PB666

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About PB666

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    Cosmic Disentangler

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  • Location Universe's piehole
  • Interests Exopsychology, Planetary inversions, Close encounters of the 1023.5th kind.
  1. Liquid Rhenium Solar Thermal Rocket

    150000 ton was an error, I use kg in the calculations, no problem. There is also thermal loss on the engine in the form or radiation, at 5800'C you are talking about fairly intense light producer (yellow green). The way to calculate is to take your Energry transfer (1298) and the apply the efficiency from that. The correct and accepted equations is Thrust (N) = 2 * power(watts) * efficiency(%) / Ve (m/s) The ISP is mediocre for external power driven space craft. Although ION drives are critically limited in thrust, their advantage is high ISP. They are a technology in wait of a decent power supply (like a fusion power plant or matter/antimatter reactor (lol)). The technology you list is an external power plant in search of a more efficient engine. Finally, what type of material can form a nozzel that remains stable at 5800'?
  2. Risk of death is increased due to the effects of lack of gravity, exposure to radiation, the risk of being 'spaced' by micrometeor collisions or system failures, the risk of starvation, the risk of acquiring a disease that is treatable on earth but not in space, the risk of going technically blind and the consequences thereof . . . . . . . . . Space aint Oslo.
  3. Liquid Rhenium Solar Thermal Rocket

    The amount of energy derived by the sun at any given distance from the sun is 2.5E25/r2 w/m2 He would not spiral past mars. The rate of acceleration is low, 6000/1200 seconds is 5N/kg For comparison at Launch a typical rocket is producing 14 N/kg and it goes all the way to 20 N/kg at max Q.
  4. 50 km long cave discovered on moon

    You do not want a greenhouse on the surface of the moon for the reasons you say. 1. The moon has a light cycle, 15 days dark, 15 days light. 2. Plants do not light direct exposure to sunlight. 3. The moons surface temperature goes from deep space cold to several hundred degrees over the monthly cycle. The whole reason for being underground is to modulate the extremes of space on the surface. Ground = insulation from heat and cold swings. cosmic and high energy hv radiation. A place to pressurize in which the chamber itself provides resistance to biogenic atmospheric pressures. IN addition the best modern greenhouses use LED (about 4 red for 1 blue) for growth. Some apply tiny amounts of UV to control bugs. Plants don't like green light, they slow growth in green light. Instead you need a 15 day power storage system such as a H2 02 fuel cell, or lithium ion batteries.
  5. Liquid Rhenium Solar Thermal Rocket

    OK so here is the deal, lets take this by the numbers. Watts are good but ISP is mediocre, infrastructure is massive. 12km/sec is exhaust velocity, seemingly good except its much less than an ION drive and not much better than a NTR. Ion drives run from about 3500 to a practical 10,000. Lets say half the rocket is fuel. from this we have dV=12000*ln(Sm/fm) in this case 12000 ln2 = 8317 m/s. Second problem, like all solar driven ION drives this drives performance drops with distance from sun. Third problem, you see the poles, the also have to be accelerated, but those poles are not secured, as you apply thrust they move and are less efficient. Forth, 20 minute burn time from earth, yeah . . . .right. For a 150000 ton system and 12000 m/s ev. Lets see launch to mars in 20 minutes needing 7000 dv. That translates into 5.8333N/kg 5.83333N * 125000 average load needs a thrust around 700,000 Newtons. So in essence solar power generates maximum 1350 Watts per meter squared. Next the Power transferance rate is = 2 * watts *efficiency/EV so to get 700,000 N you need 700,000 x 12000 / (2 * efficiency = 1.6) = 5250000 Kilowatts requiring 3,888,888 meters of solar collector. Since most of the world plays soccer you might know that a soccer (futbol) pitch is minimally 6400 square meters. So that the area covered by the panels would be equal to 607,000 soccer pitches. To create these semispherical collectors you need a rigid mess and a reflective material. lets say the plastic is a thin 5 mil, about 0.00013 meter thickness. Assuming the plastic has a density of 1.2 (adding some density for metalic reflectant) the mass per meter would be about 0.153 kg per sq. meter. So that doing 595,000 kg (not 50,000 as the authors suggest). 5 mil is a good choice because of the forces involved in traveling in LEO, where there is significant heat from drag and at least some drag forces. The authors have chosen 5 um mylar sheets. The problem is that this sheeting is about 1/5th of a mil which is several fold thinner than the cheapest painters plaster (something like 3 mil). We havent even gotten to the rigid infrastructure to hold the plastic. On top of this 600,000 soccer pitches, thats a hell of alot of hv pressure to deal with, combine that with LEO to MEO drag and you have a wonderful application of murphy's law, Everything that can go wrong did go wrong. I could imagine this craft positioning itself getting hit by the sun slowing down orbit decaying, drag sets in, sheets melt the space craft spinning uncontrollably as it hits earths atmosphere burning up 100,000 kgs of payload streaking through the sky.
  6. They all take off their clothes and tell everyone back home they skinny dipped with venusian women.
  7. No species is moving itself faster from global domination to extinction than ours. Of course we still do not know what cause snowball earth. One has to remember that Lystrosaurus represented a higher percentage of vertebrate fossils following the Permian-Triassic extinction event, within 10 million years neither they or their descendants have been observed. In finance, past performance is no indication of future success.
  8. We've been through that, the problem is that the amount of fuel required to launch the craft into a L1 orbit and block just a few percent of the suns light exceeds the benefit. To be able to do this would mean the wholesale redirection of asteroids into an L1 orbit (not only risky but hard to do) and ISRU conversion of aluminum, nickle and silicon (not the preferential materials for a blocking agent) into a solar screen. It may be possible, trapping carbon would probably be easier. Another strategy that may have longer term benefits is to use induction to move the orbit of mars and earth further out and away from the sun. The problem with this right now is some parts of the world that are in deepest trouble rely on insolance levels (pan-evaporation rates) as the energy source that drives precipitation inland. If by either means sunlight falls, East Africa could go into a deep prolonged drought killing 10s of millions of people. The best solution is to educate the worlds most vulnerable populations that their behaviors (environmental exploitation) effect them and their neighbors, and their neighbors actions likewise. If we can get a country like china to markedly decrease coal utilization and India to reduce the burning of firewood for cooking and heating, to stop burning of forest in Indochina, Oceania and Latin America as a means of generating cropland then there is some flexibility in the technique used to cool the Earth.
  9. Remediating climate change and Atmospheric carbon reduction are two separate issues. To give an example, to remediate ocean acidification in sensitive fisheries one can take limestone, heat it until it decomposes into calcuim oxide, dropwise add it to distilled water until saturated, mix this with dehydrated salt water and distribute it into the currents that feed the fisheries. That may fix the fisheries but it also adds CO2. There are many similar issues such as widening waterways, national and continental water plans that deal with extreme drought and rainfall events. All of these things require energy and technology that require CO2. Yes you can use Solar panels to move water, but how do you move water close to the coast in a 1:500 year rain event that are now happening every 20 years, given that the infrastructure and power reserves required will not be used but once every 20 years. Carbon Dioxide is very abundant in the ocean, Carbonates are major buffers in sea-water. It is easy enough to take NaCl and split it into Sodium and Chloride. Acidify the sea-water and heat it and CO2 will come out, add the NaOH back to it and you will have sodium rich sea water. The problem is what to do with the CO2 once you have it. No-one really takes carbon capture seriously because no-one as yet is talking about carbon dioxide polymerization. About the cheapest carbon polymer that can be made is formalin, and it requires the addition of two CH bonds, its easily contaminates ground water and is toxic.. In terms of Carboniferous-like tree production, it has to be remembered that tree growth (if you can call them trees) in the early terrestrial ecosystems was very rapid compared to today. That is the problem with lignite coal burning, much of the trees are bark that was contaminated with all kinds of heavy metals. Trees could grow more densely than at present make coal formation much easier. The more rapid alternative is microbial oil synthesis (biofuels) the problem is that the most prosperous that dont require CO2 producing fertilizers undergo nitrogen fixation, the cells of cyanobacterium that fix nitrogen are extremely toxic to most eucaryotes, and so this cannot be done in the oceans and require land use that could otherwise be devoted to other tasks. So before you come up with a strategy for greening the oceans for carbon capture, you first need a way of nutrient priming oil producing microbes that is also carbon neutral on the front side. This is the problem. I should make the point here that its about 10 times easier to conserve fossil fuels than remediate their damage after your burn them. If someone can come up with an efficient means of Hydrogen production (at least half is wasted in production of oxygen, something that is already abundant) then addition of hydrogen to coal emulsification plants or as a cracking agent in coal-tar sands effectively reduces the carbon footprint per btu in half. This is easy, but adding hydrogen to CO2 is significantly harder because of the stability of C=O bond versus C=C bond. A significantly higher amount of energy would be required to crack and hydrate CO bonds to form formic acid which can then be further reduced to methanol. Chain elongation is more difficult but doable. The minimum ground stable carbon polymers are C20 and longer. These steps are on the order of 'beware of the unintended consequences'. The best choice on a planet of 7 billion people is to nudge people to conserve energy ever-harder each year: about deforestation, unneccesary pastoralism, inefficient and carbon-hungry agriculture, power production/transmission inefficiencies and fertility rates. Trying to remove carbon in the current environment will only make the matter worse, the people who are removing the carbon will attempt to exact the costs out of people generating carbon which could lead to war. Get those across-the-board usages downward trending first. With regard to population size one has to remember that most of the worlds population lives within 500 feet of sea-level, so if decadal-intensity cyclones increase in frequency and people are moved out of the highest production areas (such as what has happened in burma) then population will fall anyway. The predictions in the mid-90s that moved the discussion from global warming to climate changes suggest that large areas of dense human habitation were at danger for increased intensity flooding and droughts. If people are squeezed from these areas to lower production areas then there will be wars (such as what is happening along the Burmese and Bangladeshi border) and the population will fall. The US department of defense has already accepted this as something that will happen, and almost all countries have signed the Paris accord so at least in words people deem this is important. In terms of the original post. dryland grasses increase ground water; the grass roots increase the penetration of rainwater deep into the soil and in drought grass die or rely on dormant root systems for seasonal growth. Overgrazing of semi-arid land encourages grass decline and the growth of non-edible trees (such as mexican red cedar in the southwest). This then blocks the absorption of ground water. Native americans knew the value of this and burned grasslands periodically to kill the trees. Cattle brought both mesquite and cedar from Mexico and this has increased the runoff and inhibit the penetration of water into agriculturally benefical aquifers. Africa's deserts may be making a comeback for other reasons. Of course it is smarter to control grazing and replace pastoral-derived intake with agricultural products. Management strategies may fail before they begin because of social instability, some of which has been created by climate change. There are many leading issues with regard to proper land management including composing versus chaff burning, disuse of firewood, recycling human waste and animal waste for methane production, regrading soil to trap water, restoring underground water reserves, etc. Any of these can increase carbon retention. These are all fine but who is going to northern Nigeria and Niger to teach locals how to do these things, war is all the easier way to control population overgrowth. It is, afterall, the outsiders that made matters worse to begin with.
  10. And who exactly is going to build and test the floating venutian ship. The trip to Venus exposes the crew to more radiation than ISS, the earths magnetic field takes about half of the radiation and travelers to venus on average would be exposed to 3 times as much radiation. As a consequence to get to Venus they would have to be able to do so in about 4 earth months. In addition Venus has no magnetic field like earth, it has no moons. There is no protection when astronauts get there. Colonies on mars are doable, just incredibly expensive and suicidal (that is the risk of death each year increases 10 fold that of earth). Reaching the venutian cloud level is simply insane.
  11. 50 km long cave discovered on moon

    you don have to fill the whole cave, just block off sections. Find or make a smaller lava hole. Build a air tight wall on both sides of the lava hole; this will require circumcising the tub until solid rock is reached. The each wall will be connected by a submarine door (or two). Fill the lava hole with moon dust, packing the dust as it fills, as it fills there are empty gas bags distributed at even intervals the bags will be laid out vertically hanging circles and connected to a pressurization system, rigid enough to withstand a couple of atmospheres of pressure. in areas with gaps between circular bags chains would connect the two walls with force sensors on the chains. Once the dust is compacted the lava tube/manhole is capped. As the the most distal chamber is inflated the pressure in the bags is increased so that the balance of pressure on both sides of the wall is the same. This could be done simulataneously at many spots to create a pressure gradient. BTW the material that comprises the lava tube walls is expected to be toxic to humans since the tubes have crumbly material it would need to be dressed. Thus there would need to be a way to coat the walls with an oxygen resistant material. Likewise sealing the walls to the pressure walls. Most of the cements used on earth would not stand up to the vacuum of space, so pressurization with nitrogen during application may be needed.
  12. Polar Orbits

    Magnetic North moves. Also A polar orbit passes over the both magnetic poles. A 100 minute polar orbit passes to within a few kilometers every twenty four hours. The Earth rotates under the orbit. There are 14.4 orbits a day however radiating 28.8 orbits per day at each pole. The Geomagnetic north poles is at 86.5 degrees. A degree at the equator is 60 nautical miles or 110,600 meters. The cosine of 85.6 is 0.0610. 110,600 Cos 85.6 = 6,746 meters. If a satellite cross from equator to NP or vice versa each orbit, and the number of orbits a day is not an even whole number then it creates ~ 29 areas everyday. 360/29 on average differing by 12.413 degrees however its closest proximity on either side are 6.206 degrees which is means the satellited passes within 41 kilometers of the north or south pole every day. Within a week it will pass within 5 kilometer. The magnetic pole of the earth has been moving 35 kilometer each year in a western direction. This means it moves 0.673 km per week. Thus a magnetical polar orbit would in about 2 months, obviate any need to have a magnetic polar orbit. In addition since the satellite would hold magnetic north the longest if the equatorial path was set to 86.5, and south magentic pole is less than 86.5 degrees, then it would be and not 90 degrees, the more intelligent magnetic pole crossing spacecraft would simply have an inclination of 86.5' allowing clustered mulitple north crossings per day and a few close crossings of the south pole.
  13. My guess that at 0.5 c that 150,000 km per second taking 4.5 seconds to reach the opposite side, the suns density is low. It would create a shock on the opposite side ejecting a large amount of plasma into solar orbit and possibly picked up by venus and earth. It might have a cooling effect on venus. Why do you need to collide our sun when you have nice neutron stars you can watch merge.
  14. 50 km long cave discovered on moon

    Yes, yet another bit of scenary for Jeb to fall though and get stuck in.or go poof. There are martians hiding inside the caves waiting to ambush venutian women. Mars needs women!!!!!! It goes without saying that the nation that plants a flag up on these caves will have a advantage in colonization of the moon. At least on problem just disappeared, what to do about space radiation.
  15. Well given that forum members want other forum members to volunteer to be part of the ultimate fix, I would say its now officially in verboten land.