This hypothesis was put forward by Lyttleton in 1938. According to this hypothesis, it is believed that prior to the evolution of the solar system, along with the Sun there existed another companion star which was captured later on by another huge star that came very close to the Sun and its companion star.
While the huge star started receding away the filament drawn by the attraction of the invading star came into the control of the Sun which later gave rise to the planets etc. in a similar way as explained by Jeans and Jeffreys in their ‘Tidal Hypothesis’.
Weizsacker’s Hypothesis
In 1944, a German physicist, C.F. Von Weizsacker proposed a modification of the Nebular Hypothesis. According to this hypothesis, the Sun was surrounded by a thin, flat, rapidly rotating cloud of matter that encircled its equator.
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This cloud was having a much larger quantity of hydrogen and helium which had escaped into space in course of time because of their being extremely light in weight. The materials that formed the planets were carried as floating dust particles in the rotating gaseous envelope round the Sun and by gradual accretion of these matter the planets were formed. This hypothesis suggests a cold-origin of the earth.
Merits
(i) In the words of E.W. Spencer-“Radiation from the Sun drove off most of the hydrogen and helium which are extremely light in weight. The heavier elements left behind collided with the escaping hydrogen and helium and angular momentum was transferred to them. This accounts for the concentration of momentum in the planets”.
(ii) This theory explains the distribution and differences in the density and size of the inner and outer group of planets.
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This hypothesis is also not considered to be the most satisfactory scientific explanation for the origin of earth.