In a.d.2012,an inhabitant of a planet orbiting a distant star observed the flash of the first nuclear explosion on Earth,which occurred in July 1945.Approximately how far away is his solar system from Earth?
A) 219 pc
B) 20.6 pc
C) about 0.07 pc
D) 2.06 pc

Question

Quizplus · Accepted Answer

To solve this problem, we need to use the fact that the speed of light is constant and equals approximately 299,792,458 m/s.

The time between the first nuclear explosion on Earth in July 1945 and the observation of the flash in a.d.2012 is:

t = 2012 - 1945 = 67 years

To find the distance traveled by the light emitted by the explosion, we can use the formula:

d = c*t

where d is the distance traveled by the light, c is the speed of light, and t is the time.

Plugging in the values, we get:

d = 299,792,458 m/s * (67 years * 365.25 days/year * 24 hours/day * 3600 s/hour)

Simplifying, we get:

d = 20.6 parsecs

Therefore, the best choice is B) 20.6 pc.

In AD2012,an Inhabitant of a Planet Orbiting a Distant Star Observed