EAPS 105, The Planets
Exam 1 Study Guide
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From the lecture slides you should know the following:
Unit 1: Solar System Origins
1. What the Milky Way looks like in the night sky.
a. Page 7 of Unit 1 Slides
2. How much of the solar system’s mass resides in the Sun.
a. 99.86%
3. How much of the mass of the planets in our solar system resides in Jupiter.
a. 70%
4. Which are the terrestrial planets.
a. Mercury, Venus, Earth, and Mars
5. Why our Moon creates a perfect eclipse of the Sun.
a. It is the right size at the right distance,about 30 Earth diameters away (And the
right time, as the Moon is moving away from the Earth at ~4 cm/yr)
6. What an astronomical unit (AU) is and the general distance of the planets from the
Sun in these units.
a. 1 AU= the distance from the Sun to the Earth (150 million km)
7. The relative distance from the Sun of the planets in our Solar System.
a. Mercury = .39 AU
, b. Venus = .72 AU
c. Earth = 1 AU
d. Mars = 1.5 AU
e. Jupiter = 5 AU
f. Saturn = 10 AU
g. Uranus = 19 AU
h. Neptune = 30 AU
8. Where the first helium atoms originated.
a. Some of the hydrogen ions from the Big Bang fused into helium, generating heat
and light
9. The difference in characteristics between hydrogen ions (H+) and molecular
hydrogen (H2).
a. H+ has no electron, very hot, emit light
b. H2 two hydrogen atoms each has an electron, cool, does not emit light
10. What remains the only way to fuse helium and create heat and light in the modern
universe?
a. Fusion must occur in the center of stars (core)
b. This is because all of the hydrogen ions from the big bang have been used up,
with only molecular hydrogen and helium remaining
11. The elements that can be fused (created) in the core of a low-mass star like our
Sun.
a. Hydrogen fuses into helium
b. Helium fuses into beryllium
c. Helium and beryllium fuse into carbon
d. Helium and carbon fuse into oxygen
12. What happens when helium gets used up in the core of a low-mass star. (Quiz
question)
a. Fusion shuts down and the star begins the slow process of collapsing
b. Transitions to a Red Giant as it gradually warms, then causes a planetary nebula
before reducing itself to a white dwarf
13. The two forces that maintain a force balance within a normally operating star.
a. Pressure (from fusion) and gravity
14. What happens to the temperature of the core of the collapsing star and what is the
effect on the outer regions of that star.
a. As the core contracts, it heats up the layers around it (energy is concentrated)
b. The extra heat causes the outer regions to expand and cool (energy is distributed
at a greater volume)
15. Why red giants become red.
a. The cooler temps cause the star’s light to shift to the redder part of the spectrum
16. The fate of our Sun.
a. Will transition from the sun, to a red giant, and then form a white dwarf
17. What planetary nebulae are.
a. Relatively small gas clouds of ionized hydrogen (H+) (which is why they glow)
with low mass elements like carbon and oxygen
Exam 1 Study Guide
Discord Server GroupMe
Exam 1 Study Guide Exam 2 Study Guide
Exam 3 Study Guide Exam 4 Study Guide
From the lecture slides you should know the following:
Unit 1: Solar System Origins
1. What the Milky Way looks like in the night sky.
a. Page 7 of Unit 1 Slides
2. How much of the solar system’s mass resides in the Sun.
a. 99.86%
3. How much of the mass of the planets in our solar system resides in Jupiter.
a. 70%
4. Which are the terrestrial planets.
a. Mercury, Venus, Earth, and Mars
5. Why our Moon creates a perfect eclipse of the Sun.
a. It is the right size at the right distance,about 30 Earth diameters away (And the
right time, as the Moon is moving away from the Earth at ~4 cm/yr)
6. What an astronomical unit (AU) is and the general distance of the planets from the
Sun in these units.
a. 1 AU= the distance from the Sun to the Earth (150 million km)
7. The relative distance from the Sun of the planets in our Solar System.
a. Mercury = .39 AU
, b. Venus = .72 AU
c. Earth = 1 AU
d. Mars = 1.5 AU
e. Jupiter = 5 AU
f. Saturn = 10 AU
g. Uranus = 19 AU
h. Neptune = 30 AU
8. Where the first helium atoms originated.
a. Some of the hydrogen ions from the Big Bang fused into helium, generating heat
and light
9. The difference in characteristics between hydrogen ions (H+) and molecular
hydrogen (H2).
a. H+ has no electron, very hot, emit light
b. H2 two hydrogen atoms each has an electron, cool, does not emit light
10. What remains the only way to fuse helium and create heat and light in the modern
universe?
a. Fusion must occur in the center of stars (core)
b. This is because all of the hydrogen ions from the big bang have been used up,
with only molecular hydrogen and helium remaining
11. The elements that can be fused (created) in the core of a low-mass star like our
Sun.
a. Hydrogen fuses into helium
b. Helium fuses into beryllium
c. Helium and beryllium fuse into carbon
d. Helium and carbon fuse into oxygen
12. What happens when helium gets used up in the core of a low-mass star. (Quiz
question)
a. Fusion shuts down and the star begins the slow process of collapsing
b. Transitions to a Red Giant as it gradually warms, then causes a planetary nebula
before reducing itself to a white dwarf
13. The two forces that maintain a force balance within a normally operating star.
a. Pressure (from fusion) and gravity
14. What happens to the temperature of the core of the collapsing star and what is the
effect on the outer regions of that star.
a. As the core contracts, it heats up the layers around it (energy is concentrated)
b. The extra heat causes the outer regions to expand and cool (energy is distributed
at a greater volume)
15. Why red giants become red.
a. The cooler temps cause the star’s light to shift to the redder part of the spectrum
16. The fate of our Sun.
a. Will transition from the sun, to a red giant, and then form a white dwarf
17. What planetary nebulae are.
a. Relatively small gas clouds of ionized hydrogen (H+) (which is why they glow)
with low mass elements like carbon and oxygen
