Question

Astronomers have developed several ways to measure the vast distances between Earth and the stars and galaxies. What do you know about two of these techniques? (Choose 4)

A The A.U. is used to measure distance within our solar system.The A.U. is used to measure distance within our solar system.
B An astronomical unit (A.U.) is the average distance between the Earth and the Sun.An astronomical unit (A.U.) is the average distance between the Earth and the Sun.
C Our galaxy, the Milky Way, is about 150 light-years across.Our galaxy, the Milky Way, is about 150 light-years across.
D A light-year (ly) is the distance that light can travel in one year in a vacuum.A light-year (ly) is the distance that light can travel in one year in a vacuum.
E Astronomers measure distances to objects which are outside our solar system in light-years.Astronomers measure distances to objects which are outside our solar system in light-years.
F An astronomical unit is about 93 million kilometers.

Answer 1

A. The average distance between the Earth and the Sun, or A.U., is used to measure distances within our solar system.

D. Distances to things outside of our solar system are measured in terms of light-years (ly), which are the maximum distances light can travel in a year in a vacuum.

To calculate the immense distances in the cosmos, astronomers mostly employ two methods. An astronomical unit (A.U.), often known as the average distance between the Earth and the Sun, is used as a standard measurement within our solar system. One A.U. is equivalent to 150 million kilometres or 93 million miles. Within our solar system, it is used to calculate the separations between planets, asteroids, and comets. Second, astronomers use light-years to gauge distances outside of our solar system (ly). The distance that light can cover in one year in a vacuum, or 5.88 trillion miles or 9.46 trillion kilometres, is known as a light-year. We may use this method to calculate the huge separations between stars, galaxies, and other astronomical objects. As a result, astronomers employ A.U.