Well I am also just an amateur when it comes to astrophysics but I know a little bit. Not enough to back up my statements with solid calculations though. The one with the black hole should be taken with a grain of salt, since I do not know at what mass an object the size of the traveler would collapse into a black hole. But there is a point where it would do exactly that. And considering it is very small with so much mass I just assume the point is reached already. But good thought updating your post, we can always improve on our work! Keep that post alive I think it is very interesting. Will continue to bump if I do not forget about it. It was stated somewhere that the traveler can operate outside of the laws of physics that we know of. If that is the case it would be interesting to see what exactly it does. If it can just ignore the fact it should be crushed under its own mass or pull everything towards it with gravity. But if it can operate outside the laws of physics ,then it might be useless to trying to calculate its mass, since it would have no requirement to have its size and material and mass add up to our real world physics. It can get kinda tricky when you start thinking about that. Imagine that a scoop of neutron star matter has the same mass as 50 million elephants ( a nice example that is often used by TV and some books). And that is with real world physics. What the traveler could do if it ignored this. Ha, unimaginable. But yeah, a realm of light... I wonder. I also wonder if, what is always referred to as light, does have any real light like properties at all. So many questions!!