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New dwarf planet discovered at the edge of the solar system. The new world is some 500km in diameter.
http://www.space.com/34358-new-dwarf-pl … uz224.html
This dwarf planet could be terraformed relatively easily by melting it using a nuclear heat source. The result would be a water ocean ~90km deep, overlying a silicate core. An icy shell would float on top of the ocean and would provide enough pressure at its base to prevent the water from boiling.
If the shell is 800m thick, pressure at the surface of the ocean would be 1 bar. About 300GW of heat would be required to keep the global ocean liquid, as heat flux through the shell would be about 0.5W/m2.
Pressure at the ocean bottom would be about 90bar. Mining of silicate materials would be carried out by dredging. An ocean ecosystem could be based upon algae and plankton in the global ocean. This would require some form of artificial lighting. Humans would live in floating habitats tethered beneath the ice shell. Maybe it would be possible to farm the ocean for a large proportion of food needs.
Such a terraformed world should be relatively easy to build, as aside from the provision of a nuclear heat source, no large-scale planetary engineering is required. Terraforming could presumably be carried out incrementally, with an initially small habitat and nuclear heat source, resulting in a localised ice covered sea. As colo isation proceeded the world would gradually transform into a global ocean. Ammonia dissolved within the water will provide fixed nitrogen needed to fertilise the ocean ecosystem.
Last edited by Antius (2016-10-13 15:53:34)
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Nice stuff Antius.
It seems to me that we could start with Greenland, then Antarctica, as the innermost examples, of places which could be terraformed by methods similar to what you mention. I think that it is reasonable not to do experiments of that kind on Earth, since it is where all of us live (As far as I know).
Going outward from the sun, we have two polar ice caps on Mars.
Ceres
Moons of outer planets
Minor planets.
To cut it short, the place where you should want to develop the necessary basket of skills is the polar ice caps of Mars. Two Oceans waiting. In reality of course the North and the South different. The North being low in a basin, would pancake out to cover much more area if melted. The South being high, would be made into a patchwork of basins if melted.
My point being that Mars provides the testing place for such methods, and includes solar, fission, and Fusion options (Should fusion becomes a reality).
It is the right place to start in my opinion. And upon starting, such methods could progress to the farthest parts of the galaxy, should the human race / (What follows) choose this pathway instead of extinction. Of course ages of time, required for a galactic presence, but that's not my problem.
I actually don't know why humans would be benefited by such a huge expansion. The polyneasian could be sufficient by some accounts. That is create enough worlds, so that when one dies, another is born.
Secretly I will tell you I am not that sure that I want even another world with humans on it. But what the heck, if we get the chance lets roll the dice and humans will see what they get. There is a chance of improvement.
From Mars to the stars perhaps.
Curious therefore, how would you turn Martian icecaps into ice covered oceans/seas? Seeing it will be the nursery for methods for the deeps of space.
Last edited by Void (2016-10-13 21:45:03)
I am starting to ask seriously "Why do I do this?"
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New dwarf planet discovered at the edge of the solar system. The new world is some 500km in diameter.
http://www.space.com/34358-new-dwarf-pl … uz224.html
This dwarf planet could be terraformed relatively easily by melting it using a nuclear heat source. The result would be a water ocean ~90km deep, overlying a silicate core. An icy shell would float on top of the ocean and would provide enough pressure at its base to prevent the water from boiling.
If the shell is 800m thick, pressure at the surface of the ocean would be 1 bar. About 300GW of heat would be required to keep the global ocean liquid, as heat flux through the shell would be about 0.5W/m2.
Pressure at the ocean bottom would be about 90bar. Mining of silicate materials would be carried out by dredging. An ocean ecosystem could be based upon algae and plankton in the global ocean. This would require some form of artificial lighting. Humans would live in floating habitats tethered beneath the ice shell. Maybe it would be possible to farm the ocean for a large proportion of food needs.
Such a terraformed world should be relatively easy to build, as aside from the provision of a nuclear heat source, no large-scale planetary engineering is required. Terraforming could presumably be carried out incrementally, with an initially small habitat and nuclear heat source, resulting in a localised ice covered sea. As colo isation proceeded the world would gradually transform into a global ocean. Ammonia dissolved within the water will provide fixed nitrogen needed to fertilise the ocean ecosystem.
Wonderful!
shell-world-ing and natural para-terraforming from within, simultaneously !!!
[image] http://www.space.com/images/i/000/033/3 … 04c-02.jpg [/image]
In fact what about layer of air between the water surface and the icy ceiling???
global, or pocket / domes one.
The metalo-silicate core could be mined for foam-ables ( silica, alumina, metals ... ) to cover as much as needed of the ocean surface with raft islands and continents ...
... although at such a low Gees of under 1% ... at such a world the 'vertical' won't matter so much.
Such planemos could occur to be REALLY numerous across the Galaxy and beyond - kinda stapple habitats
AND, I remember that good old nuclear fission is quite doable out there.
'Cause the 'cometary material' contains as much uranium and thorium as if the total mass is as 'calorific' as ... wood ( Granite per instance is 30 times coal on average ).
So, enough fission energy for billions of years.
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1% gees, 1 Bar under-ice habitats.
Without body-modifications, the 0.01-ish gees 'outdoors' could be mitigated by daily immersion of 1G or higher environments for certain number of hours, like.:
- the individual homes to be centrifugal.
- or.: global transport system like www.et3.com running with such speeds that to excert (say) 2G centrifugal force where the inhabitants to sleep ... mobile bedrooms ...
"few hours in the centrifuge a day keeps the doctor away"
90bar at ocean bottom is like under less then 1km water layer on Earth, which makes 'earth', 'water', 'ice', 'vacuum' all easily interface-able by mere "skyscraper" / elevator towers from bottom to top.
---
I remember discussing back in 204-2005 Ceres terraformation using water-bag layer as natural gravity pulled atmospheric counter-pressure ... cap, or spheroid dome.
Even transparent and full of sea life.
Ocean in the sky.
Upside(water)-down(air) habitat.
The ice shell / ocean air-pocket sandwitch one is a quite the same thing.
With fission reactors thus the literally ZILLIONS of such iceballs are doable.
... and they must be hundreds of thousands if not millions only in the Solar sphere alone ...
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Wait a minute. The chart on the Space.com website linked in the initial post of this thread shows details of various dwarf planets. Eris has a rotation period of 25.9 hours, and has one Moon. Earth has a rotation period of 24 hours, and one Moon. Perhaps we should look at Eris more closely. At that distance it would be extremely cold; but still, interesting coincidence. Mars has a "solar day" of 24 hours, 39 minutes, 35.244 seconds. Both Eris and Mars have a day very similar to Earth. If you want to get mystical, it's as if some creator has set out places for humanity to move to.
My argument for religious types. Mars rotation is practically the same as Earth. Mars has low gravity, low pressure, and cold. Venus has practically the same gravity and practically the same size planet as Earth. Venus has high pressure, and hot, and a ridiculously long day. Mars can be terraformed by industrial means: releasing greenhouse gasses. Venus can be terraformed with biotechnology: engineered microogranisms released into the clouds convert CO2 into polyanhydride. Mars can be colonized now with spacesuits and pressure habitats. Venus has to be terraformed first before it can be colonized. The Moon is a "tree house", small and in the back yard of our father's house, but no way you could make a home there. It's as if stepping stones have been laid out, leading us into space.
Now Eris has a 25.9 hour day? Hmm...
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Nice stuff Antius.
It seems to me that we could start with Greenland, then Antarctica, as the innermost examples, of places which could be terraformed by methods similar to what you mention. I think that it is reasonable not to do experiments of that kind on Earth, since it is where all of us live (As far as I know).
Going outward from the sun, we have two polar ice caps on Mars.
Ceres
Moons of outer planets
Minor planets.To cut it short, the place where you should want to develop the necessary basket of skills is the polar ice caps of Mars. Two Oceans waiting. In reality of course the North and the South different. The North being low in a basin, would pancake out to cover much more area if melted. The South being high, would be made into a patchwork of basins if melted.
My point being that Mars provides the testing place for such methods, and includes solar, fission, and Fusion options (Should fusion becomes a reality).
It is the right place to start in my opinion. And upon starting, such methods could progress to the farthest parts of the galaxy, should the human race / (What follows) choose this pathway instead of extinction. Of course ages of time, required for a galactic presence, but that's not my problem.
I actually don't know why humans would be benefited by such a huge expansion. The polyneasian could be sufficient by some accounts. That is create enough worlds, so that when one dies, another is born.
Secretly I will tell you I am not that sure that I want even another world with humans on it. But what the heck, if we get the chance lets roll the dice and humans will see what they get. There is a chance of improvement.
From Mars to the stars perhaps.
Curious therefore, how would you turn Martian icecaps into ice covered oceans/seas? Seeing it will be the nursery for methods for the deeps of space.
Thanks Void. I think that as Mars becomes increasingly populated, there will be a high demand for low price electricity for ore refining, manufacturing and production of food. As the size of nuclear reactors increases, it will make sense to locate them at the poles such that evaporation can provide a heat sink. This will eventually result in a thickening atmosphere and melting of water bodies. Algae could be introduced into water bodies and would begin the process of removing CO2 from the atmosphere and converting it to oxygen. Maybe other plants could be introduced as well, such as macro algae? I don’t think fish will be possible until oxygen levels in the water have risen to that equivalent of the Earth’s oceans and CO2 levels in the atmosphere have declined. But who knows? Maybe the ice layer would mitigate this problem by trapping oxygen beneath the ice and reducing the rate of permeation of CO2 into the water?
A limited ecosystem might be established relatively soon and would seem to be a natural extension of human activities on the planet. One thing would appear to make this problematic. Given what we know of Martian regolith, any seas are likely to be too salty for most of the aquatic life we know. Rather like the Dead Sea on Earth. I’m not sure how we would get around that problem without literally membrane filtering the entire sea. I guess that would naturally happen eventually as human beings desalinate water and dump waste water back into the sea. But it would take a long time.
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1% gees, 1 Bar under-ice habitats.
Without body-modifications, the 0.01-ish gees 'outdoors' could be mitigated by daily immersion of 1G or higher environments for certain number of hours, like.:
- the individual homes to be centrifugal.
- or.: global transport system like www.et3.com running with such speeds that to excert (say) 2G centrifugal force where the inhabitants to sleep ... mobile bedrooms ...
"few hours in the centrifuge a day keeps the doctor away"
90bar at ocean bottom is like under less then 1km water layer on Earth, which makes 'earth', 'water', 'ice', 'vacuum' all easily interface-able by mere "skyscraper" / elevator towers from bottom to top.
---
I remember discussing back in 204-2005 Ceres terraformation using water-bag layer as natural gravity pulled atmospheric counter-pressure ... cap, or spheroid dome.
Even transparent and full of sea life.
Ocean in the sky.
Upside(water)-down(air) habitat.
The ice shell / ocean air-pocket sandwitch one is a quite the same thing.
With fission reactors thus the literally ZILLIONS of such iceballs are doable.
... and they must be hundreds of thousands if not millions only in the Solar sphere alone ...
The gas bubble under the ice would be stable only if sheer stresses in the shell were relatively low. That means worlds not exposed to high tidal forces, which rules out inner moons, but isn't a problem for Kuiper belt objects and might work for outer gas giant moons. The air would need to be kept cold to prevent ice melting, or the underside of the shell insulated to maintain a temperature gradient. If the habitat is contained in a floating shell, then the condition of the ice wouldn't matter so much. The pressure on the outside depends only on the mass of water/ice above.
The concept could be taken all the way down to bodies perhaps 50km across. In that case a 1 bar pressure would be achieved at the sea bottom some 8km deep. The solid floor of the 'ocean' would have a 1 bar outside pressure but a gravity of only 1 thousandth of Earth's. Para terraforming would be relatively easy. With such low gravity, the membrane tension of water would prevent catastrophic floods for very small leaks and flowrate would be slow even for catastrophic leaks. At the ocean floor, habitats would need be little more than steel frames covered in a polyethylene liner. Due to buoyant forces, they would need to be tethered to the ocean floor, but at 10(-3) gees, buoyant forces would only be 1kg per cubic metre of water displaced.
Because the radius of curvature of the rocky core is smaller than the surface and convection is so weak, conduction would dominate heat transfer through the water. A substantial temperature gradient could exists between the rocky sea floor and the icy surface. That means that sea floor habitats could enjoy Hawaiian climate even if the shell at the top is frozen.
Maybe the first such terraformed world would be an outer moon of Jupiter or Saturn?
Last edited by Antius (2016-10-14 07:32:45)
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I would suggest that Jupiter's moon Pasiphae might be a good early candidate for ocean floor terraforming. It is close enough that it might be reached using the ITS architecture that Musk is working on. At 58km across, a 5GW heat source would be needed to keep the subsurface ocean liquid, with a 0.8km thick crust providing about 1KPa base pressure, which is enough to prevent the ocean from boiling. At 23million km average distance from Jupiter, tidal forces on the ice shell should be minimal.
If the entire sea floor were Para-terraformed there would likely be too much heat to allow the ice shell to be stable. Assuming the satellite is a 50/50 mix of ice and rock, the surface area of the silicate core would be 4700km2 and lighting it to Earth standard light levels would require about 500GW of electric power. This would melt the ice shell. To prevent the ocean from boiling into space a tensile shell would need to be built over the ocean to maintain a 1KPa pressure.
But for a relatively small population, the ice shell would be sufficient. This suggests that the tensile shell is something that could be added later on as population growth required generating more power. In fact, if food could be grown outside of the shell world and shipped in, 2.5GW of electric power is enough for a population of 2.5million people. This could form a densely populated city covering the entire surface area of the silicate core.
Last edited by Antius (2016-10-14 08:15:31)
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Antius:
http://www.universetoday.com/23932/lots … orth-pole/
Planum Boreum, Mar’s north polar cap contains water ice “of a very high degree of purity,” according to an international study. Using radar data from the SHARAD (SHAllow RADar) instrument on board the Mars Reconnaissance Orbiter (MRO), French researchers say the data point to 95 percent purity in the polar ice cap. The north polar cap is a dome of layered, icy materials, similar to the large ice caps in Greenland and Antarctica, consisting of layered deposits, with mostly ice and a small amount of dust. Combined, the north and south polar ice caps are believed to hold the equivalent of two to three million cubic kilometers (0.47-0.72 million cu. miles) of ice, making it roughly 100 times more than the total volume of North America’s Great Lakes, which is 22,684 cu. kms (5,439 miles).
So, the mother load of clean water on Mars. Should you melt these, winds could bring in salts. For the south cap, the solution is to let some water flow to lower latitudes, and bring excess salts out of the polar water system. Evaporation into a salt pan, the cycle then established, eventually winds bring salt back. For the North, that basin being very flat in general, a Diked polder would be a sufficient repository of excess salts.
And let us not forget that vacuum gives us excellent insulation opportunities, and that overall the solar energy received at the polar caps is similar to that received at the equator. (Not too different, that is). Collect it and inject it under an insulation of ice and artificial snow, or other insulators manufactured, over time liquid oceans should be a possibility. And that is if you only deal with the solar energy at the polar ice cap.
What if in addition you "Canal/Pipe" H20 to lower latitudes, and then use solar energy to split it to H2 and O2?
Pipe the H2 back to the polar ice cap / Oceans, and let biological organisms interact with the chemistry of CO2/CO and H2 injected into the waters. I think that like a moist hay stack, biological processes will generate heat. And of course Methane to be released to the atmosphere.
You see where I am going. Mars, can be done solar, but of course, Nuclear of both types also desired. It is quite a nursery for weaning the human race from solar energy, while still wet nursing them with solar energy. In time the proper tool box for the outer solar system would be put together.
It is a very good process, I think.
Last edited by Void (2016-10-14 08:43:28)
I am starting to ask seriously "Why do I do this?"
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Wait a minute. The chart on the Space.com website linked in the initial post of this thread shows details of various dwarf planets. Eris has a rotation period of 25.9 hours, and has one Moon. Earth has a rotation period of 24 hours, and one Moon. Perhaps we should look at Eris more closely. At that distance it would be extremely cold; but still, interesting coincidence. Mars has a "solar day" of 24 hours, 39 minutes, 35.244 seconds. Both Eris and Mars have a day very similar to Earth. If you want to get mystical, it's as if some creator has set out places for humanity to move to.
My argument for religious types. Mars rotation is practically the same as Earth. Mars has low gravity, low pressure, and cold. Venus has practically the same gravity and practically the same size planet as Earth. Venus has high pressure, and hot, and a ridiculously long day. Mars can be terraformed by industrial means: releasing greenhouse gasses. Venus can be terraformed with biotechnology: engineered microogranisms released into the clouds convert CO2 into polyanhydride. Mars can be colonized now with spacesuits and pressure habitats. Venus has to be terraformed first before it can be colonized. The Moon is a "tree house", small and in the back yard of our father's house, but no way you could make a home there. It's as if stepping stones have been laid out, leading us into space.
Now Eris has a 25.9 hour day? Hmm...
Being that far out from the Sun, its rotation rate makes no difference. Since its diameter is about 2200 km and its maximum distance from the Sun is 97 AU, if we build a mirror that is 220,000 km in diameter, we can focus enough sunlight on it to give it an Earth like level of solar intensity. if you want to know how big this is, it is bigger than Jupiter. I think Eris would be a candidate for an artificial Sun, probably fusion powered. Building a mirror this big is probably a waste of time and resources.
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Robert, Isn't it curious the patterns. My best estimate is that we are not to be given too easy a path, or too hard a path. Many in this place cannot tolerate the thought. Do what you think best, but remember we are only and not more than human. Don't break yourself on a challenge which is too much for our kind. We already have too many broken people, we don't need any more.
Last edited by Void (2016-10-15 07:18:38)
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Antius,
I like your minimum world, where 1 bar exists on top of core covered by an ocean of water covered by ice.
Of course for your first cases you would want to modify a small mass approximately off sizes you have previously mentioned. But after that since many solar system objects do not have atmospheres, and most likely outside of Pluto, few or no other Dwarf Planets will have natural atmospheres, then projection of mass to an appointed new location in space is a reasonable option presuming strong nuclear power and automation/robots.
What is most curious to me, is how many ideal sized could be created. Granted you have to start with Pluto as it is, but further out, even Nitrogen does not inflate to an atmosphere. On those worlds, how many ideal worlds where the bottom of the ocean/sea is 1 bar, can you make?
I am not very trusting of things like domes. rotating habitats, shell worlds(Per the specific definition), but I could trust the world you describe. I could imagine that the total number of them that could be constructed is just mind boggling.
I see them as eventually being powered by fusion, but not necessarily in the beginning. How many of them could be constructed from Calisto for instance? That's an interesting start.
Last edited by Void (2016-10-15 07:23:59)
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At 1/50th-g. I don't know how you get anything like that to hold onto at atmosphere, If I was standing on it, I would weigh 5 pounds. I would probably suffer the same debilitating effects of zero-g If I was there for a long time. At 1 bar, I could probably swim through the air by flapping my arms and kicking my feet. Not exactly Earthlike.
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Tom, I don't think they are strongly entertaining a standard atmosphere held by gravity. But I can be corrected on that.
I think primarily they are moving in this direction.
Cold ice layer (Significantly thick)
Under that and above the water, an insulating manufactured layer. Something like Styrofoam.
I have also looked into such before. Let's say you have a liquid body of water covered with ice.
You could take a "Tile" of Styrofoam, and press it to the bottom of the ice surface. It should then freeze to the ice surface and could provide insulation. If you "Tiled" the entire interface between ice and water, then you could have water at comfortable temperatures, and Ice that is cold.
Should the ice then crack, then water at say 20 degC would likely squirt into the crack, but should be expected to freeze the crack shut, provided that indeed the ice was sufficiently cold. So if the thermal conditions were good, you would have a well protected warm ocean from top to bottom.
Now if you dimple the interface between ice and water, making a repetition of diving bell shapes, the ice/Styrofoam can still float on the water in say ~50% of the places, but could rise above the water in ~50% of the places, if the dimples/diving bells were filled with air.
In the case of a rupture/crack in the ice above a dimple, the air within would squirt out to vacuum, unless it contained enough moisture to seal the crack. As the air rushed out of the dimple, it would be displaced by liquid water which would then seal the crack once it was sucked into the crack.
In such a situation, I think that the survival potential for humans living in the dimple would be high, if they had good training and if another dimple they could go to was near.
Now as for walking from one dimple to another without compromising the safety of other dimples, think if your sink trap.
You could have an air filled tube that was in the shape of a "V" with a staircase going up and down the "V".
Should one dimple leak air, yes some would be pulled out of the other dimple connected by the "V" staircase, but the "V" staircase would rapidly be filled with water, and would seal the connection, stopping the leakage.
Obviously if you wanted to, you could have a road network under the water, connecting various dimples, where the final connection to a dimple involved a water trap to protect the whole system from depressurizing. In that case, the trap connecting the dimple to the underwater tube highway, would require some work to make sure that it can protect the highway from being totally filled with water, and the highways air from totally leaking out. But I think that would be do-able. Just would require some engineering.
Note: This could be pioneered on Mars as a method for habitat of great size, with significant safety and utility.
Last edited by Void (2016-10-15 07:50:26)
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So your thinking about doing this with Europa? A bit or water electrolysis to produce oxygen.
Lets say a heavily shielded one of these lands on Europa. I wonder, since its surface is made of water ice, and the ITS uses methane/Oxygen engines, do you think it could use its engines to melt a hole in Europa's ice and sink into it?. Probably this ship would need some modifications if it were to be used as a submersible. Fortunately since Europa's gravity is low, the pressure doesn't build as steeply underwater as it does on Earth. With the radiation environment around Europa, you probably would want to burrow under the ice as quickly as possible, and unlike the illustration above, you probably won't see men in space suits walking on he surface. So how thick is Europa's ice? sheets? Since it is devoid of impact craters, the answer probably is not that much. So what do you think of the possibility of building a manned submersible spacecraft which can travel to Europa, land and melt a hole in is surface and go under water?
http://www.planetary.org/blogs/emily-la … /3266.html
The dwarf planet, called 2014 UZ224, measures about 330 miles (530 kilometers) across and is located about 8.5 billion miles (13.7 billion km) from the sun, NPR reported today (Oct. 11). For comparison, Pluto's largest moon, Charon, is about 750 miles (1,200 km) in diameter, and reaches a maximum distance of about 4.5 billion miles (7.3 billion km) from the sun.
A year on 2014 UZ224 (the time it takes the dwarf planet to orbit the sun) is about 1,100 Earth years. One Pluto year, for c is about 248 Earth years. The new object was also confirmed by the Minor Planet Center. [Meet the Solar System's Dwarf Planets]
So this dwarf is way out there, and it is relatively small. Getting there would take a spaceship verging on being a starship with a fusion power plant. You'd need fusion to stay alive and unfrozen anyway. It is a pretty big object. I wonder if we could make a comet out of it, lets suppose we slowed it down so it falls toward the Sun, maybe put in on a Collision course with the planet Venus to give it an ocean, it has a lot of frozen gases as well as water ice I bet. People can live in this thing for a long time as it falls toward the Sun, and when it approaches Venus, people can evacuate.
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Tom,
First of all I want to nod to Antius, who said:
I would suggest that Jupiter's moon Pasiphae might be a good early candidate for ocean floor terraforming. It is close enough that it might be reached using the ITS architecture that Musk is working on. At 58km across, a 5GW heat source would be needed to keep the subsurface ocean liquid, with a 0.8km thick crust providing about 1KPa base pressure, which is enough to prevent the ocean from boiling. At 23million km average distance from Jupiter, tidal forces on the ice shell should be minimal.
If the entire sea floor were Para-terraformed there would likely be too much heat to allow the ice shell to be stable. Assuming the satellite is a 50/50 mix of ice and rock, the surface area of the silicate core would be 4700km2 and lighting it to Earth standard light levels would require about 500GW of electric power. This would melt the ice shell. To prevent the ocean from boiling into space a tensile shell would need to be built over the ocean to maintain a 1KPa pressure.
So that is one option which Antius has included as well as 2014-UZ224.
I suggested developing the technology on Mars, and I mentioned Calisto.
I do like pretty much what Antius has offered, but I see no reason to not apply it to Mars. Since we hope to establish humans there, I see no reason not to seek to master the entire water cycle of that planet to human advantage, and this could include very large bodies of water with an ice layer over them like Europa.
In fact if there were geological energy sources under the Martian polar ice caps, you would be looking at a Europa like Mars, only it's rocky surface would be only partially covered with ice covered water.
From there, if you wanted to access the Jupiter system, a first step could be exactly what Antius suggested for Jupiter's moon Pasiphae. And the nice thing about that is in the vicinity of Jupiter, you do not have to rely on nuclear heat (But you would use it if you could). Solar heat would still be effective in the vicinity of Jupiter with concentrating mirrors that are not ridiculously large.
So, then this would be a progression from solar to nuclear energy, as humans drifted further and further out in the solar system. Adapting/making these little ocean worlds.
Once Antius had done what he intended to with tiny moons around Jupiter, some effort could move on to Saturn and so on. But still around Jupiter are four very large chunks of matter. Io, Europa, Ganymede, Callisto.
You mentioned Europa.
I would choose Callisto instead, because:
-It appears to have a mixture of materials on it's surface, is perhaps not totally differentiated.
-It suffers much less from radiation from Jupiter's magnetic field.
-It is the least deep in the Jupiter gravity well. So, it is the most accessible, per space transport methods.
In addition, we do not want to damage any potential life which could exist in the oceans of Ganymede, or Europa. Io, is the absolute worst case for exploitation, but maybe someday.
So, I will explain my intentions for Callisto more.
First of all, I do believe that that moon does not have much of a polar axis tilt.
https://en.wikipedia.org/wiki/Callisto_(moon)
Callisto is composed of approximately equal amounts of rock and ices, with a density of about 1.83 g/cm3, the lowest density and surface gravity of Jupiter's major moons. Compounds detected spectroscopically on the surface include water ice,[13] carbon dioxide, silicates, and organic compounds. Investigation by the Galileo spacecraft revealed that Callisto may have a small silicate core and possibly a subsurface ocean of liquid water[13] at depths greater than 100 km.[14][4]
So, it looks likely good for chemistry, as it does mention organic compounds, which I may hope will include some Nitrogen.
Quote:
Like most other regular planetary moons, Callisto's rotation is locked to be synchronous with its orbit.[3] The length of Callisto's day, simultaneously its orbital period, is about 16.7 Earth days. Its orbit is very slightly eccentric and inclined to the Jovian equator, with the eccentricity and inclination changing quasi-periodically due to solar and planetary gravitational perturbations on a timescale of centuries. The ranges of change are 0.0072–0.0076 and 0.20–0.60°, respectively.[10] These orbital variations cause the axial tilt (the angle between rotational and orbital axes) to vary between 0.4 and 1.6°.[27]
As far as energy, we have already established that it get's enough solar energy, to use reasonably sized concentrating mirrors. The tilt of the sun in the sky will be much simpler than that of the Earth and Mars, and no wind loads, and most likely not much of a cleaning burden per dust.
You could concentrate sunlight onto photovoltaic cells, or use power towers, or a hybrid.
Fission power? Maybe if the ores are found.
Fusion power? Sure, if it is ever achieved (Which I expect it will be eventually).
So, Antius has built a little ocean city on Pasiphae, and I want to establish a mining process on Callisto.
On Callisto, we have a palate of materials and energy sources to work from. We can build canals, seas, and oceans on Callisto, with similar characteristics suggested for the Antius worlds.
An extra complication in this case, is your bodies of water could melt down bottomlessly, unless you purposely limited the deepness, with some insulator, lets say a thick layer of mining tailings. Probably canals are the best, so that the cold of space can seep down and under these bodies of water, and so, actually you can transport heavy things about in these canals (Covered canals).
So, if the people of Callisto exported mined materials, they would also have lots of tailings, which would include excess ice, and rock. It would get into the way, so why not shoot it to an "L" location and construct a world. An Antius ocean city world.
I don't think Venus has so much to offer. And I cant imagine the effort that would be required to crash an outer solar system object into it. Also the results would most likely unsatisfactory.
So, then if we presume automation/robots, "How many little ocean worlds could you make out of Callisto?". I am thinking it is a vast amount of living space.
Last edited by Void (2016-10-15 11:53:34)
I am starting to ask seriously "Why do I do this?"
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https://en.wikipedia.org/wiki/Natural_n … on_reactor in the rocky cores?
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Tom,
First of all I want to nod to Antius, who said:
I would suggest that Jupiter's moon Pasiphae might be a good early candidate for ocean floor terraforming. It is close enough that it might be reached using the ITS architecture that Musk is working on. At 58km across, a 5GW heat source would be needed to keep the subsurface ocean liquid, with a 0.8km thick crust providing about 1KPa base pressure, which is enough to prevent the ocean from boiling. At 23million km average distance from Jupiter, tidal forces on the ice shell should be minimal.
If the entire sea floor were Para-terraformed there would likely be too much heat to allow the ice shell to be stable. Assuming the satellite is a 50/50 mix of ice and rock, the surface area of the silicate core would be 4700km2 and lighting it to Earth standard light levels would require about 500GW of electric power. This would melt the ice shell. To prevent the ocean from boiling into space a tensile shell would need to be built over the ocean to maintain a 1KPa pressure.So that is one option which Antius has included as well as 2014-UZ224.
I suggested developing the technology on Mars, and I mentioned Calisto.
I do like pretty much what Antius has offered, but I see no reason to not apply it to Mars. Since we hope to establish humans there, I see no reason not to seek to master the entire water cycle of that planet to human advantage, and this could include very large bodies of water with an ice layer over them like Europa.
In fact if there were geological energy sources under the Martian polar ice caps, you would be looking at a Europa like Mars, only it's rocky surface would be only partially covered with ice covered water.From there, if you wanted to access the Jupiter system, a first step could be exactly what Antius suggested for Jupiter's moon Pasiphae. And the nice thing about that is in the vicinity of Jupiter, you do not have to rely on nuclear heat (But you would use it if you could). Solar heat would still be effective in the vicinity of Jupiter with concentrating mirrors that are not ridiculously large.
So, then this would be a progression from solar to nuclear energy, as humans drifted further and further out in the solar system. Adapting/making these little ocean worlds.
Once Antius had done what he intended to with tiny moons around Jupiter, some effort could move on to Saturn and so on. But still around Jupiter are four very large chunks of matter. Io, Europa, Ganymede, Callisto.
You mentioned Europa.
I would choose Callisto instead, because:
-It appears to have a mixture of materials on it's surface, is perhaps not totally differentiated.
-It suffers much less from radiation from Jupiter's magnetic field.
-It is the least deep in the Jupiter gravity well. So, it is the most accessible, per space transport methods.In addition, we do not want to damage any potential life which could exist in the oceans of Ganymede, or Europa. Io, is the absolute worst case for exploitation, but maybe someday.
So, I will explain my intentions for Callisto more.
First of all, I do believe that that moon does not have much of a polar axis tilt.https://en.wikipedia.org/wiki/Callisto_(moon)
Callisto is composed of approximately equal amounts of rock and ices, with a density of about 1.83 g/cm3, the lowest density and surface gravity of Jupiter's major moons. Compounds detected spectroscopically on the surface include water ice,[13] carbon dioxide, silicates, and organic compounds. Investigation by the Galileo spacecraft revealed that Callisto may have a small silicate core and possibly a subsurface ocean of liquid water[13] at depths greater than 100 km.[14][4]
https://upload.wikimedia.org/wikipedia/ … llisto.jpg
So, it looks likely good for chemistry, as it does mention organic compounds, which I may hope will include some Nitrogen.
Quote:
Like most other regular planetary moons, Callisto's rotation is locked to be synchronous with its orbit.[3] The length of Callisto's day, simultaneously its orbital period, is about 16.7 Earth days. Its orbit is very slightly eccentric and inclined to the Jovian equator, with the eccentricity and inclination changing quasi-periodically due to solar and planetary gravitational perturbations on a timescale of centuries. The ranges of change are 0.0072–0.0076 and 0.20–0.60°, respectively.[10] These orbital variations cause the axial tilt (the angle between rotational and orbital axes) to vary between 0.4 and 1.6°.[27]
As far as energy, we have already established that it get's enough solar energy, to use reasonably sized concentrating mirrors. The tilt of the sun in the sky will be much simpler than that of the Earth and Mars, and no wind loads, and most likely not much of a cleaning burden per dust.
You could concentrate sunlight onto photovoltaic cells, or use power towers, or a hybrid.
Fission power? Maybe if the ores are found.
Fusion power? Sure, if it is ever achieved (Which I expect it will be eventually).So, Antius has built a little ocean city on Pasiphae, and I want to establish a mining process on Callisto.
On Callisto, we have a palate of materials and energy sources to work from. We can build canals, seas, and oceans on Callisto, with similar characteristics suggested for the Antius worlds.
An extra complication in this case, is your bodies of water could melt down bottomlessly, unless you purposely limited the deepness, with some insulator, lets say a thick layer of mining tailings. Probably canals are the best, so that the cold of space can seep down and under these bodies of water, and so, actually you can transport heavy things about in these canals (Covered canals).
So, if the people of Callisto exported mined materials, they would also have lots of tailings, which would include excess ice, and rock. It would get into the way, so why not shoot it to an "L" location and construct a world. An Antius ocean city world.
I don't think Venus has so much to offer. And I cant imagine the effort that would be required to crash an outer solar system object into it. Also the results would most likely unsatisfactory.
So, then if we presume automation/robots, "How many little ocean worlds could you make out of Callisto?". I am thinking it is a vast amount of living space.
What's the worst that can happen to Venus? Venus needs water, Venus needs spin, a glancing impact by a dwarf planet might spin it up. I think a similar event happened early in Earth's history with a planet the size of Mars, it ended up creating Earth's Moon. Sure it might mess up Venus's surface, but we can't live on it anyway, its too hot! Maybe it might improve the atmosphere however by adding water, and by getting ridof some of the exces carbon-dioxide. I think Venus will retain most of its mass through such an impact, though it might gain a small moon or a ring of debris as a result of it.
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Probably easier to slow Venus down to be tidally locked, and then live on it as an eye-world.
Actually the terminator on the equator only moves at a measly 8.5 mi/hr. If the atmosphere problem were solved you could probably have a biosphere with plants that have a 1-day lifecycle and animals that move with the terminator to stay in the comfortable dawn/mid-morning or twilight zones.
A bit OT for this thread, sorry.
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Yes it is a bit off topic, but perhaps it points to how dwarf planets may be easier to inhabit with benefits, than worlds which resemble Earth to a degree, but missed the boat.
Where I have the misgivings Tom, is that one of the solutions for getting rid of the Venus atmosphere to hit it with a big impactor, so that the atmosphere swells very big, and is blown away.
But if you hit it with a seriously water bearing object, the atmosphere will also likely heat up to thousands of degrees due to the increased greenhouse effect, and it will take thousands of years to cool down. And by then it will likely have shed the extra water to the solar wind. Further the process will provide an upset that makes the climate of Venus unstable, and it will have to seek some new stability.
I just don't see who gets a payday out of this. Lots of materials shed to the solar wind.
I'm not saying no, maybe you want to swell up the atmosphere of Venus, and have floating cities that much higher in the sky. Maybe then you can harvest the atmosphere for some purpose. But if you are hoping to turn Venus into an Earthly Eden, I think you are barking up the wrong tree.
Where as, sub-dwarf-planets with oceans may provide a very secure and wealthy home for humans, and perhaps much sooner, per the ideas of Antius.
And the total volume of such worlds is enormous even without creating artificial sub-dwarf-ocean-worlds.
To me it is a very attractive idea.
Last edited by Void (2016-10-15 18:05:14)
I am starting to ask seriously "Why do I do this?"
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[image] http://i.imgur.com/mV2Khfl.jpg [/image]
but with dozens of times bigger linear dimensions then on Earth.
And ice surfaces not left 'naked' but sprayed with super-insulation foam or something more sophisticated ...
Although at so little pressure it is enough to bubble up really huge pressurized air habitat structures just underneath the ice.
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Being that far out from the Sun, its rotation rate makes no difference. Since its diameter is about 2200 km and its maximum distance from the Sun is 97 AU, if we build a mirror that is 220,000 km in diameter, we can focus enough sunlight on it to give it an Earth like level of solar intensity. if you want to know how big this is, it is bigger than Jupiter. I think Eris would be a candidate for an artificial Sun, probably fusion powered. Building a mirror this big is probably a waste of time and resources.
I think we have to have separate topic on energy economics, ah?
'cause I'm pretty sure (intuitively, and exemplary) that good'ol light and gravity are by far the best energy sources and technology which we might possibly have in this universe!
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Apologies for the late reply. I've been away on a weekend break.
My reason for raising the topic was to explore a terraforming concept that could provide a large amount of habitable living space for minimum up front cost and short investment window. This is the weakness of many terraforming concepts in my opinion. Anything that requires planetary scale engineering and century long timescales is unlikely to happen, unless they happen as a byproduct of something that human beings are doing anyway. The icy world terraforming idea would require some hefty nuclear reactors to provide enough heat to melt the ice. But human colonists would tend to need those anyway and the mini-ocean world could be created on a timescale of decades rather than centuries.
For the 500km world, human habitats would float beneath the 800m thick ice sheet. Air bubbles could be used to provide giant caves, perhaps kilometres wide in which floating habitats could be sited. A problem with this idea would be sheer stresses within the ice. You are effectively building free standing roof structures under low gravity. Additional concerns would be how to limit heat fluxes into the ice, ensuring it remains far beneath freezing. Not insurmountable problems, but they may require additional engineering. And that means money and infrastructure. It all depends on the magnitude of tge stresses, heat fluxes and assumed strength of the ice.
For the 50km diameter world, I assume a world that is 50/50 ice and rock by mass. If it is melted, the result would be an ice covered ball of water, with a rocky core extending to 60% of the radius of the whole body. At the water-core boundary, pressure would be about 1 bar. So this would be the place to build non-pressurised human habitats. The really cool thing about the concept is that it can be carried out using a nuclear reactor of perhaps 5GW thermal power. Without shielding it might weigh as little as 1000 tonnes. So this is something that can be accomplished in the next century. We might even live to see it.
That much power is enough to support a civilisation of hundreds of thousands of people, even if they need to use electric power to grow their food. The limit to the habitability of the mini-world is the amount of heat that can be generated within the water mantle without melting the ice sheet floating on top. If the ice sheet gets too thin, there isn't enough pressure to prevent the water boiling into space. For a 50km body, that limits heat generation to about 5GW. This in turn limits population to a few hundred thousand, unless food can be grown outside of the world and shipped in.
Because gravity is so weak, convection in the water mantle is almost non-existent. It is therefore quite possible for habitats built on the core boundary to be warm and temperate without melting the covering ice sheet. With no differential pressure between the habitat and the water outside, the hab walls can be extremely thin. Basically, thin plastic domes with a slender frame structure maintaining their shape. With such weak gravity, any leaks will procede slowly. The city would be build under a series of tent like structures.
The closest candidate worlds would appear to be Trojan asteroids. These are close enough that they may be in reach of the ILS. This raises the prospect of building actual habitable worlds in the next century, at a price that humanity can afford.
Last edited by Antius (2016-10-16 14:07:53)
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I did a few calcs that may help or hinder the case for this type of shell world. To melt a 58km icy body would require 500GW of heat for a period of 3000 years. So in the short term, there would be no limit to habitability. The ice has enough latent heat of fusion to absorb any realistic heat load for generations. Only after 3000 years would the inhabitants need to build a covering pressure shell.
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I enjoy your work.
I am starting to ask seriously "Why do I do this?"
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