Astronomy 101 Midterm Exam 2 Study Guide, Spring 2025

What is a globular cluster?

Name the various phases of the Moon.

• New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, Waning Crescent.

• New Moon, Full Moon, Blue Moon, Red Moon.

• First Quarter, Last Quarter, Half Moon, Full Moon.

• Waxing Crescent, Waning Crescent, Solar Eclipse, Lunar Eclipse.

What is the difference between specular reflection and diffuse reflection (also known as scattering)?

• Specular reflection occurs on smooth surfaces and reflects light in a single direction, while diffuse reflection scatters light in many directions from a rough surface.

• Specular reflection occurs on rough surfaces and scatters light in all directions, while diffuse reflection occurs on smooth surfaces and reflects light in a single direction.

• Specular reflection and diffuse reflection both occur only on transparent surfaces.

• Specular reflection absorbs all light, while diffuse reflection transmits all light.

What is a retroreflector?

List the units of angle measurement.

• Degrees, arcminutes (arcmin), arcseconds (arcsec), and radians are all units of angle measurement.

• Meters, kilograms, and seconds are all units of angle measurement.

• Liters, joules, and newtons are all units of angle measurement.

• Watts, amperes, and volts are all units of angle measurement.

What is angular diameter or angular separation?

What is meant by the 'dark side' of the Moon?

• The side of the Moon that is not currently illuminated by the Sun; often refers to the far side of the Moon that is not visible from Earth.

• The side of the Moon that is always facing the Sun.

• The side of the Moon that is covered in permanent darkness and never receives sunlight.

• The side of the Moon that is made entirely of dark-colored rocks.

What is the difference between specular reflection and diffuse reflection (or scattering)?

How might the night sky look different if our planet was in a different type of environment in our Galaxy?

• It would look exactly the same.

• The number and brightness of stars might change.

• The sky would always be cloudy.

• There would be no stars visible at all.

Why are constellations not very useful to modern astronomers?

• Constellations are based on apparent patterns from Earth's perspective and do not represent actual groupings of stars in space, so they are not scientifically useful for modern astronomy.

• Constellations are only visible during the daytime, making them hard to study.

• Constellations change shape every year, so they cannot be used for reference.

• Constellations are only found in the Southern Hemisphere, limiting their usefulness.