Question

4 of 5
a star is located 20 light years away from earth. tonight, at 10:00pm, the star explodes, dies, and then goes dark. how long will earth be able to see light from that star?
a 20 days
b we wont be able to see the star immediately after it goes dark because it is no longer emitting light.
c 20 minutes
d 20 years

Explanation:

Step1: Understand Light - Year

A light - year is the distance that light travels in one year. So, if a star is 20 light - years away from Earth, the light from that star takes 20 years to reach Earth.

Step2: Analyze the Star's Explosion

When the star explodes, dies, and goes dark at its location, the light that was already emitted by the star before it went dark will still be traveling towards Earth. Since the star is 20 light - years away, the light that was emitted before it went dark will take 20 years to reach Earth. So, we will still be able to see the light from the star for 20 years after it has gone dark (because the light that was on its way to Earth when the star died will continue to travel to Earth, and it takes 20 years for that light to cover the distance between the star and Earth).

Answer:

D. 20 years