Re:You're right, they're massive enough. (Score 1)

And by 'binary pulsars' you really mean 'the only binary pulsar system that we've every seen'. While there are plenty (read: dozens) of examples of pulsars in binary systems that have a main sequence or giant star as a companion, there's just the one known example of a binary pulsar system (i.e. two pulsars orbiting each other). And yes, it's one of the best tests for the relatavistic corrections gravity that's every been measured (and the reason that Gravity Probe B got pushed back, again). Oh, and as to the gravity problem...even exotic objects like a one solar mass black whole with feel like a one solar mass star (i.e. the sun) from the outside of the object (go do a Wikipedia for "Guass' Law"). The composition, shape, density, color, sexuality, of the object has nothing to do with the gravitational potential.