Since WW2, carrier battle groups have been the way to project power around the globe. An aircraft carrier is a big hunk of military might, a seagoing city with its own air force that can be loaded with nuclear weapons as needed. With those nukes, one carrier battle group contains more firepower than all the navies of the world ever prior to 1930. (And perhaps more recently than that.)
...why do we have three surrounding North Korea?
North Korea is a stalinist, socialist shithole, where the people starve in the dark while their roly-poly dictator lives a life of luxury. NK (allegedly) has nuclear weapons, and it keeps testing missiles, and reportedly has a sub-launched ballistic missile which could conceivably hit the US from not too far away. And the leadership there is crazy, reportedly crazy enough that it's making China nervous.
I am hearing tell that the US is not the only one of the major world powers building up forces in that area, and it sounds to me as if there's some kind of plan in the works to effect "regime change" in North Korea.
We'll see how things play out. I don't know nearly enough about the situation, nor am I anything like an expert on the military, but I'd be lying if I said I wasn't nervous about it.
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In Apocalyptic Visions, both good guys and bad guys in the current conflict--no, I must start over.
There are no "good guys" and "bad guys" in the conflict, really. What we have is two opposing forces, one the aggressor. The defense force is upholding its constitutionally-mandated duties; the offensive side is acting to retain its legally-granted independence. The conflict was caused by the bad guy, who is the commander in chief on the defenders' side, but he's not doing any fighting (of course).
The defenders have the space-borne equivalent of three carrier battle groups, though thanks to budget cuts they're not at full strength. The aggressors have the same number of groups, but at full strength, and one of their "carriers" is a heavy version that has a larger number of air wings. Numbers are on their side.
But the defenders know they're coming, and because it's revealed relatively early on that the aggressors have a top-level spy inside the defenders' command staff, the defenders have done some clever things to keep defense strategies out of the enemy's hands.
So we have a "sitting duck"--a carrier with no obvious support ships--sitting in geosynchronous orbit at New York's latitude (NY is the home of the UN, you see, and like many SF writers have done, the world government in my stories, such as it is, grew out of the UN). And as the Opfor arrives, the trap is sprung! Hey, how long does it take to traverse 250,000 miles when you can boost at 50g?*
...tune in next week for the next exciting episode.
I wish that were an exaggeration. I've got the scene trembling on the brink of combat. Initial, extreme-range salvos have been fired; we've barely begun evasive action--and it's stalled there for a week because I haven't had time to write anything more. Today I have errands to run, and I've got to get the grass cut before it grows beyond all reason; if I am very lucky I'll have energy afterwards to fiddle around with the narrative. But I wouldn't count on it.
*(Answer: not bloody long. Half an hour if you flip halfway and decelerate. 21 minutes if you don't, but you'll only have one chance at hitting the opfor on your blazing-fast trip through the combat zone. In the latter case your speed is better than 630 km/s. All someone has to do is leave gravel or other junk in your path and you'll be done for.)
* * *
I can hear the less-mathematically inclined of you protesting. Why is one case 30 minutes and the other 21? Seems that if you're boosting at 50g all the way there, since you're not stopping, shouldn't it be faster?
No. The problem here is that the equation we use is d=1/2*a*t^2. Squared time is why; although you continue to boost all the way there, each additional second of boost adds less speed by proportion of your present speed. At the 15-minute mark you're moving at 450 kilometers a second; if you don't turn around to brake, but continue to boost, you have an additional six minutes before you get to your target locus--and in six minutes you can only add 180 km/s of speed.
If you stop boosting at the halfway mark but don't slow down, then it becomes the simple D=vt, and that's about 7.5 minutes from the halfway point to your target locus.
Given a maximum boost of 50g and the distance involved, if you want to arrive at your target locus with approximately zero relative velocity, 30 minutes is the fastest you can get there. If you don't care about stopping, 21 minutes is (again) the fastest you can do it.
It's basic mechanics.
* * *
This past weekend would have been Dad's 90th birthday. It's been 10 years since he died, already. Shit.
* * *
Well, the sun is shining on both sides of the street, it's a nice day outside, and I have errands and chores that I must attend to. Off I go.