Download Observing the Universe 1

Observing the sky with the naked eye
Name: …………………………………..
1. In which direction do the following appear to move during the day or night when viewed
from the Earth, east to west, west to east, north to south or south to north.
(a) Sun
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(b) Moon
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(c) Stars
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2. How could you tell that one of the objects that you observed in the sky was a planet and
not a bright star (something other than its brightness)?
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3. Which appear to move faster across the sky the Sun or the stars? ………………….
4. How will this affect the time at which a star rises above the horizon on successive nights?
(An actual number is needed in your answer here)
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5. Why does the Sun appear to move across the sky?
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6. How would you explain the motion of Mars when viewed from the Earth?
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7. Complete the diagram in Figure 1 to show
how the Moon would appear when viewed
from the Earth at the four positions shown.
B
A
8. When the Moon passes between the Sun
and the Earth the eclipse formed is called a
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C
9. When the Earth passes between the Sun
and the Moon the eclipse formed is called a
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Figure 1
D
1
10. Explain why the diagram in Figure 2 shows that eclipses do not occur very often.
Figure 2
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11. If you knew the radius of the Earth’s orbit around the Sun explain how you could use the
measurement of the angles marked A in Figure 3 to find the distance of a nearby star such
as Alpha Centauri.
Earth (January)
Distant stars
Angle (A)
Centauri
2A
Sun
Figure 3(b)
Angle (A)
Earth (July)
Figure 3
Distant stars
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2
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12. A sidereal day, measured by a rotation of the Earth by 360o, is four minutes less than a
solar day. What causes this difference? (A detailed explanation is not required here).
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13. Why are the patterns of stars seen in the sky from a given point on the Earth different at
different times of the year?
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14. The diagram in Figure 4 shows the movement of an object seen in the sky from
November 2005 to January 2006. Is this object likely to be (a) a planet (b) a star ?
(The lines show a grid of latitude and longitude on the star sphere)
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246o
248o
250o
252o
36o
9th Nov 2005
15th Nov 2005
2nd Jan 2006
34o
21st Nov 2005
27th Dec 2005
21st Dec 2005
32o
27th Nov 2005
3rd Dec 2005
15th Dec 2005
9th Dec 2005
30o
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