The Astronomy Thread

MusicForFish said:

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Manned Moon landings are much more difficult than LEO or rovers

They may still beat us back to the moon if we don’t get the lander shit sorted out. Long term Starship would be beneficial if the cargo capacity pans out, since it will significantly reduce the costs of setting up a base. Short term though it isn’t clear how much lander work they’ve done since they just seem focused on atmospheric reentry Starship at the moment

Big Phoenix said:

You can still explore and colonize the galaxy without ftl and anti matter propulsion or something equivalent.

It will just a hundred thousand or two years but still very viable. Fusion rocket could get a good sized starship to alpha centauri in 40-50 years. One way trips for anyone going.

Equally big question that is never considered is the long term effects of low gravity on human development. How healthy ia someone conceived and raised in a .5g environment? Might be you need 1g until adulthood so people don't develop into Mr glass.

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Maybe. Let's say you figure out the deep space travel part - reliable craft that can travel for decades or hundreds or thousands of years without a hitch while keeping everyone alive the entire time. At that point question becomes why? You're too far to trade or make things economically viable with our system, so the only logical reason is you just want to colonize your own planet far away from Earth.

So say that is a good enough reason. And let's say you actually find a planet with similar temperature ranges and gravity and atmosphere to Earth. If the planet has life on it, then you run the risk of having a fatal allergic reaction or dying to microbes in short order because you didn't evolve in that environment. At worst nothing is genetically compatible with you and microbes just see you as a warm bag of water they can multiply in while your immune system is helpless because it doesn't know wtf it is dealing with. Planet pollen or spores triggers extreme allergic reactions because again your immune system doesn't know wtf it is dealing with. Or if stuff is genetically compatible, then you run the risk of getting space ebola or whatever. You'd be on a planet with life and still need to survive inside environmental suits and sealed dwellings. Unless you have the technology with you to genetically engineer the next generation to be able to live on the planet no problem as if they were a true native, then that is a long term issue.

And if it doesn't have life, then in theory you have a "clean slate" to work with, but terraforming isn't trivial and you're still living in suits/sealed dwellings.

You really have to look at the "lines" from the book house of suns to get a good idea of the mindset of a traveler. Their lives are all about experiencing cool sunsets and finding amazing things to see and smell and feel. Kind of like the society of sensation from planescape.

When they first started, sunsets and rainbows and huge pretty ring systems around candy coloured gas giants were all they had. But by the time they made a circuit humanity had spread out a bit and gotten more interesting. Circuits take 250 thousand years planetary time, but for the lines only 100 or so at the start.

So eventually you can trade information for good wine or ship upgrades or better ways to pass the years. They eventually find a tech for slowing or speeding up time in a small cabinet. This is way better than cold sleep because it also reduces the forces on the body because of the time difference, so you can accelerate harder or survive impacts with rocks etc.

You still have the problem that even making a circuit, you only see a small handful of worlds. Most of your time is spent in boring transit. So what they do in the books is meet up every circuit and share memories. Eventually after 50 or so circuits you've experienced a good chunk of the galaxy.

Void said:

On top of that, unless you have perfected cryo sleep or suspended animation, you're essentially condemning generations to a life of nothing but the ship. They'll see and hear about all these cool things people that grew up on planets got to experience, but never know them. Assuming they don't eventually revolt and turn the ship around, the intermediate generations might even adopt a "who cares?" attitude because only the landing generation needs to actually know stuff besides maintaining the ship (and at that point it is likely an AI can do most of that anyway). If you're generations 3-8 of a 10+ generation trip, for example, it is going to be sort of difficult for those people to give a shit. More than likely you'll find everyone turning towards a hedonistic lifestyle because they know they are just going to die in deep space, and they may even stop having kids because why condemn your kids to that too?

Obviously there are ways to somewhat counter some of that, but it wouldn't take much to get everyone to stop giving a shit. Let's just use up all the alcohol and fuck ourselves blind (with birth control) until we die out. They literally have nothing to live for except the promise of their future generations, but just because the initial people you send have the conviction to see it through doesn't mean their grandkids do.

So yeah, without suspended animation or AI gestating embryos or something, I don't see generation ships working at all. And that's skipping all the other hurdles once you get there, like Cybsled talked about.

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Meh, how is this really any different than current people living on the current ship (earth) traveling through space? Life is what you make it. Humans adapt to their situation and their outlook depends on how they are indoctrinated & educated.

As for stories about what living on a planet was like, people opine about some fictitious golden age of past human existence all the time. White America during the 50s seems to be popular around here. If you didn't live through it, you don't really know what your missing.

Any ship capable of being a generational ship is going to need to be HUGE, similar to how they depicted the generational ship on The Expanse (plus possibly encased in some form of very thick rock shield). So it's not like they are all going to be stuck on some "tiny" aircraft carrier eating shoe leather and drinking sea water.

Except they are stuck there with no external way to resupply. Size is also a factor of population - the ship in the expanse was big from our perspective, but what about with 5000 people? 10000? more? You're going to have to manage your resources - when you start getting into decades or centuries, that problem is compounded even more. Realistically at some point you'll be forced to take draconian measures to ensure the mission survives: limiting resources, controlling who can reproduce or when, forced employment into specific fields needed to maintain the ship and population. Humans are humans: At some point, you're going to get people who resent the lack of freedom, and if that escalates you could get a situation that radically changes the entire ship/mission or destroys it, which means the people running the ship may have to take draconian measures to prevent that.

And if by some miracle you survive the journey and can make it to a planet, do the people running the ship want to relinquish that power? Once people make it planetside, that closed system suddenly isn't as closed anymore. You could almost immediately see power struggles once people situate.

Ice is the best way to survive impacts and the extreme radiation of high relative velocities. Stacking 10 or 20 miles of the stuff in a long thin spike in the front of the ship is probably the only way to survive a really long journey.

As you get closer to C all the starlight from space moves to the front of the ship and blueshifts into high energy gamma rays so you really need miles of water ice to absorb it.

20 years is kind of the magic number when it comes to space travel. It is nonintuitive but getting to a nearby destination of say 1000 lightyears is around the same ship time as crossing the known universe out to where we see quasars (though they might be long dead by the time you get there).

The ancestors of Americans didnt say "hey that sea voyage is gonna be really unformfortable, screw that". So Americans get to exist.

The ancestors of Europeans didnt say "hey leaving Africa is a lot of hiking and fighting prehistoric beasts, screw that". So Europeans get to exist.

The ancestors of future humanity will get on the ship, and future humans will get to exist.

The people whining that "hey that sounds uncomfortable" and "wait how do I make money in space?!" They'll die out and leave no descendants and be forgotten by the galaxy. The galactic equivalent of the proto hominids that never left Africa.

As it should be.

Literally every time humanity has achieved something great, there have been lots of people smugly opining "that can't be done! we've never done that before"

Imagine sitting on the internet after thousands of years of human achievement and going "I'm gonna join the smugly opining side, that'll make me look smart".

BrutulTM said:

Yeah, I think that's just a deal breaker. Even if you can have some version of manufacturing on the ship, you have no way of getting more raw materials. Everything on the ship is going to wear out and need replacing not just a few times, but possibly hundreds. How long would a car engine last if it was running 24-7? A couple of years? You could keep it going but you're going to need to be replacing parts continuously and fully rebuilding it periodically and after 8 or 10 or 20 years even things like the engine block will have to be replaced. Even food is just kind of unthinkable on a really long timeline. Even if you can manage to like, grow hydroponic grain and manufacture some sort of porridge, if something goes wrong with that system you're just SOL. The idea of building a machine that has to work for 1000 years with nothing from the outside is just preposterous. We've never even attempted 1/100th of that.

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How long can a nuclear plant generator run without a complete overhaul? How long before "things like the engine block will have to be replaced"? It's not going to be two stroke engines and pickem-up trucks running things...

Yall are acting like if humans can't do it tomorrow, it can never get done. There are big hurdles to overcome but generational ships are not that far outside of our current understanding and capacity. Humans will need decades, if not centuries of space construction experience using materials already in space and the ability to mine the asteroid belt to even be able to think about such a venture. By that time, we should also have more efficient and improved energy generation.

Edit: Decided to ask AI cause was interested enough to spend 5 minutes on it, but not a ton of research time to check the AI. Here is what Google AI has to say for "How long can a nuclear plant generator run without a complete overhaul?" (anyone pay for Grok?):

BrutulTM said:

By this logic the fact that someone said it is impossible means that it is possible? I guess the only reason we can't swim naked in molten lava or hold our breath for 100 years is because we're weak cowards?

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Its obvious from your posts that logic isnt really your strong suit, but no.

Your sentence should read, "by that logic, if someone said it is impossible, that tells me nothing about whether its possible"

But that isnt what matters. What matters is that you got to smugly feel like the "smartest guy in the room" for a minute. Did it work? Did you get all warm and fuzzy anticipating how the guys on the internet were gonna totally validate your opinion with updoots? I hope that works out for you.