Which is greater, a parsec or a light year?

Astronomers prefer to use parsecs when discussing distances because they are a convenient standard unit for measuring large distances in space. A parsec is defined as the distance that an object would have to be from the sun to have a parallax angle of 1" (one arc-second). Consequently, any measurement found using parallax will yield an answer in units of parsecs.

The distance that light travels in a year, on the other hand, is referred to as a light year. This tells us not only how far light has traveled, but also how long it has been traveling. Light years are more frequently used in popular science because they are easier for non-parallax measurement experts to understand.

To contextualize each of these units,

Be aware that the figures provided are approximate and not exact.

There are more parsecs than light years.