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Interstellar Flight: Perspectives and Patience

centauri-dreams.org

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Re: Interstellar Flight: Perspectives and Patience

#141

Post by sorcerer-mar »

Teever wrote: post #138
sorcerer-mar wrote: post #131

Earlier quoted context omitted.

> By moving mining off planet to the moon and asteroids we eliminate the carbon emissions and environmental damage that occurs from these processes. ... but this won't happen unless it's economically advantageous, with all risk, transit, and upfront investment included We already don't have the political will to force single-digit increases in cost of output to reduce environmental damage. Why would we then?

What sort of things do you think are necessary to change for this to happen?

"this" == produce political will to protect the environment at the expense of industry?

Not too sure! Probably one part is to disabuse people of the notion that we have alternatives available if only we could just dedicate more brainpower to space travel.

The real answer is to eliminate the tradeoffs through scientific innovation. As mentioned elsewhere, the real way to protect earth (and our species) is to produce better plastics, proteins, and pesticides. Each smart person wrapped up in sci-fi fantasies of simply off-planeting heavy industry is another brain dedicated to -- as far as I can tell (thus my questioning here) -- an almost completely useless endeavor.

Which is why I believe the aforementioned disabusal is critically important. There's just no evidence that big explosions and adventures are what we need. We need people in labs nudging molecules over and over with a 0.0001% success rate.

Re: Interstellar Flight: Perspectives and Patience

#142

Post by qiine »

thechao wrote: post #129
pfdietz wrote: post #75

Earlier quoted context omitted.

However, travel at 0.1c is not needed for the Fermi Argument to bite. Much slower speeds would allow a colonization wave to sweep a galaxy in time << the age of the universe.

Even at .0006c (our current tech), the galaxy would be filled with (weakly self propagating) robotic probes after just 750 million years. Unless extremely long lived self-propagating probes just ... die out ... that implies no aliens older than 750 million years from our galaxy. It implies no aliens from the nearby galactic neighborhood within 3 billion years. That kind of implies we're all alone. I have three wild-e…

you want a funny one I am starting to like more and more ?

We are simply the first.

Re: Interstellar Flight: Perspectives and Patience

#143

Post by sorcerer-mar »

expenses3 wrote: post #139
sorcerer-mar wrote: post #136

Earlier quoted context omitted.

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

No. The best thing you can do with a lot of mass in LEO is construct solar power stations that beam energy down to Earth in the form of microwaves. This is what the second book, Critical Mass, gets into. Receivers on Earth wouldn't provide as much power as solar, but would be much easier to construct and work 24/7, no matter the weather. This would be highly useful for reducing climate change and increasing climate r…

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 expensive than terrestrial alternatives and may have lifecycle costs per unit of electricity that are 12-80 times higher

https://www.nasa.gov/wp-content/uploads/2024/01/otps-sbsp-re...

Re: Interstellar Flight: Perspectives and Patience

#144

Post by CJefferson »

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 used to often hear people joke that because of Moore's law, there was no point running any computation which would take longer than 4 years, as you'd instead be better to wait 2 years for computers to double in power, then run your problem then.

Interstellar travel probably has a similar problem, even if you have an engine that can do 0.1c, you have to be sure in 5 years you won't have one that can do 0.2c, or that ship would beat you.

Re: Interstellar Flight: Perspectives and Patience

#145

Post by sirdvd »

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 very hard to imagine interstellar travel being feasible with our current understanding.

Sometimes it's hard realize the with have a good understanding of only 5% of what composes our universe. Let's hope there's still some surprise lest for ours Centauri Dreams...

Re: Interstellar Flight: Perspectives and Patience

#146

Post by expenses3 »

sorcerer-mar wrote: post #143
expenses3 wrote: post #139

Earlier quoted context omitted.

No. The best thing you can do with a lot of mass in LEO is construct solar power stations that beam energy down to Earth in the form of microwaves. This is what the second book, Critical Mass, gets into. Receivers on Earth wouldn't provide as much power as solar, but would be much easier to construct and work 24/7, no matter the weather. This would be highly useful for reducing climate change and increasing climate r…

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.

Furthermore, one main benefit of SBSP over nuclear is that the receivers don't need to be connected to the grid; each household or piece of infrastructure can have one. This would help manage situations like the power outage in Spain earlier this year or the situation at the start of KSR's Ministry for the Future where a deadly heatwave in India is made 10x worse by coinciding power outages.

Re: Interstellar Flight: Perspectives and Patience

#147

Post by thrance »

xpuente wrote: post #112

It won’t be us. It will be our descendants — the machines.

Yes, 100%. That's the blind spot to all these sci-fi speculations. Hauling cities between stars along with the environment needed to sustain them might very well be impossible. But who needs that when you can send a tiny chip with simulated human (or post-human) personalities on it?

Mandatory advertising for Greg Egan: read his novel, Diaspora. Truly mind-expanding on the subject.

Re: Interstellar Flight: Perspectives and Patience

#148

Post by Balgair »

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 always a bit revealing, with these kids of interstellar missions, how people reveal their own unseen biases.

Clearly such a mission is beyond the capabilities of our world currently. Like, obviously such a mission is something that capitalism cannot accomplish. That communism or anarchism or any -ism just cannot do. And I think that when people look at jaunts out to Alpha Centauri and think in terms of cost, they whole thing is hopeless from the get-go.

To make something like a trip out to Vega, even with just a probe one way at .1c, that's 500 years (right?). We can't fathom doing that right now as staying around to check out any answer. The ultimate 'plant trees in whose shade you'll never sit.'

Generation ships out there, even with magic hibernation tech, I just don't think we have the mental capabilities as great apes to think about this properly. The time scales, the advances in tech, the costs, just even thinking about things in this way shows to me that we're not at all ready to be serious about this.

You don't build a ship by teaching people how to hew oaks or caulk bulkheads. You build a ship by teaching people to yearn for the sea.

Space is still 'not worth it'. Until just being there in the void elicits the same feelings you get when reading about the bowsprits, white with sea-foam, before a quick and fast wind, look, we're not going to do this.

We have to love the trip itself first. The first stars until morning. The good ship to guide by them.

Re: Interstellar Flight: Perspectives and Patience

#149

Post by tenthirtyam »

sorcerer-mar wrote: post #136
tenthirtyam wrote: post #126

Earlier quoted context omitted.

I recently read "Delta-v" and the sequel "Critical Mass: A Novel" by Daniel Suarez. They're very much fiction but there is a certain amount of science underpinning the arguments and I enjoyed that aspect. And the author even states that he's trying to get across, with solid arguments, why humanity should begin planning asteroid mining ASAP. In brief, the arguments are: Firstly we're now at a point where we have lots…

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 colonize its galaxy. :-)

Re: Interstellar Flight: Perspectives and Patience

#150

Post by verzali »

kfuse wrote: post #122

Why is everyone so fixed on interstellar travel? What if the galaxy is chock full of rogue planets? There may be hundreds if not thousands of worlds between us and the surrounding stars. Hopefully, Roman Telescope set to launch in 2027 is going to find lots of them.

Those rogue worlds are frozen though, the only source they have is from radioactive decay in their cores. And eternally dark, since they have no Sun to light them.

It would make more sense to use fusion reactors to power colonies in the outer reaches of the solar system than to go to a rogue planet.

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