Astronomy and Celestial Phenomena

As "moon" is singular so "is" is the correct answer.

Correct Answer: their blooming is controlled by low temperature

The moon has no atmosphere to hold in heat at night or prevent the surface from getting hot during the day.

The revolution of Earth around the Sun (annual orbit) is the primary cause of seasons. As Earth orbits, different hemispheres receive varying amounts of solar radiation throughout the year due to the tilt of Earth's axis.

Auroras are associated with the solar wind, a flow of ions continuously flowing outward from the Sun.

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.

Earth reaches aphelion, its farthest point from the Sun, around July 4th each year. At this position, Earth is approximately 152 million kilometers from the Sun, compared to about 147 million kilometers at perihelion in early January. Despite being farther away, July is summer in the Northern Hemisphere because axial tilt is the dominant factor controlling seasons, not distance.