/sci/ - Science & Math

hey, /sci/. i've been pondering something. for the sake of this discussion, let's just discard the law "matter cannot be created or destroyed". if a mass of matter just appeared somewhere, be it an orange, a planet, a star, a black hole, or what have you, would the entire gravitational feild around that object instantly come into being? or would it expand outwards from the mass of matter at a predetermined rate?

More specifically, star fusion
I was just on /g/, and some anon mentioned that there was recently a star fusion reactor made that could put out more energy than it absorbed, although by a very small margin, but he wasn't able to provide a source, and google isn't telling me its secrets
Has anyone here heard of this? If so, can you give me the source?
Also, how close do you reckon we are to usable fusion?