For earth to be black hole the escape velocity should be at least equal to speed of light.\\\\(\ herefore\\\\) escape velocity \\\\(=\\\\) speed of light\\\\(\\sqrt { \\dfrac { 2GM }{ R } } =C\\\\)\\\\(R=\\dfrac { 2GM }{ { C }^{ 2 } } \\\\)\\\\(R=\\dfrac { 2\ imes 6.67\ imes { 10 }^{ -11 }\ imes 5.98\ imes { 10 }^{ 24 } }{ 9\ imes { 10 }^{ 16 } } =8.86\ imes { 10 }^{ -3 }m={ 10 }^{ -2 }m\\\\)