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\title{ The origin and evolution of Jupiter }
                     \author{S.S. Kumar \\
 Departement of astronomy, University of Virginia\\
 Charlottesville, VA 22903 USA}
\date{}


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\maketitle

    It is argued that Jupiter was originally formed by the collisional
accretion process in a dusty medium (around the Sun) as a planet with
mass $\simeq~10 M_E$ where $M_E$ is the Earth's mass.
Starting with this mass, the planet has been slowly accreting gas, dust         rocks, etc. from the ISM since its formation approximately $4,5 . 10^9$ yr          ago. An average accretion rate of approximately $7 . 10^{-8} M_E/yr$ could have         resulted in the transformation of the "original" planet into an object
of mass 318 $M_E$ (Jupiter's current mass). The "original Jupiter " is now         a part of the planet's core which has a mass $\simeq 20 M_E$. The atmosphere of         the present Jupiter is unlikely to be of primordial origin; it was most         probably formed by accretion during the last $1 . 10^{-6}$ yr. Observational           evidence in support of the "young atmosphere" hypothesis is discussed.
   Comments are made on the redevance of the Kant-Laplace hypothesis 
for the formation of the Soalr System and it is proposed that the
planetary formation processes most probably came into play  {\bf after} the
Sun had settled down on the hydrogen-burning main sequence.

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