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 8.71 × 10⁵ km away, would the light first arrive on Earth?

2 decimal places

Answer 1

$t=\frac sc,$

$t=\frac{8.71\cdot 10^5}{3\cdot 10^5}=2.9~\text s.$