Exercise 3: Read the text and complete it with the words in the box.

accounts

combine

temperature

system

energy

The formation and structure of the Sun

The sun and the rest of the solar (1) ................... formed from a giant, rotating cloud of gas and dust called a solar nebula about 4.5 billion years ago. As the nebula collapsed because of its overwhelming gravity, it spun faster and flattened into a disk. Most of the material was pulled toward the center to form our sun, which (2) ................... for 99.8% of the mass of the entire solar system.

            Like all stars, the sun will someday run out of (3) ................... When the sun starts to die, it will swell so big that it will engulf Mercury and Venus and maybe even Earth. Scientists predict the sun is a little less than halfway through its lifetime and will last another 6.5 billion years before it shrinks down to be a white dwarf.

            The sun, like others stars, is a ball of gas. In terms of the number of atoms, it is made of 91.0% hydrogen and 8.9% helium. By mass, the sun is about 70.6% hydrogen and 27.4% helium.

            At the core, the (4) ................... is about 27 million degrees Fahrenheit (15 million degrees Celsius), which is sufficient to sustain thermonuclear fusion. This is a process in which atoms (5) ................... to form larger atoms and in the process release staggering amounts of energy. Specifically, in the sun’s core, hydrogen atoms fuse to make helium.

Exercise 4: Read the text and answer the questions.

            Mars is the fourth planet from the Sun and is commonly referred to as the Red Planet. The rocks, soli and sky have a red or pink hue. The distinct red color was observed by stargazers throughout history. It was given its name by the Romans in honor of their god of war. Other civilizations have had similar names. The ancient Egyptians named the planet Her Descher meaning the red one.

            Before space exploration. Mars was considered the best candidate for harboring extraterrestrial life. Astronomers thought they saw straight lines crisscrossing its surface. This led to the popular belief that irrigation canals on the planet had been constructed by intelligent beings. In 1938, when Orson Welles broadcasted a radio drama based on the science fiction classic War of the Worlds by H.G. Wells, enough people believed in the tale of invading Martians to cause a near panic

            Another reason for scientists to expect life on Mars had to do with the apparent seasonal color changes on the planet’s surface. This phenomenon led to speculation that conditions might support a bloom of Martian vegetation during the warmer months and cause plant life to become dormant during colder periods.

1.  What’s another name of Mars?

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2.  Why did Mars have its name?

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3.  Was Mars considered the best candidate for harboring extraterrestrial life before space exploration?

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4.  When did Orson Welles broadcast a radio drama based on the science fiction classic War of the Worlds by H.G?

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5.  What phenomenon led to speculation that conditions might support a bloom of Martian vegetation during the warmer months?

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Exercise 7 : Look at the picture and read the text about life on other planets.

FACTS ABOUT LIFE ON OTHER PLANETS

• Scientists are looking for three things: a planet with gases like oxygen and carbon dioxide that support life; a planet with water and a planet that’s not too cold or too hot.

• The Kepler telescope’s most exciting discovery was the planet Kepler 22b. This planet is a little larger than Earth, but it is about the same distance away from its star as the Earth is from the Sun. Scientists believe it might have water on it.

Exercise 8: Read the passage in the Exercise 7 and answer the questions.

      1.  What planet are scientists looking for?

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      2.  What’s the most exciting discovery?

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      3.  Is Kepler 22b smaller than the Earth?