Astronomy and Celestial Phenomena

Correct Answer: June 2014

Earth's rotational axis currently points toward Polaris, known as the Pole Star or North Star. This happens because Polaris lies nearly directly above Earth's North Pole. The axis direction changes slowly over 26,000 years due to precession, but Polaris is our current pole star. The other options are gravitational bodies, not celestial alignment points.

The Moon exhibits tidal locking, meaning its rotational period equals its revolutionary period around Earth (approximately 27.3 days). This synchronization causes the same hemisphere to always face Earth. It is not due to equal gravitational forces or inability to change position, but rather a natural consequence of tidal forces over time.

Pluto has an extremely elongated orbit that takes it much farther from the Sun than the planets. At its average distance, it requires about 248 Earth years to complete one revolution around the Sun. This long orbital period is why Pluto was only discovered in 1930 despite being relatively bright compared to other distant objects.

The Moon is tidally locked to Earth, meaning its rotational period (27.3 days) exactly equals its orbital period. This synchronous rotation causes the same lunar hemisphere to always face Earth. The far side was not seen until spacecraft missions in the 20th century. The Moon does rotate, just at the same rate it orbits.

Singapore lies at 1°N latitude, between the Tropic of Cancer and Tropic of Capricorn. The sun is directly overhead twice annually (approximately once each when the sun crosses the zenith going north and south) due to the parallelism of Earth's inclined axis - the tilt direction stays fixed as Earth orbits, causing different latitudes to face the sun directly at different times. Options A, B, and C don't explain this phenomenon.

The heliocentric model (Sun as center of solar system) was published by Nicolaus Copernicus in 1543 in his work 'De revolutionibus orbium coelestium'. This marked a major shift from the geocentric view that had dominated for centuries.

The phrase "going to" suggest that the sentence is about a future occurence. So, 'next few' fits here. Thus, it is the correct answer.

Sunlight takes approximately 8 minutes and 20 seconds to travel from the Sun to Earth, covering a distance of about 150 million kilometers at the speed of light.

Morning is related to Dawn; similarly Evening is related to Dusk.

The Egyptian calendar was primarily a solar calendar with 12 months of 30 days each. It was one of the first solar calendars in history. Lunar calendars follow moon phases, while the Egyptian calendar was based on the sun and the star Sirius.

When referring to unique natural objects like the sun, moon, or earth, we use the definite article 'the' because there is only one in our immediate context. We say 'the sun', 'the moon', and 'the earth' for this reason.

Sir James Jeans and Chamberlin's Tidal Hypothesis (1919) proposed that a passing star exerted tidal force on the primitive sun, pulling out material that formed planets. The sun was rotating, and the intruding star's tidal force was greater than the sun's gravitational hold. Axiom 2 (star being smaller) is not part of Jeans' original formulation.

Syzygy is an astronomical term referring to the alignment of three celestial bodies in a straight line. In the context of Earth-Sun-Moon system, it occurs during new moon (Sun-Moon-Earth aligned) and full moon (Sun-Earth-Moon aligned). Option D correctly describes this linear arrangement.