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[Dozebôm Lolumzalìs]

And that's trivial. Minor improvements could change the date by over a year.

Also, PROJECT MEDUSA SQUEEEEEEE

It's an Armokdamn shame that we aren't allowed to detonate nuclear pulses in space anymore.

[mainiac]

What I'm saying is would the trip take 44 earth years (about 43.5 years for the ship), or 44 ship years (about 44.5 years for earth)

It's the same length of time.  There isn't an appreciable difference in velocity between the two solar systems.  They would experience the same number of years, just earth would experience the years slightly earlier and then the ship would catch up towards the end.

[origamiscienceguy]

No they wouldn't. The people on the ship would forever be 1 year younger than the people on earth than they were when they launched.

[Max™]

The GR effects due to acceleration will be agreed on by all observers regardless of reference frame, the SR effects due to velocity and different inertial frames are the ones that make it look like the other guy is the one being slowed down.

When you undergo acceleration you actually move slower through time, and thus age less compared to an unaccelerated observer.

More to the point, we need to chuck a starwisp over there, as it can get there in a really short amount of time compared to trying to get people over the whole "OMG NUH NUKES IN SPAEC GUIZ" thing, I can get behind a ban on orion surface launchers, though they're awesome at it, but preventing their use outside of our orbit and even outside of the magnetosphere is just absurd.

[Mephansteras]

In local system news, I recently heard about plans for a lunar orbit space station. Has this been discussed yet?

[Bralbaard]

In local system news, I recently heard about plans for a lunar orbit space station. Has this been discussed yet?

The reasoning behind the plan is that nasa is currently building this huge SLS rocket, and the orion deep space exploration vessel, both with nowhere to go. There are not nearly enough firm plans for destinations, and to keep SLS viable it needs at least one mission each year. So currently some of these space station concepts pop up, by companies that hope to get a lucrative contract.

Recently there was this other cis-lunar moon station proposal by orbital ATK:
https://www.nasaspaceflight.com/2016/05/orbital-atk-cislunar-habitat-missions-sls-orion/

And this orbital mars station by lockheed:
http://www.lockheedmartin.com/us/ssc/mars-orion.html

But with the ISS nearing the end of its life early next decade, there is certainly a need for a new station, or stations. There's quite a bit of talk that indicates modules will be split of from ISS at the end of its life to form their own separate space stations.
It should also  be noted that there are commercial efforts as well for space stations (space tourism!). Also other countries (china) have plans for building their own destinations, so I am optimistic that at least some of these will get build and that we'll have more than just one space station in the future.

[MetalSlimeHunt]

My big hope (well, one among many) is that the US will retract the ban on NASA collaboration with CNSA so they'll be able to get in on the next international station project.

The stars are more important.

[Gigaz]

In local system news, I recently heard about plans for a lunar orbit space station. Has this been discussed yet?

I think the plans are shifting more and more towards an outpost on the lunar surface, which would provide a good test environment for living on another planet, including construction from on-site materials, producing rocket fuels, testing direct launch railguns or space elevators, and so on.

[Il Palazzo]

The GR effects due to acceleration will be agreed on by all observers regardless of reference frame, the SR effects due to velocity and different inertial frames are the ones that make it look like the other guy is the one being slowed down.

When you undergo acceleration you actually move slower through time, and thus age less compared to an unaccelerated observer.

The twin paradox has nothing to do with GR or acceleration - it's a purely SR effect. You get different elapsed proper time because of different paths through space-time between the same pair of events.
It's true that in a typical twin paradox scenario an outbound twin must reverse her velocity to get back home, but: 1) the acceleration is not what causes differential ageing 2) you can construct the scenario without acceleration at all (e.g. by using a closed space, or a free-fall slingshot), 3) either wat you're not ever using GR - the space-time is a flat Minkowski space-time.

Here's a good writeup on the subject:
http://math.ucr.edu/home/baez/physics/Relativity/SR/TwinParadox/twin_paradox.html

[LordBaal]

That's why a lot of pages ago I suggested the only practical way to travel to other stars with foreseeable/feasible technology is dramatically extend our life span or send really advanced robots.

If we could live 200 or 300 years or more then a 50 years travel wouldn't be as much burden, because despite still being an awful chunk of someone's life it wouldn't be ALL of it. Someone preparing 50/100 years for such mission, going there and back using 100 years and then living here as an hero for yet another 50/100 years doesn't so bad in comparison to traveling there to die.

Of course all this are conjectures and then there's the issue of how to extend human life two or three fold, if it's even possible at all. Just that I think it could be sightly more probable that finding a way to build a feasible warp engine or something.

The other option would be triggering really extensive hibernation on humans. Sleeper ships.


On colonies I already stated my mandate, to the moon first! Hehehe... I think the moon if far more easy for a number of reasons. Relative closeness to Earth, "easy" colony setup by remote controlled machines, virtually no communication lag (I get more lag on whatsapp phone calls than what theoretically a radio call would get to the moon).

But first things first. All those people whinging about "nuking space", "nuclear contamination of space" and such, should be strapped on a rocked and exposed to the vacuum they "want to save and keep clean of radiation" (yes I heard that first hand) and then the survivors rounded to work as indentured workers on uranium mines....

[origamiscienceguy]

If we accelerate enough, though we could bring down the travel time to any amount, even under 4 years perhaps.

[LordBaal]

If we accelerate enough, though we could bring down the travel time to any amount, even under 4 years perhaps.

That's what they did on Avatar I think, mixed with cryosleep or something.

[Max™]

The GR effects due to acceleration will be agreed on by all observers regardless of reference frame, the SR effects due to velocity and different inertial frames are the ones that make it look like the other guy is the one being slowed down.

When you undergo acceleration you actually move slower through time, and thus age less compared to an unaccelerated observer.

The twin paradox has nothing to do with GR or acceleration - it's a purely SR effect. You get different elapsed proper time because of different paths through space-time between the same pair of events.

I... the different paths through spacetime as a result of the accelerating frame mean it isn't a paradox anymore, if you both start at event a and travel to event b except one twin has a longer spatial component to their journey then they must have a shorter temporal component, otherwise they aren't meeting at the same events.

It's true that in a typical twin paradox scenario an outbound twin must reverse her velocity to get back home, but: 1) the acceleration is not what causes differential ageing 2) you can construct the scenario without acceleration at all (e.g. by using a closed space, or a free-fall slingshot), 3) either wat you're not ever using GR - the space-time is a flat Minkowski space-time.

Here's a good writeup on the subject:
http://math.ucr.edu/home/baez/physics/Relativity/SR/TwinParadox/twin_paradox.html

I am extremely well versed in the workings of SR and GR, and have already read everything on Baez's site actually.

Yes, you can work through it all in SR if you want, and even construct a scenario and try to eliminate the obvious ways which GR hops in and clears everything up. We aren't in a rotating cylinder universe and the slingshot is clever, but basically boils down to making sure you keep your eyes shut and shout "LA LA LA LA, I'M NOT SWINGING PAST A STAR, I'M SITTING TOTALLY STILL AS THE UNIVERSE AND MY TWIN HURTLES AROUND ME ALONG IMPROBABLE TRAJECTORIES, DOOT DOOT DOOT" doesn't it?

Draw a spacetime diagram, look at how silly this all is, go drink a beer with your twin instead.

[Il Palazzo]

I am extremely well versed in the workings of SR and GR

[Max™]

Just saying, I'm not someone you need to explain the twin paradox or whatnot for, especially when you are just agreeing with me in a roundabout fashion.