The Great Decline - Sun

So what is this great decline about exactly?

One hundred thousand years into the future, as mankind colonized more worlds and extended it's reach always further out in the solar system, an alarming discover was made. The sun, provider of warmth and light, was entering the final stage of it's life. In this stage, it would grow into a red giant, destroying the inner planets and rendering most of the solar system inhabitable. These news would send humanity into chaos, every colony abandoned to their own fate in a world completely overtaken by panic and anarchy.

A hundred thousand more years passes. Colonies either adapt to the new harsh conditions or die. Inhabitants of the surviving colonies evolve to withstand the unique conditions of the planets they must now call their home. But the sun is at the end. Soon, it will run out of material and it's fragile balance will shatter, resulting in a supernova that will render the entire solar system sterile. The fractured and isolated colonies must band together once again to find a way to escape the solar system and find a more hospitable star. But how?

Okay so that's a veeeeery rough summary of the settings. There's a lot of lore I'm super excited to talk about, but I'll keep most of it for the book ;)

Also, bottom right is Jupiter for scale lol