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[Scelly9]

Well, if we're taking a journey several lightyears, I think that by then either a type of stasis, or just getting pumped full of muscle relaxants could help the human body cope with a journey like that. Nobody said you had to be conscious. Again, the problem is nobody has really done any studies on it, so we don't know the effect of sustained G forces.

[PanH]

I love that little note : "eyeballs-in", "eyeballs-out"

[Osmosis Jones]

Well, if we're taking a journey several lightyears, I think that by then either a type of stasis, or just getting pumped full of muscle relaxants could help the human body cope with a journey like that. Nobody said you had to be conscious. Again, the problem is nobody has really done any studies on it, so we don't know the effect of sustained G forces.

That's the thing; I'm assuming at least some crew members alive and active for maintenance purposes.

There's not really any convincing work in human stasis I am aware of, and certainly nothing I'd trust my life to for decades (despite a large number of companies willing to freeze and store your head for exorbitant fees). If you need to move around, 2g means you're effectively carrying another you on your back; doable, if you're fit, but 3g certainly isn't.

Assuming that we did have a stasis system, however, it would need to be something that stopped physiology pretty completely; if we were just sedated and doped on relaxants, we'd still have to contend with things like bedsores and blocked circulation, not to mention all sorts of unknown problems (blood pooling in the body etc.) that might arise when there is a very significant force in a constant direction for long periods of time.

In the meantime, I'll stick to my 2g star crawler thanks

[Scelly9]

Alright, fair enough. On another note: The long relativistic journey calulator here says that a trip to Alpha Centauri at 2G acceleration would take 2.3 years for this ship inhabitants, and 5.25 years for earth. Relativity is cool. Too bad it would take so long to figure out if they where successful or not.

[Osmosis Jones]

Alright, fair enough. On another note: The long relativistic journey calulator here says that a trip to Alpha Centauri at 2G acceleration would take 2.3 years for this ship inhabitants, and 5.25 years for earth. Relativity is cool. Too bad it would take so long to figure out if they where successful or not.

That link's actually really cool. Especially as I was just about to pull my old physics 101 textbook (Serway & Jewett, yeah!) out and try and integrate some relativistic formulae

[Andrew425]

With constant acceleration at least you'd have gravity for the voyagers.

[Starver]

Basically, our frail human bodies are limited to maybe only 2G's (I'm spitballing, I would appreciate any real studies) of sustained acceleration, tops. That means Andromeda is a biiiiig nope.

Going to a web-page that someone (in this thread?) mentioned, rather than working it all out myself, I plugged in the biggest value it would apparently allow for distance ("999999999999999" light-years, essentially 1x10¹⁵the Andromeda Galaxy being 'merely' 2.5x10⁶) and a 2g acceleration (that being for half the journey, an identical deceleration for the rest), a human would have to experience a 'mere' 34 years and two months (plus change) on that ship, in their largely relativistic travel to the destination.  (A few orders of magnitude of distance, either way, appear not to make the waiting time vary significantly in this circumstance.)  So a 30yo would get there before they hit retirement age. Assuming no personal or ship-wide problems en-route.

Plug in a more 'friendly' 1g acceleration/deceleration rate and Andromeda's (approximate) distance, and we're talking about 'cruising' for 28 years, seven months, 1.5-ish weeks.  Give or take the approximations (and, Andromeda is heading towards us, as well, isn't it? ...but not sure if significantly so for such a journey) I think that's not a problem for a (single-)Generation Ship.  The kids and grand-kids (or more, if the residents are bored and have nothing else to do) could get back home as well, albeit to a world changed by time and/or swallowed up by the Sun.   That is assuming that one can maintain the 1g thrust for that period, of course, for the size of ship that can contain the corresponding thrusters and fuel-sources of sufficient longevity.

(And I'm taking those figures on trust, but it seemed to work for far nearer, less relativistic calculations that I'd previously laboriously made off my own back, when I was first shown it.)

[Starver]

Alright, fair enough. On another note: The long relativistic journey calulator here says that a trip to Alpha Centauri at 2G acceleration would take 2.3 years for this ship inhabitants, and 5.25 years for earth. Relativity is cool. Too bad it would take so long to figure out if they where successful or not.

Should have read further down, it seems.  'My' website is here and an A-C trip on it (at 4.21ly distance, 2g being sustained) comes out (similarly) as 2.3 years of shiptime and like 'earthtime', so probably uses the same maths.  The latter being 6 years for a 1g sustained(/flipped) acceleration, for a tad over 3.5 years shipboard.  I'd do that.  I'd do that several times, back and forth, as regular crew on a regular commuter mission...  (But you'd have to excuse me of some of my posts to this forum become a bit necro-y whenever I'm on the outward part of my journey... )

[Osmosis Jones]

Basically, our frail human bodies are limited to maybe only 2G's (I'm spitballing, I would appreciate any real studies) of sustained acceleration, tops. That means Andromeda is a biiiiig nope.

Going to a web-page that someone (in this thread?) mentioned, rather than working it all out myself, I plugged in the biggest value it would apparently allow for distance ("999999999999999" light-years, essentially 1x10¹⁵the Andromeda Galaxy being 'merely' 2.5x10⁶) and a 2g acceleration (that being for half the journey, an identical deceleration for the rest), a human would have to experience a 'mere' 34 years and two months (plus change) on that ship, in their largely relativistic travel to the destination.  (A few orders of magnitude of distance, either way, appear not to make the waiting time vary significantly in this circumstance.)  So a 30yo would get there before they hit retirement age. Assuming no personal or ship-wide problems en-route.

Plug in a more 'friendly' 1g acceleration/deceleration rate and Andromeda's (approximate) distance, and we're talking about 'cruising' for 28 years, seven months, 1.5-ish weeks.  Give or take the approximations (and, Andromeda is heading towards us, as well, isn't it? ...but not sure if significantly so for such a journey) I think that's not a problem for a (single-)Generation Ship.  The kids and grand-kids (or more, if the residents are bored and have nothing else to do) could get back home as well, albeit to a world changed by time and/or swallowed up by the Sun.   That is assuming that one can maintain the 1g thrust for that period, of course, for the size of ship that can contain the corresponding thrusters and fuel-sources of sufficient longevity.

(And I'm taking those figures on trust, but it seemed to work for far nearer, less relativistic calculations that I'd previously laboriously made off my own back, when I was first shown it.)

Hmmm, point. I had only considered it from the earth's temporal perspective when I posted that; relativity does change things around. Of course, the fact that wherever you end up, you're quite probably going to be the last humans alive is a bit disconcerting.

Still, there always were people that wanted to be hermits. Maybe we will eventually see that happen.

Just have to figure out how to find some habitable planets once you get there; you could quite easily spend decades searching for suitable places to actually settle.

[Il Palazzo]

Here's a calculator that allows for larger distances:
http://www.convertalot.com/relativistic_star_ship_calculator.html

[Starver]

Still, there always were people that wanted to be hermits.

Makes me smile that.  Not for what you mean, but what it makes me think.  We'd be sending "a community of hermits".

[MaximumZero]

So, why not get the craft to space and do short bursts of high acceleration over a longer period of time to get the craft up to speed? (If this is a stupid question, let me know. I'm no physics major.)

[Siquo]

Let me try to translate it to a frame you'd understand:

Because someone pushing you over a longer time is better than having the energy of that push delivered to you in a short time, such as being punched in the face.

[MaximumZero]

I kind of get that, but why not have the long period of acceleration interspersed with bursts of high end acceleration to get you up to a higher top speed?

[10ebbor10]

I kind of get that, but why not have the long period of acceleration interspersed with bursts of high end acceleration to get you up to a higher top speed?

While technically possible, it is less efficient as you have to install 2 seperate drive systems. (Or a propulsion system that can rapidly change thrust). Also, while these amounts of G forces are easily survivable for both men and machine, rapid increase and decrease of force might cause metal fatigue, which is suboptimal for a spaceship. Besides, the total gain won't be that much.