again they are wrong, for they have failed to grasp the great lesson of our age--that if something is possible in theory, and no fundamental scientific laws oppose its realization, then sooner or later it will be achieved.
One day we shall discover a really efficient means of propelling our space vehicles. Every technical device is always developed to its limit and the ultimate speed for spaceships is the velocity of light. They will never reach that goal, but they will get very near it. And then the nearest star will be less than five years of voyaging from the earth.
Confronted with the new groups of cosmic reality, many educated men ______.

A:become ignorant savages again B:find the "time barrier" unbearable C:will not combine solar and stellar space D:cannot adapt to the abrupt change of scale

The marvelous telephone and television network that has now enmeshed the whole world, making all men neighbors, cannot be extended into space. It will never be possible to converse with anyone on another planet. Even with today’s radio equipment, the messages will take minutes—sometimes hours—on their journey, because radio and light waves travel at the same limited speed of 186, 000 miles a second.
Twenty years from now you will be able to listen to a friend on Mars, but the words you hear will have left his mouth at least three minutes earlier, and your reply will take a corresponding time to reach him. In such circumstances, an exchange of verbal messages is possible—but not a conversation.
To a culture which has come to take instantaneous communication for granted, as part of the very structure of civilized life, this "time barrier" may have a profound psychological impact. It will be a perpetual reminder of universal laws and limitations against which not all our technology can ever prevail. For it seems as certain as anything can be that no signal--still less any material object—can ever travel faster than light.
The velocity of light is the ultimate speed limit, being part of the very, structure of space and time. Within the narrow confines of the solar system, it will not handicap us too severely. At the worst, these will amount to twenty hours—the time it takes a radio signal to span the orbit of Pluto, the outer-most planet.
It is when we move out beyond the confines of the solar system that we come face to face with an altogether new order of cosmic reality. Even today, many otherwise educated men—like those savages who can count to three but lump together all numbers beyond four—cannot grasp the profound distinction between solar and stellar space. The first is the space enclosing our neighboring worlds, the planets; the second is that which embraces those distant suns, the stars, and it is literally millions of times greater. There is no such abrupt change of scale in the terrestrial affairs.
Many conservative scientists, appalled by these cosmic gulfs, have denied that they can ever be crossed. Some people never learn ; those who sixty years ago scoffed at the possibility of flight, and ten years ago laughed at the idea of travel to the planets, are now quite sure that the stars will always be beyond our reach. And again they are wrong, for they have failed to grasp the great lesson of our age— that if something is possible in theory, and no fundamental scientific laws oppose its realization, then sooner or later it will be achieved.
One day we shall discover a really efficient means of propelling our space vehicles. Every technical device is always developed to its limit and the ultimate speed for spaceships is the velocity of light. They will never reach that goal, but they will get very near it. And then the nearest star will be less than five years voyaging from the earth.

Confronted with the new order of cosmic reality, many educated men（）

A:become ignorant savage again B:find the " time harrier" unbearable C:will not combine solar and stellar space D:cannot adapt to the abrupt change of scale

The train came to an (abrupt) stop, making us wonder where we were.

A:slow B:noisy C:sudden D:jumpy

The train came to an {{U}}abrupt{{/U}} stop, making us wonder where we were.

A:slow B:noisy C:sudden D:jumpy

I have to apologize for my {{U}}abrupt{{/U}} departure yesterday.

A:Late B:unfriendly C:sudden D:unfold

The train came to an abrupt stop, making us wonder where we were.

A:slow B:noisy C:sudden D:jumpy