Relativity

I did a search of the forums for this topic but I didn't find much that pertained to the aspect of how relativity is addressed with regards to personnel. Lots about missiles and system though!

I realize that being in hyper is a totally different ball of wax, but getting into and out of hyper, traipsing all over the galaxy at significant fractions of light speed has relativistic effects on the personnel of the various services. I don't recall it being addressed in the books at all.

What is everyone's thoughts on it? I understand that with prolong you're not likely to never see people again because of a long trip but it will cause definite age gaps between people born of the same generation, I would think.

It's not directly touched on, but there are hints here and there about the relativistic effects.

In regards to ageing slower because you are traveling all over - I don't think the effect is so pronounced it'll matter in a prolong society. Traveling in hyperspace also changes the dilation factor, it should be based on the inverse of the speed of the current band you are traveling in.

And if you travel by wormhole, the transition is instantaneous so that doesn't factor in at all.

Short answer, there usually isn't enough to matter.

Getting to hyper - with a maximum entry velocity of 0.3c, the worst case scenario is that the people on the ship experience 95.3% in the moments before translation. Most don't go anywhere near that speed, and those who do tend to not spend much time at it so any dilation is minimal.

Traveling in hyper - I am assuming that the dilation works the same as normal space based on the velocity in hyper and not on the effective real space velocity.

Civilian particle shielding is limited to 0.5c, which has give a perceived time rate of 86.6%. Essentially, for every week (from the point of view of the universe) you spend traveling in hyper (ignoring the minor accel/decel time at the ends) at that speed you experience 6 days, 1 hr, 29 mins.

Military grade shielding will max out at 0.7c. 71.4%. A week traveling will be perceived as a hair under 5 days.

Combat generally doesn't last long enough or reach high enough velocities to matter.

---

So, for a merchant ship if we generously assume 50% of their time traveling in hyper (the rest being in system scrounging up contracts, loading/unloading cargo etc) a year of service will effectively shave about 24 days off of your effective age.

Military ships are a bit harder to judge, as it depends on the type of assignment.

Anti-piracy patrols likely represent the highest travel rate, and they seem to spend a few days traveling and then a few lurking in system, so 50% traveling is probably a reasonable upper assumption. At that rate, you are experiencing 50 or so days less each year.

Most ships won't be doing anything near that much.

Of course there are courier ships on critical routes who spend most of their time in hyper and are therefore aging at massively reduced rates. Possibly as much as 90 or so days less in a year.

zyffyr wrote:
Military grade shielding will max out at 0.7c. 71.4%. A week traveling will be perceived as a hair under 5 days.

Correction, in hyper military shielding maxes out at 0.6c. 80%. So a week of traveling will be perceived as 5.6 days.

The books allude to this time dilation for ships, occasionally, with references to how long a trip will be by ship's clocks compared to the rest of the universe.

The Honor of the Queen Ch. 2 wrote:At the moment, for example, Honor’s convoy was cruising along in the mid-delta bands, which translated their .5 C true velocity into an effective velocity of just over a thousand times light-speed. At that rate, the thirty-one light-year voyage to Yeltsin’s Star would require ten days—just under nine, by their shipboard clocks. Left to herself, Fearless could have made the same crossing in less than four.

Honor Among Enemies Ch. 10 wrote:Left to themselves, Commander Elliot's escorting destroyers could have made the trip in seven days by the universe's clocks (or just over five by their own, given the time dilation effect), but they would have had to move well up into the eta bands to do it. Given the elderly nature of some of her charges, Elliot had held the convoy to the lower delta bands, where their maximum apparent velocity was only a little over 912 c, so the trip had taken almost twenty days objective, or seventeen days subjective.

Uncompromising Honor pg399/511 rtf wrote:And whether they were a fleet or a mere task force, they were also two subjective days—just over three days, by the rest of the galaxy’s clocks—out of the Sol System. They’d reach Beowulf early the day after tomorrow…at which point they’d find out just how good Hasta really was.

zyffyr wrote:Short answer, there usually isn't enough to matter.

Getting to hyper - with a maximum entry velocity of 0.3c, the worst case scenario is that the people on the ship experience 95.3% in the moments before translation. Most don't go anywhere near that speed, and those who do tend to not spend much time at it so any dilation is minimal.

Traveling in hyper - I am assuming that the dilation works the same as normal space based on the velocity in hyper and not on the effective real space velocity.

Civilian particle shielding is limited to 0.5c, which has give a perceived time rate of 86.6%. Essentially, for every week (from the point of view of the universe) you spend traveling in hyper (ignoring the minor accel/decel time at the ends) at that speed you experience 6 days, 1 hr, 29 mins.

Military grade shielding will max out at 0.7c. 71.4%. A week traveling will be perceived as a hair under 5 days.

Combat generally doesn't last long enough or reach high enough velocities to matter.

---

So, for a merchant ship if we generously assume 50% of their time traveling in hyper (the rest being in system scrounging up contracts, loading/unloading cargo etc) a year of service will effectively shave about 24 days off of your effective age.

Military ships are a bit harder to judge, as it depends on the type of assignment.

Anti-piracy patrols likely represent the highest travel rate, and they seem to spend a few days traveling and then a few lurking in system, so 50% traveling is probably a reasonable upper assumption. At that rate, you are experiencing 50 or so days less each year.

Most ships won't be doing anything near that much.

Of course there are courier ships on critical routes who spend most of their time in hyper and are therefore aging at massively reduced rates. Possibly as much as 90 or so days less in a year.

For the Merchant example, they will gain 2 years in a 30 year career. A noticable amount, but not enough that you'll miss little Timmy's childhood on a trip - just maybe xmas or his birthday if you don't plan things right.

And David set these limits up on purpose - he didn't want it to be a focus of the series. This is Horatio Hornblower in space, afterall, and it wouldn't do for the opponent to develop steam frigates and gattling guns while HH is sailing across the ocean.

zyffyr wrote:Of course there are courier ships on critical routes who spend most of their time in hyper and are therefore aging at massively reduced rates. Possibly as much as 90 or so days less in a year.

Especially Haven's dispatch boats, some of which had to go all the way to Sol(without using wormholes) and then turn around only a few days after arriving.

There was an internal dialog by one character about her ‘real’ age and her calendar age. They were not that far apart, given she’d spend decades in space.

There is a story by another author where at the end of another vast space war, married veterans hired a starliner to run out and back repeatedly. That way when their spouses were released from service, they could reconnect and still be about the same relative ages. I do not remember the title nor who wrote it.

tlb wrote:There is a story by another author where at the end of another vast space war, married veterans hired a starliner to run out and back repeatedly. That way when their spouses were released from service, they could reconnect and still be about the same relative ages. I do not remember the title nor who wrote it.

That was "The Forever War" by Joe Haldeman

kzt wrote:There was an internal dialog by one character about her ‘real’ age and her calendar age. They were not that far apart, given she’d spend decades in space.

I believe that was Henke, something to do with a promotion that took effect on her birthday.