Editing Escape velocity (section)

=== Energy required ===
For an object of mass <math>m</math> the energy required to escape the Earth's gravitational field is ''GMm''&nbsp;/&nbsp;''r'', a function of the object's mass (where ''r'' is [[Earth radius|radius of the Earth]], nominally 6,371 kilometres (3,959&nbsp;mi), ''G'' is the [[gravitational constant]], and ''M'' is the mass of the [[Earth]], {{nowrap|''M'' {{=}} 5.9736 × 10<sup>24</sup> kg}}). A related quantity is the [[specific orbital energy]] which is essentially the sum of the kinetic and potential energy divided by the mass. An object has reached escape velocity when the specific orbital energy is greater than or equal to zero.