Introduction
The early astronomers considered the sun, stars, and planets to be the only components of the entire universe. They had a strong belief that the Earth was the heart of the whole creation. They also realized that stars’ position did not change and that there were other star-like objects as well, wandering amid them.
They called the star-like objects; planets, which is a Greek word for “wanderers”. During the early 1500’s, the first astronomer Nicholas Copernicus in a controversial statement asserted that the sun was the center of the solar system, and not the earth. This was not popular with the people and although his ideas were unpopular, he is the father of modern astronomy. Galileo Galilei came later as the first astronomer to study the planets using a telescope (Kruesi 16).
Astronomers have with a lot of effort tried to find an answer to the original place of formation of asteroids and comets. As late as mid twentieth century, the well-known theory alleging that asteroids are leftovers of an ancient planet flare-up, still existed. A number of astronomers even believed that majority of these asteroids were situated in the asteroid belt that is located amid Jupiter and mass (Ipatov).
On the other hand, they assumed that comets were hanging groups of pebbles and sand that had gathered and were just moving about haphazardly all through the solar system. The idea was that if one of those substances drew near a planet, the bigger body’s magnitude pulled the comet in the direction of the inner solar system where Venus, Earth, Mars, and Mercury inhabited (Brownlee 32).
Origin of Asteroids and Comets
Due to lack of a clear theory or explanation as to the origin of comets and asteroids, scientists had to seek explanations from diverse outlooks in an effort to give details on the beginning of the solar system. Scientists discarded the previous notion that asteroids originated from an explosion of a planet that was situated somewhere stuck between Jupiter and Mars.
This is because the whole mass of entire bodies uncovered in the asteroid belt could not yet amount to a minute portion of the Earth’s mass (Brownlee 30). The modified conclusion came to be, that the asteroid belt does not contain adequate collection to structure a whole planet.
Similarly, it was later observed that asteroids are also located in other segments of the solar system apart from Mars and Jupiter. Through this attempt of giving an explanation on how the asteroids might have left the asteroid belt, an enhanced perspective of their formation was apprehended (Ipatov and Mather 1530).
A better perception of what comets actually are and how they were possibly formed came to existence. This is attributed to a number of researchers who drew attention to the reality that the previous theory on floating sandbank was insufficient, given that it was unsuccessful in explaining how a comet possibly will repetitively structure a tail during every visit to the inner solar system (Brownlee 31).
Originally, there was an assumption that sand grains creating a comet had an ice coating that melted as the comet drew nearer to the sun and the ensuing vapor figured the tail. Consequent reviews to this theory came up with a conclusion that only a single trip to the inner solar system would exhaust the entire ice. In great efforts to discover how the solar system was created, astronomers reassessed the theory of how comets were formed, with a belief in mind that icy bodies might have just formed in particular regions (Kruesi 16).
Solar System Formation
Ultimately, it is the reworked theory of formation of comets and asteroids that finally appeared to fit precisely and rationally in the larger model developed before by scientists to give details on how the complete solar system might have formed. This bigger model was put forward from the solar nebula premise initially proposed in the 18th century through French mathematician Pierre-Simon Laplace and German philosopher, Immanuel Kant (Ipatov).
In this contemporary theory, it is projected that the development of the solar system was about 4.5 to 5 billion years back, as a result of a vast cloud of dust and gases floating all over the space. The majority of these substances were extremely and incredibly thin dispersed, although they still put forth considerable gravitational pull.
Because of this gravitational force, particles of both dust and gas were forced to move in the direction of one another. Additional materials continued falling headed to the center of the nebula as the process went on. The heavier the core developed in mass, the higher the gravitational force it produced (Ipatov).
Due to the fact that a rise in gravitational pull leads to extra materials being attracted to the core and while the mass with gravitational pull amplified, the process gathered speed even further. The course of activity of falling materials to the center of the core, led to resistance so the majority of the energy escaped inform of heat that caused the inner elements of the planet to warm up.
This growth of the amplified mass and the relative rise in heat within the core increased so immensely that the heats build up at the center of the mass could not escape any further. This led to a nuclear reaction and the ultimate formation of the sun (Brownlee 32).
This contemporary theory therefore suggests that the residual materials since the first cloud, came together to structure a compacted disk that rotates around the sun. Scientists believe that the flat disk of objects was the beginning of the planets, asteroids, comets, and moons.
The elements of the enormous disk that were far-off the hot star rapidly began cooling down and finally coagulated into elements of ice and rock. Then, due to gravitational force, the particles were stuck close to each other and therefore forming bigger particles and ultimate huge bodies many thousand miles in diameter called planetesimals (Ipatov and Mather 1526).
Planetesimals were believed to contain loose granular-like structures, enabling them to absorb energy from whichever object that knocked them hence thwarting them from bouncing back yet again. A gathering of numerous big planetesimals led to the creation of planets and moons, whereas analogous accumulations of lesser planetesimals came up with formation of comets and asteroids (Rice 48).
Asteroid Belt
The crucial departure points of asteroids and comets in the early solar system could stem from the type of materials that made each one of them, in addition to the distance of each one of them from the sun. The planetesimals formed near the inner solar system contained harder material since they were more directed to the hot sun and therefore became heat-resistant.
Nearly all the materials that endured this sort of heat were iron and heat defiant rocks. Owing to the regular friction and the gravitational pull emanating from superior bodies, a number of the rocky and metallic planetesimals were finally integrated into the bodies of the central planets (Rose 56).
On the contrary, the hard planetesimals situated on the outer surface of the inner solar system, that is, beyond Mars, possibly could not collect to structure a planet. This could be due to the fact that they were very close to Jupiter, which being the leading planet in the whole solar system, applied an extremely powerful gravitational pull keeping majority of the objects, from gathering to make a single huge planet (Rice 50).
Consequently, a good number of the planetesimals stayed separate. This might be confirmed in the sense that the asteroids are experiential as existing in an orbit that ought to have been taken by a planet therefore leading to the verity that earthly pattern projected by Titius-Bode Law could be right (Rose 56).
Asteroid belt was a tumultuous and vicious region because particles were hauled towards one another via their gravitational pull and the sturdy Jupiter’s gravity. Scientists as a result suggested that it is impossible for millions of bodies to go on floating eternally in the asteroid belt (Kruesi 16).
The main feature that always interrupts these bodies is the shock that originates from recurring collisions. The majority of the asteroids fabricated from the ordinary lab material would be anticipated to collapse as indicated in a variety of laboratory experimentations although every asteroid amid an interconnected strength greater than iron’s is very likely to stand such collisions (Kruesi 16).
The Kuiper Belt
Following the reasoning, that Jupiter’s strong gravity is responsible for the expulsion of asteroids from the asteroid belt, several questions have been asked regarding to where the steroid disappeared to after expulsion. Some scientists argue that some of the asteroids might have penetrated the inner solar system with the likelihood that they could have crashed with either the Sun or the interior planets (Brownlee 33).
Some of the other bodies might have been subjected to never-ending wandering all along the “Interstellar black gulfs space” (Brownlee 33). Another group could possibly have been established in the outer solar system, amid a key argument that Jupiter’s sturdy gravity might have enforced them in the direction of a belt of substance that lies past the major orbits of Uranus, Saturn, and Neptune (Ipatov and Mather 1526).
However, it is important to note that the largest part of materials in this area is not mainly composed of stony and metallic materials but, relatively extra icy (Ipatov and Mather 1528). Located outside the Neptune planet, the belt is at times viewed as a reservoir in which a number of planetesimals go in coming up with a cold region a distance from the sun.
In the process of the said formation of the early on planetesimals, the heat in the inner solar system was too much for ice-based composite to endure and remain intact, resulting to a large number of them being blown outwardly (Brownlee 34).
Temperature at the distant ends were low thus enabling ice-made compounds to withstand. This in turn resulted to a buildup of gases such as ammonia, carbon dioxide, and water ice among others on the external section of the solar system. While there could have been sufficient materials that led to formation of small planetesimals, it was not possible to form the main planets during this span of time and instead formed a merely diffused precinct of quite a few icy objects (Rice 51).
This presence of an icy belt lying past Neptune was established recently by scientists although, it was previously proposed by two researchers; Gerard Kuiper and Kenneth Edgeworth. The affirmation that there are reality objects in that region was appreciated in 1992 where the region came to be named Kuiper Belt in respect of Kuiper, while the bodies therein came to be known as ‘Kuiper Belt objects”, or KBOs (Ipatov and Mather 1528).
Pluto
There have been questions seeking answers as to whether Pluto is a giant comet or a planet, considering it is the smallest planet. From the time it was discovered in the early 1930s, Pluto remains to be the planet whose location is farthest from the sun. This classification has held for a long time until recently when some scientists proposed that Pluto should not be regarded as a planet anymore. This is because of the mere fact that it possibly began just as a huge object in the Kuiper Belt (Rose 57).
There is a probability that Pluto was the ever-biggest ice-based planetesimal to form beyond Neptune region. Despite the fact that Pluto is made up of a very thin atmosphere as well as having a satellite which qualify it to be a planet, there are some asteroids that have satellites in their atmosphere as well. Additionally, other large KBOs have also been found out. In 2001, researchers saw “Varuna, 2001 KX 76”, that is about 550 miles diagonally (Brownlee 34).
This object is almost as large as the Pluto’s moon; Charon, moreover considered as a huge KBO. Because of this invention, a larger KBO approximated to be 800 miles across was later found out in 2002, referred to as xQuaoar. Today, hundreds of big KBOs have been discovered, and scientists estimate it to be a small percentage of them as they are approximated to exist in millions to billions (Ipatov and Mather 1528).
The Oort cloud
Comets are not exceptionally found in the Kuiper belt. When the strong gravitational force within Jupiter ejected a number of asteroids from the belt, a mix of gravities of Saturn, Uranus, Jupiter, and Neptune too vigorously expelled millions of planetesimals, which are suspected to have gone to the inner solar system and absorbed by either the sun or the inner planets (Rice, 47).
A good number of the objects are found in the region of comets and quite a few of the asteroids are found past Pluto in the outer solar system. The region was named after a Dutch astronomer called Jan Oort who discovered it in 1940 (Ipatov).
According to estimations, the immature solar system contained comets packing its environs with the Earth’s primeval sky getting numerous dozens of comets (Rice, 53). Most comets collided with the planets, but some effectively used their gravity to land into totally fangled orbits and mostly planets.
Jupiter was the only planet that could have survived at a higher rate. Any other comet close to Jupiter’s gravity could have been plunged into the Oort cloud or forever expelled from the solar system (Rice 49).This process might have carried 500 million years from the formation of the solar system to drain the supply of comet-based materials at a quicker rate according to scientists. Today the process still goes on, but it takes place at an extremely slow rate as a baton of activities of millions of years ago (Rice 50).
Astronomers estimate that “Oort cloud does elongate for approximately ten to one hundred thousand AU from the sun containing millions to billions of icy bodies” (Brownlee 35). Latest approximates have indicated that 2 percent of the entire objects in this region are asteroids made of metal and stone discarded by the huge planets. Repeated collisions between these objects force some to travel far-off the Oort cloud into the inner solar system. Some pass so close to the earth such that they are visible to human eyes (Rice, 53).
Conclusion
From the above discussion, it is evident that the existence of comets and asteroids in the solar system is not the only evidence to the way it was formed, but also the structure shows a lot about the process of formation (Ipatov). The largest planetesimals are supposed to be the present moons and planets, whereas the lesser planetesimals resulted to be the comets and asteroids.
A greater part of the asteroids was created in the asteroid belt. This part consists of rock and metal whereas, the largely ice-based comets were expelled to the Oort cloud and Kuiper Belt (Ipatov). The current position of asteroids and comets can therefore be perceived to be an excellent pointer to the development that captured millions of years to accomplish the formation of the solar system.
Works Cited
Brownlee, Donald. “Comets and the early solar system.” Physics Today 61.6 (2008): 30-35. Print.
Ipatov, S. Migration of Celestial Bodies in the Solar System. (2003) Editorial URSS Publishing Company, Moscow. Print.
Ipatov, S and Mather, J. “Comet hazard to the Earth.” Advances in Research. 33 (2004): 1524-1533. Print.
Kruesi, Liz. “Meteorite holds hints of solar system formation.” Astronomy 39.7 (2011): 16-16. Print.
Rice, Ken. “Building, moving and destroying planets.” AIP Conference Proceedings, 1094.1(2009): 45-54. Print.
Rose, William. “Early solar systems and the formation of massive stars.” AIP Conference Proceedings 713.1 (2004): 55-58. Print.