Imagine that you have found an object out in space. When you use the inverse square law to compute its luminosity, you get a ridiculously large value. You therefore suspect that relativistic beaming is at work $-$ the radiation is coming from a jet traveling at speed v directly towards the Earth, which enhances the observed flux by a factor a $($i$.$e$.$ the measured flux is times greater than it would have been if v$=0).$ 

 

Derive an equation for the velocity v needed to produce an amplification factor a$,$ and write your answer as an equation If necessary, use the symbol c in your answer to denote the speed of light, and the symbol G to denote the Gravitational constant.