Astronomy and Celestial Phenomena

The sky appears blue because the Earth`s atmosphere scatters blue light the most.

The sentence uses a negative construction 'is not' to make a logical point. When the sky is not cloudy (covered with clouds), the sun appears bright because there are no clouds to block sunlight. 'Cloudless' would create a double negative, 'no cloud' is grammatically incorrect, and 'more cloud' doesn't fit the context.

Sun rays take approximately 8 minutes and 20 seconds (about 500 seconds) to reach Earth, traveling at the speed of light. The distance between the Sun and Earth is about 150 million kilometers. 480 seconds represents a commonly cited approximation of 8 minutes.

The zodiac is a belt-shaped region in the sky through which both the sun and moon appear to move. It's divided into 12 equal parts, each named after constellations. The apparent paths of both celestial bodies lie along this ecliptic region.

(Because) The reason here is the most important part of the sentence. So, the conjunction 'because' will be used.

(Not only does the gravitational attraction of the moon). Conjunction ''Not only….. But also'' are always used in pair. Secondly, whenever a sentence begins with a negative word, the verb is used before the subject. All these conditions are fulfilled by (3) option. 

A satellite is defined as a celestial body that orbits around another body. The Moon is called Earth's satellite because it revolves around Earth in a regular orbit, not because it lacks its own light or revolves around the Sun.

Earth's rotational axis is tilted at approximately 23.5 degrees and points toward Polaris, also known as the North Star or Polar Star. This is why Polaris appears stationary in the northern night sky while other stars appear to rotate around it.

Some words like 'last', 'yesterday', 'this morning' etc take second form of the verb after themselves. “Rose” is the right word to show the rising of the sun in the past. Hence, (1) is the correct answer.

The moon illusion is primarily caused by atmospheric refraction - light bends as it passes through different density layers of Earth's atmosphere, especially near the horizon. This refraction makes celestial objects appear larger when low in the sky. Total internal reflection, scattering, and diffraction don't cause this effect.

The plural subject 'meteors' requires the plural verb 'enter'. When meteors enter Earth's atmosphere, friction causes them to lose much of their mass as they burn up.

Apogee is the point in the moon's elliptical orbit where it is farthest from Earth's center. This occurs because the moon's orbit is not perfectly circular but elliptical, with Earth at one focus. The opposite point (closest distance) is called perigee.

Neptune takes about 165 Earth years (approximately 60,190 Earth days) to complete one orbit around the Sun due to its vast distance - about 30 times farther from the Sun than Earth is.

Earth orbits the Sun in an anticlockwise direction when viewed from above the North Pole. This is the same direction as most planets in our solar system due to the conservation of angular momentum from the solar nebula.

A lunar eclipse can only occur during a full moon when the Sun, Earth, and Moon are aligned in a straight line with Earth in the middle. The Earth's shadow then falls on the Moon's surface. During a new moon, the moon is between Earth and Sun, making a solar eclipse possible instead.