Who knows what our descendants, whatever they evolve into, will be able to do in a couple of billion years. Things we do today would seem like magic to those living a couple of hundred years ago. They may find ways that we can see or even comprehend.

The energy going into reverting a star back to hydrogen would be immense. If you have the means to generate unlimited power, I think it would still be possible. However, if you could generate that kind of power there be better ways to use it.

Stars waste a lot of energy so even if stars could be restarted others ways might be used to keep planets alive long after their stars die. A type of shell around a planet, where the inside can emit light and heat, might be a far simpler solution than trying to restart a star. If they know how to convert matter to energy, they could use the dead stars matter to power their planet shell for a long time.

There might be civilizations that live underground and may not care if their worlds surface gets light. (In a few billion years, humans will have evolved into all kinds of forms living in many different environments.)

The future is very hard to predict a century ahead, much less billions of years. No telling what they will be like or what they will think of. But I do think they will survive. Even as the universe fades, I think they will figure a way to survive.

I am merely presenting a problem life on Earth will eventually face- a dead star.

A solution- convert its matter back to hydrogen and restart.

How to get to the solution- ? It’s beyond our current technology.

A better solution IMO, Build a shell sphere around the planet. This shell emits light and heat. Less energy is wasted to achieve the same means as trying to restart the star. Plus you have more control over your world’s climate.

I guess I get tired of the doomsayers. "We are all doomed. Everything is doomed." Bahhhh. I don't beleive it.

I believe there is a solution to every problem, that solution just has to be found. Fortunately, for this problem. Humans (Or whatever we evolve into) has a long time to come up with a solution.