T

Figure 2

he planets rotate around their axes and revolve around the sun in elliptical paths determined by the force of the gravitation. Included in the solar system are the 31 satellites of the planets (not counting the earth’s artificial satellites), thousands of asteroids

which are minor planets ranging from one mile to 300 miles, comets, small masses of solid particles, held loosely together, and meteors.

There exist several hypotheses of the origin of the Solar System, there are two of them:

The “catastrophic” theory. This held that the planets were formed of material torn away from the sun by the action of another star, either by collision or by tidal phenomena. This star may have been one which its proper motion brought into the neighbourhood of the sun or it might have been a “companion”, assuming the sun to have once been a double star, like many binary systems in the universe.

The nebular theory. This theory suggested that the sun was originally surrounded by a mass of gas extending beyond the limits of the present solar system. This nebula resulted either from the evolution of the sun, or from the capture by the sun of a cloud of interstellar matter, which, condensing, separated from it and gradually agglomerated to form the planets. Our solar system seems to have developed according to this latter pattern.

6.5 Say whether the following statements are true or false

1. Galaxy is a great star system.

2. Our own galaxy, the Milky Way, is classified as an elliptical galaxy.

3. Seventeen galaxies of a supergalaxy are concentrated within a radius of about one million kilometeres.

4. The Solar System consists of the sun, its nine planets and a variety of smaller bodies.

5. The sun’s temperature is equal at its surface and at its core.

6. The sun is almost entirely solid.

7. Of all nine planets Pluto is closest to the sun.

8. Asteroids are small masses of solid particles, held loosely together.

9. There exist several hypotheses of the origin of the Solar System.

6.6 Fill in the blanks with the suitable words from the text

1. Of all nine planets Mercury is ………. to the sun .……... by Venus, Earth, Mars, ..…….., Saturn, Uranus, Neptune and Pluto in that order.

2. The ………. planets are closer together and the ………. ones are farther apart.

3. The planets ………. around their axes and ………. around the sun in elliptical ………. determined by the force of ………. .

4. The ………. diameter of ………. is about 7 billion miles.

5. As to the ………. of the Solar System there exist several hypotheses.

6. The ………. theory suggested that the planets are formed of material torn away from ………. by the action of another star.

6.7 Ask questions to which these sentences are the answers

1. The Universe as we view it today is made up of at least a billion aggregations of stars called galaxies.

2. Yes, there may be millions of star systems like our own in the universe.

3. The approximate age of our Solar System as determined by the radioactive method is about 4.5-5 thousand million years.

4. The planets rotate around their axis and revolve around the sun.

5. No, Neptune isn^’t the farthest planet to the sun. It’s Pluto.

6. According to the “catastrophic” theory the planets were formed of material torn away from the sun by the action of another star.

7. Our Solar System is believed to have originated from an immense cloud of gas and dust.

8. Stars differ in surface temperature that’s why they are of different colour: white, blue, yellow and even red.

6.8 Translate into English

1. Галактики различаются по форме и структуре. Млечный Путь – это спиральная галактика.

2. Солнечная система – это крошечная частица вселенной. Она состоит из Солнца, планет, спутников, космической пыли.

3. Структура солнца газообразная. Преобладающий газ – водород.

4. Солнечная система включает 31 спутник планет (не считая искусственных спутников Земли).

5. Астероиды – это малые планеты, размером от 1 мили до 300 миль.

6. Небулярная теория предполагает образование небесных тел путем концентрации космического вещества.

6.9 Read and translate the dialogue. Reproduce it

A.: Did the sun and the planets form at the same time?

B.: You see, there exist several concepts of the origin of the solar system. Some of them suggest that the sun and the planets originated at the same time from a tremendous cloud of gas, mostly hydrogen and cosmic dust.

A.: And what do other hypotheses suggest?

B.: Other hypotheses suggest that the planets are younger than the sun, that first the center of the cloud condensed and became a star – the sun, and then various densities gave birth to the planets.

A.: I see.

B.: But it must be said that there is still no generally accepted theory to explain how and when the sun and the planets formed.

10. Using the given chart , answer the following questions

1. Which planets have a longer day than year?

2. Which planet has the most moons?

3. Which is the hottest planet?

4. Which planet has the shortest day and the longest year?

5. Which planet has the closest length of a day to the Earth?

6. Which is the smallest planet?

7. If an Astronomical Unit is the distance from the Earth to the Sun, how many astronomical units away is Pluto?

Table 1

Name	Moons	Average Temp.C	Rotation	Orbit	Av. distance from Sun (million miles)	Diameter (miles)
Mercury	0	-167to427	58.6 days	87.97 days	36.04	3031
Venus	0	427	243.2 days	224.70 days	67.11	7521
Earth	1	-51 to 48	23.9 hrs	365.26 days	92.99	7926
Mars	2	-123to-30	24.6 hrs	686.98 days	141.61	4217
Jupiter	16	-117	9.8 hrs	11.86 years	483.66	88734
Saturn	18	-180	10.7 hrs	29.46 years	886.72	74566
Uranus	15	-221	17.2 hrs	84.01 years	1783.38	31566
Neptune	3	-216	16.0 hrs	164.79 years	2794.38	30758
Pluto	1	-230	6.3 days	247.69 years	3666.19	1429

6.11 Answer the following questions

What is the cosmos? What is the Universe?

What galaxy do we live in?

What does the Solar System consist of?

Give all the data relating to the sun.

How are the planets arranged in the Solar System?

Distinguish between the asteroids and the comets.

How could the Solar System have originated according to the “catastrophic” theory?

How could the Solar System have originated according to the nebular theory?

6.12 Write down a summarizing sentence for each paragraph of the text “The Universe and the Solar System”. On the basis of the above task prepare an oral summary of the text