why do astronomers use astronomical units au instead of kilometers km a. there are no km in outer space only au b. larger distances are easier to express in au than km c au is used for spacing while km is used for length d. au is used in astronomy while km is used in physics
The correct answer is: d. AU is used in astronomy while km is used in physics.
Astronomers use astronomical units (AU) because they are a convenient unit of measurement for distances within the solar system. AU represents the average distance between the Earth and the Sun, which is approximately 149.6 million kilometers. Using AU helps to simplify the expression of distances within our solar system, as the distances involved can be very large.
On the other hand, kilometers (km) are commonly used in physics and everyday life to express distances on Earth. Since physics deals with various aspects of the physical world, including distances on Earth, km is a more appropriate unit for this context.
In summary, astronomers use AU to measure distances within our solar system, while kilometers are more commonly used for distances on Earth in physics and everyday life.
The correct answer is:
a. there are no km in outer space, only au
Astronomical units (au) are commonly used in astronomy instead of kilometers (km) because distances in space are extremely vast, making kilometers less practical to use. The au is based on the average distance between the Earth and the Sun, which is approximately 149.6 million kilometers. This allows astronomers to express distances within our solar system more conveniently.
Astronomers use astronomical units (AU) instead of kilometers (km) for a few reasons.
Firstly, option (a) is incorrect. Kilometers do exist in outer space, just like they do on Earth. However, the vast distances involved in astronomical measurements make using kilometers less practical.
Option (b) is more accurate. Larger distances in the universe, such as the distances between planets and other celestial objects, can be difficult to express in kilometers because the numbers become extremely large. Using astronomical units provides a more compact way of representing these distances.
Option (c) is incorrect. AU is not specifically used for "spacing," but rather for astronomical distances. Kilometers are a unit commonly used to measure length on Earth.
Option (d) is partially correct. While astronomers do use AU extensively, kilometers are also used in astronomy. However, AU is specifically used in astronomy to measure distances within our solar system, as it provides an easier and more manageable scale.
To summarize, astronomers use astronomical units (AU) instead of kilometers (km) because larger distances in space are easier to express in AU, and AU provides a more convenient scale for measuring distances within our solar system.