Chapter 0, Problem 1RD

To determine

The comparison of the size of the Earth with that of the Sun, the Milky Way Galaxy, and the entire universe.

Answer to Problem 1RD

The Earth is $100$ times smaller than the Sun, ${10}^{14}$ times smaller than the Milky Way Galaxy and ${10}^{18}$ times smaller than the entire universe.

Explanation of Solution

The diameter of the Earth is about $15,000km$ while the diameter of the Sun is about $1,500,000\text{km}$. So, the size of the Sun is about $100$ times that of the Earth.

The Milky Way Galaxy is about $100,000\text{ly}$ in diameter. A light year is about ${10}^{13}\text{km}$ therefore, the Milky Way Galaxy is about ${10}^{14}$ times the size of the Earth.

The entire universe is about ${10}^4$ times the size of the Milky Way. Therefore, the size of the universe is about ${10}^{18}$ times that of the Earth.

Conclusion:

Thus, the Earth is $100$ times smaller than the Sun, ${10}^{14}$ times smaller than the Milky Way Galaxy and ${10}^{18}$ times smaller than the entire universe.