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No need for nihilism.

Alpha centauri is approximately 4.37 light years away. Project starshot is already aiming to get there. This can take anywhere from 20 to 50 years depending on the mission. We already have a spacecraft from 1977 that is still operating today which proves our potential to build on a 50 year timeframe. We'll likely have humans somewhere in our solar system besides earth before anyone attempts to go to alpha centauri but besides that I also think we would be able to live much longer. Life expectancy increases are around 1% or 0.8% per decade at its current pace. There's no guarantee this continues but even so, if that's the average in the coming decades then we'll expect people to live hundreds of years by the time we can send a ship to alpha centauri.

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So at 50 years, that requires traveling an average of 10% the speed of light. That’s 150x times faster than the peak speed ever built which got a significant amount of speed from gravitational assists. That’s a massive leap to assume we’ll have craft traveling that fast anytime soon considering the considerable fuel costs involved not to mention relativistic problems that going that fast requires (shielding against interplanetary dust, energy requirements growing exponentially etc).

And on top of everything, stopping is a huge question when you’re going that fast so how are you achieving that? Is that fuel you had to accelerate as well? And remember - that’s 150x average speed faster than peak so your actual peak to achieve a speed up followed by a slowdown would need to be even faster.

As for voyager, that craft is barely operational in some sense. At 10% and at significantly further distances than ever achieved it would be even harder to keep it operational I think.

Let’s be optimistic but let’s live in reality and not unrealistic sci-fi.

Project star shot is still very much s research project at this point, but it seems serious.

The idea is to not use self powered rockets, but launch a thousand small solar sail based probes. These would launched into orbit traditionally, then accelerated individually from a massive earth based laser array, solving the rocket equation problem while introducing a host of its own.

Many probes will not make the trip, but the hope is enough would survive to do a fly by.

A fly by at relativistic speeds would be an accomplishment but what data are you realistically capturing?

And Wikipedia captures my critique of it accurately:

> According to The Economist, at least a dozen off-the-shelf technologies will need to improve by orders of magnitude

That’s about right. That kind of orders of magnitude improvement within a lifetime requires novel scientific theories (eg similar to quantum mechanics and the impact it had). Without that growth is drastically slower. And consider that even computational and communication capabilities have basically been maxed out at our current tech level - we’re no longer growing them exponentially due to thermal and physics constraints.

It’s an ambitious goal worth doing because of the “if you aim for the moon and miss you still hit the stars” kind of effect. And there’s plenty of directed research that needs to be funded. Thinking any of this happens in our lifetimes is ambitious and spaceships carrying humans going to the stars is fantasy*

* as always, completely new physics that upend our knowledge of what’s possible changes the calculus. But those come very rarely and there’s no reason to believe the next revolution will be as impactful as quantum mechanics in terms of impact on our technological capabilities.

Its not unrealistic sci-fi. We have particle accelerators that operate at much, much higher energies. The kind of energy that would succesfully leave earth and our sun behind if these particles were shot out of the LHC. That is to say, you'd be right that any vessel carrying fuel wouldn't reach such speeds. And while its true that even the smallest sattelites today are still at least 1000grams. Getting that up to relativistic speeds would require on the order of 2 billion MJ of energy. Or the equivalent of a large power plant runnning for 20 days to supply all the energy.

But that's only the start, any advancements in making sattelites on a chip could massively reduce the weight and therefore power requirements. Even with all losses accounted for. I believe this could be doable in the next 50 years. You just need to build the most powerful laser anyone has every built and power it for as long as you can.

You’ve shifted and redefined the goalposts and even then requires orders of magnitude advancement in multiple areas (power generation, lasers, satellite shrinkage etc) and doing it all in space. Thinking any of this happens in a lifetime of anyone alive today seems unrealistically optimistic. And all of this ignores something critical OP said:

> we'll expect people to live hundreds of years by the time we can send a ship to alpha centauri.

Even hundreds of years is not a realistic life expectancy to reach the nearest star and requires not just an enormous overabundance of energy, the fuel source has to be available at the midway point so that you can decelerate. Humans at another star without discovery of faster than light travel mechanisms (mainly wormholes) seems purely in the realm of science fiction.

Your post is exactly the nihilism that can't be proven false until someone succeeds. Voyager reached the termination shock of our sun's heliosphere. It succeeded. The next voyager could only target another star.

Voyager was a once in a lifetime coincidence of taking advantage of a line up of celestial objects to achieve a distance of 0.06% to that of the nearest star. No one thought it would be impossible to achieve. Indeed, the remarkable possibility is what spurred the funding.

For comparison, Voyager would need to travel 1666x further in the same time frame. It’s not nihilistic to suggest that 3 orders of magnitude improvement in our lifetime isn’t likely. Oh and Voyager is basically on life support having shut down most systems.

I didn’t say it’s outright impossible or not worth pursuing. Just that believing it’ll happen in our lifetime is unrealistic precisely because of the currently known laws of physics and the orders of magnitude of technological achievement necessary to attain more than 10% the speed of light for anything that has any mass (and again assuming all you want to accomplish is a flyby at relativistic speeds).

Worse yet (for an equivalent vehicle mass), that's 22,500x (150^2) the energy needed.

Optimistic reality means spreading cellular life, not the great ape in particular. People by and large are uninterested in this, they feel it is pointless if not somehow immoral. Our "weakness" is not in the flesh but our attachment to it, specifically, these would-be galaxy childs' personal flesh. The 20-50 year mission duration is not a cure for the nihilism but another expression of it.

A more realistic goal: make an imaging probe that hits 1% SOL and gets just close enough to produce images better than we can generate from our solar system.

Even that is a real stretch.

Ah, that explains why 5,000 years ago the average life expectancy was just over 6 months.

Also in 1.3 Million years this star will pass 1/6 Light year from earth:

https://en.wikipedia.org/wiki/Gliese_710

Quote: Gliese 710 has the potential to perturb the Oort cloud in the outer Solar System, exerting enough force to send showers of comets into the inner Solar System for millions of years, triggering visibility of about ten naked-eye comets per year, and possibly causing an impact event.

Wild stuff!

And if it passes through our Oort cloud, we might be passing through its Oort cloud!

> Project starshot

Is it a live project? Their news section is dishearteningly quiet [1]. They still talk about 2018 in the present tense [2].

[1] https://breakthroughinitiatives.org/news

[2] https://breakthroughinitiatives.org/solicitations/3

Honestly I don't think there's that big of a material difference in difficulty between being able to (consistently) live to 150 and being able to live indefinitely (barring catastrophic accidents and intractable diseases).

I feel like we're bumping up against the edges of the lifespan that we can reasonably achieve without figuring out how to actually stop or reverse aging.

Possibly there's a world where we figure out how to dramatically slow it without stopping it, because there's some entropic principle regarding our ability to reliably lengthen telomeres where we can't replace lost data but we can reduce the rate of loss, but my money's that we don't break 150 until we actually solve aging on a fundamental level.

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