Interstellar "World Ships"

Tom Kalbfus · 2015-09-09 16:54:57

I found this on the internet:

Guess what it is?
icarus-interstellar-project-hyperion-worldship-120710-676727-.jpg
Interestingly enough, we have the technology to build these today, maybe not the resources but the technology we surely have as these ships are propelled by hydrogen bombs, just look at the scale of the one at the top. The nozzle is designed to deflect a nuclear blast. The propellant and resource bay is in front to intercept interstellar particles. There are two kinds, one has a habitat for humans the other carries an oceanarium, The oceanarium has a shorter radius. Both rotate to produce gravity. The habitat is 20 km in diameter and the oceanarium is 10 km in diameter. The 20 km habitat module rotates once every 3.33 minutes, the 10 km one rotates once every 2.36 minutes Both dwarf an O'Neill Cylinder. The oceanarium is 70 km long for 2199 square km of ocean, the other is 120 km long for 7540 square km of habitable space.

Last edited by Tom Kalbfus (2015-09-09 16:56:01)

Antius · 2015-09-15 05:00:34

Fantastic ships. As we are so far from building anything like this, technology will undoubtably produce something very different by the time demand for it arrives. But it is fun to speculate.

One way of bringing size down would be the use of volumetric habitats, i.e. smaller vessels that are compartmented to produce more internal living space.

It would certainly pay to invest in an intense telescopic investigation of any target before departure. That way you know what you need to prepare for and can equip the ship accordingly. I do think the ships are unneccesarily enormous. If the end goal is human colonisation, then you need to consider whether it is more reliably achieved by several smaller ships or one big one. Size will also be influenced by the technology sets we have available, i.e. the ability to manufacture genetic material using nano-technology. That way, you don't need to take every species of animal known to man with you.

Tom Kalbfus · 2015-09-15 20:34:16

Antius wrote:

Fantastic ships. As we are so far from building anything like this, technology will undoubtably produce something very different by the time demand for it arrives. But it is fun to speculate.
One way of bringing size down would be the use of volumetric habitats, i.e. smaller vessels that are compartmented to produce more internal living space.
It would certainly pay to invest in an intense telescopic investigation of any target before departure. That way you know what you need to prepare for and can equip the ship accordingly. I do think the ships are unneccesarily enormous. If the end goal is human colonisation, then you need to consider whether it is more reliably achieved by several smaller ships or one big one. Size will also be influenced by the technology sets we have available, i.e. the ability to manufacture genetic material using nano-technology. That way, you don't need to take every species of animal known to man with you.

Even this starship would be small for that. The big habitat looks to be 150 km long and 20 km wide, the smaller one with the ocean in it is 10 km wide by 75 km long, this is a little bigger than a standard O'Neill cylinder. If it has the mirror arrangement that the O'Neill Cylinder, it can point at one of the stars and take in some natural sunlight. The standard O'Neill can house 10 million, the big one since it has twice those dimensions can probably house 50 million people! As for interstellar Travel, probably bigger is better.

You can see how this is designed, the habitat is sandwiched between the engine nozzle and the resource propellant tank, the propellant tank plus the dust shield acts as protection against interstellar debris. As for likely targets, if the Alpha Centauri has asteroids and comets, these will likely suffice for building additional O'Neill Cylinders. Also this slow ship is a single stage, it could refuel at the destination system and move on to yet another star system, all the factories it needs to build more hydrogen bombs is already inside, it just needs raw materials, so it will have to mine asteroids for a while, it can leave some of its population behind and then move on with the rest. If you make your starship big enough, you can just live in interstellar space, it doesn't matter if you never reach the destination in your lifetime, the ship is your world. It is basically a mobile city.

Mars_B4_Moon · 2023-02-10 20:07:42

Machine Learning is a Powerful Tool When Searching for Exoplanets

https://www.universetoday.com/160003/ma … xoplanets/

Calliban · 2023-02-21 21:19:58

One of Tom's old threads. I tinkered with the idea of using Kuiper belt or Inner Oort cloud objects as long duration starships. An icy object 100km in diameter, contains enough deuterium to sustain a population of 100 million for geologic timescales. Such a body could form a long lasting aquatic ecosystem, with a warm internal ocean, surrounded by a thick shell of ice.

The problem is that accelerating such an object to even 0.1% of C (300km/s) in 1000 years would require an enormous engine, with power levels of ~1E20 watts. A solar sail capable of propelling this body to tens of km/s, would be millions of km in diameter. It would be impossible to deploy. A nuclear salt water rocket would need a billion tonnes of fissile or fissionable fuel. That would severely strain the fissile resources of the solar system. The most practical way of propelling this sort of world ship out of the solar system appears to be a planetary gravity assist, using Jupiter and Saturn. The problem is that our world ship would leave the solar system at a velocity of 10 km/s. It would take 120,000 years to reach even the nearest star. Maybe an ecosystem tended by self replicating robots could survive this long. But it is a duration comparable to all of human existance. If you want to reach the stars cheaply, this is the way to go. But it would require an impressive level of patience and a terraformed ecosystem capable of sustaining itself for a hundred millenia.

One way to cut down these very long journey times would be to take advantage of the fact that the stars are moving w.r.t Earth. All of the stars in the galaxy move on their own orbits about the Milky Way. If we wait long enough, many stars will approach our solar system considerably closer than Proxima. Our world ship will not need to travel all the way to the stars. It merely needs to travel to the point of closest approach, and be there in time to intercept the target star system.

From the link below, we learn that Proxima will reach its closest approach of 3ly in 27,000 years.
https://astronomy.com/news/2020/05/wand … ngly-often

To intercept it at closest approach, our worldship must accelerate to 1/9000 C, or 33.3km/s. A gravity assist can deliver about one third of this velocity change. Perhaps the remainder can be delivered by a low thrust fusion propulsion system. The power levels can be modest, as we only need velocity change of 30km/s over 27,000 years.

Other targets are more challenging. Lalande 21185 will pass within 4.65Ly in 19,900 years. To intercept it at cloest approach our worldship would need average speed of 70km/s. That is tough to do.

Gliese 710 will pass the sun at a predicted 10,500AU in 1.3 million years time. To intercept it at closest approach, our world ship would need average speed of just 38m/s. Wait long enough and the stars come to you!

Last edited by Calliban (2023-02-21 22:04:10)

Calliban · 2023-03-01 20:13:38

Yesterday, I watched the episode 'Swarm' of the Netflix series 'Love, Death and Robots'. The swarm was an ecosystem of plants and animals that had colonised an asteroid. Each of the many species was part of a complex symbiosis. The swarm has survived for millions of years. Vacuum dwelling jellyfish lived on the surface of the asteroid. Algae in their bodies converted sunlight into sugars and oxygen, both of which they excreted into the asteroid, thereby sustaining the internal ecosystem.

I can imagine interstellar worldships working a lot like that. The worldship would be a sphere of water, with a rocky core and an icy crust. The ecosystem would live within the water. Humans would provide the fusion energy source for the whole aquatic ecosystem. The whole system would function as a complex symbiosis between humans, animals, plants, micro-organisms, macro machines, micro machines and nanomachines. Like the swarm, such an environment would function as a closed ecosystem. Fusion would provide the energy source. Nanomachines and bacteria would break down all wastes and machines would reconcentrate diffused ions from the seawater, allowing all materials and nutrients to be used over and over again. Like the swarm, this symbiotic ecosystem could last for millions of years.

Voyager 1 is presently the most distant manmade object, at around 22 billion km. That is 3.5x further than Pluto! It is moving at 16.7km/s w.r.t the sun. It would therefore take 18,000 years to cross 1 lightyear and could reach Proxima in 80,000 years if it were heading in that direction.
https://en.m.wikipedia.org/wiki/Voyager_1

A timeframe of 80,000 years seems impossibly long by human standards - a thousand human lifespans. But this could be just a small interval in the lifetime of an aquatic worldship ecosystem. The whole system would be self maintaining and could last for as long as the deuterium supply lasts. If our ecosystem lasts for 100 million years, that may be sufficient for 1000 stellar encounters. Low thrust plasma jets would make course corrections over tens of thousands of years. This would ensure that the world ship passes within a few hundred AU of each target star, allowing humans to disembark.

The initial exit from the solar system would be carried out by using hydrogen bombs to cancel the orbital velocity of an inner Oort cloud object. This would then fall towards the sun and would be catapulted out of the solar system using a Jupiter gravity assist. A low thrust p,asma drive would then trim its trajectory over millennia, putting it on course for one of the nearest stars.

Such a journey would require immense patience. But if the humans have a comfortable and bountiful world to live in, then the journey time doesn't seem to matter so much. Within the ball of water, cities will rise and fall. Civilisations will develop. But provided that human numbers remain stable, the environment would remain habitable for as long as the fuel supply lasted. Kind of like an aquatic Pandora, drifting through the interstellar void. Awaiting the far off day in the future, where it passes through a star system, allowing humans to disembark.

Last edited by Calliban (2023-03-01 20:52:54)

Void · 2023-03-01 20:49:45

I like it. It may be possible to refuel and even accrete more matter along the way. Similar to a https://en.wikipedia.org/wiki/Bussard_ramjet, I now don't expect p-p fusion, but the collected deuterium and Helium3 could power a thrust, and the collected Helium4 and Hydrogen could be the exhaust gasses.

There is some talk that Dr. David Sinclair and his associates have had some success in turning the clock back on mouse aging. His theory is that a great deal of what goes wrong as we age is that our cells cannot read the genetic codes properly anymore. So, supposedly they were able to partly repair that.

https://www.cnn.com/videos/health/2022/ … e%3A%20CNN

The point is, some speculate that a human might eventually live 1000 years on average and die of an accident eventually. He does not necessarily proclaim that, but some do.

So, if you could get to 10% the speed of light with a ship, which I consider very ambitious, it would take about 43 years for a 57-year-old person to get there. They would be 100 years old, and maybe live an average of another 900 years.

But of course, your example is another thing, but if it is a world of its own, then that is different. So, your plan could be good as well.

Hope you don't mind my intrusion.

Other scientists have tried other paths for longevity, and they may still have more to offer, per cancer cures, and other things.

Done.

Last edited by Void (2023-03-01 21:00:58)

Calliban · 2023-03-02 04:40:24

Hmmm. Having done a few calculations of the energy resources needed, I wonder about the efficacy of the travelling world idea. I assume we start with a body 100km in diameter, with the same density as water. To produce the 300m/s velocity change needed to put the body on course for a Jupiter gravity assist, would mean imparting 334,000 GW-years of kinetic energy. The engine needed to do that would need multi-terrawatt power levels. The energy needed is just insane.

It would be less daunting if we could find a rogue planetoid that is already on its own path through the galaxy and heading in roughly the right direction. Our engine can then be smaller, as it would need only to trim the course of the body by a few degrees, over many millenia of flight time. There are some stars that have a velocity of 100's of km/s relative to the sun. Presumably, there are rogue planetoids with comparable relative velocity. If we could find a body moving at 300km/s towards Proxima, then flight time is reduced to 4000 years. We are unlikely to get that lucky. But finding an existing rogue world may be easier than trying to make a new one by releasing a body from the suns gravity well.

The idea of interstellar fights lasting for tens of millenia is daunting for most people. But when humans eventually colonise the solar system, we will be building new ecosystems. Presumably, our end goal is to inhabit those new ecosystems for as long as the sun continues to burn. This is why terraforming makes sense, even though the technological difficulties are immense. We are creating new habitats that can sustain us for geological timescales. Even with effort needed to build a newworld, it is still well worth doing if the benefits accumulate for a billion years into the future. Living on a rogue planet would simply be an extension of this philosophy. Our goal is to turn the new world into a place that will sustain us almost indefinitely. For the people colonising the body, the fact that their distant descendants will eventually reach another star, will be a side benefit for them. But their goal will be no different to that of any other group of humans that colonise a body in an orbit within our solar system. They are turning it into an effectively permanent place to live. Extending this process to rogue bodies provides a sort of default option for interstellar colonisation. A slow spreading of humans throughout the Oort cloud and then onto rogue planets. A few hundred million years of doing this would result in us colonising the whole galaxy.

Last edited by Calliban (2023-03-02 05:06:01)

Void · 2023-03-02 11:13:42

A desirable destination might be Stellar Nurseries: https://astronomy.com/news/2021/10/astr … -nurseries

The phrase "Stellar Nurseries" attributes human characteristics to something not human and presumably not alive.

What it is though is to output of exploded stars, and the sweepings collected from that explosion.

A human descended effort was to attain one, then they would be in on the ground floor of a creation and might not only benefit from the materials which were collecting into lumps but might even influence the formation of solar systems.

A world as you have suggested, coming reasonably close to such might create and send a mission to a star nursery.

Done.

Last edited by Void (2023-03-02 11:16:10)

Void · 2023-03-02 14:36:59

I thought this might be of interest: https://www.space.com/16144-kuiper-belt-objects.html

Quote:

The Kuiper Belt is far larger than the main asteroid belt, up to 20 times as wide and 20 to 100 times it's mass according to Nine Planets.

Quote:

What makes these Kuiper Belt objects interesting?
There are thousands of them that we know of, and probably hundreds of thousands bigger than 62 miles (100 km) across, waiting to be discovered and measured by astronomers. Each one of them is a little leftover bit of planetary material that formed somewhere in the solar system and was placed on its current orbit by gentle nudges from the planets or even the galaxy.

The objects suggested seeming to be in the range of your thinking for size. We can wonder if a lot of those sized objects are interstellar as well.

One solution to the fermi paradox, is that Earth is extremely lucky not to have been clobbered by one recently. That is perhaps we are beating the odds. Which is a reason to become interplanetary.

Such impacts could support Panspermia but would squish us I am afraid.

Done.

Last edited by Void (2023-03-02 14:44:05)

Calliban · 2023-03-03 03:39:45

Void wrote:

I thought this might be of interest: https://www.space.com/16144-kuiper-belt-objects.html
Quote:
The Kuiper Belt is far larger than the main asteroid belt, up to 20 times as wide and 20 to 100 times it's mass according to Nine Planets.
Quote:
What makes these Kuiper Belt objects interesting?
There are thousands of them that we know of, and probably hundreds of thousands bigger than 62 miles (100 km) across, waiting to be discovered and measured by astronomers. Each one of them is a little leftover bit of planetary material that formed somewhere in the solar system and was placed on its current orbit by gentle nudges from the planets or even the galaxy.
The objects suggested seeming to be in the range of your thinking for size. We can wonder if a lot of those sized objects are interstellar as well.
One solution to the fermi paradox, is that Earth is extremely lucky not to have been clobbered by one recently. That is perhaps we are beating the odds. Which is a reason to become interplanetary.
Such impacts could support Panspermia but would squish us I am afraid.
Done.

Void, that is interesting. It suggests that there are hundreds of thousands of aquaforming candidates in our outer solar system. Enough to keep future humans busy for a very long time! Sunlight intensity out there is only 0.1% what it is at Earth orbit. Whilst it is possible in principle to build huge concentrators out of thin metal foil, the mirror area required is huge. I suspect that humanity will need to master nuclear fusion before the Kuiper belt is an attractive prospect.

Another thing occurs to me about bodies in the 100km size range. Gravity is obviously very weak, <<1% Earth. For a spherical body, the radius of curvature of the icy crust is small compared to larger bodies like Pluto. The icy crust itself would function as a sort of dome. Provided that the underside is insulated, we could allow gaseous oxygen bubbles to accumulate under the ice. The pressure in the bubbles would balance the weight of the ice, reducing the effective stress within the ice shell to zero. Within these bubbles, floating islands could exist, with land animals and plants. Human cities could also be constructed on these islands. The buildings would rotate to produce internal gravity. Externally, gravity would be so weak that humans could easily fly. So cities could be built in 3-dimensions. Rather like the future New York in Fifth Element. The surface area of a 100km diameter KBO is 31,000km2. That is comparable to a country like Belgium or Netherlands. So our KBOs would be miniature worlds, with islands serving as miniature continents. The insulation covering the underside of the ice, could even be coloured to provide a convincing blue sky.

The only real limitations on the habitability of such a world are the volume under the ice and the waste heat produced by the lighting. We would remove waste heat by pumping 'ocean' water into radiator panels on the outer surface of the ice shell. The outer surface of the KBO should be kept at a constant temperature <200K, to prevent sublimation of the ice. So it would make sense limiting unneccesary waste heat generation under the shell. Industry and human food production should be located above the ice shell. Lighting under the shell should be optimised for frequencies that favour plant growth.

This would be a comforfable environment for human beings to live in for millenia, maybe even geological timescales. It provides a model for converting the many ice balls of the outer solar system into comfortable environments that can sustain humanity for millions of years. It also provides an interesting option for interstellar colonisation. If humans were to colonise an interstellar ice ball, which is moving w.r.t the sun at velocity of a few hundred km/s, then they have a travelling world that will eventually make close approaches to other star systems. This provides an option for interstellar colonisation by slow diffusion, without fanciful and probably impossible concepts like warp drives or wormholes. Such bodies also provide a plausible option for intergalactic travel. The Andromeda galaxy is some 2.5 million LY away. Future humans, able to harness the resources of entire star systems, could feasibly build fusion engines large enough to accelerate bodies of this size to 0.1C. That would allow our world ship to cross the galactic void and reach Andromeda in 25 million years. A closed ecosystem, with a fusion power supply, could be made last that long if nanomachines were to allow complete recycling.

Last edited by Calliban (2023-03-03 04:36:07)

Void · 2023-03-03 11:11:12

My suspicion is that in most star systems "Habitable" worlds get wacked by impactors more than for Earth. That would indicate that we are the lucky winners at the casino. But we should not press our luck.

If we think that it is good to exist and be conscious, then we might want an insurance policy or two for the family of peoples.

So, a backup copy of two, would be of a high priority.

Beyond that the "Polynesian" model might be useful. This I believe is the notion that stars can be considered to be like south sea islands, being rather isolated from each other but still reachable. This then allows island cultures to rise and fall, and yet odds are there will always be one or more that is on the ball.

But the model can now be modified, where some asteroids and with fusion just possibly some Kuiper belt objects can be made habitations by various means. The islands model will still hold true in some cases, but in many other cases it will be a collection of islands perhaps like Greece or Indonesia.

We can also mention the four major planets Jupiter, Saturn, Uranus, and Neptune, and of course their moons and trojan asteroids.

Should the human race set up such a scattering of collections of "Islands" then deviations will develop which can be good and bad. Perhaps it is a bit like a fission reaction too many interactions and conflicts arise, and too few interactions and cultures stagnate and even fall.

So, maybe this can spill into other star systems in the next few centuries, but the saying is "The future belongs to those who will be there".

The further into the future the more the projections will deviate from what may actually occur.

But God supposedly likes those who struggle, so I guess that within reason we should struggle in that direction.

Done.

Last edited by Void (2023-03-03 11:22:14)

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#1 2015-09-09 16:54:57

Interstellar "World Ships"

#2 2015-09-15 05:00:34

Re: Interstellar "World Ships"

#3 2015-09-15 20:34:16

Re: Interstellar "World Ships"

#4 2023-02-10 20:07:42

Re: Interstellar "World Ships"

#5 2023-02-21 21:19:58

Re: Interstellar "World Ships"

#6 2023-03-01 20:13:38

Re: Interstellar "World Ships"

#7 2023-03-01 20:49:45

Re: Interstellar "World Ships"

#8 2023-03-02 04:40:24

Re: Interstellar "World Ships"

#9 2023-03-02 11:13:42

Re: Interstellar "World Ships"

#10 2023-03-02 14:36:59

Re: Interstellar "World Ships"

#11 2023-03-03 03:39:45

Re: Interstellar "World Ships"

#12 2023-03-03 11:11:12

Re: Interstellar "World Ships"

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