The purpose of this paper is to study of the electromagnetic and gravitational field of a proton. The proton is a positively charged particle. Therefore in this work especially attention is given in Einstein’s gravitational field equations and Maxwell’s electromagnetic field equations. The four dimensional metric tensoris used here to solve this problem. The 4-d line elementis developed in such a way thatg11and g44are taken in terms of exponential forms and solve it in two separate ways. The solution gives the interaction of two fields within the frame of the 4-d line element with some suitable results. Later the formula is extended for the large massive body, considered as the combination of protons, gives an interesting resultthat life cannot survive in a planet having mass just greater than the 1.21 times mass of Jupiter planet. PACS: 04.20-q, 04.20. Cv
