Final answer:
The supernova explosion of Star 2 would be seen from Earth 52 years after it occurs, as the light from the explosion would first reach Star 1 before traveling to Earth, combining the distances to 52 light years.
Step-by-step explanation:
If Star 2 explodes as a supernova, we can determine how long it will take for the explosion to be seen from Earth by considering the distance light must travel. Since Star 1 is 18 light years from Star 2 and 34 light years from Earth, the explosion of Star 2 would have to be observed at Star 1 before it could be seen from Earth.
The light from the supernova would first have to travel the 18 light years to Star 1, and then travel the remaining 34 light years to Earth. Since light travels one light year per year, the total time to see the explosion from Earth is the sum of the two distances: 18 light years + 34 light-years = 52 years.
Therefore, the explosion of Star 2 would be seen from Earth 52 years after it occurs.