Question

There was a major collision of an asteroid with the Moon in medieval times. It was described by monks at Canterbury Cathedral in England as a red glow on and around the Moon. How long after the asteroid hit the Moon, which is 3.84 x 10⁵ kmaway, would the light first arrive on Earth?

Short answer

It's 1.28 s long after the asteroid hit the moon.

Step-by-step solution

Concept Introduction

A collision is defined in physics as any occurrence in which two or more bodies exert forces on each other in a brief period of time.

Calculating the distance

The usual speed of light formulation $c=\frac{x}{t}$is used to solve the problem for $t$.

$$\begin{gathered} t=\frac{x}{c} \\ =\frac{3.84\times {10}^{8}m}{3.00\times {10}^{8}m/s} \\ =1.28s \end{gathered}$$

Therefore, the required solution is$1.28s$.