1 gigametre
The following are examples of orders of magnitude for different lengths.
To help compare different orders of magnitude, the following list describes various lengths between 1.6×10−35 meters and meters.
(also called one micron)
To help compare different orders of magnitude this page lists lengths shorter than 10−23 m (10 ym).
To help compare different orders of magnitude this page lists lengths between 10−23 metres and 10−22 metres (10 ym and 100 ym).
To help compare different orders of magnitude this page lists lengths between 10−22 m and 10−21 m (100 ym and 1 zm).
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Wikipedia