On a different note, I thought the Gef asteroid subplot felt a bit silly. There's already so much stuff going on that throwing another catastrophic event into the mix just felt unnecessary, and in a lot of ways, diminishes the competence of a LOT of people in the Blue Planet universe. It's a nice touch that both Fedayeen and SOC react to the asteroid, but with so much riding on the line, you'd think there'd be contingencies for it.
Correct me if I'm wrong, but wasn't it the nuclear winter that was caused by the meteor that slowly killed off the dinosaurs and not the impact itself?
Both the UEF and GTVA have terraformation equipment so it stands to reason that they could greatly shorten the length of the nuclear winter or maybe even outright prevent it. And even if they can't, Humans still have the necessary technology to survive in such an environment or alternatively evacuate to other habitats, like Mars, some moons or hollowed out asteroids like the Gefs use.
Of course a flood of billions of refugees would cause a whole lot of new problems all over the Solar System, but also opportunities.
One last thing to remember: Macduff's rock is 40% bigger; I can't say how much worse that would make it. but the PVN and GTA did get a few hundred million out of Vasuda Prime, and the GTVA got most of everyone out of Capella, so mass exoduses are nothing new and may have contingencies.There's quite a difference right here. Both Vasuda Prime and Capella evacuations had the time to react to the threat. Vasudans probably started evacuating as soon as the word arrived that the Lucifer is headed for their homeworld - that gives us... how much? I'd say that at least a couple dozen hours or more.
There is one other piece to this equation: Impact velocity.
The Gef habitat is basically a kuiper belt object. Because those orbit so much further away from the sun, their orbital speeds are much slower. Pluto, for example, orbits at 4.7 km/sec.
Contrast with Earth, which has a much higher orbital speed, of 30 km/sec.
It's completely possible that if the Gef habitat retains its velocity through subspace transit, it could slam into Earth at 25+ km/sec.
Heaven forbid that Earth and the Gef habitat were on opposite sides of the sun during their orbits. Because then any retained velocity would be ADDITIVE. Which means impact velocity would be between 30-35 km/sec.
But wait, there's more! Order now, and I'll super-size your apocalypse!
Ships in FS2 and BP do zoom into and out of subspace much faster than they usually move (DIVE, DIVE, DIVE, HIT YOUR BURNERS PILOT!). If you fail the mission, the Gef habitat doesn't just lazily glide into subspace, it hauls butt at a few km/sec. It does not have thrusters like a ship does.
...Which means when it pops back out of subspace and fractures into a bunch of pieces, it's unlikely that they will decelerate. This cometary debris could have been moving with a relative velocity of 40 or 45 km/sec - before Earth's gravity began accelerating it.
Contrast with most near-earth asteroids, which start with velocities rather closely matched with Earth's, and you have a recipe for the biggest catastrophe in all of Earth's history. This thing would completely wreck the planet. There would still be a ball of rock that used to be Earth...but not much else.
The "how quickly" here differs between possible outcomes a lot. With a stellar body of that kind of size the Gef asteroid has got, at 5km/s it would probably partially burn down in Earth's atmosphere and result in some (a lot) of casualties, perhaps similar to debris falling after Darkest Hour.
But the same body at 25-35 km/s could just glass half a continent worth of land and cause Earth to enter something alike a post-nuclear-war winter.
So, in that spirit, I think it is more interesting to consider the political and social effects of the cataclysmic destruction of the vast majority of Earth's population and non-space infrastructure instead of trying to figure out exactly how quickly the aforementioned population and infrastructure get destroyed.
...This is (AFAIK) why BP tries not to examine the specifics of subspace in any in-depth way beyond how it applies to the strategic situation, because otherwise one wonders why SSMs don't just slam into targets at c-fractional velocities.
Of course, it also begs the question: If the Vishnans can design a civilization to their specifications (Ubuntu/UEF)...could Kostadin be a Shivan-designed civilization? Macduff might be the product of Shivans playing with Nagari sensitives. You know, a contingency in case the whole Ken/Laporte thing did not work out.
Macduff doesn't play around with any silly occupation, or annexation, or cute little orbital bombardments like the tevs do. His approach is straight and to the point: Blast the enemy into extinction with subspace ****ery, and damn the consequences!
Kostadin Cell being a product of Shivan design makes a disturbing amount of sense.
Considering that Laporte is being directed by the Shivans through the Ken anima, it seems contradictory to the Shivan's objectives. In general, I don't think the Shivans have the capacity to influence an entire civilization. I think that's more of a Vishnan thing. Shivans and Vishnans both rely on Nagari, but otherwise seem to differ quite a lot.
I can't remember where, but I recalled that the Elders might be keeping the Gef around, as a final contingency for humanity's survival, should the Shivans annihilated everything else. The Gef's adaptation to living in fringe space would give them the best ability to survive without actual colonies. I would suppose that this factor, at least for non-Kostadin, non-suicidal Gef, would work against the Shivan's interest of destroying an entire species.