▁uses ▁the ▁football ▁pitch ▁for ▁equivalent ▁purposes , ▁although ▁s occer ▁pitch es ▁are ▁not ▁of ▁a ▁fixed ▁size , ▁but ▁instead ▁can ▁vary ▁within ▁defined ▁limits ▁( ▁long , ▁and ▁ ▁wide , ▁giving ▁an ▁area ▁of ▁). ▁However ▁the ▁UEFA ▁Champions ▁League ▁field ▁must ▁be ▁exactly ▁ ▁giving ▁an ▁area ▁of ▁ ▁or ▁. ▁Example : ▁H SS ▁vessels ▁are ▁al umin ium ▁cat amar ans ▁about ▁the ▁size ▁of ▁a ▁football ▁pitch ... ▁- ▁B elf ast ▁Te legraph ▁ 2 3 ▁June ▁ 2 0 0 7 ▁ ▁Lar ger ▁areas ▁are ▁also ▁expressed ▁as ▁a ▁multiple ▁of ▁the ▁areas ▁of ▁certain ▁American ▁states , ▁or ▁sub div isions ▁of ▁the ▁UK ▁etc . ▁ ▁Energy ▁ ▁A ▁ton ▁of ▁T NT ▁equivalent , ▁and ▁its ▁multi ples ▁the ▁kil ot on , ▁the ▁meg aton , ▁and ▁the ▁gig aton . ▁O ften ▁used ▁in ▁stating ▁the ▁power ▁of ▁very ▁ener get ic ▁events ▁such ▁as ▁explos ions ▁and ▁vol can ic ▁events ▁and ▁earth qu akes ▁and ▁astero id ▁impact s . ▁A ▁gram ▁of ▁T NT ▁as ▁a ▁unit ▁of ▁energy ▁has ▁been ▁defined ▁as ▁ 1 0 0 0 ▁therm och em ical ▁cal ories ▁( ). ▁ ▁The ▁atom ▁bomb ▁dropped ▁on ▁H iro sh ima . ▁Its ▁force ▁is ▁often ▁used ▁in ▁the ▁public ▁media ▁and ▁popular ▁books ▁as ▁a ▁unit ▁of ▁energy . ▁( I ts ▁yield ▁was ▁roughly ▁ 1 3 ▁kil ot ons , ▁or ▁ 6 0 ▁T J