Interstellar Flight: Perspectives and Patience • Hacker News Board

Re: Interstellar Flight: Perspectives and Patience

#191

Post by sorcerer-mar » Sat, Jun 28, 2025, 1:19 PM UTC

pfdietz wrote: post #190

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…

> especially nuclear fission Since nuclear fission is enbarrassingly uncompetitive on Earth, where is this "especially" coming from? The comment seems to be impeaching the credibility of the study, if it concluded nuclear on Earth would be the top contender non-fossil energy source.

> didn't read the study

> study isn't credible based on misreading of a comment about the study

No, nuclear isn't the best in $/TWh, though it is quite close. The reason it's so uncompetitive has to do with the gigantic payback period and the fact that renewables (increasingly) eat into its demand intermittently which lengthens the payback period even further.

But if you include environmental impact, nuclear is absolutely amazing. Which, if you'll recall, was a dimension named as important by the GP: "[space based solar generation] would be highly useful for reducing climate change and increasing climate resilience"

It seems you have plenty of time to form your opinions about what's scientifically and economically sound based on sci-fi novels, but not enough to read the executive summary of a NASA study that actually investigated the proposal at hand.

Re: Interstellar Flight: Perspectives and Patience

#192

Post by jvm___ » Sat, Jun 28, 2025, 8:59 PM UTC

kbelder wrote: post #187

jvm___ wrote: post #7

Earlier quoted context omitted.

The Sun: 99.86% of the solar system's total mass. Jupiter: ~0.095% of the total mass, and ~71% of the non-solar mass. Saturn: ~0.03% of the total mass, and ~19% of the non-solar mass. Uranus and Neptune: Contribute a small percentage to the remaining non-solar mass. All other objects: (inner planets, dwarf planets, moons, asteroids, comets, etc.) account for less than 0.002% of the solar system's total mass. Your bra…

insignificant to whom?

That'a a very philosophical question. Insignificant to the universe's total mass I guess.

Are we the chemicals or just the electrical signals, that makes the mass that makes up "you" even less of an thing.

Re: Interstellar Flight: Perspectives and Patience

#193

Post by sdpy » Sun, Jun 29, 2025, 9:09 AM UTC

rakejake wrote: post #177

baxtr wrote: post #124

Earlier quoted context omitted.

Maybe not humans, what about robots though? I recently read this in an interview with Juergen Schmidhuber: > Of course, such life-like hardware won't be confined to our little biosphere. No, variants of it will soon exist on other planets, or between planets, e.g. in the asteroid belt. As I have said many times in recent decades, space is hostile to humans but friendly to suitably designed robots, and it offers many…

Or humans with their consciousness uploaded to a silicon or other substrate. Of course, this is in the realm of science fiction but so is interstellar travel. Greg Egan's Diaspora has a fantastic treatment of interstellar travel - it involves sending copies of your consciousness to different spaceships traveling to different destinations. On arrival, a preset program will verify if the planel/galaxy is worth waking u…

A similar idea appears in a more recent short story, How It Unfolds (2023) by James S.A. Corey. The premise is using a technology called “slow light,” which can clone people and objects using “enriched light.” The National Space Agency scans a group of 200 people (not only their physical forms, but also their consciousness, memories, and feelings) and transmits several thousand copies of this data package across the galaxy. The hope is that, on arrival, each package can "unfold" into a fully reconstructed version of the original team and habitat on some distant alien world.

Re: Interstellar Flight: Perspectives and Patience

#194

Post by MrMorden » Sun, Jun 29, 2025, 6:44 PM UTC

usuallyalurker wrote: post #79

krunck wrote: post #16

The comment by Benjamin Stockton on the article page is spot-on: >I just wonder if humanity’s adventurous nature is leading us away from a proper focus on the sustainability of our civilization, our specie, and our fragile planetary environment? But we still need spaceflight at least for planetary defense against asteroids, mining asteroids(so we don't have to mine Earth), etc.

Not only is that comment a false dichotomy (we can both explore space and make humanity more sustainable at the same time), it also presumes that space exploration and sustainability are at odds with one another and not synergistic. Humans, simply by existing on Earth, have a huge and often negative impact on the environment. If we could somehow shift the human population off Earth, either by terraforming planets (li…

We can't even terraform the Empty Quarter. Doing it to Mars and then somehow giving that planet a magnetic field is fantasy.

Re: Interstellar Flight: Perspectives and Patience

#195

Post by dakial1 » Mon, Jun 30, 2025, 2:18 PM UTC

troyvit wrote: post #156

dakial1 wrote: post #137

Earlier quoted context omitted.

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 boa…

Ah yes! I remember that from "The expanse" as well: "let's do a meeting to decide how to evade the missile!"

I think that Physics-compliant sci-fi novels are more entertaining because the solutions (feasible or not) are more ingenious and the consequences more surprising.

Re: Interstellar Flight: Perspectives and Patience

#196

Post by econ » Tue, Jul 01, 2025, 11:43 PM UTC

vjvjvjvjghv wrote: post #97

econ wrote: post #28

You first have to build the perpetual motion engine and the reactionless drive. Current thinking is quite hostile to doing the work. You might not be able to build the things you think you can. You certainly won't build the things you think you can't.

I am not aware of any approaches that even remotely could deliver a perpetual motion engine or a reactionless drive. You need something to start from but there is nothing in sight.

https://youtube.com/@madsciencelptech?si=3XO72NQMpecoUwOR