The distance of Venus from the sun is $0.72\, AU$. The orbital period of Venus is ............ days.

The radius of the Martian orbit around the Sun is about $4$ times the radius of the orbit of Mercury. The Martian year is $687$ Earth days. What is the length of $1$ year on Mercury?

The kinetic energies of a planet in an elliptical orbit about the Sun,at positions $A, B$ and $C$ are $K_A, K_B$ and $K_C$,respectively. $AC$ is the major axis and $SB$ is perpendicular to $AC$ at the position of the Sun $S$ as shown in the figure. Then

$A$ planet moving around the Sun sweeps out an area $A_{1}$ in $2$ days,$A_{2}$ in $3$ days,and $A_{3}$ in $6$ days. Then,the relation between $A_{1}, A_{2}$,and $A_{3}$ is

The period of a planet around the sun is $8$ times that of earth. The ratio of the radius of the planet's orbit to the radius of the earth's orbit is:

Earth's orbit is an ellipse with eccentricity $e = 0.0167$. Thus,the Earth's distance from the Sun and its speed as it moves around the Sun vary from day to day. This means that the length of the solar day is not constant throughout the year. Assume that the Earth's spin axis is normal to its orbital plane and find the length of the shortest and the longest day. $A$ day should be taken from noon to noon. Does this explain the variation in the length of the day during the year?