Why does the same side of the Moon always face Earth?

• The Moon rotates faster than it revolves

• The Moon does not rotate

• The Moon’s rotation period equals its revolution period

• Earth’s gravity locks the Moon’s position

Answer explanation

The Moon’s rotation period equals its revolution period, meaning it takes the same time to spin on its axis as it does to orbit Earth. This synchronous rotation causes the same side of the Moon to always face our planet.

Which of the following best explains why seasons are not caused by Earth’s distance from the Sun?

• Earth’s orbit is perfectly circular

• Earth’s tilt remains constant during its orbit

• The Moon stabilizes Earth’s temperature

• The Sun’s energy output is constant

Answer explanation

Seasons are primarily caused by Earth's axial tilt, which remains constant as it orbits the Sun. This tilt affects the angle and intensity of sunlight received, not the distance from the Sun.

During which Moon phase would you expect the highest variation in ocean tides?

• First quarter

• Full moon

• Waning crescent

• Last quarter

Answer explanation

The highest variation in ocean tides occurs during the full moon phase. This is when the Earth, moon, and sun are aligned, resulting in stronger gravitational forces and higher high tides, known as spring tides.

Which condition is necessary for a solar eclipse to occur?

• Earth must be between the Sun and Moon

• The Moon must be full

• The Moon must be between Earth and the Sun

• Earth must be tilted toward the Sun

Answer explanation

A solar eclipse occurs when the Moon is positioned directly between Earth and the Sun, blocking sunlight. This alignment is essential, making 'The Moon must be between Earth and the Sun' the correct condition for a solar eclipse.

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Why does the Moon appear to change shape throughout the month?

• Its orbit is elliptical

• It rotates at different speeds

• We see different portions of its sunlit side

• Its surface reflects light unevenly

Answer explanation

The Moon appears to change shape because we see different portions of its sunlit side as it orbits Earth. This phenomenon is known as the lunar phases, which result from the relative positions of the Earth, Moon, and Sun.

Which of the following best explains why Pluto is classified as a dwarf planet?

• It is not spherical

• It does not orbit the Sun

• It shares its orbital path with other objects

• It has no moons

Answer explanation

Pluto is classified as a dwarf planet because it shares its orbital path with other objects in the Kuiper Belt, which is one of the criteria for this classification. It is spherical and does orbit the Sun.

Why do outer planets have more moons than inner planets?

• They are closer to the asteroid belt

• Their stronger gravity can capture more objects

• They rotate more slowly

• They formed earlier than inner planets

Answer explanation

Outer planets have stronger gravity, allowing them to capture more moons and objects from the surrounding space. In contrast, inner planets are smaller and have weaker gravity, resulting in fewer moons.

Which planet has a day shorter than 12 Earth hours and contains more mass than all other planets combined?

• Saturn

• Jupiter

• Neptune

• Uranus

Answer explanation

Jupiter has a day lasting about 10 hours, making it shorter than 12 Earth hours. Additionally, it contains more mass than all other planets combined, making it the correct answer.

What makes Venus hotter than Mercury, even though Mercury is closer to the Sun?

• Venus has a thicker atmosphere that traps heat

• Venus rotates faster

• Mercury has no atmosphere

• Venus reflects more sunlight

Answer explanation

Venus is hotter than Mercury because it has a thick atmosphere rich in carbon dioxide, which traps heat through the greenhouse effect. In contrast, Mercury has a very thin atmosphere, allowing heat to escape.

Which of the following objects can become a meteorite?

• Asteroid

• Comet

• Meteoroid

• Moon fragment

Answer explanation

A meteoroid is a small rocky or metallic body in outer space that can enter Earth's atmosphere. When it survives the journey and lands on the surface, it is called a meteorite. Thus, the correct answer is meteoroid.