<P> As an illustration , consider two objects attracting each other in space through their gravitational field . The attraction force accelerates the objects and they gain some speed toward each other converting the potential ( gravity ) energy into kinetic ( movement ) energy . When either the particles 1 ) pass through each other without interaction or 2 ) elastically repel during the collision , the gained kinetic energy ( related to speed ) , starts to revert into potential form driving the collided particles apart . The decelerating particles will return to the initial distance and beyond into infinity or stop and repeat the collision ( oscillation takes place ) . This shows that the system , which loses no energy , does not combine ( bind ) into a solid object , parts of which oscillate at short distances . Therefore , in order to bind the particles , the kinetic energy gained due to the attraction must be dissipated ( by resistive force ) . Complex objects in collision ordinarily undergo inelastic collision , transforming some kinetic energy into internal energy ( heat content , which is atomic movement ) , which is further radiated in the form of photons -- the light and heat . Once the energy to escape the gravity is dissipated in the collision , the parts will oscillate at closer , possibly atomic , distance , thus looking like one solid object . This lost energy , necessary to overcome the potential barrier in order to separate the objects , is the binding energy . If this binding energy were retained in the system as heat , its mass would not decrease . However , binding energy lost from the system ( as heat radiation ) would itself have mass . It directly represents the `` mass deficit '' of the cold , bound system . </P>
<P> As an illustration , consider two objects attracting each other in space through their gravitational field . The attraction force accelerates the objects and they gain some speed toward each other converting the potential ( gravity ) energy into kinetic ( movement ) energy . When either the particles 1 ) pass through each other without interaction or 2 ) elastically repel during the collision , the gained kinetic energy ( related to speed ) , starts to revert into potential form driving the collided particles apart . The decelerating particles will return to the initial distance and beyond into infinity or stop and repeat the collision ( oscillation takes place ) . This shows that the system , which loses no energy , does not combine ( bind ) into a solid object , parts of which oscillate at short distances . Therefore , in order to bind the particles , the kinetic energy gained due to the attraction must be dissipated ( by resistive force ) . Complex objects in collision ordinarily undergo inelastic collision , transforming some kinetic energy into internal energy ( heat content , which is atomic movement ) , which is further radiated in the form of photons -- the light and heat . Once the energy to escape the gravity is dissipated in the collision , the parts will oscillate at closer , possibly atomic , distance , thus looking like one solid object . This lost energy , necessary to overcome the potential barrier in order to separate the objects , is the binding energy . If this binding energy were retained in the system as heat , its mass would not decrease . However , binding energy lost from the system ( as heat radiation ) would itself have mass . It directly represents the `` mass deficit '' of the cold , bound system . </P>
where does the gravitational potential energy of an object come from ( site 1 )
where does the gravitational potential energy of an object come from ( site 1 )
gravitational field
gravitational field