To determine the time it takes for sunlight to reach Earth, we need to consider the average distance between the Sun and Earth and the speed of light. Light travels at a constant speed in a vacuum, and this speed is a fundamental physical constant.
Correct Option: B) About 8 minutes — Sunlight travels at the speed of light, and given the average distance between the Sun and Earth, it takes approximately 8 minutes and 20 seconds for light to cover this distance. The closest option is 8 minutes.
The question asks for the classification of the Sun among celestial bodies. To answer this, we need to understand the definitions of different celestial bodies like satellites, asteroids, planets, and stars, and then identify which definition best fits the Sun's characteristics.
Correct Option: D) Star. The Sun is a star because it is a massive, luminous ball of plasma that generates heat and light through nuclear fusion in its core.
The question asks to identify the star closest to Earth. This requires knowledge of our solar system and nearby stars.
Correct Option: D) The Sun
The Sun is the star at the center of our solar system. Earth, along with other planets, orbits the Sun. Therefore, by definition and proximity, the Sun is the nearest star to Earth. Its average distance from Earth is approximately \(149.6 \times 10^6\) kilometers (or 1 Astronomical Unit).
The question asks for the orbital period of Mercury around the Sun. This is a fundamental fact in astronomy, specifically related to the properties of planets in our solar system. We need to recall the orbital periods of the inner planets to answer this question.
C) About 88 days — Mercury is the innermost planet in our solar system. Its close proximity to the Sun results in the shortest orbital period among all planets, completing one revolution in approximately 88 Earth days.
The question asks to identify the planet that has virtually no atmosphere due to its low gravity and close proximity to the Sun, which causes gases to escape. We need to evaluate each option based on these two criteria: gravity and distance from the Sun.
Correct Option: A) Mercury has virtually no atmosphere. It is the smallest planet and closest to the Sun. Its low mass results in weak gravity, and the intense solar radiation heats any atmospheric gases, giving them enough energy to escape its gravitational pull.
The question asks to identify the pair of planets in our solar system that do not possess any natural satellites (moons). This requires knowledge of the basic characteristics of the planets.
Correct Option: D) Mercury and Venus are the only two planets in our solar system that do not have any natural satellites (moons).