Answer:
906.27931 years
8.34 minutes
2.56266 seconds
Explanation:
v = Velocity of light = [tex]3\times 10^8\ m/s[/tex]
s = Distance
Time is given by
[tex]t=\dfrac{s}{v}\\\Rightarrow t=\dfrac{8.58\times 10^{18}}{3\times 10^8\times 365.25\times 24\times 3600}\\\Rightarrow t=906.27931\ years[/tex]
We would see the star disappear after 906.27931 years after it actually disappeared.
Distance between Earth and Sun = 150.18 billion m
[tex]t=\dfrac{150.18\times 10^9}{3\times 10^8\times 60}\\\Rightarrow t=8.34\ minutes[/tex]
It takes 8.34 minutes for sunlight to reach Earth.
Distance between Earth and Moon = 384.4 million m
[tex]t=\dfrac{2\times 384.4\times 10^6}{3\times 10^8}\\\Rightarrow t=2.56266\ s[/tex]
It takes 2.56266 seconds for a microwave radar signal to travel from Earth to the Moon and back.
