Chapter 3, Problem 56A

Grandparents are interested in the educational progress of their grandchildren. Many have little science background. It’s possible that relatives far back in your family tree believed that Earth was stationary in the center of the universe. Write a letter to Grandma or Grandpa. Tell what you've learned about a moving Earth and how a person who might be unsure of it could be convinced.

To determine

To Write: A letter to grandparents explaining that Earth is moving constantly.

Explanation of Solution

Introduction:

For many centuries, hundreds of years B.C., world’s great thinkers believed the idea of cosmos to be geocentric or Earth-centered. Then, the exceptional idea of a Greek scientist Aristarchus became notable who proposed a helio-centric model of the universe.

The true nature of the cosmos was pretty confusing for our ancestors. They believed that the Earth was stationary and the ‘heavens’ (sun, moon and stars) moved around them.

One can explain the concept of moving earth by taking a daily-life example. Convince the grandparents by making them think about a situation where they are sitting in a moving train having closed windows. Since, they won’t be able to feel the movement of the train as they can’t see it moving. Similarly, if we consider the case of Earth, then it is moving about its own axis steadily and in an orbit around the Sun constantly. So, consider yourself as a passenger here. Hence, you will not feel the Earth moving.

Conclusion:

Hence, the Earth is moving not stationary.