Worldly Talk

Civil discussion and debate on real world events and issues.


Xavier Dumusque's Alpha Centauri

   
Quote:
Originally Posted by silveroak View Post
Yes, but getting the power to accelerate to .9 c is problematic. Remember this is real engineering being discussed, not just how could it hypothetically work if we had our dream technology (which incidentally would be a wormhole jump drive powered by dark energy)
Bingo, which is why by and large time dialtion is a moot point for the projects we talked about which are, at least, conceivable by present technology. That said .9c needn't require dark energy or wormhole drives: the Valkyrie Project is based on conventional reaction propulsion just with anti-matter for fuel. Granted, to do anything meaningful you need huge amounts of antimatter which in turn requires huge ammounts of energy to produce but it's a problem of
A common answer postulated by one of the authors is the Icarus array, many near-sol solar arrays beaming power to the rest of the solarsystem. Again it's a matter of scale and infrastructure but we could capture vastly more of the suns energy than we already do, and we can do so without resorting to magitek wormhole siphons or the like.
scale rather than concept. That said, Valkyrie style designs are at the far, far end of practical theory and again are more proof of concept ideas that big as interstellar distances are they're not insurmountable. And that can be important to keep in mind in these discussions because the line between impossible/improbable/impractical gets blurred very quickly.

As for the why - well, you're right, Silveroak, profitable return will be hard but the resources of the Solar System are finite; if we're talking long term species survival type future at some point humanity has to expand beyond the solar system. That point may be so far off as to seem hypothetical but it's there, all the same.

Having done the math on antimatter, let me say that it's the most attractive fuel I have ever seen, and also the most unobtainable in the quantities we would need. Production efficiencies are close to zero, and the energy demands are massive, so the end result is a whole lotta power going nowhere fast to produce almost nothing. Unless we can harness a large chunk of the energy output of the sun, then we will start to get good quantities.
Then we get to storage... I'm pretty much of the opinion that neutral antihydrogen ice is the way to go. Stored at close to absolute zero, using paramagnetic effects as the heart of the storage system.

I'm fairly confident we will have developed better technologies long before the survival of teh species is dependant on leaving the solar system. Population growth is not always exponential, so the only thing that would drive us to have to leave the solar system (as opposed to just being uncomfortable with the resources available here) would be the death of the sun. NASA's new expiriments with warp drive have a good chance of getting us to Alpha Centuari within the next 200 years, well short of the sun expiring.

When talking generation ships, don't forget the ship is not completely isolated from earth, so a lot of culture could still be sent there at light speed, and even the last generation could receive occasional news from family. Information about how stuff works is undoubtedly stored on the ship in very clear instructions.
There is also very clearly no point in rebelling. They would not be able to turn the ship around, because it would not contain enough fuel to brake and then accelerate again in the opposite direction, if e.g. the aim was to return.

We're also not running out of resources any time soon. The asteroid belt contains massive amounts of minerals and we have enough deuterium in our oceans to provide us with energy until the sun swallows the Earth. The main reason is to ensure our survival in case something happens to Earth, such as a massive asteroid or the inevitable end of the sun.

Colonizing near earth asteroids could provide security against a massive asteroid strike plus provide reources to the earth, at a much lower price tag.

I wouldn't buy a ticket to this planet. From what I've heard, at that distance from a sun, the planet is probably in its death throes, and ever-so-slowly losing distance, spiralling inward. It may even be losing mass to the sun's gravity.

@Silveroak: You do have a point in that unless something happens to the entire solar system chances are relocation and resettlement could be done quite happily inside the oort cloud and for a fraction of the cost. And you're right. But there are celestial events which can and would render the entire solar system uninhabitable - gamma ray bursts & near earth supernovae are the most commonly cited. And that's before we get into the really bizarre posibilities of rogue stars or gravitational bodies ripping the solar system apart on a near miss/transit.

Thing is, humanity might get lucky and get the width and breadth of what's left of sol's main sequence. We might not. It's a nonzero chance - not a big nonzero chance, but a nonzero chance - and the kind of fundamental quetion that has to be, when you're talking about the survival of a species, is how low can that chance be and still be acceptable. What's an acceptable percentile on which to gamble everything we ever were and could be?

Granted, that's not going to be compelling logic to people who want returns on their investment now and frankly when it comes to long term planning we as a species kind of suck. But that's the math, if we care to look at it. There is a reason to make the attempt, even if it seems unnecesary now.

@Agricolus. I'm not so sure it would be in its death throes, honestly. A three day orbital period represents a fair chunk of kinetic energy and while the orbit is likely decaying it's likely doing so about on the same
100K to millions of years. Not billions though, so in celestial terms pretty quickly
timescale as that of our moon, so as a piece of physical real-estate it should be around long enough even if it did take a 40,000 year mission. The big thing here though is that where there's one there are probably more - with the exoplanet detectiont echniques we have the other potential planets are just orders of magnitude harder to detect. Xavier Dumusque in one of these articles mentioned in the original post said that they could try and observe the signs of a planet in the habitable zone of the system, where it would have an orbital period of about 200 days, but it would take about a decade of continous observation of Alpha Centauri to have enough data as to hazard a substantive guess.

Quote:
Originally Posted by Muggie2 View Post
That's the first generation raised aboard. Now, assuming that there are not a sufficient number of rebels (and, I mean, it's not as if teenagers rebel all *that* much), they will be the people who raise the second generation. Who will start to critique exactly why they're stuck there on the ship, and will start to cut corners, partly because they feel put upon, and partly because what they have is the whats and hows, and not so much of the whys.
Why shall they be unaware of the "whys"? I mean there must be organized on the ship a system of education, so already from the kindergarten one would be taught (read: indoctrinated) about his duty and the greatness of whole mission. The most of brighter sceptic should be convinced that they are already beyond the point of no return, so discussion is a bit academic.

Quote:
By the time you hit the third generation, things are starting to go wrong. Maintenance starts failing to cut it because things are just too old, and replacement of parts is necessary. But where and how? As new problems crop up, there's nobody who knows how to solve them, because nobody remembers... maybe in the holy books somewhere there's an answer...
I don't get why you envision here almost a space version of "The lord of the flies", with kids left not knowing neither about ideology or technical know how. More realistic system would involve both really good data bases where everything is backed up. A new generation would have to be taught about everything from kindergarten and education would be continued till somewhere around university level.

Quote:
When talking generation ships, don't forget the ship is not completely isolated from earth, so a lot of culture could still be sent there at light speed, and even the last generation could receive occasional news from family.
After a while? Presumably will be watched with interest though consider a bit exotic like ex. manga. In practice more interesting would be peer reviewed journals. Maybe even DNA codes of modified organisms would be sent via e-mail. (attachment ".dna" )

Assuming that we deal with problems like "the inevitable end of the sun" then the mission can wait a bit for techs like transhumans + A.I. that has to dumb down to pass Turing test + effective hibernation + possibility of grow foetus in a tank on industrial scale. Which would facilitate everything.


EDIT: realistic star travel? Really high tech (beating contemporary as much as we beat now early industrial revolution period), more a back up mission, lead by A.I. which is updated during the missions, transhumans to be defrost; unimpressive speed because is no point to hurry)

Also keep in mind that the further you get from teh eart the greater the lag and the greater the data restrictions due to power requirements. Aside from teh fact that nobody wants to wait 6 years for a response to their email, similarly nobody would be willing to sacrifice a signifigant portion of tehir power capacity to stream in Law & Order demiliterized zone (which is about where the series will be in 50 years) when they have the exciting everyday world of real time astrophysics and quantum mechanics to deal with, which not only has fewer inconsistancies on the part of quantum mechanics, astrophysics has fewer holes in the plot.
And really, the 3 year old version of the 6 oclock news for a pace you will just never get to is not worth teh power drain, heck even kids shows won't be worth the power drain, especially when they are mostly hyping the toys and live performance, and other merchandise that nobody on board will ever see...

Quote:
Originally Posted by silveroak View Post
Also keep in mind that the further you get from teh eart the greater the lag and the greater the data restrictions due to power requirements. Aside from teh fact that nobody wants to wait 6 years for a response to their email, similarly nobody would be willing to sacrifice a signifigant portion of tehir power capacity to stream in Law & Order demiliterized zone (which is about where the series will be in 50 years) when they have the exciting everyday world of real time astrophysics and quantum mechanics to deal with, which not only has fewer inconsistancies on the part of quantum mechanics, astrophysics has fewer holes in the plot.
And really, the 3 year old version of the 6 oclock news for a pace you will just never get to is not worth teh power drain, heck even kids shows won't be worth the power drain, especially when they are mostly hyping the toys and live performance, and other merchandise that nobody on board will ever see...
And when you're talking about a ship large enough to hold a generational crew, a few hundred terabytes of existing-at-the-time-of-launch entertainment material being brought along for the ride isn't much of an imposition. All your favourite shows and movies from the past 50 years available on demand through any of the ship's non-critical view screens (best not be watching Big Bang Theory on the screen meant for monitoring reactor output, after all).




 

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