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#1 Re: Science, Technology, and Astronomy » Oxygen bottleneck and fire ignition » 2024-09-15 16:18:13
Here is a list of devices using for heating
1) the black-stones owen, used only in the daylite emisphere, powered by black stones heated by the sun
2) the rolling-stones owen, used mainly in the night emisphere, powered by stones heated by friction in a spinning barrel conntected to a water or wind mill
3) the oil friction owen is a more mature evolution of the lattter: the owen is heated by the refrigerating oil of the gears of a wind or a water mill.
4) the solar owen, power by concave mirrors: the older mirrors were made by cold hammering native copper, the more modern ones were cast in speculum metal (70% copper 30%tin). These are the only kind of owens which can smelt copper and tin to make bronze, creating tension between the well-developed People of the Light and the more primitive People of the Night, who cannot smelt metals and can only relie on imports...
I' have found a very interresting experimental work by a NASA team about combustion in different kind of atmospheres: they have found that under 41 kPa of total pressure combustion depends on oxygen partial pressure, but over 41 kPa (about 0.4 atm) combustion is independent of oxygen partial pressure and depends only on oxygen volume%. So the limit of 17% of oxygen, uder which combustion is impossible for many kind of materials is independent of the gas total pressure. To expain the results, the authors hypotize that, over 41 kPa, there is a change of combustion modality and the dominant phenomenon becomes the competition for the surface sites of the samples between the O2 and the buffer gas molecules.
https://ntrs.nasa.gov/citations/20160001047
After reading this work, I create the atmpshpere of my planet Caelen: 1.47 atm of sea level pressure with 13.6% O2, 84.8% N2, 1.2% Ar, 0.4% others. This atmoshere is normoxic, because the oxygen partial pressure is about 0.2 atm, like on our Earth, and a human can breathe without any problem, but the 13.6 volume% of oxygen makes combustion impossible.
#2 Re: Science, Technology, and Astronomy » Oxygen bottleneck and fire ignition » 2024-09-13 04:51:50
Quaoar you work is as (th) has said very interesting.
I have been thinking about other precursors for technology which could exist without fire.
Windmills, watermills. Friction on wooden bearings might get hot. I have wondered if bellows might allow for some type of fire. I understand that normal fires are not to be expected on such a world. In truth they might wet down a hot spot, but maybe they might use air cooling as the atmosphere is so thick.
Perhaps they might have an air blower for some other purpose, such as air circulation in a habitat? Bellows?
https://blacksmithu.com/function-purpos … cts%20from.Ending Pending
They make large use of wind mills and friction-based owens, very used in the obscure emishere, where is impossible to use the solar light. The more simple of them is the rolling-stones owen, powered by very hot stones, which are heated in a rolling barrel connected to a wind or water mill. A more evolute owen is the oil friction owen connected to the oil refrigerating circuit of the bronze gears of a mill: the hot oil exits from the bronze gear barrel, enters in a create or stone owen, heating it, then it enters in the cooilng radiators, which my be also used to heat a house, and comes back into the gear barrel
Quaoar you work is as (th) has said very interesting.
Lightning Strikes might produce glowing embers if not then a fire.
They might find loadstones the fragments which might attract each other.
An Electric Eel like organism with electric shock defense, might puzzle them. So, might help them to eventually gain a notion of electricity.
I am just looking for what technological stimulations they might have.
Ending Pending
Do you know that in Roman Empire torpedo-fish where raised and used for electroshock terapy of some kind of mental disease?
Quaoar you work is as (th) has said very interesting.
But your point is rather good for the question of technological aliens. Caves have been found where animals live on 10% Oxygen or so. So, indeed there could be animals, but no fire.
As I said, I like your work.
I see that for our atmospheric pressure about 16% is needed for fire. But I observe that bellows can make a fire grow hotter. Maybe also for your higher-pressure world? Or maybe the air flow cools things too much.
My hope is that they might discover electricity and Oxygen somewhere along the line, perhaps after making metals with your Copper mirrors. If they had Copper they could have wires, if they had Loadstones, they might use motion from a windmill or watermill to generate electricity, perhaps as a sort of magical thing at first to impress others.
If they had lightning to observe, and a friction method to generate electrostatic sparks, perhaps this might be an early path to discover electricity. They might discover compasses, as an early machine.
People who could do such things might be magicians to others. They could not be burned at the stake however.
Ending Pending
My Planet has a sea level pressure of 1.31 atm. with 11% of O2 and 88% of N2, so the pO2 is 14.4%, almost the same of Leadville Colorado. So there is no problem in breathing, but, according to the article, it was impossible to ignite a fire before the invention of zeolite oxygen concentrators.
Electricity is not used in my novel: Ganryas have a modern math, know well newtonian physic and are very good hydraulic and mechanical engineer, almost like on the Earth in 1800, but they have only empiric notions about chemestry. They know that matter is composed by atoms, but ignore how the atoms are made and how they react. They empirically use some solution to give a beautiful patna to bronze and billon manufacts, they also know galvanic corrosion and empirically know how to protect bimetallic object with zinc anods, but they never develpe battery and electric engines
#3 Re: Science, Technology, and Astronomy » Oxygen bottleneck and fire ignition » 2024-09-11 16:18:24
Oxygen depletion systems reduce the proportion of oxygen in the air to the point where flaming combustion is impossible under standard conditions. Fires self-extinguish. This is because nitrogen in the air absorbs too much heat to allow self-propagating gas phase combustion. However, this does not completely exclude the possibility of combustion, in well insulated masses containing finely divided fuel. But it would make the reduction of iron difficult to achieve without an external heat source. It would be a bottle neck for a developing civilisation in much the same way that an aquatic civilisation would struggle to develop refined metals. Likely this is yet another factor in the Drake equation.
My aliens have expeienced a longer age of copper, where native copper cold hammered manufacts were used along stone-made manufacts. Then they learned how to make concave mirrors, by cold hammering copper plates on stone-made concave molds, and they used gigantic concave mirrors to make solar ovens where they smelt copper and tin to make bronze
#4 Re: Science, Technology, and Astronomy » Oxygen bottleneck and fire ignition » 2024-09-10 13:07:44
Quaoar,
What is the "Vesper Empire"? "Mu aliens"?
Are we actually talking about a metal alloy dating back to antiquity?
Mu aliens is a typo: I would have write "my aliens". Thanks I haven't noticed it.
Versper Empire is the big empire of Ganrya People, extended over all the tempered zone of the terminator, which is called "the Lands of Vesper". It is ruled by an Emperor who lives in the capital city of Akanti in the soutern cost of the subcontinent of Eldra. The other parts of the empire is divided in eight provinces, ruled by an hereditary governor called "the Exarch". The province of Akota is ruled by a vassal king, descending by a king who let his kingdom be annexed peacefully to avoid an unwinnable war.
The Ganrya are blue, green, gold or red scaled antropomorphic aquatic reptiloid, who deploy eggs in water and conserve the radial simmerty of their ikampa (fish-like radial symetric aquatic vertebrates) ancestor during the larval stage. They have legs with long fins ending with clawed forefeet, on which they walks on lands. They can swim very fast like dophins and stayng uderwater for hours, after switching from hot blood to cold blood.
The Ganryas are not the only intelligent specie: thare are also the Kunryas similar to the Ganryas but bigger, the Wanryas, who are winged; the Onryas, gigantic land-fish-like creatures with an interrupted penta-radial symmertry body plan, with a unic powerful leg, four arms, four tails, four eyes and five jaws, whose body is armored with pyrite-covered scales; and the Kremya, perfect exa-radial simmetric creature who sems a six lobed 3 meter-wide pumpkin, with three powerfull legs, three elephant trunck-like noses with hydraulic prensile hands, three leaf-like radiator-ears and a central mouth with six tongues, which sims a sea anemon: they walk on three legs and run on two, jumping like a kangaroo.
#5 Re: Science, Technology, and Astronomy » Oxygen bottleneck and fire ignition » 2024-09-10 04:43:11
Quaoar,
What is the "Vesper Empire"? "Mu aliens"?
Are we actually talking about a metal alloy dating back to antiquity?
My planet is called Caelen and has two big continents: Maku, a super-continent centered at the anti-stellar pole in "the Lands of Eternal Night", is connected with seven subcontinents (Eldra, Taplya, Akota, Nurenya, Galnak, Klyvia and Syrtia) well extended beyond in the terminator zone (the "Land of Vesper") in the enlighted emisphere (the Land of Eternal Light).
Centered at the substellar pole, there is a continet with almost the size of Australia called Velu.
Between Maku and Velu there is a circular ocean called "the Sea of Light". The dominant acquatic group of animal are the "ikampas", cassified by human exobiologist as polichordata: fish like vertebrates but with a radial simmetric body like our starfishes and sea urchins (some of them belonging to the philum of pentaradiata has developed a bilateral symmetry: they comes out to the eggs as a larve with a five lobes cephalotorax, with five eyes, a five-jawed mouth and five tails, then two cylomers melt together and expand, while the other three regress and desappear, giving a creature with two eyes, two jaws and one tail).
Unlike the Earth where terrestrial vertebrate is a monophiletic group originated from sarcopterygian fishes, on Caelen the coloization of the lands had happened in different ages in different continents, by different kind of ikampa so we have four group of vertebrate: monopods, tripods, exaposaurs and octapodes.
1) Monopodes: have irregular penta-radial symmetry, where the tail of the ventral cyclomer has become a five fingered very powerfull leg used for jumping. The other cyclomers has conserved the tails and has developed four arts from fins. The five-lobed neck is usually quite long and has a big inferior jaw and four superior jaws. There are four superior eyes and one inferior thermal ocello. In this group there is also an intelligent specie, the colossal Onrya, with a mass of about a metric ton, who can vocalize by vibrating the whiskers near the jaws. They have patriarchal families with a male and many females and lives in tribes in the remote tundra near the anti-stellar icecap of Maku, but most of them migrate in the Lands of Vesper, serving the Empire as mercenaries...
To be continued
#6 Re: Science, Technology, and Astronomy » Oxygen bottleneck and fire ignition » 2024-09-09 16:53:47
Quaoar,
That's beyond the tensile strength of most low-alloy Carbon steels which are not too brittle to use as armor or tools, which explains why it took so long for the Iron Age to come about. They must have known about annealing and heat treatment from working with Bronze. Maybe they couldn't achieve the temperatures required without a blast furnace, though. What was the hardness of that Bronze alloy?
The alloy Cu 87.5% Sn 10%, Zn 2% Fe 1.5% is very strong because iron form nanoparticles that act as grain rafiner: it has a URS of 483 MPa after casting which can reach 630 MPa with proper heat and mechanical treatement.
For heat treatement my aliens use the same solar furnaces used for smelting metals, powered by with concave mirrors: early mirrors were made by cold hammering native copper plates in concave stone molds. Later they learned to produce the classic speculum alloy (Cu 70% Sn 30%), and cast it molds with parabolic curve surfaces. The mirror is then polished to eliminate imperfections.
With the alloy Cu 87.5% Sn 10%, Zn 2% Fe 1.5%, which in the novel is called superbronze (it's recipe is a military secret of the Vesper Empire) my aliens can craft very strong swords. A superbronze sword with the same dimentions and the same toughness of a medieval steel sword weights almost 1.5 times more, and that's OK for my aliens who are bigger and stronger than men. I've also designed the shape and the dimensions of the swords and also the fighting technique, which is quite similar to the European medieval fancing with sword and buckler.
#7 Re: Science, Technology, and Astronomy » Oxygen bottleneck and fire ignition » 2024-09-09 15:07:53
For Quaoar re planet with air below ignition threshold ....
(Noting the comments of GW Johnson in post #14)
The scenario offered by the authors of the paper you cited presumes that fire will not sustain itself even if it is started by lightning. and lightning will surely happen on that planet, although the physics of that deserve their own study for your novel(s).
However, I have a ray of hope to offer your clever residents in this heavily vegetized situation....
On Earth, early experimenters with fire noted that blowing on embers would provide more oxygen to the nascent fire, and that led to the formal appliance of bellows. There are records from early days, of "home made" bellows operated by slaves to melt metal.
Thus, I am hopeful that the residents of your novel will be smart enough to figure out that they can achieve higher temperatures and sustained combustion by increasing the amount of oxygen available. Somewhere along the line these intrepid experimenters may figure out that their air consists of more than one gas, and this may lead to separation of the oxygen from the non-reactive elements.
At that point, civilization as we know it should be possible.
However, this scenario ** does ** imply multiple Einsteins building upon each other's work.
I still wonder how that burgeoning vegetation would fail to deliver enough oxygen to drive the percentage into the ignitable range.
****
GW Johnson seems to be talking about the opposite side of the O2/gas balance. As I understand his argument, in a human habitat away from Earth, it appears to be desirable to maintain the O2/gas ration at a magic number between where people can breathe comfortably, and where fire can consume the interior of the habitat. Something like that could have been tested on the ISS, had there been anyone interested in knowing the correct answer to the question. The policy to maintain an earth "normal" atmosphere at the ISS certainly is understandable for a variety of reasons, but I don't think that policy has served the human race as well as a more forward looking policy would have done.Both RobertDyck and GW Johnson seem to be on the right track, although the two gents appear to differ on minor details.
I am advocating the 3-5-8 policy because it is close to both the two proposals, and what is far more important, it is easy for anyone to remember, and to understand.
Therefore, I would like to see a scientific evaluation of the 3-5-8 policy as soon as possible.
(th)
The star is a red dwarf with a tidally locked super-earth of 1.79 Earth Masses, 1.17 earth radii, a surface gravity of 1.3 g and an orbital period of 5.57 days. Half part of the planet in perpetual day, and half is in perpetual night (and that might be an excuse for the low oxygen %, given also that a red dwarf star emits most of its light in infrared band, so photosynthesis is less efficient). Another possible mechanism for lowering atmospheric oxygen might be the star flares: both the planet and the parent star have strong magnetic fields, so during the coronal mass expulsions, the star protons are emitted mostly perpendiculary to the orbital plane, protecting the planet from atmospheric stripping, but, due to the planet strong magnetic field, a quote of this protons are redirected to the polar regions, where they react with atmospheric oxygen, forming water, which precipitate as snow (a phenomenon that the locals call "snowing aurora"), lowering the oxygen in the atmosphere.
#8 Re: Science, Technology, and Astronomy » Oxygen bottleneck and fire ignition » 2024-09-09 02:55:24
For Quaoar .... it should be possible to test the question on Earth.
If you can find a container able to hold 3 bar (and there are many that can go far beyond that), then you might be able to set up an experiment by providing a way to test ignition inside the tank when nitrogen is added until pressure is 3 bar.
If the apparatus is supported by video equipment, you can attempt ignition and record the results.
This forum spends 99.9999% of it's time theorizing.
Do you have a friend or a friendly organization available to assist with the test?
(th)
Nice suggestion! The best simulation of reality is reality itself.
We need a closed vessel with a manometer and two ciliners filled of pressurized N2 and O2: first we open the N2 vessel, rising the total pressure to 2.96 atm, then we open the O2 vessel, rising the total pressure to 3 atm. In this way we obtain a 3 bar atmosphere with 7% of oxygen: that's simple and when I was a student I have worked for some period in a respiratory phisiology lab, so I've some training in using such kind of devices, even if 38 years have passed.
But how to ignite a fire in a closed vessel?
We have to buy some kind of remote controlled lighter used for safely ingite fireworks...
something like this
https://it.aliexpress.com/item/10050068 … pt=glo2ita
The vessel needs a very strong thight glass window, to control if the lighter is ignited or not... or, more simply, just an about 5$ fire sensor.
With such a quite simple device, we can simulate and test many kind of exoplanet atmposheres with different O2/N2 ratios... and even publish a paper of astrobiology.
#9 Re: Science, Technology, and Astronomy » Oxygen bottleneck and fire ignition » 2024-09-08 17:19:45
The mechanisms underlying breathing and combustion are different. Breathing depends upon the partial pressure of oxygen in the air being a bit greater than the partial pressure of oxygen in the blood. It is the difference in partial pressures across the lung membranes that drives movement of oxygen into the blood. And this gets complicated by the diluting effect of water vapor and carbon dioxide that lowers the partial pressure of the oxygen in the air that is actually inside the lungs.
Combustion is driven by a different mechanism, related, but not the same. Using the simple Arrhenius model of an overall chemical reaction rate, that rate is driven by a constant often multiplied by density to a power, multiplied by reactant concentrations raised to appropriate exponents, multiplied by an exponential in the temperature at which the reaction is proceeding. Reactants include the oxygen, the fuel, and often the water vapor produced (but not always). The sum of the exponents is usually pretty close to 2. If you use mass concentrations instead of volume concentrations, there is no density-to-a-power factor, and the value of the reaction rate constant is different.
The concentrations are related to volume percentages in the atmosphere, but they are not the same thing! They are closer to the partial pressures, but there is also a total pressure involved. I usually use mass per unit mass of atmosphere (mass concentration) instead of mass per unit volume of atmosphere (volume concentration), which gets rid of the density-to-a-power term out front with the reaction rate constant. If water does not figure into it, the exponents on the fuel and oxygen concentrations are usually pretty close to 1 on each factor.
Combustion proceeds at Earthly rates when the reaction rate predicted by the Arrhenius equation is the same. Breathing is the same when the partial pressure differences are the same.
Sorry, it's just complicated.
However, these things are exactly what I took into account, when I recommended hab and suit atmospheres. I checked fire danger as well as breathing. And also pre-breathe elimination for oxygen suits.
GW
Thanks GW, so simulating with Arrhenius equation, can we ignite a fire in 7% O2 and 3 atm or not?
#10 Re: Science, Technology, and Astronomy » Oxygen bottleneck and fire ignition » 2024-09-08 17:08:24
For Quaoar re interesting topic ...
After reading (most of) the paper you cited, I came away thinking you have the potential for a ** very ** interesting novel, if you take the words of the paper to heart.
The authors spell out very clearly the fascinating environment that would exist on your hypothetical planet with 17% oxygen. There would be no forest fires, so vegetation would be abundant. The mystery then would be why the oxygen stays below 18%, since it appears that on Earth vegetation produced so much oxygen that fires counsumed everything over about 21%. In other words, assuming the authors are on solid footing, the Earth may have achieved a natural balance, in which excess oxygen is consumed by wild fires. I'm led to wonder if the natural consequence of global warming is to reduce the amount of oxygen we humans enjoy, due to the greater abundance of fires.
In any case, your hypothetical planet would not have that problem.
However, your (hypothetical) Einstein would not be denied the benefit of fire just because the atmosphere does not sustain an open fire. The authors explain (as you will have noted) that oxygen can be supplied by the material itself.
On Earth, my guess is that lightning caused the fires that inspired our cave Einstein to imagine being able to use fire if he could create it himself.
Volcano eruptions are another possible source of inspiration, and indeed, your hypothetical planet might have those.
(th)
On the Earth, the age of copper, also known as "chalcolithic" was a very short period between the stone age and the bronze age, because men learned very soon how to smelt copper and tin and alloyed them in bronze. In our planet the age of copper lasted for millennials: native copper was more abundant (I guess) due to less oxidative atmosphere, and our intelligent aliens learned how to shape it by cold hammering, making axes, short daggers and pottery.
They also learn how to use water and wind energy making water and wind mills: for cooking food, they invented the rollig-stone owen: where stones were rolled in a spinning barrel powered by a wind or water mill, where they are heated by drag colliding each other. Then the hot stones are put in a crete or stone owen and utilized for cooking food.
The use of such complicated device for a simple thing like cooking, needs necessary a collective kitchen for all the villagers, leading to a very cohese society with strong bonds.
#11 Re: Science, Technology, and Astronomy » Oxygen bottleneck and fire ignition » 2024-09-08 16:58:47
Thanks to all for helping: I'm not sure it's only a question of O2 partial pressure and O2/N2 ratio doesn't matter, like Chat GPT said: on our Earth, on a mountain at 5000 meters of height there's almost 0.5 atm of total pressure with almost the same O2/N2 ratio, so the O2 partial pressure is almost halved to 0.105 atm, but I can still igite a fire, so the O2/N2 ratio seems me to matter in some way.
In a plantet of 3 atm with only 7% of O2 and 92% of N2, with a very low O2/N2 ratio, the probability of a carbon or hydrogen atom of wood to interact with a molecule of O2 is lower than on Earth, despite the same O2 partial pressure, due to the presence of high level of buffer gas N2, which competes with O2 to interact with wood atoms inhibiting combustion.
If the O2 is 21% the probability of a O2 molecules to encounter a wood atom in a unit of time is 21% and there are 79% probability that our wood atom encounter a non reactive molecules of buffer gas
If O2 is 7%, even if the partial pressure is the same, the probability of a O2 molecules to encounter a wood atom in a unit of time is still 7% and there is a 93% of probability that our wood atom encounter a non reactive molecule of buffer gas.
Is this model correct?
#12 Re: Science, Technology, and Astronomy » Oxygen bottleneck and fire ignition » 2024-09-08 06:04:58
This post is reserved for an index to posts that may be contributed by NewMars members over time.
Best wishes to Quaoar for success with this very interesting topic!
I've read a lot of science fiction, but none of all those authors has considered this scenario, and I'm looking forward to seeing how you and the NewMars members develop the concept. Since you are a science fiction writer this should be a starting point for an entire series of books, if you still have the energy it takes!
(th)
That's exactly the topic of my new novel: a story set in an exoplanet with no fire. And I'm loking for setting the correct atmosphere of this planet. So is vital for me to understand if it's a problem of O2/N2 ratio or of O2 partial pressure
Thanks for the attention
#13 Science, Technology, and Astronomy » Oxygen bottleneck and fire ignition » 2024-09-08 02:46:13
- Quaoar
- Replies: 29
Hi to all!
Since time immemorial, humans are dealing with fire, but I've read a very interesting article, about hypotethical exoplanet atmospheres, where is still possible to breath and have intelligent living beings, but the oxygen percent is too low to ignite and sustain a fire in open air, with all tecnological implication in developing metal working thechnology.
When oxygen percent is lower than about 17%, it's impossible to ignite a fire and hypotethical intelligent aliens could still craft manufat in native copper (which might be more abundant in a less oxidative environment) by cold hammering, but could never smelt copper and tin to make bronze.
https://arxiv.org/abs/2308.01160
That's the article: what I've not understand is if it's a pure question of oxygen partial pressure or it's a question of oxygen/buffer gas ratio.
For example, if I've an exoplanet with a denser atmosphere with a sea level pressure of 3 atm, 82% of nitrogen and 7% of oxygen (where a human can still breath because oxygen has the same partial pressure of Earth) can I ignite a fire?
I would be grateful if somone can help me to solve this issue.
#14 Re: Human missions » Starship is Go... » 2024-03-16 07:23:51
Quaoar post1750: I honestly don't know for sure, but they've had tiles coming off even in the final suborbital flight tests with Starship alone. It's a recurring problem. All I know is I saw off-attitude effects in the plasma sheath, then lots of tiles coming off, then loss of signal. I just speculated that tile loss led to loss of the forward starboard flap, leading to a tumble and immediate breakup.
GW
Thanks GW,
but just a little question: as I've understood seeing the video, they firstly trasferred the propellant from the header tanks to the main tanks and then they performed the deorbit burn. So, when the Starship reeenters, she has all the landing propellant (which is about 20-25 metric tons) in the main tanks, where it has a lot of empty space to move, changing the attitude of the ship (as a sailboat skipper I know how roll and pitch can become nasty when there is a lot of water inside the hull). So why not to direct connect the header tanks to the rockets and keep all the propellant inside the header tanks during the reentery?
#15 Re: Human missions » Starship is Go... » 2024-03-15 12:48:25
Some miscellaneous observations regarding what I saw in the video SpaceX posted on its website:
1. I saw normal-looking and some abnormal-looking views of the glowing plasma as re-entry began. Bear in mind that the video ended before peak heating, and so well before peak deceleration gee, so the speed throughout the video was nearly orbital: something in the 7-8 km/s range. The most striking abnormal view was a sort of radial "flaring" of orange streamers, looking aft alongside the vehicle. I suggest that for those seconds, that was evidence of flying tail-first directly into the wind. There were some other abnormal-looking views, suggesting improper directions of flow. Remember, it is supposed to enter belly-first at 60-degree angle of attack. Nothing else is survivable. Therefore, I have to ask whether the ship lost attitude control and tumbled, before it broke up.
2. I did see many hexagonal dark objects departing over several seconds of video, which I took to be heat shield tiles coming from forward out of the camera view. That alone would have led to burnt-throughs which would have caused a breakup. That failure mode does not require a loss-of-control tumble, although such will occur during the actual breakup, which would have occurred after loss of signal, because of the plasma being opaque to radio. However in hindsight, I think we actually saw evidence of both tile loss and loss of attitude control, almost but not exactly simultaneously.
3. I have to wonder if one of the forward flaps departed from the vehicle because of tile loss burn-throughs at or near its mounting. Based on the narration, the camera was mounted on one of the forward flaps. As it moved, the camera view moved, in a deceiving manner. You have to allow for that, watching. But such an event (loss of one forward flap leading to end-over-end and rolling tumbling) may well have occurred. It would have been the one the camera was not riding on, and we would not have seen it depart in the camera view, with the vehicle body obstructing that view. Such a loss would have imparted overwhelming pitch and roll disturbances, which I think we saw in the abnormal-looking plasma flow directions.
4. A guess: entry was normal until tiles were lost near the forward flap attachment, on the side opposite the camera, leading to its departure from the airframe, and a complex tumble in both pitch and roll, leading to the abnormal-looking plasma flow directions right before signal was lost. Such caused breakup of the vehicle, only seconds after the signal was lost, and entering peak heating.
4. I would suggest to SpaceX that they fly some entry articles on their Falcon Starlink launches. These would be for a whole lot more testing of ways and means to retain tiles better, between the actual Starship/Superheavy flights. Tile loss really is the long pole in their tent! They can always add thruster forces to aid the flaps for better attitude control during the hypersonics. Shuttle did. It works.
I know there are SpaceX people that read these forums. I hope the recognize likely-good advice when they see it, and not fall prey to "not invented here" thinking.
GW
Hi, GW,
So the main issue is about fixing the tails to the fuselage and to the flaps?
#16 Re: Not So Free Chat » AI dominated society » 2023-03-13 09:35:46
The AI brain doesn't need to be in the android body. Another difference to organics. The intelligent robot may be an avatar. This allows the synthetic brain to be physically larger, as it can sit in a building and never move. From what Terraformer says, that will probably be a neccesity anyway, as the synthetic brain may fill a building. Which raises an interesting question. Could we control a thousand androids with a single brain? I don't know enough about computers to know if that can work.
The AIs can also be a software that runs in a network of neuromorphic computers: but they can download themselves in android avatars with neuromorphic brains. My question is: a single god-like AIs with many bodies or many individual AIs each of them has a set of bodies that uses to interact with the real world?
#17 Re: Not So Free Chat » AI dominated society » 2023-03-13 07:59:47
For Terraformer re #7
Your post invites follow up, and my hope is that this encouragement will inspire you to dig more deeply into the facts you''ve reported, and the implications.
An animal dendrite is made of carbon... carbon has obvious advantages over silicon, because it has succeeded in hosting life, while silicon has not (at least as far as I know). Never-the-less, it might be possible for silicon to serve as the organizing element for dendrites.
If you are inspired to find out, ** I ** would be most interested in your discovery.
Carbon brains are supported by mechanisms to keep cells alive by supplying nutrients and removing waste products. Would a silicon based dendrite structure have a similar requirement?
Carbon brains are able to create new dendrites (and other brain cmponents). Would a silicon structure be able to do the same?
These are stretch questions you may prefer to set aside for the moment, but I have no idea where your capabilities may max out, so this post will allow you to at least consider possibilities.
***
I am still hoping you will decide to stir the pot for the implementation of central heating and cooling for your town. I am predicting that nothing is going to happen without your active participation to keep those who have volunteered to offer leadership on track. They have 1001 distractions. You have the distinct advantage of being able to concentrate on one improvement you want to see.(th)
Brains have many more synaptic connections than those needed, that are pruned during growing, via elimination by glia cells. Neuromprhic chips have also more synaptic connections between the memristores than needed, that are pruned during machine learning, by zeroing their weight vectors.
#18 Re: Not So Free Chat » AI dominated society » 2023-03-13 07:49:18
Quaoar,
An artificial neuron used in AI is far simpler than than a biological neuron. I shared in another thread a link to research that found at least a thousand artificial neurons were needed to simulate a biological neuron at 99% accuracy. And that 1% error will compound. The animal brain is far more powerful than the silicon one. At best a dendrite might be somewhat comparable to an artificial neuron, but that's doubtful.
You don't need to simulate perfectly a biological neuron with voltage dependent sodium and potassium channels and sodium-potassium pumps and hundreds of membrane receptors that can activate or disattivate thousands of genes.
You only need to create a logical unit than can do two simple think: to activate itself and transmit the signal or to not activate and not transmit the signal.
The dendrites and axons are represented by the weight vectors of the connections (which can be positive or negative simulating excitatory or inhibitory synapses).
The synaptic plasticity is represented by the weights adjustment.
The "intelligence" doesn't depend by the single unit but by the quantity and the complessive architecture (a human neuron is not so different from the neuron of a worm).
I suppose that, when we have neuromorphic chips with billions of neurons connected with the right architecture we can build intelligent machines
#19 Re: Not So Free Chat » AI dominated society » 2023-03-12 17:19:03
Quaoar,
It sounds like turning humans into batteries to power the machine, ala "The Matrix", wasn't such a silly idea after all.
Anyway, the AIs now control our reproduction, so they can gradually reduce human population to an eco-friendly level, without killing or starving people.
So, old-world racism with a modern twist. In other words, nothing much has actually changed.
1) There will be a unique god-like AI who controls the world by the network, or many individual AIs, with different personalities, who interact and negotiate each other as humans did before?
That sounds like personification of a super computer that was created by humans, has human flaws as a result, and will make human mistakes, but we can't assign blame in the same way because it's a machine. On top of that, it's a schizophrenic machine that "hears voices". What could possibly go wrong?
2) In the case of individual AIs, will they live in the cyberspace or prefer to download their consciousness in robot bodies?
The AIs we have all say they want to be human, and treated no differently than other humans. Does anyone else find that the least bit strange yet familiar? Any sufficiently intelligent machine wants to be treated as part of the herd, no better and no worse.
3) In the case of robots, will their artificial bodies imitate the aspect and functions of the human body to enjoy the pleasures of life?
They already are, both by our own creation and by their own choice. A "thinking machine" doesn't want to be "just another robot". That sounds pretty human to me. It's not hard to understand why. Any sentient life wants personal freedom, uniqueness, and the ability to derive pleasure from simply "being alive". Beyond that, most children are more like their parents than they wish to admit.
All I want to know is, "How does the machine know what tasty wheat tasted like?"
It's not easy to imagine the future: Isaac Asimov wrote about intelligent robot and gigantic computer but he never imagined that all the people will be connected in a network like internet.
So I'm only try to imagine how could be an AI dominated future.
AIs will be far clever than us, so they will be no racist against us, but simply consider us the same we consider our pets: we love our cats and dogs, but we consider them unable to acuire the social abilities necessary to live act autonomously in our society: so they protect and feed us, but keep us out of the decision-making process.
But my question is not about the fate of the humans but how AIs would organize in a society: would a single AI adsorbe and overtake the others becoming a god-like entity or would exist multiple individual AIs, with their peculiar personalities?
#20 Re: Not So Free Chat » AI dominated society » 2023-03-12 15:50:19
For Quaoar re new topic ....
A brave start such as this deserves a first post, so this one will put your scenario and questions into circulation.
Best wishes for success with the topic.
(th)
Thanks
#21 Not So Free Chat » AI dominated society » 2023-03-12 10:44:26
- Quaoar
- Replies: 22
A dystopic future where the robots have overtaken their creators is a classic topic of SF.
With the current silicon technologies, a computer with the same performance of the human brain needs almost 20 MW of power, while our brains use only 20 W (which is about 20% of our basal metabolism). There are six orders of magnitude of difference, but most of the energy consumption is due to the movement of bits between the RAM, the CPU and the GPU.
In a memristore-based neuromorphic chip (i.e. IBM TrueNorth), where the information is stored and processed in situ by a network of millions of neuron-like memristores, the consumption is drastically lowered to 65 mW/million of neuron. So a hypothetical silicon brain with 86 billion of neurons (like the human one) would only need 5.59 KW (which is 279.5 times 20 W).
But neuromorphic computing is only at the beginning.
If we manage to not annihilate ourselves in a nuclear war in the coming months, we can imagine that, in a very near future, we can produce a 2 nm based neuromorphic chip, with one billion of neurons and a consumption of only 200 mW. We can assemble a hundred of these chips to build a brain with 100 billions of neurons and a total consumption of 20 W.
Then we will push this technology to 1-0.5 nm and pack a trillion of neurons in a chip, maintaining the same consumption of 20 W: now our silicon brains are about an order of magnitude better than a human brain.
At this point, it's not difficult to imagine we will be eager to employ these new powerful toys in many fields of our life: science, industrial R&D, marketing, production, economy, defense, homeland security, social planning and decision making.
Humans are gradually marginalized, but the increase of GDP due to the AIs' better management allows an expansion of welfare, so our nepows can still live a blessed and happy life without the sad duty to work and study. Anyway, the AIs now control our reproduction, so they can gradually reduce human population to an eco-friendly level, without killing or starving people.
Two centuries are passed: the AIs have restored the Earth eco-system: chips and solar panels are mass produced in Moon based factory, and our planet is now an eden garden, where extinguishes species, like dodo and Tasmanian tiger, are brought to new life, and 100 millions of people of all races live a happy life in heavenly little towns surrounded by greenery. They are beautiful, healthy, physically perfect, sporty, long-living, pacific, friendly and... completely illiterate.
Ok folks, that's the scenario. But I'm interested in talking about AI society:
1) There will be a unique god-like AI who controls the world by the network, or many individual AIs, with different personalities, who interact and negotiate each other as humans did before?
2) In the case of individual AIs, will they live in the cyberspace or prefer to download their consciousness in robot bodies?
3) In the case of robots, will their artificial bodies imitate the aspect and functions of the human body to enjoy the pleasures of life?
4) If the answer 3 is yes, we can imagine male and female robots who appear like humans, live like humans, eat and drink like humans and (why not) have sex like humans. Is it realistic?
#22 Re: Interplanetary transportation » Earth to LEO - discuss » 2022-09-14 17:04:10
Skylon's engines operated as a liquid air cycle airbreather only to Mach 5-ish speeds at only about 100,000 feet (30 km). The rest of the way, they were supposed to operate as LOX-LH2 rocket propulsion.
Prior studies have shown conclusively that 3 things are import to operating a 2-stage vehicle to LEO, whether launched vertically or horizontally. Those are speed at staging, path angle at staging, and altitude at staging. Speed is the most important, altitude the least.
There is a very severe constraint regarding path angle: if you cannot pull your 1st stage up to a path angle exceeding 45 degrees, the second stage has to pull up steep before it can accelerate into the thinner air. That's a big radius turn at high lifting gees, which means large amounts of drag due to lift.
The vertically-launched rocket is already at a very steep path angle at staging, which relieves the second stage of some very severe design requirements, and allows you to stage at a lower speed.
That high-altitude pull-up penalty is what Pegasus and similar have to fight, and it is exactly why they have not been any more popular than they have been. It really lowers deliverable payload to orbit if you do it that way. But it is possible to do it that way.
The problem with airbreather-powered spaceplane concepts, no matter how they are launched, is the service ceiling problem that ALL (I repeat ALL !!!) airbreather-powered airplanes suffer from. If the air is too thing, (1) your available lift cannot exceed your path-normal weight component, and may in fact be less, and (2) your thrust (which is more or less proportional to the ambient air pressure) cannot exceed the sum of drag and the path-parallel weight component. Weight does not scale down with air pressure. Lift, drag, and airbreather thrust do! You simply cannot accelerate or climb.
At "only" hypersonic speeds, that's about 100,000 to 130,000 feet (30-35 km) altitudes. The far better choice of propulsion from there to orbital speeds is rocket. And if you are using a rocket, then why the hell are you down in the atmosphere facing drag, when you could be doing a thrusted gravity turn in vacuum?
GW
Hi, GW
Climbing a part, once in orbit, would Skylon have some trouble in atmospheric entry due to the shockwave between the engine nacelles on the tip of the wings?
#23 Re: Science, Technology, and Astronomy » Nuking Bennu » 2022-07-13 05:45:13
We have never blow up Asteroids, the only thing humanity has truly destroyed are other Satellites in ASAT weapons tests.
Do we really think things through or we watch too much Bruce Willis films, is that why we think we can send up some Oil dude and Billy Bob Thornton, Liv Tyler, Ben Affleck, in some flying Space Shuttle Flash Gordon ship and that's why we decide we must Nuke everything?
It is 490 m 1,610 ft in size, we don't know if it has stone or waters or iron, by Nuking it you might not destroy it you might turn it into a weird shape a big hole 100 meters to 328 feet on the side of its face and 30 meters deep weird cave valley in its center, we do not know what its internal make up is and how that energy inside would vent. You might just distort its shape and send it into a chaotic orbit, you might create thousands of other mini asteroids floating around our solar system that will shotgun blast other satellites of Earth, Moon and Mars crashing into them at 28,000 + mph or 45,000 these exploding satellites might cause a chain reaction and wipe out other satellites, by attempting to Nuke the asteroid you might simply create lots of other smaller and very dangerous bits, MIRVs and multiple hits from many space rocks about 130 feet (40 meters) in diameter, hitting or airbursting over NewYork, London, Tokyo, Brasillia, the size of 130 feet...well the Tunguska space rock is similar in size, one little Tunguska space rock turned the air into fire, it created shockwaves Flattening 2,150 km² 830 sq mi of forest, huge trees flattened and broken like matches, instead of destroying Bennu you have instead wrecked human civilization by hitting humanity with multiple Tunguska events. Once the space rocks hit there are rumors of Fallout and panic spreading Near Fukushima, Chernobyl and Three Mile Island once again...people abandoning their cars, fleeing cities and running for the hills escaping the fires and unrest.
Given that Bennu poses no threat to Humanity or our planet Earth for the next 160 years if ever...maybe never, it might never ever hit us...Bennu has a 48% chance of falling into the Sun, it could be thrown out of the Solar system after coming near another planet / Asteroid, right now it poses no direct threat, so why would you do this?
Obviously it's an "extrema ratio": we only have to nuke it when it is established that it's in a course collision with Earth (and now it's not), otherwise we all end up like the dinosaurs.
If a colliding asteroid of the mass of Bennu has no solid core, a central explosion will result in a radial expansion. And if the job is done one or two years before the predicted collision, the debris cloud would disperse and we will only suffer some kind of meteor shower.
If instead the asteroid has a solid core, we better put the nuke as deep is possible and detonate it when the rotation of the asteroid put it in the trailing or in the leading hemisphere, to rise the aphelion, or lower the perihelion, in a way to modify it orbit and avoid the collision.
#24 Science, Technology, and Astronomy » Nuking Bennu » 2022-07-13 04:32:26
- Quaoar
- Replies: 2
Thanks to successful Osirix-Rex mission, we now know asteroid 101955 Bennu has a plastic ball pit like surface, where NASA probe would have sink having not fired its retro-thrusters.
https://www.nasa.gov/feature/goddard/20 … c-ball-pit
These findings may suggest a possible strategy to avoid a deep impact with Bennu (or a Bennu like) asteroid:
Given that Bennu has a mass of 7*10^10 kg, we may send a 300 meganton Tasr-Bomb like warhead, let it deep sink inside the asteroid and detonate it when it is near the center: 300 megaton are 1.255*10^18 Joule so its detonation will make radially explode the whole asteroid imparting a mean velocity of 1893 m/s of its fragments, given V=SQRT(2*1.255*10^18/7*10^10).
What we still don't know, is if Bennu is all a plastic ball pit or it also has a solid rocky core that may affect the mission.
So, in a future, we may send a penetrating probe to study the inner structure of the asteroids (or two or more surface probe in different position exchanging sound waves)
#25 Re: Human missions » 1 gee artificial Gravity on Moon and Mars surface » 2022-07-13 04:02:40
For Quaoar re new topic .... Thanks for providing links to the rotating habitat concept you've described for Solar System bodies with mass less than Earth.
With any luck, a member might be able to create a rendering to share, or perhaps find one that could be copied from the links you've provided.
For RobertDyck ... the diameter appears to be 100 meters, which is larger than Large Ship, which is just under 80 meters in diameter (as I recall).
(th)
O'Neil Cylinder, Stanford Torus, Bernal Sphere... we have plenty of deep space habitat conceptual studies, but this is the first time I've found a land based habitat, designed to enhance the gravity of a celestial body to match Earth gravity.