As we
know, force multiplied by distance equals energy:

E=F.d

E
represents energy; F represents force and
considers d as distance. Also the
gravitational force between two masses is calculated by the
following equation:

Where G
equals to the global constant of gravity and M
is the first mass (celestial substance) and m represents the second
mass of a material and r is the distance between
two centers. So gravitational potential energy obtain by following
ways:

U
represents gravitational potential energy that equals and
equivalent to the corresponding mass and it will increase to the
mass. Now we calculate the mass amount:

m0
is the initial mass of a material, c is the
speed of light, Δm
is increase in mass of a material in gravitational field and m
is the final mass of a material in the gravitational field. Hence,
we calculate 1kg mass of a material in the sun surface: