light year

valovuosi puhekieltä A unit of length (abbreviation ly; equal to just under 10 trillion kilometres (1016 metres)) equal to the distance light travels in one Julian year; used to measure extremely large distances.
{{quote-magazine|date=2012-01
puhekieltä A very long way.

The marathon runner in the lead is light years ahead of the one at the back.

Some of Leonardo da Vinci’s inventions were light years ahead of their time.