Scientists use the light-year to describe the relationships between objects in space. What does a light-year measure?

Astronomers use the light-year to describe the relationship between objects in space. For example, the Andromeda galaxy is 2.5 million ly from Earth. Which of the following units is most similar to the light-year?

Distances between objects in space can be enormous. Which of the following distances is the longest?

A light-year (ly) is the distance that light travels in one year. If a star is 3 ly from Earth, how long does it take light from that star to reach Earth?

The sun is much larger than the moon. However, as viewed from Earth, the sun and moon appear to be the same size. Why do the sun and moon appear to be the same size when viewed from Earth?

Which two objects in space are located farthest apart?

Space exploration has advanced our knowledge of the universe. Which space journey would take the longest?

Which object is closest to Earth?