1 0 1 3   mi ). ▁Com bin ing ▁it ▁with ▁the ▁" atto - " ▁prefix ▁( × 1 0 − 1 8 ) ▁yields ▁att op ar sec ▁( ap c ), ▁a ▁convenient ly ▁human - scale d ▁unit ▁of ▁about ▁ ▁that ▁is ▁used ▁only ▁humor ously . ▁ ▁Be ard - second ▁The ▁be ard - second ▁is ▁a ▁unit ▁of ▁length ▁inspired ▁by ▁the ▁light - year , ▁but ▁applicable ▁to ▁extremely ▁short ▁distances ▁such ▁as ▁those ▁in ▁integrated ▁circ uits . ▁The ▁be ard - second ▁is ▁defined ▁as ▁the ▁length ▁an ▁average ▁be ard ▁grows ▁in ▁one ▁second . ▁K emp ▁Ben nett ▁Kol b ▁defines ▁the ▁distance ▁as ▁exactly ▁ 1 0 0   ang st rom s ▁( 1 0   nan om eters ). ▁as ▁does ▁Nord ling ▁and ▁Ö st erman ' s ▁Physics ▁Hand book . ▁However , ▁Google ▁Calcul ator ▁supports ▁the ▁be ard - second ▁for ▁unit ▁convers ions ▁using ▁the ▁value ▁ 5   nm . ▁ ▁The ▁be ard - second ▁establish es ▁a ▁related ▁unit ▁of ▁time , ▁the ▁be ard - inch ▁which ▁is ▁ 2 9 . 4   days ▁( or ▁ 5 8 . 8   days ▁according ▁to ▁Google ). ▁ ▁Jimmy ▁Griff in ▁Snow ▁Index ▁Television ▁station ▁W KB W - TV ▁in ▁Buff alo , ▁New ▁York ▁developed ▁the ▁" J im my ▁Griff in ▁Snow ▁Index " ▁to ▁measure ▁the ▁potential ▁sever ity ▁of ▁a ▁snow