In medium-strength rock, things looked far different. The #GBU57 could only go around 7.9 meters (about 25 feet) beneath the earth — far short of the 60 meters claimed by the infographics.

This may be an important part of the reason the weapon failed to destroy its target — if indeed the bombs did #fail as the #DIA assessment claims.

#Iran #FactCheck #TrumpLies

"It depends enormously on the kind of rock," says Raymond Jeanloz, a professor at the University of California, Berkeley & one of the original authors of the 2005 National Academies Study on earth penetrators.

When I ran the calculations, using a key equation from that study, Geoff Brumfiel found out that the #GBU57 could go up to 80 meters (262 feet) underground if it was dropped in silty clay.

#Iran #FactCheck #TrumpLies