he's talking more about the shape of the smoke clouds.... i hope.
I would what would happen is our universe followed the rules that the universe in Sins of a Solar Empire follows?
Well, for starters... if the nebulae were bright enough to see colors (which I still maintain doesn't happen), I would think that magnitude of radiation would make it impossible for life to exist (via the magnetic field shutting down and solar radiation blasting away the atmosphere, along with enough radiation to kill anything holding an oxygen tank)
Next, if the sun was that small... it might fix the above problem because there's not enough radiation to blast away the atmosphere... but then the planets wouldn't be able to stay in orbit due to the sun not having enough mass... so they'd probably go flying out (assuming they had any trajectory at all... which you would want for the next part). Now, since there is some nuclear fusion going on in the sun, but it's smaller, there's not enough gravity to hold it together and it would just explode.
Before the Star explodes, I'd expect the planets to start gravitationally attracting each other, colliding into one another. The gas (non-)giants would break apart due to planets flying through them since they dont have enough mass to swallow the rocky planets and hold together after such a collision.
resource asteroids would fall to the planet since they're so close. Since they're the size of a moon, they would kill anything on the planet.
The star systems would merge and some would fly off into interstellar space. In the process, some planets would be flung into interstellar space as well, but all alone.
the dumb ship captains that don't think they have to actually orbit planets, they can just 'park' would crash into the planet.
....On the plus side, you could definitely get around the solar system faster... for the 10 minutes it held together/didn't explode/time you could survive the radiation. So... win?