Paper 1 - Planetary Formation_SPST501_Kaplan
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Paper # 1 – Planetary Formation and the Nebula Theory
Shawn Kaplan
SPST501: Introduction to Space
Dr. Woodman
October 21, 2023
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Planetary Formation and the Nebula Theory
I.
Introduction
How the planets are formed
Planet formation and origins of the universe is a mechanical phenomenon that
has been intriguing astronomers and scientists alike since the dawn of time. Ancient
civilizations have been looking up at the stars formulating and updating their hypothesis
for centuries as technological advances improves and new data is unearthed. It was not
until the scientific revolution in the 1500s when astronomers began to study the factual
process of planet formation through in-depth observations and accurate record keeping.
The Nebula theory resulting in complex accumulation of cosmic materials with
protoplanetary discs that are surrounded by young stars (Planet Formation | Center for
Astrophysics, n.d.). This coupled with extreme gravitational forces leading to the
building blocks of the universe is the most widely accepted theory of how the universe
was created over 4.5 billion years ago (Woolfson, 2007). This research paper will
explore in more detailed the planetary formation process spanning from the first building
blocks of the universe to the conditions required to make it all transpire to the era of
stabilization and the final stages of planetary evolution.
II.
Nebula Theory
Explanation of nebula theory’s planet formation
The Nebula Theory also often referred to as the nebular hypothesis explains how
the universe was initially created. It states that planetary systems formed from colossal
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gasses of primarily hydrogen and helium, clouds and dust in outer space. As the solar
nebular cooled and condensed the sun was created as the center of the universe.
Adversely, the surrounding materials created the cosmic planets. Those vital materials
burned up destroying itself and becomes a super nova. (Camdan et al., 2021). Over
time, it eventually stabilizes, and collapses. The nebula theory is comprises of four main
principles: Gravitational collapse, conservation of angular momentum, protoplanetary
disc formation and condensation and accretion. Scientists and astronomers believe the
nebular theory to the most accurate based upon an immense and comprehensive
testing of evidence over centuries. This includes the observations of distant planets and
its outer compositions, protoplanetary discs that surround young stars. This formulation
of materials is a key concept and processes and helps explain how astronomers believe
this to be the basics and critical factor in how planets are created and evolve.
III.
Gravity
Gravity’s role in planet formation
Gravity and angular motion flatten cloud into an expanding protoplanetary discs
disc in the center where molecules collir4 together. A protostar cloud increases to
incredible pressures and temperatures. Under the stress of gravity tiny dust particles,
not much larger than the grain of sand clump together are formed created are super-
heated into droplets of molten rocks known as chondrules and forms a flattened
protoplanetary disk. Although the source of the heat remains a vast mystery, chondrules
are believed to be the building blocks of the solar system (Boccaletti, 2020).
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Massive collisions begin to transpire around the protoplanetary disk in which they
begin to collide and clump together forming much larger and more complicated
structures known as accretion process creates larger bodies ranging in sizes and is the
foundation for the building blocks of what is known as planets. Over time massive
gravitational pulls merge these bodies in the asteroid belt into a singular unit – and this
process repeated continuously disrupting countless asteroid bodies. As protoplanets
grow they conversely generate enormous heat due to acceration and absorbs other
bodies, thus steadily increasing in size and volume. They continue to grow from the
surrounding disk and become individual planets with its own gravitational properties and
forces that work shape the forming of the solar system (Woolfson, 2007).
IV.
Planet formation
Planet growth and stabilization
Similar to biological evolution, planets change over the course of its lifespan. This
is true with numerous factors indicating its ability to change, grow, and survive
throughout their development. As the solar system calms and cools over billions of
years, protoplanets and planetary bodies migrates towards the sun in its solar orbit. As
a result planets gravitational pulls and acceration with altering trajectories. These bodies
tighten and interact with other bodies to pull each other – often resulting in violent
collisions, further increasing its size and mass. This immense heat due to the
continuation of accretion and gravitational pulls, leads to formation of layers (Pfalzner et
all, 2015).
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Astronomers have observed superheated layers dense dust material in the
center of mass creating a core. More gaseous materials reside on the surface forming
the outer layers. Additionally, the nebula hypothesis dictated how the solar system
arranged the planets with heat and solar winds from the sun. Rocky terrestrial planets
such as Mercury, Venus, Earth, and Mars orbit closer to the sun, and lighter more
gaseous planets such as Jupiter, Saturn, Uranus, and Neptune were situated further
from the sun.
As planets become larger, less particles are within the universe at large that are
not part of a larger planets gravitational force and eventually stabilizes to a certain
extent. Solar nebula breaks up its own self-gravity and over time with violent collisions
can often become more eccentric; however, a small change in gravitational momentum
can and often changes the entire gravitational pull of the solar system sending it into
chaos (
Cadman et al., 2021). This further creates momentous changes therefore
changing entire planets gravitational orbit and pull over time.
V.
Final stages of planet formation
Cleaning up the solar system
The last and longest stage in planet formation is the cleanup of small bodies.
Unfortunately, this stage is also brings the challenges of vast uncertainty. An important
distinction is the growth of the inner planets continued through cleanup, whereas
cleanup from the outer planets were primarily complete by the end of oligarchy, or the
growth of planets.
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The remaining gas in protoplanetary disk is gradually dispersed in a process that
formalizes a planetary system in which new planets that undergo further
transformations. In this step they typically acquire moons, migrate with other systems
and interact with other planets. As the oligarchs grew, their number density decreased,
but its surface mass density increased. Major assumptions indicate as that as big
bodies got bigger then smaller ones got smaller as the result of undergoing collisional
fragmentation. This process was a short phase in planet formation growth (Goldreich et
al., 2004)
Research indicates that ejections from the outer planets was set by the accretion
rate at the inner planet region and by the ejection rate at intense gravitational forces of
the cross sections of inner planets. It is possible that Earth was formed after Uranus and
Neptune since they acquired most of their mass by the end of oligarchy.
VI.
Critical Thinking
Alternative hypothesis and validation
The solar nebula theory was not the only theory; just the most accepted to date.
The monistic theory states that the sun and planets were all created in a single process.
This has major flaws including the assumption that most of the angular momentum of
the system is the sun – however this is not true. Research on the nebula theory has
been based upon a wide body of knowledge that has been peer reviewed and
respected by experts in their field of study for corroboration (Woolfson, 2007).
The Theory introduced by scientist Otto Schmidt and suggested that stars
passing through one of many dense clouds would acquire a dusty-gas envelope. The
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floccule or protoplanet theory introduced in 1960 links planetary formation with the
production of a stellar cluster. Its starting point was a cloud of gas and dust that was to
form a galactic cluster. Testing for theories are based on observations from planets
forming in distant galaxies with powerful telescopes. Forming theories and validity is
difficult to impossible to prove on earth. The current solar nebula paradigm may not be
valid and requires an unusual approach to find out what experiments and observations
are indicating rather than trying to force them is not what the observations are
indicating.
Richard Feynaman quoted: “The test of all knowledge is an experiment.
Experiment is the sole judgment of scientific ‘truth’.”
Critical thinking is important aspect of a wide array of hypothesis, and exploring
alternatives is an important factor. By studying what is known and unknown either
through lacking evidence or the inability to test hypothesis due to scientific constraints
due to the harsh immense environment that space exists in.
VII.
Conclusion
Summary of how planets are formed
Planet formation is still a major mystery to scientists, and the orbital spacing of
planets resulting towards stability against large-scale chaotic pertubrations is still largely
unknown. Although the nebula theory is the most likely scenario that the planets in the
solar system were created and been debated for centuries and future generations will
continue to debate the question.
At the heart most agree that the solar system began
with primordial gases and dust cooling to form the sun to form protoplanetary discs.
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Gravity played an important role with angular momentum to capture dust
particles in forming the protoplanetary discs and eventually lead to the massive
instability of colossal collisions between larger and small bodies to form planets. Later
stabilization of the solar system played an important role into the current solar system.
Considering the age of the solar system, the solar system is not complete, nor will it
ever be; change of this magnitude is inevitable and our time on earth is a tiny fraction of
what is out there and understood. Science will continue to explore the light years of
research ahead of us.
Sections of theories will be validated by science, while others
disputed in the quest to finally answer the age old question of what and how the solar
system was created.
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References
Boccaletti, A., E Di Folco, Pantin, E., Dutrey, A., Guilloteau, S., Tang, Y. W., Piétu,
V., Habart, E., Milli, J., Beck, T. L., & A -L Maire. (2020). Possible evidence of
ongoing planet formation in AB Aurigae. A showcase of the SPHERE/ALMA
synergy.
arXiv.org
.
https://doi.org/10.1051/0004-6361/202038008
Cadman, J., Rice, K., & Hall C. (2001). AB Aurigae: possible evidence of planet
formation through The gravitational instability. Monthly Notices of the Royal
Astronomical Society, 504(2), 2877-2888.
https://doi.org/10.1093/mnras/stab905
Goldreich, P., Lithwick, Y., & Sari, R. (2004). Final Stages of Planet Formation [Review
of Final Stages of Planet Formation]. The Astrophysical Journal, 614-497-
507(Octover 2004).
New Frontiers in the Solar System: An Integrated Exploration Strategy, National
Academies Press, 2002. ProQuest Ebook Central,
https://pweb.cfa.harvard.edu/research/topic/planet-formation
Pfalzner, S., Davies, M. B., Gounelle, M., Johansen, A., Münker, C., Lacerda, P., Zwart,
S. P.,
Testi, L., Trieloff, M., & Veras, D. (2015). The formation of the solar system.
Physica Scripta, 90(6), 068001.
https://doi.org/10.1088/0031-8949/90/6/068001
Woolfson, Michael Mark. Formation Of The Solar System, The: Theories Old And New,
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World Scientific Publishing Company, 2007. ProQuest Ebook Central,
https://ebookcentral.proquest.com/lib/apus/detail.action?docID=1681464