But I mean... in the Light Gauss example, that is 612 kilometers firing distance. Compared to ground warfare, that is just plain insane.
Ground warfare really doesn't rate for space combat. The lack of an atmosphere to get in the way is that much of a game changer. Add in the need for engines powerful enough to get anywhere in a timely matter and ranges just don't mean the same thing.
A ship actively accelerating at 1G will cover 612 kilometers in 350 seconds, a bit under 6 minutes. A tank that has a road speed of 64 km/h will cover all of 6.2 km in the same time. Pretty much any Aerotech craft meant for combat can actually go faster than 1G during combat, so the 612 kilometers end up meaning even less than the 6.2 kilometers mean to a tank.
It's all a matter of perspective.
Though I'm no physicist either... yet to me these numbers are just enormous.
They are actually on the very small side for a real life leaning space setting. Visual scifi in general is just ridiculously close ranged, which is probably where you're getting the confusion from. Just to give you some perspective, take virtually any battle you've seen on TV, in games, or on the big screen, it'll be rare for them to take up more space than 2 hexes in Aerotech terms during their overly dramatic firing sequences and dogfights. More often than not they'd actually fit comfortably inside a single hex, with lots of room to spare.
There are only a tiny handful of exceptions in visual scifi that actually portray more realistic distances. One I can remember is in Babylon 5 (I forgot the episode, it's an Omega shooting at what looks like deep space to the background of a planet), another is from Star Trek of all places, when they have phaser shots barely miss a runabout just come out of seemingly nowhere because the firing ship is still that far away. Andromeda Ascendant had quite long ranges as well, which usually were quite hard to realize since you just saw a system plot with overly large icons representing ships giving the illusion of closeness.
Situations like that would actually be the norm, in terms of realistic ranges, in space. The average viewer just can't wrap their minds around that, apparently, so the usual approach is to have everything within the same frame to give an easy reference and more drama.
To throw in another Aerotech example, fighter battles at even a lowly 10 hexes, which would still be capital short range/standard medium range, has them shooting at minuscule pinpricks of light as far as the naked eye is concerned. To an audience used to having their WWII in space dogfights that would likely be utterly boring, thus we get the current format in visual media. It's a vicious, self-reinforcing circle.
Space is just that mind bogglingly big. You can fairly easily get into lightsecond ranges (1 lightsecond being the distance covered by light in a vacuum during one second, or about 299792 km, which would be roughly 16655 hexes in Aerotech terms) for realistic space combat before the lightspeed lag starts to really screw with you. And one lightsecond is still only about the distance the Moon is from Earth (well, 1.3 lightseconds, to be precise). The average distance between the Sun and Earth, one astronomical unit (AU for short), takes light a bit over 8 minutes (499 seconds) to cover. The standard jump points for the Sol system are 10 AU away from Earth orbit, which would take light about 83 minutes to cross.
