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1 .agriculture (agriculture) |
10. hydrosphere (hi-dro-sfeer) |
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2. artificial (artificial) |
11. meteorite (meteorite) |
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3. asteroid (as-ter-oid) |
12. meteoroid (meteoroid) |
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4. astronomer (astronomer) |
13. satellite (satellite) |
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5. atmosphere (at-mos-feer) |
14. silicates (silicates) |
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6. biosphere (bi-o-sfeer) |
15. sulphuric (sul-fur-ic) |
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7. circumference (circumference) |
16. terrestrial (terrestrial) |
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8. galaxy (gal-ax-ee) |
17. Uranus (U-ray-nus) |
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9. gravitational (gravitational) |
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The centre of our solar system is a star called the sun. The sun is
the largest object in our solar system. The planets and other objects
travel in orbits around the sun. An orbit is a curved path.
Our solar system is part of a galaxy called the Milky Way. A galaxy
is a system of stars, dust and gases held together by gravity.
Astronomers believe there are billions of galaxies scattered
throughout the universe. There are more than 1 00 million stars in the
Milky Way.