Final answer:
Light takes approximately 1.28 seconds to travel from the Moon to Earth. The time is calculated by dividing the distance between the Moon and Earth by the speed of light, which is 299,792 km/s.
Step-by-step explanation:
When considering the time it takes for light to travel from the Moon to Earth after a major collision, such as the one described by monks in medieval times, we must use the known speed of light to calculate the duration of the journey. The distance between the Moon and Earth is 3.84 × 10^5 km. Since light travels at 299,792 km/s in a vacuum, we can find out the travel time by dividing the distance by the speed of light.
To calculate: Time = Distance / Speed, thus:
Time = 3.84 × 10^5 km / 299,792 km/s.
When performing the calculation, we find that it takes approximately 1.28 seconds for light to travel from the Moon to the Earth. This would be the time it would take for the red glow described by the monks to be seen on Earth after the collision.