EARTH SCIENCE​ | ​GRADE 11/12
Unit 1
The Origin of the
Universe and the Solar
System
Answer Key
Lesson 1.1: Big Bang Theory
Check Your Understanding
A.
1.
2.
3.
4.
5.
Hubble
Hubble
Hubble
Lemaitre
Penzias and Wilson
6. Hubble
7. Penzias and Wilson
8. Hubble
9. Lemaitre
10.Lemaitre
B.
1. See graph below.
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2. The range is from 0.45 to 2 megaparsecs. Since 1 megaparses = 3.26 light
years, the range is 450,000 parsecs x 3.26 light years/parsec = 1,467,000 light
years to 2,000,000 parsecs x 3.26 light years/parsec = 6,520,000 light years.
3. The data indicates a correlated relationship between the two quantities since
it shows an increasing speed with increasing distance.
4. As the galaxy gets farther away from Earth, its velocity increases.
5. The Hubble’s law states that the relationship of the velocities of distant
objects in the universe is in proportion to their distance from Earth.
Challenge Yourself
1. The bread-raisin model can be compared to the expanding universe. ​The
bread is compared to the universe while the raisins are the galaxies. The
raisin does not expand. It only moves apart as the dough rises. Therefore,
distances in relation to other galaxies just increased because of the
expanding universe.
2. As the universe expands, the volume increases but the mass is not altered
since no new matter is added. Therefore, the density decreases.
3. Lemaitre explained that the universe originated in an explosive act of
primeval atom or the ‘Cosmic egg’ which was like a huge atomic nucleus;
Hubble formulated the Hubble’s law wherein he identified that the
relationship of the velocities of distant objects in the universe in proportion
to their distance from Earth; The discovery of Penzias and Wilson on the
cosmic radiation provided a strong evidence that the universe began from
the sudden expansion of a singularity, which supported Lemaître’s study.
4. The relationship of the velocities of distant objects in the universe is directly
proportional to their distance from Earth.
5. Nucleosynthesis is the formation of elements, such as hydrogen and
helium. The presence of these elements led to the formation of the stars and
the galaxies.
Lesson 1.2: Steady State Theory and Oscillating
Theory
Check Your Understanding
A.
1. S
2. O
3. S
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4. S
5. S
6. O
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7. S
8. O
9. O
10. S
B.
Challenge Yourself
1. It is termed as steady state theory because during the expansion of the
universe, the density of the universe remains constant.
2. The similarity of both theories is that they both predicted that the universe is
expanding. The difference is that the big bang shows that as the universe
expands, the density of matter decreases over time. On the other hand, the
steady state shows that the universe maintains a constant density as it
expands.
3. Matter such as stars and galaxies are continually added to the universe.
Therefore, making the density of the universe constant.
4. Other astronomers did not favor this theory since it did not follow the law of
conservation of energy and mass.
5. The term oscillate means to move from one position to another and back. In
the case of the oscillating universe, it explains that the universe is in a series.
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Lesson 1.3: Nebular Theory
Check Your Understanding
A.
1.
2.
3.
4.
5.
3
5
2
1
4
B.
Challenge Yourself
1. The dust cloud accretes forming clumps. Then, clumps form protoplanets.
These protoplanets collide to form planets.
2. Possible reasons are shockwaves from a supernova or the result of a passing
star.
3. The collapsed cloud of interstellar gas and dust results to a smaller radius
which means it will spin faster.
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4. Inner planets include Mercury, Venus, Earth, and Mars. They formed closer to
the sun. In addition, these planets could not grow very huge because the
amount of metallic elements is only a small fraction of solar nebula. Outer
planets, on the other hand, are composed of Jupiter, Saturn, Uranus, and
Neptune. They are huge planets made up of gases without land surfaces.
These planets were formed farther from the sun because the temperature
away from the sun was cool enough for gases to condense, forming these
massive, but low-density planets.
5. The core is composed of iron and nickel while the mantle and crust are
composed of silicates.
Lesson 1.4: Encounter Theory
Check Your Understanding
Planetesimal Theory
1. 3
2. 5
3. 4
4. 2
5. 1
Tidal Theory
1. 5
2. 2
3. 4
4. 3
5. 1
Challenge Yourself
1. The encounter theory is called such because planets formed from the
material ejected from the sun during an “encounter” with another celestial
object.
2. Unlike the nebular theory which describes Earth starting from molten mass,
the planetesimal theory describes Earth starting from a solid mass smaller
than its present size.
3. This theory is no longer accepted today due to the fact that hot material from
the sun will expand and dissipate rather than contract.
4. Unlike the planetesimal theory, the tidal theory proposes that the hot gas
from the passing star condensed into planets instead of condensing into
planetesimals.
5. It is not widely accepted anymore. This is because one problem of the tidal
theory is that the hot material from either star cannot contract; thus planets
will not form.
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