Chapter 33, Problem 3RAT

The star nearest Earth is

(a) Alpha Centauri.

(b) Polaris.

(c) Mercury.

(d) the Sun.

To determine

The correct option for the statement “The star nearest Earth is”.

Answer to Problem 3RAT

The correct option for the statement “The star nearest Earth is” option (d).

Explanation of Solution

Alpha Centauri, itself is not a star. It is a system of stars comprised of Alpha Centauri $A$, Alpha Centauri $B$ and Proxima Centauri. Proxima Centauri is the second closest star to the Earth. It is at a distance of $4.24\text{light years}$ away from the Earth.

Mercury is one of the nine planets in the Solar System. It revolves around the stationary Sun and it is the nearest planet to the Sun. Thus, mercury is not a star but is a planet.

Polaris is a star at a distance of $4.34\text{light years}$ from the Earth. It is located near the northern part of the Earth’s axis. North Star is the other name of Polaris which itself implies that the Polaris is a star.

The Sun is a star about which all the planets including the Earth, move in circular orbits. It is a star which generates light due to the nuclear fusion of hydrogen and helium contained in its core. It is at a distance of $1.58\times {10}^{-5}\text{light years}$ from the Earth. Thus, the Sun is the nearest star to the Earth.

Conclusion:

Therefore, the correct option for the statement “The star nearest Earth is” is option (d).