▁danger . ▁It ▁is ▁estimated ▁that ▁an ▁impact ▁would ▁produce ▁the ▁equivalent ▁of ▁ 1 0 0 ▁meg at ons ▁of ▁T NT , ▁roughly ▁twice ▁that ▁of ▁the ▁most ▁powerful ▁nuclear ▁weapon ▁ever ▁det on ated ▁( T s ar ▁Bom ba ). ▁This ▁is ▁powerful ▁enough ▁to ▁damage ▁a ▁region ▁at ▁least ▁a ▁hundred ▁miles ▁wide . ▁ ▁Old er ▁ris ks ▁▁ ▁Virtual ▁cl ones ▁of ▁the ▁astero id ▁that ▁fit ▁the ▁mid - 2 0 1 2 ▁uncertainty ▁region ▁in ▁the ▁known ▁traject ory ▁showed ▁four ▁potential ▁impact s ▁between ▁ 2 0 4 0 ▁and ▁ 2 0 4 7 . ▁It ▁had ▁a ▁ 1 ▁in ▁ 5 0 0 ▁chance ▁of ▁impact ing ▁the ▁Earth ▁on ▁ 5 ▁February ▁ 2 0 4 0 . ▁In ▁September ▁ 2 0 1 3 , ▁there ▁was ▁an ▁opportunity ▁to ▁make ▁additional ▁observations ▁of ▁ ▁when ▁it ▁came ▁within ▁ ▁of ▁Earth . ▁The ▁ 2 0 1 3 ▁observations ▁allowed ▁a ▁further ▁ref in ement ▁to ▁the ▁known ▁traject ory . ▁The ▁astero id ▁will ▁also ▁pass ▁ ▁from ▁the ▁Earth ▁on ▁ 3 ▁February ▁ 2 0 2 3 . ▁The ▁ 2 0 2 3 ▁gravit ational ▁key hole ▁was ▁ 2 2 7 ▁miles ▁( 3 6 5 ▁kilom eters ) ▁wide . ▁With ▁a ▁Pal ermo ▁Techn ical ▁Sc ale ▁of ▁- 1 . 0 0 , ▁the ▁odd s ▁of ▁impact ▁by ▁ ▁were ▁about ▁ 1 0 ▁times ▁less ▁than ▁the