The Sun may be considered as a uniform sphere with a mass of 
and a surface temperature of 
. A probe with a mass of 
moves in a straight line towards the Sun. When it is at a distance 
from the centre of the Sun, the probe measures the gravitational field strength 
due to the Sun and the radiant flux intensity 
of radiation from the Sun. For the position of the probe where 
:
calculate
determine the gravitational potential energy 
of the probe.
.
.
