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Comment by oooooof | Hacker News Reader

The idea that humanity will ever travel even to the nearest star is pure fiction.

Anyone who thinks otherwise just fails to grasp the distances involved. They are so large as to be beyond understanding.

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The idea that humanity won't ever travel even to the nearest star is pure fiction.

Anyone who thinks otherwise just fails to grasp exponential growth. They are so large as to be beyond understanding.

"...won't ever... is pure fiction"

Do you mean to say humanity certainly could travel to the nearest star?

I'm skeptical that anything resembling humanity could because everlasting exponential growth requires infinite resources. And humanity evolved on an abundant--but far from infinite--gravity well.

I was mostly making a point that grandiose statements can be rebutted by similar (in this case, changing 3 words) grandiose statements.

To answer your question though, the main problem with space travel isn't physics (assuming you are ok with long travel times), it's economics. We have sent astronauts to the moon and probes all across the solar system. The main reason we don't do more though is because of how expensive it is. However, a thousand years of 2% growth (not a given but again, grandiose) means we would have 400 million times more money to possibly spend on space travel. A NASA budget 400 million times larger could certainly build and send a spaceship 4 light years to alpha centauri.

Now how long will we sustain exponential growth? Well that's anyones guess but I don't see us becoming resource constrained for a long long time. The sun produces 10^13 more energy than the world used in 2013 according to [0] and we have plenty of resources in the solar system to build with (and we can recycle more).

[0]: https://www.quora.com/How-much-energy-does-the-sun-produce-p...

> To answer your question though, the main problem with space travel isn't physics (assuming you are ok with long travel times), it's economics.

I'd argue it's biology, not physics. Sending a rock to another star is easy. Sending a rock that can send back data is probably possible with our technology, but it's unlikely it would retain data transmission capabilities long enough to actually report back from another star. Sending a bunch of humans and keeping them alive the entire journey? It's not clear we can do that for a round trip to Mars, let alone an interstellar journey.

The 2 biggest health problems that I am aware of with spaceflight are due to weightlessness and radiation. However, both can be probably be solved with enough money (make the spaceship a rotating one with artificial gravity and add more shielding). There might be others but I am pretty confident you could engineer your way past each and every one given a large enough budget.

You're sort of missing the biggest health problem of all: how do you make a self-sustaining closed ecosystem?

True, I was thinking more in the context of the mars trip you mentioned where you can generally take the resources you need for the trip. For intersteller travel, you would need to make it self sustaining since the travel times are so long and that would be extremely expensive.

The article suggests moving stars.

Let's be a bit more positive on Humanity's progress eh?

Humanity is on the cusp of three major technological breakthroughs that will quite literally change everything.

1) AI. Even if we don't reach ASI in the near term, we'll have ANI to help us research new technologies in months/years rather than decades.

2) Asteroid Mining. Whether it's Musk/Bezos/A. N. Other, the very first time someone brings down an asteroid. It will herald the dawn of abundance for precious metals. What will happen to prices is another topic. But this will allow researchers to develop even more exotic materials.

With better materials resistant to heat, more conductive elements, etc, etc. Humanity be able to build what can only be dreamt of.

3) 7 Billion (now). 13 Billion with Mars, 50+ Billion with Europa, Titan, Ganymede, etc, etc, etc. There will be a time where Humans will stretch beyond this solar system. Imagine how many breakthroughs will be possible with 100m researchers and AI trying to crack something?

What will make this possible? With 1 and 2, we'll be able to finally crack fusion reactors. This will enable faster space travel than with current engines. Habitats will evolve from those initial Mars missions and will sprawl into mega cities. Who knows, there may even be Luxury apartments hovering in the upper atmosphere of Venus.

All this progress is exponential and if you stop to look around. The seeds are being sewn right now. By 2050, some things we consider Sci-fi will be reality.

Oh and I'll just throw this one in.

4) Nasa has been doing some work on the Alcubierre drive. Who is to say, that the issues that cannot be surmounted now, will be in the future? For those that want to know more. I'll leave a channel that goes into such things [0].

[0]: https://www.youtube.com/channel/UC2kkCGRqZWaSIK3BmLC8vaw/vid...

> 2) Asteroid Mining. Whether it's Musk/Bezos/A. N. Other, the very first time someone brings down an asteroid. It will herald the dawn of abundance for precious metals. What will happen to prices is another topic. But this will allow researchers to develop even more exotic materials.

Say what? The idea that asteroid mining will enable material science revolutions is fanciful. We're not exactly short on metals (even precious metals). And interplanetary space is less extreme than environments we can create in terrestrial situations, so we're not going to find weird new stuff by poking around asteroids.

Well, it is possible that if rare and expensive metals become dirt cheap, new exotic alloys may be developed that were previously economically inconceivable.

I don't know how likely this is. I imagine plenty of research has already been done on exotic alloys, however I wonder how much that research has been affected by economic constraints.

>We're not exactly short on metals (even precious metals).

Last I checked, the price of most metals was greater than zero. They're commodity markets, so that means they're scarce. If you mean "available at any price," then we were not short on iron during the Bronze age or short on Aluminum during the early 1800s.

Alcubierre drives require exotic matter which is not quite ruled out by the laws of physics. Hopefully they don't require Jupiter-sized masses of the stuff, although some have suggested as much. However, that solved, there are two slight problems with this idea. One is that FTL inherently violates causality, which is sort of a problem. The other is that the spacecraft is expected to pick up and accelerate with it basically any matter it runs into along its superluminal path, releasing these as a spectacular shower of near-c particles whenever it stops. Your other speculations have their own defects, but I'll let others address them.

The distance to the moon is already beyond intuition, but you can still understand how to get there by doing calculations. If the numbers say that it's possible then it's possible.

My vote is still with the brain in a jar (or something close to it). Fewer resources, less area, and much of the life support equipment could be shared between many individuals. There's reason to believe it would extend lifespans as well, provided that an entirely virtual life could be made worth living.

I honestly think we'll achieve this long before we're able to properly or effectively simulate a brain with computers of any kind.

the _nearest_ star is actually quiet close :-]

thats pretty accurate as far as current technology goes, but then again with a few additional centuries of research we never know what we end up achieving.

We could just about do interstellar now if an existential threat called for it. Project Orion or a nuclear salt water rocket are both possible already.

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