Гвоздева Пхысицс фор адванцед студентс 2011
.pdfTHE ESCAPE VELOCITY
Study the passage. Mind the underlined grammar points.
As far as I know, the first person to discuss black holes was a Cambridge man called John Mitchell, who wrote a paper about them in 1783. His idea was this. Suppose you fire a cannon-ball vertically upwards from the surface of the earth. As it goes up, it will be slowed down by the effect of gravity. Eventually, it will stop going up and will fall back to the earth. If it started with more than a certain critical speed, however, it would never stop rising but would continue to move away. This critical speed is called the escape velocity. It is about 7 miles a second for the earth, and about 100 miles a second for the sun. These velocities are greater than the speed of a real cannon-ball, but they are much smaller than the velocity of light, which is 186,000 miles a second. This means that gravity does not have much effect on light; light can escape without difficulty from the earth or the sun. However, Mitchell reasoned that it would be possible to have a star that was both massive and small in size so that its escape velocity would be greater than that of light. We would not be able to see such a star because light from its surface would not reach us; it would be dragged back by the star’s gravitational field. However, we might be able to detect the presence of the star by the effect that its gravitational field would have on nearby matter.
Light always travels at the same constant velocity. How then can gravity affect light?
According to general relativity, space and time together can be regarded as forming a four-dimensional space called space-time. This space is not flat; it is distorted or curved by the matter and energy in it. We observe this curvature in the bending of the light or radio waves that travel near the sun on their way to us. In the case of light passing near the sun, the bending is very small. However, if the sun shrinks until it is only a few miles across, the bending would be so great that light leaving the sun would not get away but would be dragged back by the sun’s gravitational field. According to the theory of relativity, nothing can travel faster than light, so there would be a region from which it would be impossible to escape. The region is called a black hole. Its boundary is called the event horizon. It is formed by the light that fails to get away from the black hole but stays hovering on the edge.
Stephen Hawking
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Vocabulary Notes
1.to reason – to come to a particular conclusion by thinking carefully
2.to affect something – to influence something
3.sufficiently – adequately – enough
4.to regard – to consider
5.to distort – to curve – to deform – a curvature
6.to shrink – to become smaller – to contract
7.to bend – when something bends it changes its shape to form a curve
8.to hover – to stay in the same position
9.an edge – the physical limit of an object or place
POST-READING TASK
(To be done at home in writing) I. Complete the sentences.
1.The first person .. …. … … was John Mitchell.
2.He wrote .. … about them in ….
3.When you fire a cannon-ball it … .. … … by the effect of gravity.
4.Eventually, it … … … .. and ... … … to the surface of the earth.
5.But if it started with a certain critical speed it .. … … …
6.The critical speed is called … … …
7.The critical speed is … .. .. . .. .. .. ..
8.It is … … … for the sun
9.This means that gravity … … … … .. light.
10.But the escape velocity of a star which is … massive … small in size would be greater than …. of light.
11.The light from such a star … .. … … by the star’s gravitational
field.
12.But the star might be detected by .. … … .. … … … … … .. .. …
II. Make your own conclusion. |
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III. Give words close in meaning. |
|
1. finally |
4. to consider |
2. to influence |
5. to deform |
3. so |
6. to contract |
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CLASS EXERCISES
Exercise 1 (in groups)
Checking up understanding
1.What was John Mitchell’s idea?
2.In what case would a cannon-ball continue to move away?
3.What is the critical speed called?
4.What is the critical speed for the earth?
5.If you compare the critical speed of a cannon-ball with the velocity of light what conclusion can you make?
6.Why would it be impossible to see a star which is both massive and small in size?
7.How can we detect the presence of such a star?
8.What is space-time in other words?
9.Why is space not flat?
10.How can gravity affect light?
Exercise 2 (do it yourself)
Study grammar point II and put the verbs into the passive.
1.The first paper about black hole (write) in 1783.
2.A cannon ball (slow down) by the effect of gravity.
3.This critical speed (call) the escape velocity.
4.Light from the star’s surface (drag back) by the star’s gravitational
field.
5.The presence of the star may (detect) by the effect that its gravitational field would have on nearby matter.
6.Light (not affect) by gravity.
7.A four-dimensional space (call) space-time.
8.This space (distort) by the matter and energy in it.
9.The curvature in the bending of the light or radio waves can (observe).
10.The region from which it is impossible to escape (call) a black
hole.
11.Its boundary (call) the event horizon.
12.The event horizon (form) by the light that fails to get away from the black hole.
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UNIT 5
THE THIRD PLANET FROM THE SUN
Earth is a minor planet going around a very average star in the outer suburbs of a fairly typical spiral galaxy.
PREREADING TASK
Study some grammar points.
I. The participle |
|
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The English verb changes in four forms: |
|
|
I |
II |
III |
to use (the infinitive) – used (the past simple) – used (the passive parti-
ciple) = нный |
IV |
|
using (the active participle) = ющий |
Ving (or Ved) characterizes the noun which it follows.
Study the sentences.
1.You can think of ordinary, real time as a horizontal line, going from left to right.
2.There might also be quite a number of very much smaller black holes scattered around the universe, formed not by the collapse of stars but by the collapse of highly compressed regions in the hot, dense medium that has existed shortly after the big bang, in which the universe originated.
3.One of the problems facing physicists is to make general relativity compatible with quantum mechanics.
4.The earth is trying to move on a straight line through space-time, but the curvature of space-time produced by the mass of the sun causes it to go in a circle around the sun.
II. We use modal verbs + have V3 to say that it was possible or highly probable in the past.
May, might, can, could + have V3 = possible (Russian – возможно
было).
Must + have + V3 = highly probable (Russian – вероятно было,
наверняка было)
Can’t, couldn’t + have V3 = hardly possible (Russian – вряд ли
было)
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Study the sentences.
1.The observations indicate that the early universe must have been non-turbulent.
2.Heavy elements could have been formed by nuclear synthesis of the early generation of nearby stars.
3.The pyramids of Egypt and ancient Peru couldn’t have been built by any known methods of engineering.
Give Russian correspondence:
relative to, to realize (to understand), fairly (rather), typical (usual), N + that, normally (usually), a few (some), before, to make (to force), by 1930s, the only (single), via (by means of), ordinarily (normally), eventually (finally)
EARTH IS A UNIQUE PLANET
Study the passage. Mind the underlined grammar points.
Earth is a unique planet which has everything for the development of life and human evolution: the unique composition of air, the unique properties of water, the unique mineral composition of soils which feed all the living things, the unique position relative to the sun, and even the unique position of the solar system in the galaxy (Milky Way). The solar system is about 60000 light years from the centre of the galaxy, the distance which protects life on the earth from rigid radiation of the galactic centre.
What do we know about our position in the Universe? In ancient times people believed that the earth was at the centre of the universe. Now we realize that we are among the many inhabiting a minor planet going around a very average star in the outer suburbs of a fairly typical spiral galaxy that is only one of a hundred billion galaxies we can see. We know now that we cannot claim any special position in the universe.
FYI
1.A spiral galaxy is an enormous pancake-shaped collection of stars and gas.
2.An eclipse of the sun is an occasion when the moon comes between the earth and the sun so that for a short time you cannot see part or all of the sun.
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Vocabulary Notes
1.to inhabit – if a place is inhabited, people live there
2.average – ordinary
3.outer – (ant. inner)
4.suburbs – periphery
5.to claim – to pretend to something
WHAT MAKES THE SUN SHINE?
Study the passage. Mind the underlined grammar points.
The sun is certainly a prerequisite of our existence, as is the earlier generation of nearby stars in which heavy elements could have been formed by nuclear synthesis. The Sun is the size it is because it is so hot. It is burning hydrogen into helium, like a controlled H-bomb. The era’s best estimate of the sun’s age --- provided by the eminent British physicist William Thompson (better remembered as Lord Kelvin) ---- concluded that the sun couldn’t be more than a few tens of millions of years old. It would be another seven decades before scientists would develop the tools necessary to understand what made the sun shine. By the 1930s scientists knew that all the matter is made up of atoms and that these atoms have a nucleus of positively charged protons and neutral neutrons. (Hydrogen is the only exception --- its nucleus has only a proton.) Albert Einstein had demonstrated that the sun is not made of molten rock, as Thompson assumed --- it is composed mostly of hydrogen, together with some helium.
In 1938 physicist Hans Bethe realized that at the center of the sun, the pressure must be so great that individual hydrogen nuclei would be squeezed together with such force that they could overcome the repulsion that ordinarily keeps ions of like charges apart. Bethe laid out the four-step chain by which hydrogen ions fuse together. The final products of the reaction are a bit lighter than the ingredients that go into it, and this missing mass becomes converted (via E = mc2) into the energy that powers the sun.
The heat released in this process generates a pressure that enables the sun to resist the attraction of its own gravity, which is trying to make it smaller. Eventually, however, the sun will run out of nuclear fuel.
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Vocabulary Notes
1.a prerequisite – a precondition – something that must exist before another thing is possible.
2.a generation of stars – a group of stars of the same period of time
3.an estimate – a calculation
4.a tool – an instrument
5.to assume – to believe – to consider
6.repulsion – (ant.) attraction
7.to enable – to allow
POST-READING TASK
(To be done at home in writing)
I. Innumerate the points that make Earth a unique planet. II. Explain.
What makes the sun shine?
II. Put in the prepositions.
1.People believed that the earth was …. the centre of the universe.
2.Earth is a minor planet going … a very average star.
3.The sun is certainly a prerequisite …… our existence.
4.Heavy elements could have been formed in nearby stars ….. nuclear synthesis.
5.The sun is burning hydrogen ….. helium.
6.The sun couldn’t be more than ………………..
7.Eventually the sun will run out … nuclear fuel.
III. Give words close in meaning.
1. to understand |
5. a tool |
2. ordinary |
6. finally |
3. to believe |
7. to pretend to something |
4. by means of |
8. to make somebody do something |
CLASS EXERCISES
Exercise 1 (in groups)
Checking up understanding
1.What makes Earth a unique planet for the development of life and human evolution?
2.What kind of planet is Earth?
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3.What does the sun provide us with?
4.Why is the earlier generation of nearby stars considered to be a prerequisite of our existence?
5.What makes the sun comparable with a controlled H-bomb?
6.Why is the sun the size it is?
7.What man-made device can you compare the sun with?
8.What keeps ions of like charges apart?
Exercise 2 (do it yourself)
Formulate questions.
1.Matter is made up of atoms. (What ……….. of?)
2.The sun is composed of hydrogen, together with some helium. (What ……….. of?)
3.The repulsion keeps ions of like charges apart. (What?)
4.The mass of the final products of the reaction becomes converted into the energy that powers the sun. (What energy?)
5.The sun will eventually run out of its fuel. (Why?)
6.The earth goes in a circle around the sun. (Why?)
Exercise 3 (in pairs)
Ask the questions formulated by you in ex. 2 and give answers.
Exercise 4 (do it yourself)
Reconstruct the passage by formulating simple sentences with the key words.
1.Earth is a unique planet …………………..
2.60000 light years from the center of the galaxy is the distance which ……………..
3.Earth is a minor planet …………………….
4.The sun is a prerequisite of … ….
5.The sun .. …. hydrogen into helium.
6.The heat … .. … … generates a pressure that ….. the sun to resist the attraction of its own gravity.
7.Eventually the sun .. … … .. nuclear fuel.
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UNIT 6
THE DIVERSITY OF LIFE ON EARTH
DARWIN’S IDEA OF NATURAL SELECTION
Charles Darwin’s theory of evolution by natural selection required billions of years of incremental change to explain the incredible diversity of life on earth. Yet the era’s best estimate of the sun’s age provided by William Thompson concluded that the sun couldn’t be more than a few tens of millions of years old.
Darwin considered Thompson’s critique one of the gravest blows to the theory of evolution.
Scientific American, 2010
PRE-READING TASK Brainstorming
What do your think? Give your interpretations using: I agree entirely; I doubt it; I do believe that; I’m sure; I’m convinced; In my opinion; It is incredible that…
1.Life arose spontaneously on the planet of the solar system called earth as a result of chance combinations of atoms.
2.It was by chance that the first generation of life species developed the ability to reproduce themselves.
3.The transition from a one-cell organism to a many-cell one was ca-
sual.
4.It was by pure chance that as a result of evolution there appeared millions of different life species.
5.Males and females appeared by pure chance.
6.The appearance of vertebral species is a chance occurrence.
7.Vertebral species evolved into mammals by pure chance.
8.The appearance of an anthropoid ape as a species of the mammals was a chance occurrence.
9.A kind of anthropoid apes evolved into human beings by pure chance.
FYI
1.species – living groups.
2.a male – a man
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3.a female – a woman
4.a vertebrate is a creature that has a back bone. Mammals, birds, reptiles, amphibians, and most fishes are all vertebrates.
5.a mammal is an animal, the female of which feeds babies with milk from her body.
6.apes are animals such as chimpanzees or gorillas. They are similar to monkeys but are larger and do not have tails.
Study some grammar points. I. We use can’t and couldn’t to say that the action is hardly possible = вряд ли
Study the sentence.
1. The sun couldn’t be more than a few tens of millions of years old.
II. Would is used to talk about the natural course and behavior of things and events as a result of some action. It is the less definite form of will.
Study the sentences.
1. The white hole could be in another part of the universe. This would offer the possibility of rapid intergalactic travel.
III. We use would have when you are saying that something happened or was true. You don’t translate would in this case.
Study the sentence.
Very high particle energies would have occurred in the early universe.
IV. This structure expresses the probability of the action in the present or in the future.
S + is likely + to V = probably S + is unlikely + to V = hardly (вряд ли)
Study the sentence.
1. As much as 90 percent of the matter in the universe is likely to be invisible.
b. This structure expresses the probability of action in the past.
S + is likely + to have V3 S + is unlikely + to have V3 Study the sentence.
1. Millions of different life species are unlikely to have appeared by pure chance.
We use both variants:
1.It is (un)likely that some very primitive form of life arose spontaneously on earth from chance combinations of atoms.
2.Some very primitive form of life is (un)likely to have arisen spontaneously on the earth from chance combinations of atoms
V. We use may + have V3 and might + have V3 to say what
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