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Comment by rntn | Hacker News Reader

Sadly, as discussed here, the technical problems with propulsion systems for interstellar travel are non-trivial:

https://news.ycombinator.com/item?id=29638529

Of course that doesn't necessarily preclude a nearby higher level Kardashev Civilization becoming interested in all the noise we're making and heading over.

As we put up systems beyond Webb, it may be possible to observe a hypothetical inbound craft / fleet some years off, which would have interesting effects on our current human society, once it became generally known..

My suspicion is that the social media generation would react a lot worse than the radio generation did to the 1938 broadcast of H. G. Wells' War of the Worlds:

https://www.space.com/40435-finding-aliens-humanity-reaction...

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If Breakthrough Starshot happens some of us may get to at least see it in our lifetimes.

I don’t think we will or should be trying for interstellar at this time; but something being non-trivial doesn’t mean we shouldn’t do it.

I thought the nuclear propulsion options were viable and relative simple.

Even if you get a very high specific impulse, you still need to pack a lot of reaction mass. You'll also need a lot of supplies (or a biome) because even if you get to 0.1 c, it's still 40 years to get there.

I'm not losing hope that there are ways to travel faster than the speed of light that we haven't yet discovered, like bending the spacetime around the spacecraft, or wormholes, or something else of that kind. If various forms of rapidly ejecting matter out of a nozzle really are the only physically viable option for spaceflight, it would be an extremely disappointing universe.

> If various forms of rapidly ejecting matter out of a nozzle really are the only physically viable option for spaceflight, it would be an extremely disappointing universe.

Indeed. If that's the case, the universe is an infinitely big and infinitely boring place.

OTOH, our future uploaded selves may be able to slow down their clock rates and make the trip so much shorter.

And you don't need to leave your dear ones on Earth - just bring forks of them along you (chances are a fork of you will remain on Earth anyway).

Frankly, I believe that any form of mind upload or consciousness transfer is a much harder problem than both rejuvenation and interstellar spaceflight.

Looking at current aging research, there's a good possibility we'll see rejuvenation in the next decade or two and it'll profoundly change our society. In 20 years, everyone will be looking 25 years old and pointing at frail people with wrinkly faces and laughing, same way we do today with antivaxxers.

Once that's out of the way, we'll eventually get comfortable with building arbitrarily large objects on orbit, and we could as well build a huge spaceship with an onboard self-sustaining ecosystem and fly that to other stars, the boring way. Yes, it will be a very long journey, but it's possible without the reliance on yet to be discovered new physics.

Any chance you could link to some stuff that's making you so optimistic about rejuvenation on that timeline?

https://old.reddit.com/r/longevity has a lot of links to various articles and papers, and I also collect relevant videos and talks into a playlist: https://www.youtube.com/playlist?list=PLLvA7pB41pDk27XOjqbXi...

Look up the stuff David Sinclair is doing with his team. They are already rejuvenating and regrowing severed optic nerves with Yamanaka factors in mice and are preparing to start human trials.

It's not rock-solid that this is going to happen for the whole body soon, but some truly breakthrough things are happening right now in this field, nothing like the previous decades.

That doesn’t solve the issue that the passengers will need to live on the ship for a thousand years, even if their relatives will be on Earth for twice as long.

Even a very big ship can be boring after a sufficiently long time.

> pointing at frail people with wrinkly faces and laughing, same way we do today with antivaxxers.

Except those people are more likely to be too poor to afford it instead of unwilling to take it.

Or, worse, the young will never get any power because the old will not relinquish control.

Then you have the "surfeit of princes" problem.

This isn't just grand political power: imagine being unable to progress in your career because geriatrics above you aren't retiring.

That's just one possible secondary effect. We could enumerate many others.

Oh yes. That's a very clear concern. I'm reacting to the "people who decline will he like antivaxers" comment. But it seems far more likely people will be priced out as opposed to voluntarily refuse treatment.

This logic is flawed. It would be much more economically sensible to just rejuvenate everyone regularly instead of doing what we do today — try, and eventually fail, to manage all the conditions related to old age. Since aging affects literally everyone, this huge scale would drive the cost of that intervention down to pennies.

Just to be clear: I'm not from the US, we do have not a very good but nevertheless somewhat working public health system over here.

> It would be much more economically sensible to just rejuvenate everyone regularly instead of doing what we do today — try, and eventually fail, to manage all the conditions related to old age.

In the US, we just will do neither for the majority of Americans. If you're too poor to afford rejuvenation, you'll be too poor to afford other treatments. And you'll just die.

Sure the cost of each treatment might be pennies (although it probably will cost a lot and not have those economies of scale) but total profit is not maximized by a smaller markup. Better to get Gates/Bezos/Musk/other billionaires to give you 90% of their fortunes.

They’ll sneer at the masses without eternal youth anyway.

Unless, of course, living a thousand years brings some wisdom with it.

I’m guessing we have to choose between capitalism and eternal youth.

I’m totally ok with a post-scarcity socialist society.

That's insane optimism to me. We don't even know how to get a nail to re-attach to a nail bed. We can't put some crystals on a tooth. We can't create a single hair follicle. We have zero non-surgical ways to repair arteries. Etc, etc, etc. We have made zero progress in anti-aging other than controlling blood pressure and identifying harmful chemicals in an environment.

We ARE good at extreme, surgical and or heavy medicating intervention. Doesn't go hand-in-hand with life extension at all.

We're now capable of programming cells to produce arbitrary proteins at will, how cool is that?

Also please do look through the playlist in a sibling comment. Michael Levin's research is truly badass. He has grown tadpoles with an extra working eye on the back, and recently he has regrown an amputated leg on a frog.

There's an astonishing amount of untapped possibilities in biology that are opening up only now as we finally have the right tools.

Right, CRISPR is ok, but they haven't figured out that many real applications. This approach to vaccines has actually been around forever.

I bookmarked this thread specifically to watch your links later. I appreciate them and will watch, as I am really interested in the topic.

My hope is that biotech is the next step, but as I mentioned, for now I am highly pessimistic. We can't seem to treat virtually anything in any real sense, despite the experiments you mention. If anything, the progress in prosthetics (including the spinal bypass) has been great, but nothing to do with life extension or genuine recovery of lost functionality without surgical intervention.

Personally, it seems to be me that the closest thing we can do so far as individuals is reduce risk factors and try to stay high on Death Clocks: https://www.lifespan.io/news/grimage-is-the-best-clock-for-p...

Completely unrelated, but this reminded me that we can't seem to regrow cartilage either. This is a huge issue after cancers and cardiac deaths. Any falls, excessive wear and tear, etc all destroy quality of life with the joints. Latest efforts here: https://www.studyfinds.org/arthritis-pain-regrowing-cartilag...

We can now treat a lot of conditions we couldn't before. People used to die all the time of infections or any number of other conditions we now consider fully curable. Medicine as we know it is a relatively young science compared to physics or mathematics for example. We can treat most bacterial infections. We can manage most virus infections. We can perform life-saving, high-precision surgeries. We couldn't do any of these things just 100 years ago — that's nothing on a historical timescale.

Thing is, medicine/biology is a unique field because it relies quite a lot on advancements in other fields for its tools. You couldn't research cells before microscope was invented. You can't begin figuring out what each part of a genome does before you've sequenced it. You can't begin to research functions of specific proteins before you've solved their structures and got the ability to manipulate their production and/or attach markers to them. And so on, and so forth. Not so long ago the main approach in medical research was basically "try stuff randomly on lab animals and see what has a beneficial effect". Now that we can peek into the internal workings of biological systems we can use a more direct, more engineering-like approach.

At least there is such a thing as growing tissues from stem cells. Nothing at all in the category of "uploading" one's consciousness anywhere exists. Not "uploading a memory", not "uploading a thought process", those are abstract concepts we've made to describe what the extremely strange organs that brains are do, anyway, and we're nowhere near close to understanding its biology much less replicating what it actually does with a machine.

What would that fork think of it?

If I were to fork myself in this situation, I'd make one fork who thinks that making the trip will be awesome and another that will think that staying home is the coolest thing.

If we can, from time to time, merge our memories and refork, this wouldn't be a big issue, as both forks would experience both lives.

I think that, at this point, we wouldn't be that much human anymore.

You don't even have to modify it. If you are a person that thinks going and leaving a fork would be cool, and also thinks staying and sending a fork would be cool, the job is done.

At the moment I have more faith that our AI overlords - or, future self-replicating robots, insert various levels of intelligence and self-reliance here - will be the ones going interstellar, not so much us unless we revolutionize spaceflight. That said, the picture of the future that The Expanse investigates seems to be the most realistic, just minus the somewhat magic propulsion system.

Not a huge problem if, after the robots terraform the planet and build our settlements, I can opt to be printed into a new organic body.

We'll still need some form of magical propulsion or, worse, some magical power source. There aren't many things that can keep providing energy for thousands of years. I'm pretty sure fission is a non-starter here and even nuclear fusion designs would need a source of tritium because, after a couple thousand years, there won't be much left of the initial fuel.

All of the descriptions I've seen were "viable" in the sense of "we could hypothetically accomplish this in a few decades a for around $100 trillion". At least that was the estimate for Project Daedalus, which designed a nuclear pulse propulsion probe to do a 50-year flyby of Barnard's Star. Fun to think about but it's going to be a while before even the largest governments can afford to fund a project that most of its creators will never see completed.

With all the messages we’re sending I’m sure a curvature propulsion drive is just around the corner ;)

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