Astronomy 101 - Final Exam Review
(Answered) 78 Questions and Correct
Answers. 2025/2026.
Approximately how far is the Sun from Earth?
1 AU, 150 million km, 93 million miles, 8 light minutes
About how far is the closest star to the Sun?
4 light years
Explain why Earth has seasons.
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.
Objects in the sky rise in the east and set in the west because Earth rotates from ___ to ___ about its
axis.
West to East
What two main factors dictate how bright a star is as seen from Earth?
How intrinsically bright it is and how far away it is.
What are commonly recognized star patterns known as?
Constellations
What is significant about the Zodiac in the sky?
They lie along the plane of the ecliptic (the plane of the solar system)
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.
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.
Gamma, x-ray, ultra violet, visible, infra red, microwave, radiowave
What is the light carrying particle known as?
Photon
A fundamental limitation of a telescope's ability to resolve images, based on the wave-like nature of
light is known as _____.
Diffraction
What can be determined by the peak of a blackbody spectrum?
, 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?
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)
How is an absorption spectrum generated?
Photons are absorbed by atoms raising electrons in atoms to higher energies
How is an emission spectrum spectrum generated?
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?
All elements have their own unique absorption/emission spectra
What types of telescopes can be used on Earth? Why?
Radio and optical/visible. Earth's atmosphere is transparent at those wavelengths.
How can Earth based observatories (telescopes) reduce interference from the atmosphere?
Locate the observatory in high and dry location and use adaptive optics.
What are five major differences between the inner planets and outer planets?
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?
1/2 the moon is always lit
What causes the phases of the Moon?
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?
The ecliptic
How could the ancients tell that the planets were different from the stars?
The planets moved compared to the background stars
Describe the major contribution Copernicus made to out understanding of the solar system.
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?
Galileo Galilei
What force is responsible for keeping planets in orbit about the sun?
Gravity
(Answered) 78 Questions and Correct
Answers. 2025/2026.
Approximately how far is the Sun from Earth?
1 AU, 150 million km, 93 million miles, 8 light minutes
About how far is the closest star to the Sun?
4 light years
Explain why Earth has seasons.
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.
Objects in the sky rise in the east and set in the west because Earth rotates from ___ to ___ about its
axis.
West to East
What two main factors dictate how bright a star is as seen from Earth?
How intrinsically bright it is and how far away it is.
What are commonly recognized star patterns known as?
Constellations
What is significant about the Zodiac in the sky?
They lie along the plane of the ecliptic (the plane of the solar system)
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.
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.
Gamma, x-ray, ultra violet, visible, infra red, microwave, radiowave
What is the light carrying particle known as?
Photon
A fundamental limitation of a telescope's ability to resolve images, based on the wave-like nature of
light is known as _____.
Diffraction
What can be determined by the peak of a blackbody spectrum?
, 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?
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)
How is an absorption spectrum generated?
Photons are absorbed by atoms raising electrons in atoms to higher energies
How is an emission spectrum spectrum generated?
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?
All elements have their own unique absorption/emission spectra
What types of telescopes can be used on Earth? Why?
Radio and optical/visible. Earth's atmosphere is transparent at those wavelengths.
How can Earth based observatories (telescopes) reduce interference from the atmosphere?
Locate the observatory in high and dry location and use adaptive optics.
What are five major differences between the inner planets and outer planets?
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?
1/2 the moon is always lit
What causes the phases of the Moon?
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?
The ecliptic
How could the ancients tell that the planets were different from the stars?
The planets moved compared to the background stars
Describe the major contribution Copernicus made to out understanding of the solar system.
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?
Galileo Galilei
What force is responsible for keeping planets in orbit about the sun?
Gravity
