Question

Suppose the distance between earth and sun becomes half of its present distance. What is likely to happen to life?

Answer 1

Explanation

1. The temperature of the earth will become very high that it will be unbearable for all living creatures. It will wipe out the entire planet.
2. The water will evaporate out and the planet will run out of water.
3. Our protective shield the ozone layer of the Earth will be destroyed by the intense heat of the Sun.
4. The number of days in a year will be reduced since from Kepler's law we know that $T^2\propto r^3$ where $T$ is the time take for one revolution and $R$ is the distance between the earth and the Sun.

Let $T_1=365$ days $T_2=$ Time for one revolution when the radius is half, $r_1=$present radius$r_2=\frac{r_1}{2}$

$$\begin{gathered} \therefore \frac{T_1^2}{T_2^2}=\frac{r_1^3}{r_2^3} \\ \Rightarrow \frac{T_1^2{\left({\displaystyle \frac{r_1}{2}}\right)}^3}{r_1^3}=T_2^2 \\ \Rightarrow {365}^2·\frac{1}{8}=T_2^2 \\ \Rightarrow T_2^{}=129 \end{gathered}$$

So the time taken for one revolution will be $129$ days

Hence, if the distance between the earth and the sun becomes half of its present distance life on Earth will end