ASTRONOMY 101 - FINAL EXAM REVIEW
Explain the physical reason why we on Earth experience day and night. - Answers -
Earth rotates about an axis of rotation once every 24 hours.
What is a light year? - Answers - The distance light travels in one year.
Approximately how far is the Sun from Earth? - Answers - 1 AU, 150 million km, 93
million miles, 8 light minutes
About how far is the closest star to the Sun? - Answers - 4 light years
Explain why Earth has seasons. - Answers - Earth's axis is tilted with respect to the
orbital plane. When the northern hemisphere is tilted toward the Sun it is summer, even
though we are further from the Sun.
Explain why stars appear at the same locations on the celestial sphere while the Sun,
Moon, and planets move during the course of the year. - Answers - The stars are so
incredibly far away that even though they are moving, the motion is hardly recognizable
from Earth .
List the 7 major types of electromagnetic radiation (light) from highest to lowest energy. -
Answers - Gamma, x-ray, ultra violet, visible, infra red, microwave, radiowave
What is the light carrying particle known as? - Answers - Photon
A fundamental limitation of a telescope's ability to resolve images, based on the wave-
like nature of light is known as _____. - Answers - Diffraction
What can be determined by the peak of a blackbody spectrum? - Answers - Peak
indicates the temperature of the object
How would the blackbody spectrum of stars that are the same temperature differ
between a large and small star? - Answers - The peaks would be at the same location,
since they are the same temperature, but the peak would be higher for the larger star
(more energy emitted per second)
Objects in the sky rise in the east and set in the west because Earth rotates from ___ to
___ about its axis. - Answers - West to East
What two main factors dictate how bright a star is as seen from Earth? - Answers - How
intrinsically bright it is and how far away it is.
What are commonly recognized star patterns known as? - Answers - Constellations
, What is significant about the Zodiac in the sky? - Answers - They lie along the plane of
the ecliptic (the plane of the solar system)
How is an absorption spectrum generated? - Answers - Photons are absorbed by atoms
raising electrons in atoms to higher energies
How is an emission spectrum spectrum generated? - Answers - Photons are emitted by
atoms lowering the energy of electrons in the atom
Do any elements on the periodic table have the exact same absorption/emission
spectrum? - Answers - All elements have their own unique absorption/emission spectra
What types of telescopes can be used on Earth? Why? - Answers - Radio and
optical/visible. Earth's atmosphere is transparent at those wavelengths.
How can Earth based observatories (telescopes) reduce interference from the
atmosphere? - Answers - Locate the observatory in high and dry location and use
adaptive optics.
What are five major differences between the inner planets and outer planets? - Answers
- Inner planets are rocky, warmer, have few moons, short years, and are small in size
Excluding eclipses, how much of the moon is lit at all times? - Answers - 1/2 the moon is
always lit
What causes the phases of the Moon? - Answers - The relative location of the Sun,
Moon and Earth
What is the apparent path that the sun and planets take during the course of a year as
observed from Earth known as? - Answers - The ecliptic
How could the ancients tell that the planets were different from the stars? - Answers -
The planets moved compared to the background stars
Describe the major contribution Copernicus made to out understanding of the solar
system. - Answers - Developed a helio-centric (sun centered) model of the solar system
Who was the first human credited for observing the night sky with a telescope? -
Answers - Galileo Galilei
What force is responsible for keeping planets in orbit about the sun? - Answers - Gravity
What is the primary difference between astronauts traveling to the Moon versus
astronauts traveling into low Earth orbit? - Answers - The distance to the moon is about
1000 times farther
Explain the physical reason why we on Earth experience day and night. - Answers -
Earth rotates about an axis of rotation once every 24 hours.
What is a light year? - Answers - The distance light travels in one year.
Approximately how far is the Sun from Earth? - Answers - 1 AU, 150 million km, 93
million miles, 8 light minutes
About how far is the closest star to the Sun? - Answers - 4 light years
Explain why Earth has seasons. - Answers - Earth's axis is tilted with respect to the
orbital plane. When the northern hemisphere is tilted toward the Sun it is summer, even
though we are further from the Sun.
Explain why stars appear at the same locations on the celestial sphere while the Sun,
Moon, and planets move during the course of the year. - Answers - The stars are so
incredibly far away that even though they are moving, the motion is hardly recognizable
from Earth .
List the 7 major types of electromagnetic radiation (light) from highest to lowest energy. -
Answers - Gamma, x-ray, ultra violet, visible, infra red, microwave, radiowave
What is the light carrying particle known as? - Answers - Photon
A fundamental limitation of a telescope's ability to resolve images, based on the wave-
like nature of light is known as _____. - Answers - Diffraction
What can be determined by the peak of a blackbody spectrum? - Answers - Peak
indicates the temperature of the object
How would the blackbody spectrum of stars that are the same temperature differ
between a large and small star? - Answers - The peaks would be at the same location,
since they are the same temperature, but the peak would be higher for the larger star
(more energy emitted per second)
Objects in the sky rise in the east and set in the west because Earth rotates from ___ to
___ about its axis. - Answers - West to East
What two main factors dictate how bright a star is as seen from Earth? - Answers - How
intrinsically bright it is and how far away it is.
What are commonly recognized star patterns known as? - Answers - Constellations
, What is significant about the Zodiac in the sky? - Answers - They lie along the plane of
the ecliptic (the plane of the solar system)
How is an absorption spectrum generated? - Answers - Photons are absorbed by atoms
raising electrons in atoms to higher energies
How is an emission spectrum spectrum generated? - Answers - Photons are emitted by
atoms lowering the energy of electrons in the atom
Do any elements on the periodic table have the exact same absorption/emission
spectrum? - Answers - All elements have their own unique absorption/emission spectra
What types of telescopes can be used on Earth? Why? - Answers - Radio and
optical/visible. Earth's atmosphere is transparent at those wavelengths.
How can Earth based observatories (telescopes) reduce interference from the
atmosphere? - Answers - Locate the observatory in high and dry location and use
adaptive optics.
What are five major differences between the inner planets and outer planets? - Answers
- Inner planets are rocky, warmer, have few moons, short years, and are small in size
Excluding eclipses, how much of the moon is lit at all times? - Answers - 1/2 the moon is
always lit
What causes the phases of the Moon? - Answers - The relative location of the Sun,
Moon and Earth
What is the apparent path that the sun and planets take during the course of a year as
observed from Earth known as? - Answers - The ecliptic
How could the ancients tell that the planets were different from the stars? - Answers -
The planets moved compared to the background stars
Describe the major contribution Copernicus made to out understanding of the solar
system. - Answers - Developed a helio-centric (sun centered) model of the solar system
Who was the first human credited for observing the night sky with a telescope? -
Answers - Galileo Galilei
What force is responsible for keeping planets in orbit about the sun? - Answers - Gravity
What is the primary difference between astronauts traveling to the Moon versus
astronauts traveling into low Earth orbit? - Answers - The distance to the moon is about
1000 times farther
