The correct formula to use is: F = G [M1*M2] /r^2
Where,
G = the force of gravity
M1 = the mass of the first object [the mass of the astronaut]
M2 = the mass of the second object [the mass of the planet]
r = the distance between the two objects in metre
F = 6.67 * 10^-11 [66.5 * 8.43 * 10^23] / [4.40 * 10^6]^2
F = 193N.<span />
<span>The answer to this question would probably be "</span><span>D. The same background radiation was observed coming from all directions of space."
The background radiation here is referring to the Cosmic Microwave Background Radiation, one of the observational evidences of the Big Bang Theory which was discovered by Penzias and Wilson as they were doing some observations with a microwave receiver. </span>