Harrison Clark realized something else, something he should have noticed but had completely unconsciously overlooked.
The generalized gravitational radius of the Solar System is 2 light-years, almost bordering Proxima Centauri.
When they reached the edge of the Solar System, they should have arrived at the Proxima Centauri System as well.
But they hadn't, Proxima Centauri was still at the far end of the distant starry sky.
Moreover, the maximum flight speed of a Super Heavy Spacecraft is one-tenth the speed of light.
How could they have reached the edge of the Solar System, which was next to the Invader Barrier, within a month from Earth?
But they had done so and were completely unaware of this obvious paradox.
The Invader Barrier had been compressing the Solar System, and the closer it got to the Sun, the lower the compression ratio.
