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Planetesimal
Planetesimals /plænᵻˈtɛsᵻməlz/ are solid objects thought to exist in protoplanetary disks and in debris disks. A widely accepted theory of planet formation, the so-called planetesimal hypotheses, the Chamberlin–Moulton planetesimal hypothesis and that of Viktor Safronov, states that planets f…
What is the tidal theory of mass?
The tidal theory, proposed by James Jeans and Harold Jeffreys in 1918, is a variation of the planetesimal concept: it suggests that a huge tidal wave, raised on the sun by a passing star, was drawn into a long filament and became detached from the principal mass. What is the planetesimal theory?
What is the planetesimal hypothesis?
Planetesimal Hypothesis, a theory of the origin of the solar system. It was proposed by Forrest R. Moulton and Thomas C. Chamberlin about 1900. The theory states that the planets were formed by the accumulation of extremely small bits of matterplanetesimalsthat revolved around the sun.
What is the jeans and Jeffreys tidal theory?
The tidal theory, proposed by James Jeans and Harold Jeffreys in 1918, is a variation of the planetesimal concept: it suggests that a huge tidal wave, raised on the sun by a passing star, was drawn into a long filament and became detached from the principal mass. What is the basic assumption of jeans Jeffrey tidal theory?
Does the tidal hypothesis explain the distance between the planets?
(3) N.N. Parisky has proved on the basis of mathematical calculation that tidal hypothesis fails to explain the real distances between the sun and the planets in our present solar system.
What do you mean by planetesimals?
Definition of planetesimal : any of numerous small celestial bodies that may have existed at an early stage of the development of the solar system.
What is the difference between planetesimal hypothesis and tidal hypothesis?
The planetesimal hypothesis is no longer considered a likely explanation of the origin of the solar system. The tidal hypothesis is one of the modern hypotheses of the origin of the earth and the solar system.
What is planetesimal accretion theory?
Accretion theory explains the process of small clumps of dust gathering together to gradually form planetesimals. These planetesimals accumulate more materials and form protoplanets. These protoplanets build until they form planets within the solar system.
What is tidal hypothesis theory?
The tidal hypothesis is a recent theory for the beginnings of the earth and solar system. Jeans' theory was founded on a set of axioms. Bernoulli defined the static reaction of the Earth's waters to the tidal potential, whereas Newton addressed the tide-producing forces.
Who proposed the planetesimal theory?
Thomas Chrowder Chamberlin, (born Sept. 25, 1843, Mattoon, Ill., U.S.—died Nov. 15, 1928, Chicago), U.S. geologist and educator who proposed the planetesimal hypothesis, which held that a star once passed near the Sun, pulling away from it matter that later condensed and formed the planets.
What are the two types of accretion?
There is probably not one accretion process but several, depending on the scale at which accretion operates. A first process is the sticking of microscopic dust into larger grains and pebbles. A second process is the formation of an intermediate class of objects called planetesimals.
Where are planetesimals found?
Planetesimals are the building blocks of the rocky terrestrial planets (Mercury, Venus, Earth, and Mars) as well as the cores of the gas giants (Jupiter and Saturn) and the ice giants (Uranus and Neptune).
What are the four theories of the solar system?
These are the Nebular Hypothesis of Laplace, the Planetesimal Hypothesis of Chamberlin and Moulton, and the Capture Theory of See. Darwings theory of Tidal Friction is scarcely a distinct hypothesis, but is mentioned separately on account of its application to all of the others.
What are the 2 types of planets?
Planets are generally divided into two groups: the terrestrial and the giant planets....Mercury.Venus.Earth.Mars.Jupiter.Saturn.Uranus.Neptune.More items...
What are the four theories of the solar system?
These are the Nebular Hypothesis of Laplace, the Planetesimal Hypothesis of Chamberlin and Moulton, and the Capture Theory of See. Darwings theory of Tidal Friction is scarcely a distinct hypothesis, but is mentioned separately on account of its application to all of the others.
Which hypothesis is based on dualistic concept?
According to dualistic concept (binary hypothesis), the Solar System originated from two stars.
Which hypothesis is about original solar system is convenience to you give your opinion?
The nebular hypothesis is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System (as well as other planetary systems). It suggests the Solar System is formed from gas and dust orbiting the Sun.
Who developed the planetesimal theory?
Planetesimal theory. was put forth by Viktor Safronov in 1941; the theory explained planet formation in the early solar system from accretion of small bodies, growing in size as gravity attracted more and more objects. Learning Outcomes. Our lesson on planetesimals aims to prepare you to:
What is a planetesimal?
Definition. A planetesimal is a rock-type object formed in the early solar system from collisions with other objects in the solar system. The collisions eventually formed larger objects that led to the formation of planets. 3:17.
What is the driving force that allowed planetesimals to collide into each other?
As the solar system formed from a nebula, gases and molecules combined and grew larger and larger. Gravity was the driving force that allowed the planetesimals to collide into each other as they orbited the young Sun.
What is the theory of planets?
The planetesimal theory, put forth by Viktor Safronov in 1941, explains planet formation in the early solar system from accretion of small bodies, growing in size as gravity attracted more and more objects. As the small bodies orbit, their gravity is very weak and they must rely on non-gravitational forces to stay together, such as radiation pressure and the emission of thermal photons.
What were the common causes of the formation of the solar system?
Collisions were common during the formation of the solar system and planets. Planetesimals continually collided and destroyed each other, but some planetesimals were able to withstand the impacts and grow, eventually forming into planets.
What is planetesimals lesson?
Planetesimals are small rock fragments that combined together to eventually form planets. This lesson will discuss the theory behind planet formation and the importance of planetesimals.
When did planets become large?
Nearly a billion years after the formation of Earth, during the Hadean Era 3800 million years ago, most planetesimals had combined and become large enough to be considered planets. The fragments that did not make it were either thrown out to the outer edges of the solar system or possibly captured as moons by the larger planets.
What is the planetesimal hypothesis?
Planetesimal Hypothesis, a theory of the origin of the solar system. It was proposed by Forrest R. Moulton and Thomas C. Chamberlin about 1900. The theory states that the planets were formed by the accumulation of extremely small bits of matterplanetesimalsthat revolved around the sun. This matter was produced when a passing star almost collided with the sun. During the near-collision, hot gases were pulled out of both stars and the gases then condensed. The planetesimal hypothesis was widely accepted for about 35 years.
How was planetesimal matter produced?
This matter was produced when a passing star almost collided with the sun. During the near-collision, hot gases were pulled out of both stars and the gases then condensed. The planetesimal hypothesis was widely accepted for about 35 years.
Why did the solar system expand?
Once the material was pulled away to where the gravitational forces were weaker, it would expand because of its heat. Before condensation could take place, the gases would have almost entirely dissipated. The planetesimal hypothesis is no longer considered a likely explanation of the origin of the solar system. Advertisement.
What is the greatest flaw in the theory of condensation?
The greatest flaw in the theory is the assumption that the material drawn out of the stars would condense. The extremely hot gases that make up a star are held together by the gravitational forces within the star.
What is the evidence in favour of the Tidal Hypothesis?
Evidence in Favour of the Hypothesis: The ‘tidal hypothesis’ of James Jeans has not only explained the origin of the solar system and the earth but has also attempted successfully to some extent, to solve various problems of the solar system related to its shape, size, structure and peculiar motion.
Why did Jeffreys suggest modifications in the tidal hypothesis of James Jeans?
It may be pointed out that Jeffreys suggested modifications in the tidal hypothesis of James Jeans with the intention to remove major inherent weak points of the tidal hypothesis so that it can withstand the criticisms of the modern scientific world.
How many planets were formed by James Jeans?
According to James Jeans nine planets of our solar system were formed due to cooling and condensation of the incandescent mass of gaseous matter of the filament. The filament, after being detached from the sun, began to cool down. Thus, the filament started contracting in size on cooling. The contraction of the filament led to its breaking in several pieces and each piece was condensed to form one separate planet. This process led to the formation of nine planets.
What did James Jeans postulate about the universe?
James Jeans postulated that due to massive gravitational force of the ‘intruding star’, huge amount of matter was ejected from the primitive sun , which later on became the building material of future planets. According to the Newton’s law of universal gravitation (1687) everybody in the universe attracts every other body with a force which is directly proportional to the product of the masses of the two bodies and inversely proportional to the square of the distance between them.
How are planets formed?
According to James Jeans the planets were formed from the filament which was revolving around the sun. Thus, the planets of our solar system should also revolve around the sun. In our present day solar system all the planets are revolving around the sun in the same direction and also in the same orbital plane (the orbital plane of Pluto is however slightly inclined).
What force did the intruding star exert on the surface of the primitive sun?
Evolution of filament: According to James Jeans the ‘intruding star’ was continuously moving along such a path that it was coming nearer to the primitive sun and thus exerted gaseous tidal force (gravitational pull) on the surface of the ‘primitive sun’. As the ‘intruding star’ came nearer and nearer to the ‘primitive sun’, ...
What is the cigar shaped tide?
When the ‘intruding star’ came nearest to the ‘primitive sun’ its gravitational force became maximum, with the result a giant cigar-shaped tide, thousands of kilometres in length, was created on the outer surface of the ‘primitive sun’ and ultimately huge mass of matter, in the shape of a cigar, was ejected from the ‘primitive sun’. James Jeans called this cigar-shaped matter as filament which was much thicker in the centre and thinner and sharper at the ends (tapering ends) (see fig. 2.1).
