Astronomy Quiz Unit 2

What is the celestial sphere?

• A dome that surrounds the Earth

• A physical object in space

• A constellation of stars

• A model of the solar system

Answer explanation

The celestial sphere is best described as a dome that surrounds the Earth. It is an imaginary sphere, with the observer at its center, on which the stars, planets, sun, and moon appear to be placed. It is not a physical object nor a constellation of stars, and it is not a model of the solar system.

What are constellations?

• Groups of stars that form patterns

• Stars that are physically related to each other

• Stars that move rapidly across the sky

• Stars that are all the same distance from Earth

Answer explanation

Constellations are indeed groups of stars that form patterns. They are not necessarily physically related to each other, nor they all are at the same distance from Earth. Also, they do not move rapidly across the sky. Instead, their perceived movement is due to Earth's rotation.

What causes the change in constellations with the seasons?

• The Earth's rotation on its axis

• The Earth's revolution around the Sun

• The movement of the celestial equator

• The tilt of the Earth's rotation axis

Answer explanation

The change in constellations with the seasons is caused by Earth's revolution around the sun. As the Earth orbits the sun, our perspective of the sky changes, causing different constellations to become visible with each season. The other options, such as Earth's rotation on its axis and the tilt of the Earth's rotation axis, do not directly affect the visibility of different constellations throughout the year.

What are solstices?

• The dates when the Sun crosses the celestial equator.

• The dates when the Sun is at its highest point in the sky.

• The dates when the Sun pauses in its north-south motion.

• The dates when the Sun rises and sets due east and due west.

Answer explanation

Solstices are the two points in the year where the sun's path in the sky is the furthest north or south from the equator. This occurs when the tilt of Earth's axis is most inclined towards or away from the Sun, causing the Sun to appear to 'pause' in its north-south motion before changing direction. Hence, the correct answer is 'The dates when the Sun pauses in its north-south motion.'

What is the path called that the Sun takes as it moves through the constellations?

• The celestial sphere

• The celestial equator

• The ecliptic

• The zodiac

Answer explanation

The ecliptic is the path the Sun takes as it moves through the constellations. The celestial sphere is only an imaginary sphere where the observer is at the center. The celestial equator is the projection of the Earth's equator onto the celestial sphere. The zodiac is the band of the 12 constellations through which the Sun passes, but it's not the path itself.

What causes the phases of the Moon?

• The Moon's rotation on its axis

• The Moon's revolution around the Earth

• The Earth's rotation on its axis

• The Earth's revolution around the Sun

Answer explanation

The phases of the Moon are caused by the Moon's revolution around the Earth. As the Moon orbits the Earth, different portions of its surface are illuminated by the Sun, creating the various phases. This rules out the other options, which involve rotations on their axes and the Earth's revolution around the Sun.

What is a solar eclipse?

• When the Moon passes between the Sun and the Earth

• When the Earth passes between the Sun and the Moon

• When the Earth casts its shadow on the Moon

Answer explanation

A solar eclipse is an astronomical event that occurs when the Moon passes between the Sun and the Earth. This disrupts the Sun's light and casts a shadow on the Earth. The other options are incorrect as they describe different celestial phenomena.

What happens during a total lunar eclipse?

• The Moon is completely blocked by the Earth's shadow

• The Moon is partially blocked by the Earth's shadow

• The Moon is completely blocked by the Sun

• The Moon is partially blocked by the Sun

Answer explanation

During a total lunar eclipse, the Moon moves into the Earth's shadow, which blocks all direct sunlight from reaching the Moon. As a result, the Moon is completely blocked by the Earth's shadow. The other options are incorrect because they involve partial blocking or being blocked by the Sun, which is not the case in a total lunar eclipse.

What is the motion of the Sun across the sky from north to south called?

• Rotation

• Revolution

• Ecliptic

• Solstice

Answer explanation

The motion of the Sun north and south in the sky is called the Ecliptic. This term refers to the Sun's apparent yearly path across the celestial sphere. The options 'Rotation' and 'Revolution' refer to other types of motions, and 'Solstice' refers to the point at which the Sun is at its greatest distance from the celestial equator. Hence, 'Ecliptic' is the correct choice.

What is the tilt of the Earth's rotation axis?

• 23.5 degrees

• 45 degrees

• 90 degrees

• 180 degrees

Answer explanation

The tilt of the Earth's axis, also known as axial tilt or obliquity, is approximately 23.5 degrees. This tilt is responsible for the changing seasons as the Earth orbits the Sun. The other options, 45 degrees, 90 degrees, and 180 degrees, are incorrect as they do not correspond to the Earth's actual axial tilt.