Question

What is known as the Astronomical Unit (AU)?
A. Average distance between Earth and Sun
B. Average distance between Sun and Moon
C. Average distance between Moon and Earth
D. Average distance between Earth and Star

Answer 1

Hint: This question basically asks what is meant by astronomical unit. From the options given to us we can say that it is a unit to measure large distances in the Solar system. So we will define what is an Astronomical Unit and accordingly select our answer. There is no other way around to answer this particular question.

Complete step by step answer:
Astronomical Unit is the unit basically used to measure large distances such as distance between solar systems and the distances between the stars. Astronomical unit is the distance between Earth and the Sun. The distance between Earth and Sun is approximately 150 billion meters.

So, the correct answer is “Option A”.

Additional Information: The IAU (International Astronomical Union) has specified that the term AU is incorrect. This term is in lower case as said by the IAU. The first planet in our solar system Mercury is 1/3 AU from the Sun, while the farthest planet Pluto is 40 AU from the Sun. Which means that Pluto is 40 times away from the Sun as compared to Earth.

Note: Students must not be confused between light years and astronomical unit as both are units to measure a distance. One light year is approximately 9500000000000 km. It takes approximately 500 seconds for light from the Sun to reach Earth. Therefore, to travel a distance of 1 AU it takes approximately 500 seconds.