Keeping Time with the Skies

The Sun appears to RISE in the:

1. aNorth
2. bEast
3. cSouth
4. dWest

The time taken by the Earth to complete ONE rotation on its axis (with respect to the Sun) is approximately:

1. a1 hour
2. b24 hours
3. c12 hours
4. d1 month

Why does a stick stuck upright in the ground cast the SHORTEST shadow around noon?

1. aThe stick is shortest at noon
2. bShadows always disappear at noon
3. cThe Sun is highest in the sky around noon, so its rays are most overhead and the shadow is shortest
4. dThe earth tilts at noon

In a purely lunar calendar, a festival that falls in the rainy season in one year falls in a different season some years later. Why does this happen?

1. aThe Moon’s phases repeat faster in some seasons than in others
2. bA lunar year has about 365 days, while the seasons repeat in about 354 days
3. cA lunar month is the time the Earth takes to rotate 12 times on its axis
4. dA lunar year of 12 lunar months has about 354 days, while the seasons repeat in about 365 days

The Earth revolves around the Sun once in about:

1. a24 hours
2. b1 month
3. c1 year
4. d1 day

Day and night are caused by Earth’s:

1. aRotation on its own axis
2. bRevolution around the Sun
3. cTilt only
4. dAtmosphere

1. I. The Sun appears to rise in the east and set in the west each day.
2. II. This apparent motion is because the Sun moves around the Earth.
3. III. This apparent motion is because the Earth rotates from west to east on its axis.

Which of the above statements about the daily motion of the Sun are correct?

1. aI and II only
2. bI and III only
3. cII and III only
4. dI, II and III

Assertion (A): On a given day, people in different parts of the Earth see nearly the same phase of the Moon.

Reason (R): The Moon completes one revolution around the Earth in about one day.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

Why does the SHAPE of the moon visible in the sky CHANGE over a month?

1. aThe Moon physically changes shape each night
2. bThe Sun’s light changes colour each night
3. cClouds cover different parts of the Moon
4. dWe see different fractions of the Moon’s sunlit half from Earth as the Moon orbits us

On a NEW-MOON night, the Moon is:

1. aClosest to the Earth
2. bInside Earth’s shadow
3. cOn the opposite side of the Earth from the Sun
4. dBetween the Earth and the Sun, with its dark side facing the Earth — so almost invisible

Match each phenomenon with its cause:

1. a(i)-P, (ii)-Q, (iii)-R, (iv)-S
2. b(i)-Q, (ii)-P, (iii)-S, (iv)-R
3. c(i)-Q, (ii)-S, (iii)-P, (iv)-R
4. d(i)-R, (ii)-P, (iii)-Q, (iv)-S

Which of the following statements about the MOON is TRUE?

1. aWe always see the same face of the Moon from Earth
2. bThe Moon has its own light
3. cThe Moon has a thick atmosphere similar to Earth
4. dThe Moon is bigger than the Earth

1. I. It is a solar calendar with 365 days in a regular year.
2. II. Like the Gregorian calendar, its months have 28, 30 or 31 days.
3. III. In a leap year, a day is added to Chaitra, its first month, so the year begins on 21 March.

Which of the statements above about the Indian National Calendar is/are correct?

1. aI and II only
2. bII and III only
3. cI and III only
4. dI, II and III

Assertion (A): We can see the Moon at night because of sunlight reflected from its surface.

Reason (R): The Moon does not produce its own light; it shines by reflecting sunlight from its surface.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

A LUNAR ECLIPSE occurs when:

1. aThe Earth comes between the Sun and the Moon, casting its shadow on the Moon
2. bThe Moon comes between the Sun and the Earth
3. cThe Moon comes between the Earth and the Sun, but only at full moon
4. dThe Moon disappears completely from the sky

A SOLAR ECLIPSE occurs when:

1. aThe Earth comes between the Sun and the Moon
2. bThe Moon comes between the Sun and the Earth, blocking the Sun’s light from us
3. cThe Sun moves to the other side of the Galaxy
4. dThe Moon disappears

Soon after sunset, Ananya sees a point of light moving very fast across the sky; it crosses from one side to the other in a few minutes. What is it most likely to be?

1. aA star, appearing to move because the Earth rotates
2. bA planet, moving in its orbit around the Sun
3. cAn artificial satellite, orbiting about 800 km above the Earth
4. dThe crescent Moon, setting soon after the Sun

Kavya marks the point where the Sun rises, from the same spot, at the start of every month for a year. She finds it rises a little north of East in summer and a little south of East in winter. During which months does the rising point move northward, and what is this movement called?

1. aFrom June to December; Dakshinayan
2. bFrom June to December; Uttarayan
3. cFrom December to June; Dakshinayan
4. dFrom December to June; Uttarayan

On which of these festivals does the entire illuminated half of the Moon face the Earth?

1. aHoli
2. bDiwali
3. cEid-ul-Fitr
4. dDussehra

Assertion (A): Eclipses do not occur every month, even though there is a full Moon and a new Moon every month.

Reason (R): The Moon’s orbit around the Earth is slightly tilted with respect to the Earth’s orbit around the Sun.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

Which of the following statements about a CALENDAR is TRUE?

1. aA solar calendar is based mainly on the Moon’s phases
2. bA solar calendar is based mainly on the Earth’s revolution around the Sun
3. cA lunar calendar is based mainly on the cycle of seasons
4. dAll calendars use only Earth’s rotation

1. I. The time between successive spring equinoxes is called the tropical year, and the Gregorian calendar is based on it.
2. II. The time taken for the same stars to rise again at sunset is called the sidereal year.
3. III. The sidereal year is shorter than the tropical year by about 20 minutes.

Which of the statements above is/are correct?

1. aI only
2. bII and III only
3. cI and II only
4. dI, II and III

In a Purnimant calendar, each month starts on the day after the full Moon and ends on the full Moon. During the first two weeks of such a month, the Moon is in its:

1. aWaxing period, called Shukla Paksha
2. bWaning period, called Shukla Paksha
3. cWaxing period, called Krishna Paksha
4. dWaning period, called Krishna Paksha

A school buries a time capsule to be opened on 29 February of a future century year. Using the Gregorian calendar’s leap-year rules, which of these years will actually have a 29 February?

1. a2200
2. b2100
3. c2400
4. d2300

Assertion (A): Makar Sankranti and Pongal fall on different Gregorian dates each year, shifting by up to a month, just as Diwali does.

Reason (R): Makar Sankranti and Pongal follow a solar sidereal calendar.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

Which of the following is the BEST description of the difference between ROTATION and REVOLUTION of the Earth?

1. aRotation is the spinning of the Earth on its own axis (1 day); revolution is the going around of the Earth in its orbit around the Sun (1 year)
2. bRotation and revolution are two names for the same motion
3. cRotation is the Earth going around the Sun; revolution is the Earth going around the Moon
4. dBoth rotation and revolution are completed in 24 hours

About one week after the morning described in the passage, where will Mira find the Moon at sunrise, and what will it look like?

1. aLow in the western sky, as a full circle
2. bOverhead, as a half circle
3. cOverhead, as a thin crescent
4. dLow in the eastern sky, as a full circle

Why does the moonrise time that Mira reads in the newspaper get later each day?

1. aThe Earth rotates more slowly at night than during the day
2. bThe Earth’s shadow hides the rising Moon for a little longer each day
3. cThe Sun rises about 50 minutes later every day, and the Moon follows it
4. dWhile the Earth rotates once, the Moon moves ahead in its orbit, so the Earth must turn a little more to bring it back to the same place in the sky

Compared with last year’s Diwali, when will this year’s Diwali most likely fall in the Gregorian calendar?

1. aAbout 18 days later
2. bOn the same date
3. cAbout a month earlier
4. dAbout 11 days earlier

Which of the following is the BEST one-line summary of what Mira learns from her uncle?

1. aThe Sun and Moon move around the Earth in fixed paths each day
2. bThe motions of the Earth (rotation and revolution) and of the Moon around the Earth give us our daily and monthly time-cycles
3. cThe Earth is the centre of the universe
4. dTime depends on the time-zone we live in only