Question

A person travelling in a fast spaceship measures the distance between the earth and the moon. Is it the same, smaller or larger than the value quoted in this book?

Answer 1

Explanation:

• The distance between the Moon and the Earth can be measured by the person either by sending a light pulse or by using a metre scale.
• As we know, when the metre scale is used, there will be the contraction of length in a relatively affecting frame.
• Consequently, more than the actual distance, this distance will be lesser. On the contrary, the time difference between the reception and the emission is observed on using a light pulse.
• It is to be understood that there will be a dilation of time in the moving frame. So, in this case, the measured difference will be greater.
• So, more than the actual distance, the measured distance can either be larger or smaller, but it can never be the same.