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Your guide: Miss RabiaReads every story twice: once for fun, once for the paper.
Count every grain of sand on every beach in the world. Sir James Jeans says that is roughly how many stars there are. Most of them could swallow hundreds of thousands of earths. Our home is a millionth part of one grain.
Then he asks how the earth began. His answer is a story about one rare meeting between two stars, a mountain of fire, and pieces that cooled until one of them carried life.
Jeans wrote this around 1930. Scientists today think the planets formed from a disc of gas and dust around the young sun. For the exam, answer from the text, but know that science has moved on.
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Count every grain of sand on every beach in the world. Sir James Jeans says that is roughly how many stars there are. Most of them could swallow hundreds of thousands of earths. Our home is a millionth part of one grain.
Then he asks how the earth began. His answer is a story about one rare meeting between two stars, a mountain of fire, and pieces that cooled until one of them carried life.
Jeans wrote this around 1930. Scientists today think the planets formed from a disc of gas and dust around the young sun. For the exam, answer from the text, but know that science has moved on.
Author: Sir James Jeans, a British astronomer. Main idea: our earth is tiny and lonely in a vast, mostly lifeless universe; life needs a narrow temperature belt, which is extremely rare.
Q1. How is it that a star seldom finds another star near it?
The universe is so immense that most stars travel alone, like ships on an empty ocean. In a scale model where the stars are ships, the average ship is well over a million miles from its nearest neighbour.
Q2. What are planets and how did they come into existence?
Planets are the pieces of the sun that go round it. About two thousand million years ago a wandering star came near the sun and raised a huge tidal mountain on it. Its pull tore the mountain to pieces, which have circled the sun ever since.
Q3. Why is the universe, of which our earth is a part, so frightening?
Its distances and stretches of time are too great to imagine, and they make human history seem very small. We are lonely, and our home is only a millionth part of a grain of sand. Above all, we find no sign of life like ours anywhere except on the earth.
✗ Writing that the moon's pull tore the sun apart.
✓ The moon is only the comparison. It was a second, wandering star whose tidal pull tore the mountain on the sun to pieces.
✗ Copying the glossary: “a planet is a star moving round the sun”.
✓ A planet is not a star: it gives no light of its own. In the text, planets are cooled pieces of the sun, warmed by its radiation.
✗ Mixing up the essay's numbers, e.g. “one star in a million has a planet”.
✓ One star in 100,000 has a planet at the right distance. A million miles separates the “ships”. Two thousand million years ago the planets formed. 484 degrees of frost is the cold of space.
1. Jeans compares the total number of stars to the number of:
(b) “Something like the total number of grains of sand on all the seashores of the world.”
2. In the scale model, the average “ship” is from its nearest neighbour:
(c) The text says the average ship is well over a million miles from its nearest neighbour.
3. According to Jeans, the planets were formed when:
(b) A wandering star raised a tidal mountain on the sun; its pieces became the planets.
4. The most important condition for life, according to the text, is:
(b) Life needs suitable physical conditions, the most important of which is a temperature at which substances can exist as liquids.
5. How many stars probably have a planet at the right distance for life?
(c) “Probably only one star in 100,000 has a planet going round it at the right distance for life.”