Question

How many kilometers is the earth from the sun?

Answer 1

Hint: In this question we have to write the distance between earth and sun. Sun is a star and Earth is a planet. You can think how far they can be by observing light.

Complete answer:
To find the distance between earth and sun first we will find the distance between earth and Venus because the orbits of earth and Venus are perfectly round around the sun. These orbits are on the same plane so we can say that there are two places where the sun, earth and Venus will have 90 degree angles. These two points are farthest from the sun; it results in the visibility of Venus in the sky. We can understand this by considering the motion of Venus. When Venus orbits around the sun it reaches a maximum distance or separation from the sun, in this case we see Venus. Venus goes around the sun again. This is the cause that Venus is not visible in the evening after sunset and before sunrise for 3 hours. First rigorous calculation of distance between earth and sun was found by Cassini in 1672 by doing parallax measurement of Mars.
Relevant outcomes of this experiment are given below:
Distance between earth and sun = 149.6 million Km.
Orbital speed of earth = 30 Km/s
Radius of sun =700,000 Km
Result- Hence, from the above explanation we can see that the distance between earth and sun is 149.6 million Km.

Note: This is an astronomical method to find distance between earth and sun. This is a very tedious calculation. It involves so many steps and efforts to find the distance between earth and sun. Astronomy is a very difficult field of Physics; we have to be very careful while doing these questions.