[abobrick]

I believe spherically symmetric bubbles in subluminal regime are more interesting than any warp drive solutions suggested so far. Firstly, they do not require negative energy. Secondly, the passengers in such bubbles age less by the time they reach any destination compared to other warp drives or conventional rockets. Given that exceeding the speed of light is fundamentally prohibited by physics, I would say that spherically symmetric warp drives are the most interesting warp drive constructions we got so far.