The solar system has
come a long way, from its original form, the solar nebula to a star system
complete with terrestrial and jovial planets, it is a wonder how this all came
to be. Humans like to think and in this
thinking they are able to comprehend the factors that came into the conditions
of the terrestrial planets. What is
unique however, is planet Earth and its ability to harbor not only life but
intelligent life. Humans have become
technologically capable of leaving planet Earth and have landed on the Moon. This has given humans the ability to know
what to expect if they ever decide to colonize another planet. The closest planet that humans may be able to
achieve this feet is planet Mars as it has certain characteristics which make
it a possibility that life could exist there.
Beyond this however, communities and corporations are eyeing prospects
which could rapidly increase the value of the economy. Thanks to the landings on the moon, man has
developed the technical knowledge to both survive in space and the ability to extract
resources from objects such as asteroids which could give humanity the edge to
be able to advance civilization on another planet.
There is evidence
available which explains how the solar system formed. Proposed by Immanuel Kant, in 1755 he
specified that, “star systems are born through the gravitational collapse of
huge clouds of gas in space”(Bennett 2020). His theory came to be known as the, “nebular
theory,” of solar system formation. A
nebula or cloud also referred to as a solar nebula gave birth to the solar
system about 4.5 billion years ago (Bennett 2020). It is believed that this nebula was made up
of 98% hydrogen and helium and only 2% of everything else combined (Bennett 2020). It is further believed that the solar nebula
began as a spherical cloud of very cold, low density gas. These gasses were so spread widely apart that
gravity was unable to pull it together to initiate a collapse. Therefore, it is theorized that a cataclysmic
event such as the explosion of a nearby star caused the collapse. When the collapse commenced, gravity took
hold and continued the process. Heating,
spinning and flattening altered the solar nebula’s density, temperature and
shape. The solar nebula caused orderly
motions where the planets all orbit the Sun on nearly the same plane resulting
from their formation via the flat disc.
Further, the direction in which the disk was spinning explains how the Sun
rotates in that direction. In the center
of the disc, gravity pulled the material together to form the Sun. Gas surrounded the disc and these materials
clumped together to form seeds. Through
condensation, solid materials were created.
There were four types of materials present in the solar nebula which are
as follows: hydrogen and helium,
hydrogen compounds, rock and metals (Bennett 2020). Materials were not able to condense if they
were close to the Sun because the temperature was too hot. As materials moved further out, the
temperature became cooler, enough for metals and rocks to condense into solid
particles. Ices formed on the frost line
which is in between the orbit of Mars and Jupiter. The process whereby seeds grew to become
planets is accretion. The development
starts with microscopic solid particles formed from gas from the solar
nebula. These particles began to collide
and combine. Once large enough, they
became planetesimals. They began than to
attract other large mass through gravity which accelerated their growth. Towards the inner solar system, these
planetesimals were able to form because metal and rock could condense into
solid particles. Evidently these
planetesimals became large enough to become terrestrial planets. Past the frost line however, lower
temperatures allowed ice to condense along with metal and rock allowing them to
become icy planetesimals. They gathered
enough mass to capture and hold hydrogen and helium. This is how the Jovial planets came to
be. Lastly, the materials that were left
over which did not accrete into planetesimals became either asteroids or
comets. Asteroids are rocky while
comments are icy. These asteroids and comets
bombarded the planets causing landscape changes to the surface of the
planets. Further, water bearing
planetesimals that accreted beyond the frost line collided with the terrestrial
planets causing them to have their unique features.
Now
that the creation of the solar system has been briefed, this essay will explore
each of the terrestrial planets present in the solar system. Terrestrial worlds, “were all formed from the
accretion of rocky planetesimals, and all have been shaped by the same
geological and atmospheric processes” (Bennett 2020). Geological activity is variable to the
planets size. This means that the
ability for the surface to change is dependent on how big the planet is. Most geological activity is caused by the
heat that is generated by the planet. The
larger the planet the longer it takes to cool.
When these terrestrial planets were young, they all were hot enough to
have molten interiors. Through the
process of differentiation, materials separated by density which caused the
layers of the planets as follows, the core, mantle and the crust. The core is the most dense and it consist of
metals such as nickel and iron while the crust is the outer most layer
consisting of less dense material such as rock.
Interior heat generated at the center supplies the energy needed to melt
and move rocks to reshape the surface of these planets. Terrestrial planets resulting from this
geological activity have four main geological processes which shape their
crust, impact cratering, volcanism, tectonics and erosion (Bennett 2020).
Impact cratering is a result of objects hitting the surface of the
planet causing changes to the surface.
Volcanism on the other hand happens when molten rock from underground is
forced to the surface. Substantial
amounts of heat are required for this process to take place. Through eruptions, gasses are released. It is widely believed that through this
process atmospheres are created. Venus,
Earth and Mars all have atmospheres.
Earth is a unique terrestrial planet because its interior heat creates a
magnetic field as a result of convection in the core creating electrical
currents. Its a strong magnetic field
protects the planet from charged particles coming from the Sun which could take
away atmospheric gas and cause genetic damage to life. The magnetic field serves to deflect these
creating an environment in which life can exist on the surface. Next, tectonics. This process stretches or compresses the
lithosphere to reshape the crust. This
process can create mountains, valleys and seas amongst others. Earth’s tectonics are unique as it is the way
that species were able to be distributed throughout the continents. The plate tectonics of the Earth forced the
creation of its terrain in which animals have evolved accordingly to
adjust. Erosion on Earth plays a major
role for example, it shapes valleys, sifts sand dunes, creates rivers amongst
others. Erosion is what built the Earth
as sediment layers formed. Lastly,
erosion is the breakdown or transport of material. Ice, liquid and gas are all vehicles by which
this process occurs.
Mercury
is similar to the moon. There are
numerous impact craters and during bombardment molten lava covered these
up. These flows of lava occurred most
likely as a result of the radioactive decay accumulated to melt part of the
mantle. Mercury has large cliffs which
were formed from early tectonic forces which compressed the crust. This planet has a large metallic core. This core expands and contracts and in its
history this cooled causing the planet to shrink.
Venus
is about 5% smaller than earth in radius (Bennett 2020). Earth and Venus are geologically
similar. There are volcanoes, tectonic
features and impact craters present on the planet. However, Venus lacks erosion as a result of a
lack of water and it has slow surface winds caused by its slow rotation. Also, there is no plate tectonics on
Venus. The atmosphere contains 200,000
times more carbon dioxide than Earth’s atmosphere (Bennett 2020). This causes the carbon dioxide to be
dispersed into the atmosphere rather than in the rocks making the planet
uninhabitable. The disappearance of
water on the planet is likely as a result of ultraviolet light from the sun
breaking down molecules of water vapor causing the hydrogen atoms to escape
into space. The fact that Venus is so
close to the Sun is the reason why the planet does not have oceans. The runaway greenhouse effect completely
evaporated water on its surface. The
planet has a thick atmosphere full of greenhouse gases which cause the
temperature of Venus to increase so intensely making it uninhabitable.
Earth
has four significant features which make life possible. These are as follows; surface liquid water,
atmospheric oxygen, plate tectonics and the climate (Bennett 2020). The
water on Earth originally outgassed from volcanoes which caused rain to fall
creating the oceans. This water did not
freeze or evaporated but remained on the surface. This is a result of the moderate green house
gas effect and the safe distance from the Sun.
Oxygen makes up about 21% of the Earth’s atmosphere (Bennett 2020). Oxygen is essential to animal life. The oxygen on earth is a product of the
plants and wildlife that inhabit the Earth.
The production of oxygen makes it possible for the Earth to have a protective
layer, the ozone layer. Plate tectonics
is a slow process wherein continents are rearranged over millions of
years. This reorganizes the crust
building mountains, valleys etc. Lastly,
Earth has a moderate temperature. The
temperature on Earth is regulated via the carbon dioxide cycle which
atmospheric carbon dioxide dissolves rain, then eroding the rocks which then
minerals are funneled through the oceans and combine to make carbonite rocks. These rocks are then moved into the mantel
via plate tectonics causing these rocks to melt and are then outgassed by
volcanoes regulating the temperature.
Mars
is estimated to be half as large as Earth.
This planet has several volcanoes rising higher than Mount Everest. It shows evidence of tectonics which created
various valleys throughout the planet.
Erosion plays a major role in this planet. Scientists believe that this planet was once
warm and wet which can be an indication that life was once possible on this
planet. There is, however, no liquid
water that exist on the planet as the surface conditions do not permit it. The planet is so cold that any liquid water freezes. Further, the air pressure is so low that
liquid water evaporates. Despite this
however, there is frozen water to be found on the planet, specifically on its
poles. Evidence suggest that water once
flowed freely on this planet. The
erosion that has occurred on the planet indicate that the lack of small craters
and the indistinct rims of large craters were as a result of ancient rainfall. The evidence of flowing water on the planet
suggest that the planets temperature and atmospheric pressure was much higher
than they are today. The small size of
the planet caused it to not be able to maintain internal heat which prevented
the magnetic field to retain water and gas.
Now
that the terrestrial planets are looked at, this essay will then brief on the
criteria which make life possible on such planets. Clearly if life was to be harboured in other
planets, the planet itself should be similar to the conditions found on Earth. As these conditions were explained previously,
there are additional features which could bring the possibility of life to
other planets. Scientist often refer to
a, “habitable zone.” This means that the
planet has to be a comfortable distance from the star so that liquid water can
be maintained on the surface. This
mentioned star or stars around the planet also have to be stable. For example, overly luminous stars can cause
everything to burn up. These types of
stars would then not support life. The
planet should also not have a low mass.
Having a low mass would cause issues with gravity. If there is low gravity, the planet won’t be
able to maintain an atmosphere. A habitable planet must further rotate on its
axis and revolve around its star. This
would cause seasons and allow life to evolve.
The planet must also possess a molten core. Such core would then create a magnetic field
protecting the planet from flares given off by nearby stars. Further, it should hold an atmosphere. This would then allow the trapping of gasses
such as carbon dioxide to regulate the temperature. Moreover, having an atmosphere blocks harmful
radiation from getting onto the surface of the planet. According to NASA there should also be
regions of liquid water. This would
allow complex organic molecules to thrive.
These are some of the features that habitable planets have. It is clear that if humans are to colonize
other planets, they would have to consider these findings and further input
from the scientific community (Ashish 2019).
The
Moon landing was a significant feat of human ingenuity. This landing allowed humans to be able to
predict and speculate the conditions on other bodies within the solar
system. The Apollo 11 program was the
first Moon landing. On July 20, 1969
America landed three astronauts onto the moon.
They were able to observe the harsh conditions of outer space. The astronaut’s setup Apollo Lunar
Experiments Package and retroreflector which would continue to gather data from
the moon. They also brought back several
undiscovered minerals to Earth tranquillityite, armalcolite, and pyroxferroite (Perkins
2012). The discovery of these minerals
implies that humans have a lot to learn yet about their solar system. Through the Moon landing, humans were able to
increase their awareness of outer space.
In contemporary society, both private companies and government agencies
are exploring space. Resulting from the
successful Moon landings and other ventures into space, humans have begun to
think of the possibility of colonizing Mars.
As mentioned earlier herein, Mars was once a place where water
thrived. Its polar caps contain frozen
water. There is evidence of
erosion. However, its mass is small
which would then cause issues with gravity.
Therefore, Mars lacks a significant atmosphere to allow life to occur on
the planet. This nonetheless has not
stopped scientist from dreaming about it’s colonization. Scientist have proposed a solution however,
to the lack of atmosphere on Mars. They
propose that if humans were to colonize the planet, it would have to be
terraformed. This means that humans need to
release “gases from a variety of sources on the Red Planet to thicken the
atmosphere and increase the temperature to the point where liquid water is
stable on the surface” (Steigerwald 2018). If the Moon landing provided humanity with
the technical knowledge to be able to be able to carry out human operations in
space, the future landing of Mars can further this development. Like with the discovery of minerals on the
Moon, it is very possible that humans will also discover something that has yet
to occur or has not or does not occur on Earth.
With that said, these significant prospects resulting from the Moon
landing have not stopped scientist from thinking about landing on asteroids to
mine their resources. In order to
colonize other planets such as Mars, humans would need a vast amount of
resources to be able to build infrastructure.
Asteroids can fill that void.
Luxemburg aims to “be the global leader in the nascent race to mine
resources in outer space” as “Asteroids, … predominat[ing] between Mars and
Jupiter, are veritable treasure chests, packed with gold, platinum, and alloys
that are needed to produce modern technologies” (Zaleski 2018). There are
asteroids which astronomers have been observing which contains large amounts of
rare minerals that would surpass the total value of Earths current day
economy. Such is the case with the
asteroid 16
Psyche. This asteroid was discovered by NASA’s Hubble Telescope. This is an asteroid is made of solid metals and
its apparently worth $10,000 quadrillion (Jamasmie 2020). Economically speaking, these asteroids
are a source of wealth for those that are rich enough to be able to afford to
launch a ship onto space. Along with
Luxembourg, Japan also has plans to mine asteroids. They launched the Hayabusa 2 which will” touch down on
the asteroid Ryugu” (Crane 2020). The Hayabusa 2 will then “use explosives to
blast a large lump of copper into the surface. This will create an artificial
crater and reveal the asteroid’s insides” (Crane 2020). This process will allow the Japanese to be
able to gather significant data with regards to mining. The USA, Russia and several EU nations
are mobilizing to take advantage of this in the near future and they are
certainly aware of the benefits it could provide their economy. Prioritizing asteroid mining by developing
national interest could very well pay off for these countries as these
government agencies and their private companies could surge in the stock market
resulting from these vast resources which could then be used to colonize
habitable planets. In sum, what results
here is the expansion of humanity.
It is very important to know the origins of the solar system because it gives scientist data on what to expect in outer space. The contrasting differences of the terrestrial planets gives humanity the ability to be able to determine habitable planets. Resources are then needed to be able to colonize potential plants such as Mars. Evidence from the Moon landings allowed scientist to broaden their perspective of the solar system. It showed them that there are things out there that have yet to be discovered, as is the case with the rare minerals discovered on the Moon. With the discovery of these minerals, governments and the private industries aspire to exploit the resources of asteroids. This should then allow humans to have the necessary resources to be able to build infrastructure on colonized planets. With this, new industry are going to emerge and the future of the economy looks to be attractive as humans set their sights beyond Earth.
WORK CITED
Ashish.
(2019). “What Makes A Planet Habitable?” Retrieved from: https://www.scienceabc.com/nature/what-makes-a-planet-habitable.html
Bennett et al. (2020). “The Cosmic Perspective,” (USA),
Pearson Education inc.
Crane, L. (2020). “Japan's Hayabusa 2 may finally kick-start
the asteroid mining era.” Retrieved
from: https://www.newscientist.com/article/mg24132182-500-japans-hayabusa-2-may-finally-kick-start-the-asteroid-mining-era/
Jamasmie, C.
(2020). “NASA finds rare metal
asteroid worth more than global economy.”
Retrieved from: https://www.mining.com/nasa-finds-rare-metal-asteroid-worth-more-than-global-economy/
Perkins, S.
(2012). “Rare Moon Mineral Found
on Earth,” Retrieved from: https://www.sciencemag.org/news/2012/01/rare-moon-mineral-found-earth
Steigerwald, B.
(2018). “Mars Terraforming Not
Possible Using Present- Day Technology.”
Retrieved from: https://www.nasa.gov/press-release/goddard/2018/mars-terraforming
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