Unit Definition (gigaparsec) The Gigaparsec is a non-metric unit of distance equal to one billion parsecs, 3.2616 billion light years, or 30.856 78 zettameters (30.856 78 x 1021 kilometers). The unit is used in astronomy.
Unit Definition (nanometer) Equal to 0.000000001 meters (formerly millimicron), or 0.03937 microinch.
Length/Distance 
