Astronomy: Unit 2, Sky (Part One)

What is light pollution and its effect on stargazing?

Light pollution reduces the number of stars visible at night.

How many stars are typically visible at one time?

About 3,000 stars.

How many official constellations are there?

There are 88 official constellations.

What is an example of cultural variation in constellations?

The Tupi people in Brazil see an 'old man' in Orion.

Why are constellations not real groupings of stars?

Stars that appear close together may actually be at different distances.

What causes the daily motion of stars in the sky?

Earth's rotation causes the Sun to rise and set and makes stars appear to move.

What is the zenith?

The zenith is the point directly overhead.

How does the altitude of Polaris relate to latitude?

The altitude of Polaris equals your latitude.

What happens to the visibility of constellations throughout the year?

Different constellations are visible at different times of the year.

What are the constellations along the ecliptic called?

The Zodiac.

What determines the phases of the Moon?

The Moon's phases depend on its position relative to Earth and the Sun.

How long is the cycle of moon phases?

Approximately 29.5 days.

What is synchronous rotation in relation to the Moon?

The Moon rotates once per orbit, so the same side always faces Earth.

Is there a permanent 'dark side' of the Moon?

No, all parts of the Moon get sunlight at different times.

What occurs during a lunar eclipse?

A lunar eclipse occurs when Earth blocks sunlight from reaching the Moon.

What are the two types of eclipses mentioned?

Lunar eclipses and solar eclipses.

What are umbra and penumbra in the context of shadows?

Umbra is the total shadow, and penumbra is the partial shadow.

What causes the Moon to appear red during a lunar eclipse?

Earth's atmosphere scatters sunlight, allowing red light to illuminate the Moon.

How are lunar eclipses visible from Earth?

Lunar eclipses are visible from half of the Earth at once.

What characterizes a total solar eclipse?

A total solar eclipse occurs when the Moon completely covers the Sun.

What is an annular eclipse?

An annular eclipse occurs when the Moon is farther away and does not fully cover the Sun, creating a 'ring of fire.'