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Interstellar Flight: Perspectives and Patience

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Re: Interstellar Flight: Perspectives and Patience

#151

Post by sorcerer-mar »

expenses3 wrote: post #146
sorcerer-mar wrote: post #143

Earlier quoted context omitted.

NASA did a feasibility study of this even accounting for future technology improvements/cost reductions and it doesn't seem to come close to earthbound alternatives, especially nuclear fission. Nuclear fission is more stable, less maintenance, less risky, less upfront and ongoing environmental damage, less vulnerable to all sorts of risks, and produces way way more energy. > We find the SBSP designs are more expensiv…

I was talking about having mass in orbit from mined asteroids (or the moon), like the grandparent comment. This survey is based entirely on launched SBSP: > This study assessed lifecycle cost and emissions based on the following scenario: SBSP systems are developed on the ground in the 2030s and launched to low-Earth orbit (LEO), and then transferred to and assembled in geostationary orbit (GEO) in the 2040s. Further…

I see -- so we're going to build an end-to-end solar panel/reflector factory in space, from initial mined materials through to operational energy production and transmission. Color me skeptical.

> This would help manage situations like...

Aren't these situations trivially solvable with batteries if there were political will to be prepared for them?

Re: Interstellar Flight: Perspectives and Patience

#152

Post by sorcerer-mar »

tenthirtyam wrote: post #149
sorcerer-mar wrote: post #136

Earlier quoted context omitted.

This is predicated on it being worthwhile to colonize the moon or Mars, no?

Indeed. It's a certainty that Mars is far far less hospitable than Earth even in the worst of the climate change outcomes. I suppose the most useful thing about colonizing Mars would be for species survival - e.g. the Giant-Asteroid-Strikes-the-Earth-but-luckily-not-Mars scenario. In any case, a nearby planet or its orbit would seem to be the most logical place to start for any supervillain species seeking to coloniz…

I haven't done the math but I suspect if we really cared about that risk, it'd be orders of magnitude easier to build far better asteroid detection and deflection systems. The reason we haven't is because in reality we don't care much about that risk relative to the costs of addressing it (even with the cheapest possible solutions, which are not "colonize another planet").

Re: Interstellar Flight: Perspectives and Patience

#153

Post by rbanffy »

andrewflnr wrote: post #100
antonvs wrote: post #99

Earlier quoted context omitted.

Happily when Asimov wrote the same story, he didn't give away the punchline in the title.

Sure, if you put it in the title you need a different punchline. :D

It would be a different tale altogether - probably engineers discussing how ludicrous the idea is, until it's feasible, and then debating the consequences before pressing the red button.

Re: Interstellar Flight: Perspectives and Patience

#154

Post by rbanffy »

sorcerer-mar wrote: post #72
rbanffy wrote: post #65

Earlier quoted context omitted.

There is many times more water in gas giant moons than on Earth. If we develop the technology needed to make a multi-generation ship we also have the technology to make deep space habitats - enough for trillions or quadrillions of people. Just imagine the economic output of a civilisation a million times the size of ours.

It’s a lot easier to imagine the economic output of simply raising all of the current Homo sapiens out of poverty and into economic productivity, no? Then we can use all of that new productivity to start working toward the next rung? Our economy is not currently throughput limited on water or space so I don’t find this compelling.

That's a false dilemma. You can do both things at the same time. In fact, doing one will most likely also cause the other.

Re: Interstellar Flight: Perspectives and Patience

#155

Post by K0balt »

echelon wrote: post #115
imoreno wrote: post #109

With Alpha Centauri being only 4 light years away, interstellar travel seems almost feasible. But then you consider all the inconvenient details, and realize such a journey would have to take hundreds, maybe thousands or even more years on top of some incredible advances in rocket tech. If you go to something like Trappist (40 ly) at 0.01c (very optimistic), it's not just that everyone you know will be dead when you…

> it's not just that everyone you know will be dead when you arrive. Your entire nation will have disappeared to the sands of time. Humans are just a stepping stone. Earth intelligence will transcend our 77 year lifespans and primate brains. Our lungs are adapted to gas exchange on this particular gravity well and its unique biogeochemistry. There's no reason redox reactions need to happen like this, or indeed even b…

This exactly. Evolution is a stepping stone to engineering., which then will also be subject to evolution. (Is there a word for engineered evolution?)

The trick will be to remain -human- perhaps. Or we just accept the fate of the loser of natural selection, and are replaced by our children of an obsolete god.

I have posited an idea on how this could work and done a bit of world building in that space, perhaps I will overcome my reticence toward writing fiction and publish one day.

Re: Interstellar Flight: Perspectives and Patience

#156

Post by troyvit »

dakial1 wrote: post #137
imoreno wrote: post #109

With Alpha Centauri being only 4 light years away, interstellar travel seems almost feasible. But then you consider all the inconvenient details, and realize such a journey would have to take hundreds, maybe thousands or even more years on top of some incredible advances in rocket tech. If you go to something like Trappist (40 ly) at 0.01c (very optimistic), it's not just that everyone you know will be dead when you…

I love science fiction because they usually try to play these scenarios in a somewhat feasible future. The 3 Body Problem series (more specifically the 3rd book) goes well into what it would take for humanity to be interestellar even without lightspeed or wormholee tech. Avoiding spoilers it would basically be through hibernation and/or generational ships. Which basically implies of losing all ties to earth and anyon…

I've been reading some sci-fi by Kate Elliott lately. While she gets around large distances with the usual FTL tech of sci-fi, in-system space battles hew a little more to physics, so that you get situations like, "Crap! The bad guys fired all their missiles at us! We have sixteen hours to decide what to do ...." Fun stuff.

I bet you're right about emergency situations. On top of that, people have been getting on boats and pushing off into the ocean for at least 25,000 years[1] when there was plenty of good land to keep them occupied. It's not that we're talking the same time scales, but rather the fact that they probably did it despite completely unknown time scales. It makes me wonder if the right philosophy or religion will come along that makes somebody try a generation ship for non-emergency reasons.

[1] https://teara.govt.nz/en/pacific-migrations/page-1

Re: Interstellar Flight: Perspectives and Patience

#157

Post by naasking »

sfink wrote: post #104
naasking wrote: post #91

Earlier quoted context omitted.

Perhaps, some fraction of the laser energy beamed to move the sail is redirected directly in front of the spacecraft to vaporize any dust particles in its path. Fragments of a circular sail could be angled in the right way so as to take some fraction of the light's momentum in its desired direction with the rest reflected at an angle to clear the opposite side of the sail. For a circular sail you'd then get a circula…

You're avoiding the energy that would be imparted by hitting the dust spec by... adding energy to the dust spec? Perhaps splitting it so it damages a larger area? It seems better to let it plow as small a hole as possible in the sail.

1. Dust specs would respond to momentum imparted by the light much more quickly, which would reduce the momentum difference between the ship and the specs.

2. Enough incident light could vaporize the specs entirely leaving only gas or plasma, which doesn't carry the same danger to the ship.

Re: Interstellar Flight: Perspectives and Patience

#158

Post by sorcerer-mar »

rbanffy wrote: post #154
sorcerer-mar wrote: post #72

Earlier quoted context omitted.

It’s a lot easier to imagine the economic output of simply raising all of the current Homo sapiens out of poverty and into economic productivity, no? Then we can use all of that new productivity to start working toward the next rung? Our economy is not currently throughput limited on water or space so I don’t find this compelling.

That's a false dilemma. You can do both things at the same time. In fact, doing one will most likely also cause the other.

I didn't say we had to choose one or the other, I'm suggesting actually the opposite: the clearly superior way to do it is to first do one (ensure we are maximally leveraging all IQ points born to humans on earth) then do the other (now armed with billions more brains that freed from the daily task of avoiding premature death).

If you have an argument for why the reverse ordering, or in parallel, would be better, that's what I'm asking for: what's the argument?

Flesh it out beyond just "imagine if we succeed with no substantial opportunity loss!"

Re: Interstellar Flight: Perspectives and Patience

#159

Post by rbanffy »

sorcerer-mar wrote: post #158
rbanffy wrote: post #154

Earlier quoted context omitted.

That's a false dilemma. You can do both things at the same time. In fact, doing one will most likely also cause the other.

I didn't say we had to choose one or the other, I'm suggesting actually the opposite: the clearly superior way to do it is to first do one (ensure we are maximally leveraging all IQ points born to humans on earth) then do the other (now armed with billions more brains that freed from the daily task of avoiding premature death). If you have an argument for why the reverse ordering, or in parallel, would be better, tha…

Since the expansion is a far longer term project, I always assumed eradicating poverty on Earth would be a trivial endeavor in comparison. We kind of can do that today, if we really put our minds to it.

The benefit, however, is minuscule compared to what an expansion into quadrillions of highly educated humans could create.

Re: Interstellar Flight: Perspectives and Patience

#160

Post by rbanffy »

jiggawatts wrote: post #93
sorcerer-mar wrote: post #72

Earlier quoted context omitted.

It’s a lot easier to imagine the economic output of simply raising all of the current Homo sapiens out of poverty and into economic productivity, no? Then we can use all of that new productivity to start working toward the next rung? Our economy is not currently throughput limited on water or space so I don’t find this compelling.

These people are dreamers that grew up watching Star Wars and Star Trek. The world painted by those shows has lodged in their minds, and no amount of logic will shake it loose. In the past, I've challenged the "Let's colonize Mars!" people to do something that's far easier : Move to Bouvet island, now.[1] This is a frozen uninhabited rock that is nonetheless a tropical paradise compared to Mars. It's far easier to re…

> It's far easier to reach, has free unlimited oxygen and water, and gets more solar radiation also for power! It's luxurious compared to the colder, dryer deserts of Mars where there's only dry rocks and near-vacuum.

You miss the whole point. The point of becoming an interplanetary civilization is not to fill every barren rock you see (and there are plenty on Earth, and, if climate change isn't controlled, there'll soon be more). The point is to put just enough humankind on all the places we can easily reach (at that given time) so we can expand from there with in-situ resources rather than only expand from here, using only Earth resources (which WILL run out).

Some humans seem to have evolved a motivation to explore their surroundings. At first we walked, then we learned to ride animals, wheels, boats, airplanes, and, recently, spacecraft. We travel to learn both about other places as we do to learn about ourselves. Some people might feel content with our current reach, but I feel constrained.

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