Lesson: Stars and Solar System
Morning star is the name given to:
(a) Pole star
(b) Planet Jupiter
(c) Star Sirius
(d) Planet Venus
Which of the following figures depicts the position of pole star correctly?
Sun appears to move from east to west around the earth. This means that earth rotates from
(a) East to west
(b) North to south
(c) West to east
(d) West to north
An astronaut standing on the surface of the moon throws a ball upwards. The ball would
(a) Directly fall down from the point it is released.
(b) Hang in space.
(c) Go up and then come back to the surface of the moon.
(d) Keep going up never to come back.
Suppose a new planet is discovered between Uranus and Neptune.
Its time period would be
(a) Less than that of Neptune.
(b) More than that of Neptune.
(c) Equal to that of Neptune or Uranus.
(d) Less than that of Uranus.
The change in seasons on the earth occurs because
(a) The distance between the earth and the sun is not constant.
(b) The axis of rotation of the earth is parallel to the plane of its orbit.
(c) The axis of rotation of the earth is perpendicular to the plane of its orbit.
(d) The axis of rotation of the earth is tilted with respect to the plane of its orbit.
The first of a month is the new moon day. On fifteenth of the same month, which of the following figures would represent the phase of the moon?
Very Short Answer Questions
Do stars emit light only during night?
No, stars emit light during night and day as well.
Paheli and Boojho observe a bright object in the night sky which was not twinkling. Paheli says, it is a star and Boojho says it is a planet. Who is correct?
Planets do not have their own light so they do not twinkle. Hence Boojho is correct from this perspective.
State whether the following statements are ‘True’ or ‘False’.
(a) The planet nearest to us is Jupiter.
(b) All the stars are at the same distance from us.
(c) The planets do not emit light of their own.
(d) The planets keep changing their position with respect to stars.
(e) The planet Venus appears in the eastern sky before sunrise.
(f) The plane in which the earth revolves around the sun is called equatorial plane of earth.
John saw full moon on a particular day. After how many days will he be able to see the full moon again?
John will be able to see the full moon approximately after 29 days.
In the picture of rotating earth given below, mark the position of pole star.
In the given figure, find out of the positions A, B, C and D which will indicate the position of the sun? Draw the sun at the appropriate position.
Sun will be at position B.
In the given figure, mark the arrows (←), (→), (↓), or (↑) to show the direction of sunlight.
Direction of the sunlight will be towards the left as shown in the figure given below.
Short Answer Questions
A star is ten light years away from the earth. Suppose it brightens up suddenly today. After how much time shall we see this change?
As we know that light covers one light year in one year. Hence, we will see the change after 10 years.
Meteors are not visible during the daytime. Explain the reason.
During the daytime sun rays are very bright. On the other hand, brightness of meteor is very low in comparison with sun. Due to this, meteors are not visible during the daytime.
Why does the moon change its shape daily?
Moon appears to be changing its shape daily because we are able to see only that part of the moon from which the light of the sun is reflected towards us.
Paheli saw the moon through a glass window at 8:00 p.m. She marked the position of the moon on the glass pane. She got up at 4 a.m. in the morning. Will the moon be visible at the same position?
No, the moon will not be visible at the same location because the position of the moon keeps changing due to the motion of the earth and the moon throughout the day and night.
Long Answer Questions
Suppose the moon emits light of its own. Would it still have phases? Justify your answer.
No. The moon will not have phases because if it had its own light, it would not be dependent on the sun light to glow. Therefore, it would have been glowing continuously.
The figure given below, shows comets without their tail. Show the tails of the comets at position A, B, and C. In which position will the tail be longest?
As shown in the figure below, the tail will be longest at point B.
Explain why we always see the same side of moon.
The period of rotation of the moon on its axis is equal to the period of its revolution round the earth. That is why we see the same side of moon.
Look at the figure carefully and answer the following question:
(a) In which part of the sky would you see the full moon in the evening?
(b) In which part of the sky would you see the crescent moon in the evening?
(a) In the eastern part of the sky.
(b) In the western part of the sky.
Write the names of all planets in the given figure.
Suppose the distance between earth and sun becomes half of its present distance. What is likely to happen to life?
Life may no longer exist. If the distance between earth and sun becomes half of its present distance, then temperature on earth will increase and survival of species on earth will be in danger or they may not survive at all.
Explain with a diagram how you can locate pole star with the help of the constellation Great Bear (Ursa Major).
Pole star can be located using the following steps:
1. Locate the two end stars of the constellation Ursa Major.
2. Imagine a straight line passing through these stars, as shown in the figure given below.
3. Extend this imaginary line towards the north direction. This line will lead to a star which is not too bright. This is the pole star.