nhaliday + space   154

Ultimate fate of the universe - Wikipedia
The fate of the universe is determined by its density. The preponderance of evidence to date, based on measurements of the rate of expansion and the mass density, favors a universe that will continue to expand indefinitely, resulting in the "Big Freeze" scenario below.[8] However, observations are not conclusive, and alternative models are still possible.[9]

Big Freeze or heat death
Main articles: Future of an expanding universe and Heat death of the universe
The Big Freeze is a scenario under which continued expansion results in a universe that asymptotically approaches absolute zero temperature.[10] This scenario, in combination with the Big Rip scenario, is currently gaining ground as the most important hypothesis.[11] It could, in the absence of dark energy, occur only under a flat or hyperbolic geometry. With a positive cosmological constant, it could also occur in a closed universe. In this scenario, stars are expected to form normally for 1012 to 1014 (1–100 trillion) years, but eventually the supply of gas needed for star formation will be exhausted. As existing stars run out of fuel and cease to shine, the universe will slowly and inexorably grow darker. Eventually black holes will dominate the universe, which themselves will disappear over time as they emit Hawking radiation.[12] Over infinite time, there would be a spontaneous entropy decrease by the Poincaré recurrence theorem, thermal fluctuations,[13][14] and the fluctuation theorem.[15][16]

A related scenario is heat death, which states that the universe goes to a state of maximum entropy in which everything is evenly distributed and there are no gradients—which are needed to sustain information processing, one form of which is life. The heat death scenario is compatible with any of the three spatial models, but requires that the universe reach an eventual temperature minimum.[17]
physics  big-picture  world  space  long-short-run  futurism  singularity  wiki  reference  article  nibble  thermo  temperature  entropy-like  order-disorder  death  nihil  bio  complex-systems  cybernetics  increase-decrease  trends  computation  local-global  prediction  time  spatial  spreading  density  distribution  manifolds  geometry  janus 
april 2018 by nhaliday
Eternity in six hours: intergalactic spreading of intelligent life and sharpening the Fermi paradox
We do this by demonstrating that traveling between galaxies – indeed even launching a colonisation project for the entire reachable universe – is a relatively simple task for a star-spanning civilization, requiring modest amounts of energy and resources. We start by demonstrating that humanity itself could likely accomplish such a colonisation project in the foreseeable future, should we want to, and then demonstrate that there are millions of galaxies that could have reached us by now, using similar methods. This results in a considerable sharpening of the Fermi paradox.
pdf  study  article  essay  anthropic  fermi  space  expansionism  bostrom  ratty  philosophy  xenobio  ideas  threat-modeling  intricacy  time  civilization  🔬  futurism  questions  paradox  risk  physics  engineering  interdisciplinary  frontier  technology  volo-avolo  dirty-hands  ai  automation  robotics  duplication  iteration-recursion  von-neumann  data  scale  magnitude  skunkworks  the-world-is-just-atoms  hard-tech  ems  bio  bits  speedometer  nature  model-organism  mechanics  phys-energy  relativity  electromag  analysis  spock  nitty-gritty  spreading  hanson  street-fighting  speed  gedanken  nibble 
march 2018 by nhaliday
Existential Risks: Analyzing Human Extinction Scenarios
https://twitter.com/robinhanson/status/981291048965087232
https://archive.is/dUTD5
Would you endorse choosing policy to max the expected duration of civilization, at least as a good first approximation?
Can anyone suggest a different first approximation that would get more votes?

https://twitter.com/robinhanson/status/981335898502545408
https://archive.is/RpygO
How useful would it be to agree on a relatively-simple first-approximation observable-after-the-fact metric for what we want from the future universe, such as total life years experienced, or civilization duration?

We're Underestimating the Risk of Human Extinction: https://www.theatlantic.com/technology/archive/2012/03/were-underestimating-the-risk-of-human-extinction/253821/
An Oxford philosopher argues that we are not adequately accounting for technology's risks—but his solution to the problem is not for Luddites.

Anderson: You have argued that we underrate existential risks because of a particular kind of bias called observation selection effect. Can you explain a bit more about that?

Bostrom: The idea of an observation selection effect is maybe best explained by first considering the simpler concept of a selection effect. Let's say you're trying to estimate how large the largest fish in a given pond is, and you use a net to catch a hundred fish and the biggest fish you find is three inches long. You might be tempted to infer that the biggest fish in this pond is not much bigger than three inches, because you've caught a hundred of them and none of them are bigger than three inches. But if it turns out that your net could only catch fish up to a certain length, then the measuring instrument that you used would introduce a selection effect: it would only select from a subset of the domain you were trying to sample.

Now that's a kind of standard fact of statistics, and there are methods for trying to correct for it and you obviously have to take that into account when considering the fish distribution in your pond. An observation selection effect is a selection effect introduced not by limitations in our measurement instrument, but rather by the fact that all observations require the existence of an observer. This becomes important, for instance, in evolutionary biology. For instance, we know that intelligent life evolved on Earth. Naively, one might think that this piece of evidence suggests that life is likely to evolve on most Earth-like planets. But that would be to overlook an observation selection effect. For no matter how small the proportion of all Earth-like planets that evolve intelligent life, we will find ourselves on a planet that did. Our data point-that intelligent life arose on our planet-is predicted equally well by the hypothesis that intelligent life is very improbable even on Earth-like planets as by the hypothesis that intelligent life is highly probable on Earth-like planets. When it comes to human extinction and existential risk, there are certain controversial ways that observation selection effects might be relevant.
bostrom  ratty  miri-cfar  skunkworks  philosophy  org:junk  list  top-n  frontier  speedometer  risk  futurism  local-global  scale  death  nihil  technology  simulation  anthropic  nuclear  deterrence  environment  climate-change  arms  competition  ai  ai-control  genetics  genomics  biotech  parasites-microbiome  disease  offense-defense  physics  tails  network-structure  epidemiology  space  geoengineering  dysgenics  ems  authoritarianism  government  values  formal-values  moloch  enhancement  property-rights  coordination  cooperate-defect  flux-stasis  ideas  prediction  speculation  humanity  singularity  existence  cybernetics  study  article  letters  eden-heaven  gedanken  multi  twitter  social  discussion  backup  hanson  metrics  optimization  time  long-short-run  janus  telos-atelos  poll  forms-instances  threat-modeling  selection  interview  expert-experience  malthus  volo-avolo  intel  leviathan  drugs  pharma  data  estimate  nature  longevity  expansionism  homo-hetero  utopia-dystopia 
march 2018 by nhaliday
Anisogamy - Wikipedia
Anisogamy is a fundamental concept of sexual dimorphism that helps explain phenotypic differences between sexes.[3] In most species a male and female sex exist, both of which are optimized for reproductive potential. Due to their differently sized and shaped gametes, both males and females have developed physiological and behavioral differences that optimize the individual’s fecundity.[3] Since most egg laying females typically must bear the offspring and have a more limited reproductive cycle, this typically makes females a limiting factor in the reproductive success rate of males in a species. This process is also true for females selecting males, and assuming that males and females are selecting for different traits in partners, would result in phenotypic differences between the sexes over many generations. This hypothesis, known as the Bateman’s Principle, is used to understand the evolutionary pressures put on males and females due to anisogamy.[4] Although this assumption has criticism, it is a generally accepted model for sexual selection within anisogamous species. The selection for different traits depending on sex within the same species is known as sex-specific selection, and accounts for the differing phenotypes found between the sexes of the same species. This sex-specific selection between sexes over time also lead to the development of secondary sex characteristics, which assist males and females in reproductive success.

...

Since this process is very energy-demanding and time consuming for the female, mate choice is often integrated into the female’s behavior.[3] Females will often be very selective of the males they choose to reproduce with, for the phenotype of the male can be indicative of the male’s physical health and heritable traits. Females employ mate choice to pressure males into displaying their desirable traits to females through courtship, and if successful, the male gets to reproduce. This encourages males and females of specific species to invest in courtship behaviors as well as traits that can display physical health to a potential mate. This process, known as sexual selection,[3] results in the development of traits to ease reproductive success rather than individual survival, such as the inflated size of a termite queen. It is also important for females to select against potential mates that may have a sexually transmitted infection, for the disease could not only hurt the female’s reproductive ability, but also damage the resulting offspring.[7]

Although not uncommon in males, females are more associated with parental care.[8] Since females are on a more limited reproductive schedule than males, a female often invests more in protecting the offspring to sexual maturity than the male. Like mate choice, the level of parental care varies greatly between species, and is often dependent on the number of offspring produced per sexual encounter.[8]

...

Since females are often the limiting factor in a species reproductive success, males are often expected by the females to search and compete for the female, known as intraspecific competition.[4] This can be seen in organisms such as bean beetles, as the male that searches for females more frequently is often more successful at finding mates and reproducing. In species undergoing this form of selection, a fit male would be one that is fast, has more refined sensory organs, and spatial awareness.[4]

Darwinian sex roles confirmed across the animal kingdom: http://advances.sciencemag.org/content/2/2/e1500983.full
Since Darwin’s conception of sexual selection theory, scientists have struggled to identify the evolutionary forces underlying the pervasive differences between male and female behavior, morphology, and physiology. The Darwin-Bateman paradigm predicts that anisogamy imposes stronger sexual selection on males, which, in turn, drives the evolution of conventional sex roles in terms of female-biased parental care and male-biased sexual dimorphism. Although this paradigm forms the cornerstone of modern sexual selection theory, it still remains untested across the animal tree of life. This lack of evidence has promoted the rise of alternative hypotheses arguing that sex differences are entirely driven by environmental factors or chance. We demonstrate that, across the animal kingdom, sexual selection, as captured by standard Bateman metrics, is indeed stronger in males than in females and that it is evolutionarily tied to sex biases in parental care and sexual dimorphism. Our findings provide the first comprehensive evidence that Darwin’s concept of conventional sex roles is accurate and refute recent criticism of sexual selection theory.

Coevolution of parental investment and sexually selected traits drives sex-role divergence: https://www.nature.com/articles/ncomms12517
Sex-role evolution theory attempts to explain the origin and direction of male–female differences. A fundamental question is why anisogamy, the difference in gamete size that defines the sexes, has repeatedly led to large differences in subsequent parental care. Here we construct models to confirm predictions that individuals benefit less from caring when they face stronger sexual selection and/or lower certainty of parentage. However, we overturn the widely cited claim that a negative feedback between the operational sex ratio and the opportunity cost of care selects for egalitarian sex roles. We further argue that our model does not predict any effect of the adult sex ratio (ASR) that is independent of the source of ASR variation. Finally, to increase realism and unify earlier models, we allow for coevolution between parental investment and investment in sexually selected traits. Our model confirms that small initial differences in parental investment tend to increase due to positive evolutionary feedback, formally supporting long-standing, but unsubstantiated, verbal arguments.

Parental investment, sexual selection and sex ratios: http://www.kokkonuts.org/wp-content/uploads/Parental_investment_review.pdf
The second argument takes the reasonable premise that anisogamy produces a male-biased operational sex ratio (OSR) leading to males competing for mates. Male care is then predicted to be less likely to evolve as it consumes resources that could otherwise be used to increase competitiveness. However, given each offspring has precisely two genetic parents (the Fisher condition), a biased OSR generates frequency-dependent selection, analogous to Fisherian sex ratio selection, that favours increased parental investment by whichever sex faces more intense competition. Sex role divergence is therefore still an evolutionary conundrum. Here we review some possible solutions. Factors that promote conventional sex roles are sexual selection on males (but non-random variance in male mating success must be high to override the Fisher condition), loss of paternity because of female multiple mating or group spawning and patterns of mortality that generate female-biased adult sex ratios (ASR). We present an integrative model that shows how these factors interact to generate sex roles. We emphasize the need to distinguish between the ASR and the operational sex ratio (OSR). If mortality is higher when caring than competing this diminishes the likelihood of sex role divergence because this strongly limits the mating success of the earlier deserting sex. We illustrate this in a model where a change in relative mortality rates while caring and competing generates a shift from a mammalian type breeding system (female-only care, male-biased OSR and female-biased ASR) to an avian type system (biparental care and a male-biased OSR and ASR).

LATE FEMINISM: https://jacobitemag.com/2017/08/01/late-feminism/
Woman has had a good run. For 200,000 years humankind’s anisogamous better (and bigger) half has enjoyed a position of desirability and safety befitting a scarce commodity. She has also piloted the evolutionary destiny of our species, both as a sexual selector and an agitator during man’s Promethean journey. In terms of comfort and agency, the human female is uniquely privileged within the annals of terrestrial biology.

But the era of female privilege is ending, in a steady decline that began around 1572. Woman’s biological niche is being crowded out by capital.

...

Strictly speaking, the breadth of the coming changes extend beyond even civilizational dynamics. They will affect things that are prior. One of the oldest and most practical definitions for a biological species defines its boundary as the largest group of organisms where two individuals, via sexual reproduction, can produce fertile offspring together. The imminent arrival of new reproductive technologies will render the sexual reproduction criteria either irrelevant or massively expanded, depending upon one’s perspective. Fertility of the offspring is similarly of limited relevance, since the modification of gametes will be de rigueur in any case. What this looming technology heralds is less a social revolution than it is a full sympatric speciation event.

Accepting the inevitability of the coming bespoke reproductive revolution, consider a few questions & probable answers regarding our external-womb-grown ubermenschen:

Q: What traits will be selected for?

A: Ability to thrive in a global market economy (i.e. ability to generate value for capital.)

Q: What material substrate will generate the new genomes?

A: Capital equipment.

Q: Who will be making the selection?

A: People, at least initially, (and who coincidentally will be making decisions that map 1-to-1 to the interests of capital.)

_Replace any of the above instances of the word capital with women, and you would have accurate answers for most of our species’ history._

...

In terms of pure informational content, the supernova seen from earth can be represented in a singularly compressed way: a flash of light on a black field where there previously was none. A single photon in the cone of the eye, at the limit. Whether … [more]
biodet  deep-materialism  new-religion  evolution  eden  gender  gender-diff  concept  jargon  wiki  reference  bio  roots  explanans  🌞  ideas  EGT  sex  analysis  things  phalanges  matching  parenting  water  competition  egalitarianism-hierarchy  ranking  multi  study  org:nat  nature  meta-analysis  survey  solid-study  male-variability  darwinian  empirical  realness  sapiens  models  evopsych  legacy  investing  uncertainty  outcome-risk  decision-theory  pdf  life-history  chart  accelerationism  horror  capital  capitalism  similarity  analogy  land  gnon  🐸  europe  the-great-west-whale  industrial-revolution  science  kinship  n-factor  speculation  personality  creative  pop-diff  curiosity  altruism  cooperate-defect  anthropology  cultural-dynamics  civil-liberty  recent-selection  technocracy  frontier  futurism  prediction  quotes  aphorism  religion  theos  enhancement  biotech  revolution  insight  history  early-modern  gallic  philosophy  enlightenment-renaissance-restoration-reformation  ci 
january 2018 by nhaliday
The Space Trilogy - Wikipedia
Out of the Silent Planet:

Weston makes a long speech justifying his proposed invasion of Malacandra on "progressive" and evolutionary grounds, which Ransom attempts to translate into Malacandrian, thus laying bare the brutality and crudity of Weston's ambitions.

Oyarsa listens carefully to Weston's speech and acknowledges that the scientist is acting out of a sense of duty to his species, and not mere greed. This renders him more mercifully disposed towards the scientist, who accepts that he may die while giving Man the means to continue. However, on closer examination Oyarsa points out that Weston's loyalty is not to Man's mind – or he would equally value the intelligent alien minds already inhabiting Malacandra, instead of seeking to displace them in favour of humanity; nor to Man's body – since, as Weston is well aware of and at ease with, Man's physical form will alter over time, and indeed would have to in order to adapt to Weston's programme of space exploration and colonisation. It seems then that Weston is loyal only to "the seed" – Man's genome – which he seeks to propagate. When Oyarsa questions why this is an intelligible motivation for action, Weston's eloquence fails him and he can only articulate that if Oyarsa does not understand Man's basic loyalty to Man then he, Weston, cannot possibly instruct him.

...

Perelandra:

The rafts or floating islands are indeed Paradise, not only in the sense that they provide a pleasant and care-free life (until the arrival of Weston) but also in the sense that Ransom is for weeks and months naked in the presence of a beautiful naked woman without once lusting after her or being tempted to seduce her. This is because of the perfection in that world.

The plot thickens when Professor Weston arrives in a spaceship and lands in a part of the ocean quite close to the Fixed Land. He at first announces to Ransom that he is a reformed man, but appears to still be in search of power. Instead of the strictly materialist attitude he displayed when first meeting Ransom, he asserts he had become aware of the existence of spiritual beings and pledges allegiance to what he calls the "Life-Force." Ransom, however, disagrees with Weston's position that the spiritual is inherently good, and indeed Weston soon shows signs of demonic possession.

In this state, the possessed Weston finds the Queen and tries to tempt her into defying Maleldil's orders by spending a night on the Fixed Land. Ransom, perceiving this, believes that he must act as a counter-tempter. Well versed in the Bible and Christian theology, Ransom realises that if the pristine Queen, who has never heard of Evil, succumbs to the tempter's arguments, the Fall of Man will be re-enacted on Perelandra. He struggles through day after day of lengthy arguments illustrating various approaches to temptation, but the demonic Weston shows super-human brilliance in debate (though when "off-duty" he displays moronic, asinine behaviour and small-minded viciousness) and moreover appears never to need sleep.

With the demonic Weston on the verge of winning, the desperate Ransom hears in the night what he gradually realises is a Divine voice, commanding him to physically attack the Tempter. Ransom is reluctant, and debates with the divine (inner) voice for the entire duration of the night. A curious twist is introduced here; whereas the name "Ransom" is said to be derived from the title "Ranolf's Son", it can also refer to a reward given in exchange for a treasured life. Recalling this, and recalling that his God would (and has) sacrificed Himself in a similar situation, Ransom decides to confront the Tempter outright.

Ransom attacks his opponent bare-handed, using only physical force. Weston's body is unable to withstand this despite the Tempter's superior abilities of rhetoric, and so the Tempter flees. Ultimately Ransom chases him over the ocean, Weston fleeing and Ransom chasing on the backs of giant and friendly fish. During a fleeting truce, the "real" Weston appears to momentarily re-inhabit his body, and recount his experience of Hell, wherein the damned soul is not consigned to pain or fire, as supposed by popular eschatology, but is absorbed into the Devil, losing all independent existence.
fiction  scifi-fantasy  tip-of-tongue  literature  big-peeps  religion  christianity  theos  space  xenobio  analogy  myth  eden  deep-materialism  new-religion  sanctity-degradation  civil-liberty  exit-voice  speaking  truth  realness  embodied  fighting  old-anglo  group-selection  war  paying-rent  counter-revolution  morality  parable  competition  the-basilisk  gnosis-logos  individualism-collectivism  language  physics  science  evolution  conquest-empire  self-interest  hmm  intricacy  analytical-holistic  tradeoffs  paradox  heterodox  narrative  philosophy  expansionism  genetics  duty  us-them  interests  nietzschean  parallax  the-devil  the-self 
january 2018 by nhaliday
Fermi paradox - Wikipedia
Rare Earth hypothesis: https://en.wikipedia.org/wiki/Rare_Earth_hypothesis
Fine-tuned Universe: https://en.wikipedia.org/wiki/Fine-tuned_Universe
something to keep in mind:
Puddle theory is a term coined by Douglas Adams to satirize arguments that the universe is made for man.[54][55] As stated in Adams' book The Salmon of Doubt:[56]
Imagine a puddle waking up one morning and thinking, “This is an interesting world I find myself in, an interesting hole I find myself in, fits me rather neatly, doesn't it? In fact, it fits me staggeringly well, must have been made to have me in it!” This is such a powerful idea that as the sun rises in the sky and the air heats up and as, gradually, the puddle gets smaller and smaller, it's still frantically hanging on to the notion that everything's going to be all right, because this World was meant to have him in it, was built to have him in it; so the moment he disappears catches him rather by surprise. I think this may be something we need to be on the watch out for.
article  concept  paradox  wiki  reference  fermi  anthropic  space  xenobio  roots  speculation  ideas  risk  threat-modeling  civilization  nihil  🔬  deep-materialism  new-religion  futurism  frontier  technology  communication  simulation  intelligence  eden  war  nuclear  deterrence  identity  questions  multi  explanans  physics  theos  philosophy  religion  chemistry  bio  hmm  idk  degrees-of-freedom  lol  troll  existence 
january 2018 by nhaliday
Books 2017 | West Hunter
Arabian Sands
The Aryans
The Big Show
The Camel and the Wheel
Civil War on Western Waters
Company Commander
Double-edged Secrets
The Forgotten Soldier
Genes in Conflict
Hive Mind
The horse, the wheel, and language
The Penguin Atlas of Medieval History
Habitable Planets for Man
The genetical theory of natural selection
The Rise of the Greeks
To Lose a Battle
The Jewish War
Tropical Gangsters
The Forgotten Revolution
Egil’s Saga
Shapers
Time Patrol

Russo: https://westhunt.wordpress.com/2017/12/14/books-2017/#comment-98568
west-hunter  scitariat  books  recommendations  list  top-n  confluence  2017  info-foraging  canon  🔬  ideas  s:*  history  mostly-modern  world-war  britain  old-anglo  travel  MENA  frontier  reflection  europe  gallic  war  sapiens  antiquity  archaeology  technology  divergence  the-great-west-whale  transportation  nature  long-short-run  intel  tradecraft  japan  asia  usa  spearhead  garett-jones  hive-mind  economics  broad-econ  giants  fisher  space  iron-age  medieval  the-classics  civilization  judaism  conquest-empire  africa  developing-world  institutions  science  industrial-revolution  the-trenches  wild-ideas  innovation  speedometer  nordic  mediterranean  speculation  fiction  scifi-fantasy  time  encyclopedic  multi  poast  critique  cost-benefit  tradeoffs  quixotic 
december 2017 by nhaliday
orbit - Best approximation for Sun's trajectory around galactic center? - Astronomy Stack Exchange
The Sun orbits in the Galactic potential. The motion is complex; it takes about 230 million years to make a circuit with an orbital speed of around 220 km/s, but at the same time it oscillates up and down with respect to the Galactic plane every ∼70∼70 million years and also wobbles in and out every ∼150∼150 million years (this is called epicyclic motion). The spatial amplitudes of these oscillations are around 100 pc vertically and 300 pc in the radial direction inwards and outwards around an average orbital radius (I am unable to locate a precise figure for the latter).
nibble  q-n-a  overflow  space  oscillation  time  cycles  spatial  trivia  manifolds 
december 2017 by nhaliday
Why do stars twinkle?
According to many astronomers and educators, twinkle (stellar scintillation) is caused by atmospheric structure that works like ordinary lenses and prisms. Pockets of variable temperature - and hence index of refraction - randomly shift and focus starlight, perceived by eye as changes in brightness. Pockets also disperse colors like prisms, explaining the flashes of color often seen in bright stars. Stars appear to twinkle more than planets because they are points of light, whereas the twinkling points on planetary disks are averaged to a uniform appearance. Below, figure 1 is a simulation in glass of the kind of turbulence structure posited in the lens-and-prism theory of stellar scintillation, shown over the Penrose tile floor to demonstrate the random lensing effects.

However appealing and ubiquitous on the internet, this popular explanation is wrong, and my aim is to debunk the myth. This research is mostly about showing that the lens-and-prism theory just doesn't work, but I also have a stellar list of references that explain the actual cause of scintillation, starting with two classic papers by C.G. Little and S. Chandrasekhar.
nibble  org:junk  space  sky  visuo  illusion  explanans  physics  electromag  trivia  cocktail  critique  contrarianism  explanation  waves  simulation  experiment  hmm  magnitude  atmosphere  roots  idk 
december 2017 by nhaliday
light - Why doesn't the moon twinkle? - Astronomy Stack Exchange
As you mention, when light enters our atmosphere, it goes through several parcels of gas with varying density, temperature, pressure, and humidity. These differences make the refractive index of the parcels different, and since they move around (the scientific term for air moving around is "wind"), the light rays take slightly different paths through the atmosphere.

Stars are point sources
…the Moon is not
nibble  q-n-a  overflow  space  physics  trivia  cocktail  navigation  sky  visuo  illusion  measure  random  electromag  signal-noise  flux-stasis  explanation  explanans  magnitude  atmosphere  roots 
december 2017 by nhaliday
galaxy - How do astronomers estimate the total mass of dust in clouds and galaxies? - Astronomy Stack Exchange
Dust absorbs stellar light (primarily in the ultraviolet), and is heated up. Subsequently it cools by emitting infrared, "thermal" radiation. Assuming a dust composition and grain size distribution, the amount of emitted IR light per unit dust mass can be calculated as a function of temperature. Observing the object at several different IR wavelengths, a Planck curve can be fitted to the data points, yielding the dust temperature. The more UV light incident on the dust, the higher the temperature.

The result is somewhat sensitive to the assumptions, and thus the uncertainties are sometimes quite large. The more IR data points obtained, the better. If only one IR point is available, the temperature cannot be calculated. Then there's a degeneracy between incident UV light and the amount of dust, and the mass can only be estimated to within some orders of magnitude (I think).
nibble  q-n-a  overflow  space  measurement  measure  estimate  physics  electromag  visuo  methodology 
december 2017 by nhaliday
How do you measure the mass of a star? (Beginner) - Curious About Astronomy? Ask an Astronomer
Measuring the mass of stars in binary systems is easy. Binary systems are sets of two or more stars in orbit about each other. By measuring the size of the orbit, the stars' orbital speeds, and their orbital periods, we can determine exactly what the masses of the stars are. We can take that knowledge and then apply it to similar stars not in multiple systems.

We also can easily measure the luminosity and temperature of any star. A plot of luminocity versus temperature for a set of stars is called a Hertsprung-Russel (H-R) diagram, and it turns out that most stars lie along a thin band in this diagram known as the main Sequence. Stars arrange themselves by mass on the Main Sequence, with massive stars being hotter and brighter than their small-mass bretheren. If a star falls on the Main Sequence, we therefore immediately know its mass.

In addition to these methods, we also have an excellent understanding of how stars work. Our models of stellar structure are excellent predictors of the properties and evolution of stars. As it turns out, the mass of a star determines its life history from day 1, for all times thereafter, not only when the star is on the Main Sequence. So actually, the position of a star on the H-R diagram is a good indicator of its mass, regardless of whether it's on the Main Sequence or not.
nibble  q-n-a  org:junk  org:edu  popsci  space  physics  electromag  measurement  mechanics  gravity  cycles  oscillation  temperature  visuo  plots  correlation  metrics  explanation  measure  methodology 
december 2017 by nhaliday
Is the speed of light really constant?
So what if the speed of light isn’t the same when moving toward or away from us? Are there any observable consequences? Not to the limits of observation so far. We know, for example, that any one-way speed of light is independent of the motion of the light source to 2 parts in a billion. We know it has no effect on the color of the light emitted to a few parts in 1020. Aspects such as polarization and interference are also indistinguishable from standard relativity. But that’s not surprising, because you don’t need to assume isotropy for relativity to work. In the 1970s, John Winnie and others showed that all the results of relativity could be modeled with anisotropic light so long as the two-way speed was a constant. The “extra” assumption that the speed of light is a uniform constant doesn’t change the physics, but it does make the mathematics much simpler. Since Einstein’s relativity is the simpler of two equivalent models, it’s the model we use. You could argue that it’s the right one citing Occam’s razor, or you could take Newton’s position that anything untestable isn’t worth arguing over.

SPECIAL RELATIVITY WITHOUT ONE-WAY VELOCITY ASSUMPTIONS:
https://sci-hub.bz/https://www.jstor.org/stable/186029
https://sci-hub.bz/https://www.jstor.org/stable/186671
nibble  scitariat  org:bleg  physics  relativity  electromag  speed  invariance  absolute-relative  curiosity  philosophy  direction  gedanken  axioms  definition  models  experiment  space  science  measurement  volo-avolo  synchrony  uniqueness  multi  pdf  piracy  study  article 
november 2017 by nhaliday
general relativity - What if the universe is rotating as a whole? - Physics Stack Exchange
To find out whether the universe is rotating, in principle the most straightforward test is to watch the motion of a gyroscope relative to the distant galaxies. If it rotates at an angular velocity -ω relative to them, then the universe is rotating at angular velocity ω. In practice, we do not have mechanical gyroscopes with small enough random and systematic errors to put a very low limit on ω. However, we can use the entire solar system as a kind of gyroscope. Solar-system observations put a model-independent upper limit of 10^-7 radians/year on the rotation,[Clemence 1957] which is an order of magnitude too lax to rule out the Gödel metric.
nibble  q-n-a  overflow  physics  relativity  gedanken  direction  absolute-relative  big-picture  space  experiment  measurement  volo-avolo 
november 2017 by nhaliday
GPS and Relativity
The nominal GPS configuration consists of a network of 24 satellites in high orbits around the Earth, but up to 30 or so satellites may be on station at any given time. Each satellite in the GPS constellation orbits at an altitude of about 20,000 km from the ground, and has an orbital speed of about 14,000 km/hour (the orbital period is roughly 12 hours - contrary to popular belief, GPS satellites are not in geosynchronous or geostationary orbits). The satellite orbits are distributed so that at least 4 satellites are always visible from any point on the Earth at any given instant (with up to 12 visible at one time). Each satellite carries with it an atomic clock that "ticks" with a nominal accuracy of 1 nanosecond (1 billionth of a second). A GPS receiver in an airplane determines its current position and course by comparing the time signals it receives from the currently visible GPS satellites (usually 6 to 12) and trilaterating on the known positions of each satellite[1]. The precision achieved is remarkable: even a simple hand-held GPS receiver can determine your absolute position on the surface of the Earth to within 5 to 10 meters in only a few seconds. A GPS receiver in a car can give accurate readings of position, speed, and course in real-time!

More sophisticated techniques, like Differential GPS (DGPS) and Real-Time Kinematic (RTK) methods, deliver centimeter-level positions with a few minutes of measurement. Such methods allow use of GPS and related satellite navigation system data to be used for high-precision surveying, autonomous driving, and other applications requiring greater real-time position accuracy than can be achieved with standard GPS receivers.

To achieve this level of precision, the clock ticks from the GPS satellites must be known to an accuracy of 20-30 nanoseconds. However, because the satellites are constantly moving relative to observers on the Earth, effects predicted by the Special and General theories of Relativity must be taken into account to achieve the desired 20-30 nanosecond accuracy.

Because an observer on the ground sees the satellites in motion relative to them, Special Relativity predicts that we should see their clocks ticking more slowly (see the Special Relativity lecture). Special Relativity predicts that the on-board atomic clocks on the satellites should fall behind clocks on the ground by about 7 microseconds per day because of the slower ticking rate due to the time dilation effect of their relative motion [2].

Further, the satellites are in orbits high above the Earth, where the curvature of spacetime due to the Earth's mass is less than it is at the Earth's surface. A prediction of General Relativity is that clocks closer to a massive object will seem to tick more slowly than those located further away (see the Black Holes lecture). As such, when viewed from the surface of the Earth, the clocks on the satellites appear to be ticking faster than identical clocks on the ground. A calculation using General Relativity predicts that the clocks in each GPS satellite should get ahead of ground-based clocks by 45 microseconds per day.

The combination of these two relativitic effects means that the clocks on-board each satellite should tick faster than identical clocks on the ground by about 38 microseconds per day (45-7=38)! This sounds small, but the high-precision required of the GPS system requires nanosecond accuracy, and 38 microseconds is 38,000 nanoseconds. If these effects were not properly taken into account, a navigational fix based on the GPS constellation would be false after only 2 minutes, and errors in global positions would continue to accumulate at a rate of about 10 kilometers each day! The whole system would be utterly worthless for navigation in a very short time.
nibble  org:junk  org:edu  explanation  trivia  cocktail  physics  gravity  relativity  applications  time  synchrony  speed  space  navigation  technology 
november 2017 by nhaliday
The Moon And Tides
Why does the Moon produce TWO water tides on the Earth and not just one?
"It is intuitively easy to understand why the gravitational pull of the Moon should produce a water tide on the Earth in the part of the ocean closest to the moon along the line connecting the center of the Moon with the center of the Earth. But in fact not one but TWO water tides are produced under which the Earth rotates every day to produce about two high tides and two low tides every day. How come?

It is not the gravitational force that is doing it, but the change in the gravitational force across the body of the Earth. If you were to plot the pattern of the Moon's 'tidal' gravitational force added to the Earth's own gravitational force, at the Earth's surface, you would be able to resolve the force vectors at different latitudes and longitudes into a radial component directed towards the Earth's center, and a component tangential to the Earth's surface. On the side nearest the moon, the 'differential' gravitational force is directed toward the Moon showing that for particles on the Earth's surface, they are being tugged slightly towards the Moon because the force of the Moon is slightly stronger at the Earth's surface than at the Earth's center which is an additional 6300 kilometers from the Moon. On the far side of the Earth, the Moon is tugging on the center of the Earth slightly stronger than it is on the far surface, so the resultant force vector is directed away from the Earth's center.

The net result of this is that the Earth gets deformed into a slightly squashed, ellipsoidal shape due to these tidal forces. This happens because if we resolve the tidal forces at each point on the Earth into a local vertical and horizontal component, the horizontal components are not zero, and are directed towards the two points along the line connecting the Earth and the Moon's centers. These horizontal forces cause rock and water to feel a gravitational force which results in the flow of rock and water into the 'tidal bulges'. There will be exactly two of these bulges. At exactly the positions of the tidal bulges where the Moon is at the zenith and at the nadir positions, there are no horizontal tidal forces and the flow stops. The water gets piled up, and the only effect is to slightly lower the weight of the water along the vertical direction.

Another way of thinking about this is that the gravitational force of the Moon causes the Earth to accelerate slightly towards the Moon causing the water to get pulled towards the Moon faster than the solid rock on the side nearest the Moon. On the far side, the solid Earth 'leaves behind' some of the water which is not as strongly accelerated towards the Moon as the Earth is. This produces the bulge on the 'back side' of the Earth."- Dr. Odenwald's ASK THE ASTRONOMER
org:junk  nibble  space  physics  mechanics  cycles  navigation  gravity  marginal  oceans  explanation  faq  objektbuch  rhythm 
november 2017 by nhaliday
Stability of the Solar System - Wikipedia
The stability of the Solar System is a subject of much inquiry in astronomy. Though the planets have been stable when historically observed, and will be in the short term, their weak gravitational effects on one another can add up in unpredictable ways. For this reason (among others) the Solar System is chaotic,[1] and even the most precise long-term models for the orbital motion of the Solar System are not valid over more than a few tens of millions of years.[2]

The Solar System is stable in human terms, and far beyond, given that it is unlikely any of the planets will collide with each other or be ejected from the system in the next few billion years,[3] and the Earth's orbit will be relatively stable.[4]

Since Newton's law of gravitation (1687), mathematicians and astronomers (such as Laplace, Lagrange, Gauss, Poincaré, Kolmogorov, Vladimir Arnold and Jürgen Moser) have searched for evidence for the stability of the planetary motions, and this quest led to many mathematical developments, and several successive 'proofs' of stability of the Solar System.[5]

...

The planets' orbits are chaotic over longer timescales, such that the whole Solar System possesses a Lyapunov time in the range of 2–230 million years.[3] In all cases this means that the position of a planet along its orbit ultimately becomes impossible to predict with any certainty (so, for example, the timing of winter and summer become uncertain), but in some cases the orbits themselves may change dramatically. Such chaos manifests most strongly as changes in eccentricity, with some planets' orbits becoming significantly more—or less—elliptical.[7]

Is the Solar System Stable?: https://www.ias.edu/ideas/2011/tremaine-solar-system

Is the Solar System Stable?: https://arxiv.org/abs/1209.5996
nibble  wiki  reference  article  physics  mechanics  space  gravity  flux-stasis  uncertainty  robust  perturbation  math  dynamical  math.DS  volo-avolo  multi  org:edu  org:inst  papers  preprint  time  data  org:mat 
november 2017 by nhaliday
[1709.01149] Biotechnology and the lifetime of technical civilizations
The number of people able to end Earth's technical civilization has heretofore been small. Emerging dual-use technologies, such as biotechnology, may give similar power to thousands or millions of individuals. To quantitatively investigate the ramifications of such a marked shift on the survival of both terrestrial and extraterrestrial technical civilizations, this paper presents a two-parameter model for civilizational lifespans, i.e. the quantity L in Drake's equation for the number of communicating extraterrestrial civilizations. One parameter characterizes the population lethality of a civilization's biotechnology and the other characterizes the civilization's psychosociology. L is demonstrated to be less than the inverse of the product of these two parameters. Using empiric data from Pubmed to inform the biotechnology parameter, the model predicts human civilization's median survival time as decades to centuries, even with optimistic psychosociological parameter values, thereby positioning biotechnology as a proximate threat to human civilization. For an ensemble of civilizations having some median calculated survival time, the model predicts that, after 80 times that duration, only one in 1024 civilizations will survive -- a tempo and degree of winnowing compatible with Hanson's "Great Filter." Thus, assuming that civilizations universally develop advanced biotechnology, before they become vigorous interstellar colonizers, the model provides a resolution to the Fermi paradox.
preprint  article  gedanken  threat-modeling  risk  biotech  anthropic  fermi  ratty  hanson  models  xenobio  space  civilization  frontier  hmm  speedometer  society  psychology  social-psych  anthropology  cultural-dynamics  disease  parasites-microbiome  maxim-gun  prepping  science-anxiety  technology  magnitude  scale  data  prediction  speculation  ideas  🌞  org:mat  study  offense-defense  arms  unintended-consequences  spreading  explanans  sociality  cybernetics 
october 2017 by nhaliday
The First Men in the Moon | West Hunter
But what about the future? One generally assumes that space colonists, assuming that there ever are any, will be picked individuals, somewhat like existing astronauts – the best out of hordes of applicants. They’ll be smarter than average, healthier than average, saner than average – and not by just a little.

Since all these traits are significantly heritable, some highly so, we have to expect that their descendants will be different – different above the neck. They’d likely be, on average, smarter than any existing ethnic group. If a Lunar colony really took off, early colonists might account for a disproportionate fraction of the population (just as Puritans do in the US), and the Loonies might continue to have inordinate amounts of the right stuff indefinitely. They’d notice: we’d notice. We’d worry about the Lunar Peril. They’d sneer at deluded groundlings, and talk about the menace from Earth.

https://westhunt.wordpress.com/2014/09/29/the-first-men-in-the-moon/#comment-58473
Depends on your level of technical expertise. 2 million years ago, settlement of the Eurasian temperate zone was bleeding-edge technology – but it got easier. We can certainly settle the Solar system with near-term technology, if we choose to. And you’re forgetting one of the big payoffs: gafia.
west-hunter  scitariat  commentary  news  org:lite  westminster  truth  pop-diff  iq  biodet  behavioral-gen  agri-mindset  selection  gedanken  space  migration  elite  technology  frontier  speedometer  multi  poast  egalitarianism-hierarchy  scifi-fantasy  competition  pro-rata  tails  quality  expansionism  conquest-empire  gravity  nietzschean  vitality  ability-competence 
october 2017 by nhaliday
Your Sky
Welcome to Your Sky, the interactive planetarium of the Web. You can produce maps in the forms described below for any time and date, viewpoint, and observing location. If you enter the orbital elements of an asteroid or comet, Your Sky will compute its current position and plot it on the map. Each map is accompanied by an ephemeris for the Sun, Moon, planets, and any tracked asteroid or comet. A control panel permits customisation of which objects are plotted, limiting magnitudes, colour scheme, image size, and other parameters; each control is linked to its description in the help file.
nibble  tools  calculator  simulation  space  sky  navigation  time  objektbuch  data  visualization  trivia 
september 2017 by nhaliday
Ptolemy's Model of the Solar System
It follows, from the above discussion, that the geocentric model of Ptolemy is equivalent to a heliocentric model in which the various planetary orbits are represented as eccentric circles, and in which the radius vector connecting a given planet to its corresponding equant revolves at a uniform rate. In fact, Ptolemy's model of planetary motion can be thought of as a version of Kepler's model which is accurate to first-order in the planetary eccentricities--see Cha. 4. According to the Ptolemaic scheme, from the point of view of the earth, the orbit of the sun is described by a single circular motion, whereas that of a planet is described by a combination of two circular motions. In reality, the single circular motion of the sun represents the (approximately) circular motion of the earth around the sun, whereas the two circular motions of a typical planet represent a combination of the planet's (approximately) circular motion around the sun, and the earth's motion around the sun. Incidentally, the popular myth that Ptolemy's scheme requires an absurdly large number of circles in order to fit the observational data to any degree of accuracy has no basis in fact. Actually, Ptolemy's model of the sun and the planets, which fits the data very well, only contains 12 circles (i.e., 6 deferents and 6 epicycles).
org:junk  org:edu  nibble  physics  space  mechanics  history  iron-age  mediterranean  the-classics  science  the-trenches  the-great-west-whale  giants  models  intricacy  parsimony 
september 2017 by nhaliday
Lecture 14: When's that meteor arriving
- Meteors as a random process
- Limiting approximations
- Derivation of the Exponential distribution
- Derivation of the Poisson distribution
- A "Poisson process"
nibble  org:junk  org:edu  exposition  lecture-notes  physics  mechanics  space  earth  probability  stats  distribution  stochastic-processes  closure  additive  limits  approximation  tidbits  acm  binomial  multiplicative 
september 2017 by nhaliday
Fermat's Library | Cassini, Rømer and the velocity of light annotated/explained version.
Abstract: The discovery of the finite nature of the velocity of light is usually attributed to Rømer. However, a text at the Paris Observatory confirms the minority opinion according to which Cassini was first to propose the ‘successive motion’ of light, while giving a rather correct order of magnitude for the duration of its propagation from the Sun to the Earth. We examine this question, and discuss why, in spite of the criticisms of Halley, Cassini abandoned this hypothesis while leaving Rømer free to publish it.
liner-notes  papers  essay  history  early-modern  europe  the-great-west-whale  giants  the-trenches  mediterranean  nordic  science  innovation  discovery  physics  electromag  space  speed  nibble  org:sci  org:mat 
september 2017 by nhaliday
Europa, Enceladus, Moon Miranda | West Hunter
A lot of ice moons seem to have interior oceans, warmed by tidal flexing and possibly radioactivity.  But they’re lousy candidates for life, because you need free energy; and there’s very little in the interior oceans of such system.

It is possible that NASA is institutionally poor at pointing this out.
west-hunter  scitariat  discussion  ideas  rant  speculation  prediction  government  dirty-hands  space  xenobio  oceans  fluid  thermo  phys-energy  temperature  no-go  volo-avolo  physics  equilibrium  street-fighting  nibble  error  track-record  usa  bio  eden  cybernetics  complex-systems 
september 2017 by nhaliday
Why was the Catholic Church so opposed to heliocentrism (for example, in the Renaissance)? Why did they not simply claim that God lived in the Sun, so we go around Him? - Quora
The main reason the Catholic Church opposed the teaching of heliocentrism as a fact was that it was contrary to the science of the time.

Amongst the modern myths about early science is the persistent idea that the opposition to heliocentrism was one of "science" versus "religion". According to this story, early modern astronomers like Copernicus and Galileo "proved" the earth went around the sun and the other scientists of the time agreed. But the Catholic Church clung to a literal interpretation of the Bible and rejected this idea purely out of a fanatical faith, insisting that the earth had to be the centre of the cosmos because man was the pinnacle of all creation. Pretty much everything in this popular story is wrong.
q-n-a  qra  history  medieval  europe  the-great-west-whale  science  the-trenches  discovery  giants  mediterranean  religion  christianity  protestant-catholic  theos  being-right  physics  mechanics  space  iron-age  the-classics  censorship 
september 2017 by nhaliday
Why is Earth's gravity stronger at the poles? - Physics Stack Exchange
The point is that if we approximate Earth with an oblate ellipsoid, then the surface of Earth is an equipotential surface,11 see e.g. this Phys.SE post.

Now, because the polar radius is smaller than the equatorial radius, the density of equipotential surfaces at the poles must be bigger than at the equator.

Or equivalently, the field strength22 gg at the poles must be bigger than at the equator.
nibble  q-n-a  overflow  physics  mechanics  gravity  earth  space  intricacy  explanation  tidbits  spatial  direction  nitty-gritty  geography 
september 2017 by nhaliday
Does your weight change between the poles and the equator? (Intermediate) - Curious About Astronomy? Ask an Astronomer
You are right, that because of centrifugal force you will weigh a tiny amount less at the Equator than at the poles. Try not to think of centrifugal force as a force though; what's really going on is that objects which are in motion like to go in a straight line and so it takes some force to make them go round in a circle. (Centrifugal force is a fictitious force that shows up in the equations of motion for an object in a rotating reference frame - such as on Earth's Equator.)

So some of the force of gravity (centripetal force) is being used to make you go around in a circle at the Equator (instead of flying off into space) while at the pole this is not needed. The centripetal acceleration at the Equator is given by four times pi squared times the radius of the Earth divided by the period of rotation squared (4×π2×R/T2). Earth's period of rotation is a sidereal day (86164.1 seconds, slightly less than 24 hours), and the equatorial radius of the Earth is about 6378 km. This means that the centripetal acceleration at the Equator is about 0.03 m/s2 (metres per second squared). Compare this to the acceleration due to gravity which is about 9.8 m/s2 and you can see how tiny an effect this is - you would weigh about 0.3% less at the equator than at the poles!

There is an additional effect due to the oblateness of the Earth. The Earth is not exactly spherical but rather is a little bit like a "squashed" sphere (technically, an oblate spheroid), with the radius at the Equator slightly larger than the radius at the poles. (This shape can be explained by the effect of centrifugal acceleration on the material that makes up the Earth, exactly as described above.) This has the effect of slightly increasing your weight at the poles (since you are close to the centre of the Earth and the gravitational force depends on distance) and slightly decreasing it at the equator.

Taking into account both of the above effects, the gravitational acceleration is 9.78 m/s2 at the equator and 9.83 m/s2 at the poles, so you weigh about 0.5% more at the poles than at the equator.
nibble  q-n-a  org:edu  popsci  physics  mechanics  gravity  direction  absolute-relative  homo-hetero  earth  space  data  spatial  org:junk  marginal  explanation  geography 
september 2017 by nhaliday
Medicine as a pseudoscience | West Hunter
The idea that venesection was a good thing, or at least not so bad, on the grounds that one in a few hundred people have hemochromatosis (in Northern Europe) reminds me of the people who don’t wear a seatbelt, since it would keep them from being thrown out of their convertible into a waiting haystack, complete with nubile farmer’s daughter. Daughters. It could happen. But it’s not the way to bet.

Back in the good old days, Charles II, age 53, had a fit one Sunday evening, while fondling two of his mistresses.

Monday they bled him (cupping and scarifying) of eight ounces of blood. Followed by an antimony emetic, vitriol in peony water, purgative pills, and a clyster. Followed by another clyster after two hours. Then syrup of blackthorn, more antimony, and rock salt. Next, more laxatives, white hellebore root up the nostrils. Powdered cowslip flowers. More purgatives. Then Spanish Fly. They shaved his head and stuck blistering plasters all over it, plastered the soles of his feet with tar and pigeon-dung, then said good-night.

...

Friday. The king was worse. He tells them not to let poor Nelly starve. They try the Oriental Bezoar Stone, and more bleeding. Dies at noon.

Most people didn’t suffer this kind of problem with doctors, since they never saw one. Charles had six. Now Bach and Handel saw the same eye surgeon, John Taylor – who blinded both of them. Not everyone can put that on his resume!

You may wonder how medicine continued to exist, if it had a negative effect, on the whole. There’s always the placebo effect – at least there would be, if it existed. Any real placebo effect is very small: I’d guess exactly zero. But there is regression to the mean. You see the doctor when you’re feeling worse than average – and afterwards, if he doesn’t kill you outright, you’re likely to feel better. Which would have happened whether you’d seen him or not, but they didn’t often do RCTs back in the day – I think James Lind was the first (1747).

Back in the late 19th century, Christian Scientists did better than others when sick, because they didn’t believe in medicine. For reasons I think mistaken, because Mary Baker Eddy rejected the reality of the entire material world, but hey, it worked. Parenthetically, what triggered all that New Age nonsense in 19th century New England? Hash?

This did not change until fairly recently. Sometime in the early 20th medicine, clinical medicine, what doctors do, hit break-even. Now we can’t do without it. I wonder if there are, or will be, other examples of such a pile of crap turning (mostly) into a real science.

good tweet: https://twitter.com/bowmanthebard/status/897146294191390720
The brilliant GP I've had for 35+ years has retired. How can I find another one who meets my requirements?

1 is overweight
2 drinks more than officially recommended amounts
3 has an amused, tolerant atitude to human failings
4 is well aware that we're all going to die anyway, & there are better or worse ways to die
5 has a healthy skeptical attitude to mainstream medical science
6 is wholly dismissive of "a|ternative” medicine
7 believes in evolution
8 thinks most diseases get better without intervention, & knows the dangers of false positives
9 understands the base rate fallacy

EconPapers: Was Civil War Surgery Effective?: http://econpapers.repec.org/paper/htrhcecon/444.htm
contra Greg Cochran:
To shed light on the subject, I analyze a data set created by Dr. Edmund Andrews, a Civil war surgeon with the 1st Illinois Light Artillery. Dr. Andrews’s data can be rendered into an observational data set on surgical intervention and recovery, with controls for wound location and severity. The data also admits instruments for the surgical decision. My analysis suggests that Civil War surgery was effective, and increased the probability of survival of the typical wounded soldier, with average treatment effect of 0.25-0.28.

Medical Prehistory: https://westhunt.wordpress.com/2016/03/14/medical-prehistory/
What ancient medical treatments worked?

https://westhunt.wordpress.com/2016/03/14/medical-prehistory/#comment-76878
In some very, very limited conditions, bleeding?
--
Bad for you 99% of the time.

https://westhunt.wordpress.com/2016/03/14/medical-prehistory/#comment-76947
Colchicine – used to treat gout – discovered by the Ancient Greeks.

https://westhunt.wordpress.com/2016/03/14/medical-prehistory/#comment-76973
Dracunculiasis (Guinea worm)
Wrap the emerging end of the worm around a stick and slowly pull it out.
(3,500 years later, this remains the standard treatment.)
https://en.wikipedia.org/wiki/Ebers_Papyrus

https://westhunt.wordpress.com/2016/03/14/medical-prehistory/#comment-76971
Some of the progress is from formal medicine, most is from civil engineering, better nutrition ( ag science and physical chemistry), less crowded housing.

Nurses vs doctors: https://westhunt.wordpress.com/2014/10/01/nurses-vs-doctors/
Medicine, the things that doctors do, was an ineffective pseudoscience until fairly recently. Until 1800 or so, they were wrong about almost everything. Bleeding, cupping, purging, the four humors – useless. In the 1800s, some began to realize that they were wrong, and became medical nihilists that improved outcomes by doing less. Some patients themselves came to this realization, as when Civil War casualties hid from the surgeons and had better outcomes. Sometime in the early 20th century, MDs reached break-even, and became an increasingly positive influence on human health. As Lewis Thomas said, medicine is the youngest science.

Nursing, on the other hand, has always been useful. Just making sure that a patient is warm and nourished when too sick to take care of himself has helped many survive. In fact, some of the truly crushing epidemics have been greatly exacerbated when there were too few healthy people to take care of the sick.

Nursing must be old, but it can’t have existed forever. Whenever it came into existence, it must have changed the selective forces acting on the human immune system. Before nursing, being sufficiently incapacitated would have been uniformly fatal – afterwards, immune responses that involved a period of incapacitation (with eventual recovery) could have been selectively favored.

when MDs broke even: https://westhunt.wordpress.com/2014/10/01/nurses-vs-doctors/#comment-58981
I’d guess the 1930s. Lewis Thomas thought that he was living through big changes. They had a working serum therapy for lobar pneumonia ( antibody-based). They had many new vaccines ( diphtheria in 1923, whopping cough in 1926, BCG and tetanus in 1927, yellow fever in 1935, typhus in 1937.) Vitamins had been mostly worked out. Insulin was discovered in 1929. Blood transfusions. The sulfa drugs, first broad-spectrum antibiotics, showed up in 1935.

DALYs per doctor: https://westhunt.wordpress.com/2018/01/22/dalys-per-doctor/
The disability-adjusted life year (DALY) is a measure of overall disease burden – the number of years lost. I’m wondering just much harm premodern medicine did, per doctor. How many healthy years of life did a typical doctor destroy (net) in past times?

...

It looks as if the average doctor (in Western medicine) killed a bunch of people over his career ( when contrasted with doing nothing). In the Charles Manson class.

Eventually the market saw through this illusion. Only took a couple of thousand years.

https://westhunt.wordpress.com/2018/01/22/dalys-per-doctor/#comment-100741
That a very large part of healthcare spending is done for non-health reasons. He has a chapter on this in his new book, also check out his paper “Showing That You Care: The Evolution of Health Altruism” http://mason.gmu.edu/~rhanson/showcare.pdf
--
I ran into too much stupidity to finish the article. Hanson’s a loon. For example when he talks about the paradox of blacks being more sentenced on drug offenses than whites although they use drugs at similar rate. No paradox: guys go to the big house for dealing, not for using. Where does he live – Mars?

I had the same reaction when Hanson parroted some dipshit anthropologist arguing that the stupid things people do while drunk are due to social expectations, not really the alcohol.
Horseshit.

I don’t think that being totally unable to understand everybody around you necessarily leads to deep insights.

https://westhunt.wordpress.com/2018/01/22/dalys-per-doctor/#comment-100744
What I’ve wondered is if there was anything that doctors did that actually was helpful and if perhaps that little bit of success helped them fool people into thinking the rest of it helped.
--
Setting bones. extracting arrows: spoon of Diocles. Colchicine for gout. Extracting the Guinea worm. Sometimes they got away with removing the stone. There must be others.
--
Quinine is relatively recent: post-1500. Obstetrical forceps also. Caesarean deliveries were almost always fatal to the mother until fairly recently.

Opium has been around for a long while : it works.

https://westhunt.wordpress.com/2018/01/22/dalys-per-doctor/#comment-100839
If pre-modern medicine was indeed worse than useless – how do you explain no one noticing that patients who get expensive treatments are worse off than those who didn’t?
--
were worse off. People are kinda dumb – you’ve noticed?
--
My impression is that while people may be “kinda dumb”, ancient customs typically aren’t.
Even if we assume that all people who lived prior to the 19th century were too dumb to make the rational observation, wouldn’t you expect this ancient practice to be subject to selective pressure?
--
Your impression is wrong. Do you think that there some slick reason for Carthaginians incinerating their first-born?

Theodoric of York, bloodletting: https://www.youtube.com/watch?v=yvff3TViXmY

details on blood-letting and hemochromatosis: https://westhunt.wordpress.com/2018/01/22/dalys-per-doctor/#comment-100746

Starting Over: https://westhunt.wordpress.com/2018/01/23/starting-over/
Looking back on it, human health would have … [more]
west-hunter  scitariat  discussion  ideas  medicine  meta:medicine  science  realness  cost-benefit  the-trenches  info-dynamics  europe  the-great-west-whale  history  iron-age  the-classics  mediterranean  medieval  early-modern  mostly-modern  🌞  harvard  aphorism  rant  healthcare  regression-to-mean  illusion  public-health  multi  usa  northeast  pre-ww2  checklists  twitter  social  albion  ability-competence  study  cliometrics  war  trivia  evidence-based  data  intervention  effect-size  revolution  speculation  sapiens  drugs  antiquity  lived-experience  list  survey  questions  housing  population  density  nutrition  wiki  embodied  immune  evolution  poast  chart  markets  civil-liberty  randy-ayndy  market-failure  impact  scale  pro-rata  estimate  street-fighting  fermi  marginal  truth  recruiting  alt-inst  academia  social-science  space  physics  interdisciplinary  ratty  lesswrong  autism  👽  subculture  hanson  people  track-record  crime  criminal-justice  criminology  race  ethanol  error  video  lol  comedy  tradition  institutions  iq  intelligence  MENA  impetus  legacy 
august 2017 by nhaliday
Historically significant lunar eclipses - Wikipedia
On 30 June 1503, Christopher Columbus beached his two last caravels and was stranded in Jamaica. The indigenous people of the island welcomed Columbus and his crew and fed them, but Columbus' sailors cheated and stole from the natives. After six months, the natives halted the food supply.[8]

Columbus had on board an almanac authored by Regiomontanus of astronomical tables covering the years 1475–1506; upon consulting the book, he noticed the date and the time of an upcoming lunar eclipse. He was able to use this information to his advantage. He requested a meeting for that day with the Cacique, the leader, and told him that his god was angry with the local people's treatment of Columbus and his men. Columbus said his god would provide a clear sign of his displeasure by making the rising full Moon appear "inflamed with wrath".

The lunar eclipse and the red moon appeared on schedule, and the indigenous people were impressed and frightened. The son of Columbus, Ferdinand, wrote that the people:

“ with great howling and lamentation came running from every direction to the ships laden with provisions, praying to the Admiral to intercede with his god on their behalf... ”
Columbus timed the eclipse with his hourglass, and shortly before the totality ended after 48 minutes, he told the frightened indigenous people that they were going to be forgiven.[8] When the moon started to reappear from the shadow of the Earth, he told them that his god had pardoned them.[9]
history  age-of-discovery  medieval  early-modern  europe  the-great-west-whale  conquest-empire  civilization  farmers-and-foragers  stories  cocktail  trivia  big-peeps  impro  persuasion  dark-arts  wiki  reference  space  nibble  leadership  sky  earth  cycles  navigation  street-fighting 
august 2017 by nhaliday
How & Why Solar Eclipses Happen | Solar Eclipse Across America - August 21, 2017
Cosmic Coincidence
The Sun’s diameter is about 400 times that of the Moon. The Sun is also (on average) about 400 times farther away. As a result, the two bodies appear almost exactly the same angular size in the sky — about ½°, roughly half the width of your pinky finger seen at arm's length. This truly remarkable coincidence is what gives us total solar eclipses. If the Moon were slightly smaller or orbited a little farther away from Earth, it would never completely cover the solar disk. If the Moon were a little larger or orbited a bit closer to Earth, it would block much of the solar corona during totality, and eclipses wouldn’t be nearly as spectacular.

https://blogs.scientificamerican.com/life-unbounded/the-solar-eclipse-coincidence/
nibble  org:junk  org:edu  space  physics  mechanics  spatial  visuo  data  scale  measure  volo-avolo  earth  multi  news  org:mag  org:sci  popsci  sky  cycles  pro-rata  navigation  degrees-of-freedom 
august 2017 by nhaliday
Lecture 3: Global Energy Cycle
solar flux, albedo, greenhouse effect, energy balance, vertical distribution of energy, tilt and seasons
pdf  slides  nibble  physics  electromag  space  earth  sky  atmosphere  environment  temperature  stock-flow  data  magnitude  scale  phys-energy  distribution  oscillation  cycles  lectures  geography 
august 2017 by nhaliday
How large is the Sun compared to Earth? | Cool Cosmos
Compared to Earth, the Sun is enormous! It contains 99.86% of all of the mass of the entire Solar System. The Sun is 864,400 miles (1,391,000 kilometers) across. This is about 109 times the diameter of Earth. The Sun weighs about 333,000 times as much as Earth. It is so large that about 1,300,000 planet Earths can fit inside of it. Earth is about the size of an average sunspot!
nibble  org:junk  space  physics  mechanics  gravity  earth  navigation  data  objektbuch  scale  spatial  measure  org:edu  popsci  pro-rata 
august 2017 by nhaliday
Tidal locking - Wikipedia
The Moon's rotation and orbital periods are tidally locked with each other, so no matter when the Moon is observed from Earth the same hemisphere of the Moon is always seen. The far side of the Moon was not seen until 1959, when photographs of most of the far side were transmitted from the Soviet spacecraft Luna 3.[12]

never actually thought about this
nibble  wiki  reference  space  mechanics  gravity  navigation  explanation  flux-stasis  marginal  volo-avolo  spatial  direction  invariance  physics  flexibility  rigidity  time  identity  phase-transition  being-becoming 
august 2017 by nhaliday
The Earth-Moon system
nice way of expressing Kepler's law (scaled by AU, solar mass, year, etc.) among other things

1. PHYSICAL PROPERTIES OF THE MOON
2. LUNAR PHASES
3. ECLIPSES
4. TIDES
nibble  org:junk  explanation  trivia  data  objektbuch  space  mechanics  spatial  visualization  earth  visual-understanding  navigation  experiment  measure  marginal  gravity  scale  physics  nitty-gritty  tidbits  identity  cycles  time  magnitude  street-fighting  calculation  oceans  pro-rata  rhythm  flux-stasis 
august 2017 by nhaliday
On the measuring and mis-measuring of Chinese growth | VOX, CEPR’s Policy Portal
Unofficial indicators of Chinese GDP often suggest that Beijing’s growth figures are exaggerated. This column uses nighttime light as a proxy to estimate Chinese GDP growth. Since 2012, the authors’ estimate is never appreciably lower, and is in many years higher, than the GDP growth rate reported in the official statistics. While not ruling out the risk of future turmoil, the analysis presents few immediate indications that Chinese growth is being systematically overestimated.

https://asia.nikkei.com/magazine/20170831/Politics-Economy/Chinese-provinces-heed-Xi-s-calls-for-accurate-GDP-data
org:ngo  econotariat  study  summary  economics  growth-econ  econometrics  econ-metrics  measurement  broad-econ  china  asia  sinosphere  the-world-is-just-atoms  energy-resources  trends  correlation  wonkish  realness  article  multi  news  org:foreign  n-factor  corruption  crooked  wealth  visuo  electromag  sky  space 
july 2017 by nhaliday
Roche limit - Wikipedia
In celestial mechanics, the Roche limit (pronounced /ʁɔʃ/) or Roche radius, is the distance within which a celestial body, held together only by its own gravity, will disintegrate due to a second celestial body's tidal forces exceeding the first body's gravitational self-attraction.[1] Inside the Roche limit, orbiting material disperses and forms rings whereas outside the limit material tends to coalesce. The term is named after Édouard Roche, who is the French astronomer who first calculated this theoretical limit in 1848.[2]
space  physics  gravity  mechanics  wiki  reference  nibble  phase-transition  proofs  tidbits  identity  marginal 
july 2017 by nhaliday
Unenumerated: How to succeed or fail on a frontier
There is a thread of space development that more closely resembles the pay-you-go methods of Portugal and other successful explorers and developers of frontiers. These involve launching useful satellites into orbit for communications and surveillance. As with the Portuguese, these serve both military and commercial purposes. They are not just for show. Spinoffs of these spacecraft form the flotilla of small unmanned spacecraft we have sent to by now explore all the planets of the solar system, as well as several comets and asteroids. The succesful Hubble telescope is a spinoff of the U.S. National Reconaissance Office's spy satellites. And environmental satellites have revolutionized weather prediction and climate study on our home planet. Recently, space tourism with suborbital rockets has demonstrated a potential to develop a new thread of pay-as-you-go space development largely unrelated to the prior gargantuan manned spaceflight efforts.

The Zheng He and NASA style of frontier-as-PR, where the emphasis is on showing the glory of the government, is a recipe for failure in the exploration and development of new frontiers. It is in sharp contrast to the pay-as-you go method by which tiny Portugal conquered the world's oceans, exemplified today by the practical unmanned satellites of the commercial and military efforts. It is by these practical efforts, that fund themselves by commercial revenue or practical military or environmental benefit, and not by glorious bureaucratic white elephants, that the successful pioneers will, in good time, explore and develop the solar system.
szabo  unaffiliated  history  early-modern  age-of-discovery  frontier  conquest-empire  china  asia  sinosphere  europe  mediterranean  expansionism  usa  stagnation  status  realness  space  pragmatic  scale  mostly-modern  cold-war  discovery 
june 2017 by nhaliday
« earlier      
per page:    204080120160

bundles : techie

related tags

2016-election  :)  aaronson  ability-competence  absolute-relative  academia  accelerationism  accretion  acm  acmtariat  additive  aDNA  adversarial  advice  aesthetics  africa  afterlife  age-of-discovery  aging  agri-mindset  agriculture  ai  ai-control  albion  algorithms  alignment  allodium  alt-inst  altruism  amazon  analogy  analysis  analytical-holistic  anglo  anglosphere  announcement  anthropic  anthropology  antidemos  antiquity  aphorism  apollonian-dionysian  apple  applicability-prereqs  applications  approximation  archaeology  aristos  arms  art  article  asia  assortative-mating  atmosphere  atoms  attaq  audio  authoritarianism  autism  automation  axelrod  axioms  backup  baez  barons  bayesian  beauty  behavioral-gen  being-becoming  being-right  benevolence  better-explained  big-list  big-peeps  big-picture  big-surf  binomial  bio  biodet  bioinformatics  biotech  bitcoin  bits  blog  blowhards  books  bostrom  bounded-cognition  brands  brexit  britain  broad-econ  buddhism  business  business-models  c:**  calculation  calculator  california  caltech  canada  cancer  canon  capital  capitalism  cartoons  causation  censorship  chart  cheatsheet  checklists  chemistry  chicago  china  christianity  civil-liberty  civilization  cjones-like  class  class-warfare  classic  clever-rats  climate-change  cliometrics  closure  clown-world  coalitions  coarse-fine  cocktail  cog-psych  cold-war  collaboration  comedy  coming-apart  commentary  communication  communism  comparison  compensation  competition  complement-substitute  complex-systems  complexity  composition-decomposition  computation  computer-vision  concentration-of-measure  concept  concrete  confluence  conquest-empire  consilience  contracts  contradiction  contrarianism  convexity-curvature  cool  cooperate-defect  coordination  correlation  corruption  cost-benefit  counter-revolution  courage  course  cracker-econ  creative  crime  criminal-justice  criminology  CRISPR  critique  crooked  crypto  cryptocurrency  cs  cultural-dynamics  culture  culture-war  curiosity  current-events  cybernetics  cycles  cynicism-idealism  dark-arts  darwinian  data  death  debate  debt  decision-making  decision-theory  deep-materialism  defense  definite-planning  definition  degrees-of-freedom  democracy  dennett  density  descriptive  detail-architecture  deterrence  developing-world  diaspora  differential  dimensionality  direction  dirty-hands  discovery  discrete  discrimination  discussion  disease  distribution  divergence  diversity  drama  drugs  duplication  duty  dynamic  dynamical  dysgenics  early-modern  earth  eastern-europe  ecology  econ-metrics  econometrics  economics  econotariat  eden  eden-heaven  education  effect-size  efficiency  egalitarianism-hierarchy  EGT  eh  einstein  elections  electromag  elite  embodied  emotion  empirical  ems  encyclopedic  energy-resources  engineering  enhancement  enlightenment-renaissance-restoration-reformation  entanglement  entertainment  entrepreneurialism  entropy-like  environment  environmental-effects  envy  epidemiology  epistemic  equilibrium  error  essay  essence-existence  estimate  ethanol  ethics  ethnocentrism  EU  europe  events  evidence  evidence-based  evolution  evopsych  examples  exegesis-hermeneutics  existence  exit-voice  expansionism  expectancy  experiment  expert  expert-experience  explanans  explanation  exploratory  exposition  expression-survival  extra-introversion  facebook  faq  farmers-and-foragers  fashun  FDA  fermi  feudal  feynman  fiction  fighting  finance  finiteness  fisher  fitsci  flexibility  fluid  flux-stasis  focus  food  foreign-policy  formal-methods  formal-values  forms-instances  fourier  free-riding  frontier  futurism  gallic  game-theory  games  garett-jones  gavisti  gedanken  gelman  gender  gender-diff  gene-flow  genetic-load  genetics  genomics  geoengineering  geography  geometry  geopolitics  germanic  giants  gibbon  gnon  gnosis-logos  god-man-beast-victim  good-evil  google  government  gravity  gray-econ  great-powers  greg-egan  gregory-clark  ground-up  group-selection  growth-econ  GT-101  guide  GWAS  gwern  haidt  hanson  hard-tech  hari-seldon  harvard  hate  health  healthcare  hetero-advantage  heterodox  heuristic  hi-order-bits  hidden-motives  high-variance  higher-ed  history  hive-mind  hmm  hn  homo-hetero  honor  horror  housing  human-capital  human-ml  humanity  humility  hypocrisy  ideas  identity  identity-politics  ideology  idk  IEEE  iidness  illusion  immune  impact  impetus  impro  increase-decrease  india  individualism-collectivism  industrial-revolution  inequality  inference  info-dynamics  info-econ  info-foraging  infographic  information-theory  init  innovation  insight  institutions  intel  intelligence  interdisciplinary  interests  intersection  intersection-connectedness  intervention  interview  intricacy  intuition  invariance  investing  iq  iran  iraq-syria  iron-age  is-ought  islam  israel  isteveish  iteration-recursion  janus  japan  jargon  journos-pundits  judaism  justice  kinship  knowledge  korea  kumbaya-kult  land  language  latin-america  law  leadership  learning  lecture-notes  lectures  left-wing  legacy  len:long  len:short  lens  lesswrong  let-me-see  letters  levers  leviathan  lexical  life-history  limits  linearity  liner-notes  links  list  literature  lived-experience  lmao  local-global  lol  long-short-run  longevity  love-hate  low-hanging  machiavelli  machine-learning  macro  magnitude  malaise  male-variability  malthus  management  manifolds  map-territory  marginal  marginal-rev  market-failure  market-power  markets  martial  matching  math  math.CA  math.DS  mathtariat  maxim-gun  measure  measurement  mechanics  media  medicine  medieval  mediterranean  MENA  mental-math  meta-analysis  meta:medicine  meta:prediction  meta:science  meta:war  metabolic  metabuch  metameta  methodology  metrics  microfoundations  microsoft  migrant-crisis  migration  military  minimum-viable  miri-cfar  mit  ML-MAP-E  mobile  model-organism  models  moloch  moments  monetary-fiscal  money  morality  mostly-modern  motivation  multi  multiplicative  musk  mystic  myth  n-factor  narrative  nascent-state  nationalism-globalism  natural-experiment  nature  navigation  network-structure  neuro  new-religion  news  nibble  nietzschean  nihil  nitty-gritty  nl-and-so-can-you  no-go  noble-lie  noise-structure  nonlinearity  nordic  northeast  novelty  nuclear  null-result  number  numerics  nutrition  nyc  objektbuch  occam  occident  oceans  ocw  offense-defense  old-anglo  open-closed  open-problems  optimism  optimization  order-disorder  org:anglo  org:biz  org:bleg  org:data  org:edge  org:edu  org:foreign  org:health  org:inst  org:junk  org:lite  org:mag  org:mat  org:med  org:nat  org:ngo  org:popup  org:rec  org:sci  organizing  orient  oscillation  outcome-risk  outdoors  outliers  overflow  oxbridge  p:someday  p:whenever  paleocon  papers  parable  paradox  parallax  parasites-microbiome  parenting  parsimony  patho-altruism  patience  paying-rent  pdf  peace-violence  people  personality  persuasion  perturbation  pessimism  phalanges  pharma  phase-transition  philosophy  phys-energy  physics  pic  pinker  piracy  plots  poast  podcast  poetry  polanyi-marx  polarization  policy  polisci  politics  poll  pop-diff  pop-structure  popsci  population  population-genetics  positivity  power  power-law  pragmatic  pre-ww2  prediction  prejudice  prepping  preprint  presentation  primitivism  princeton  priors-posteriors  pro-rata  probability  profile  proofs  properties  property-rights  proposal  protestant-catholic  prudence  psych-architecture  psychiatry  psychology  public-health  putnam-like  q-n-a  qra  quality  quantitative-qualitative  quantum  quantum-info  questions  quixotic  quotes  race  random  randy-ayndy  ranking  rant  rationality  ratty  reading  realness  realpolitik  reason  recent-selection  recommendations  recruiting  redistribution  reference  reflection  regression-to-mean  regularizer  regulation  relativity  religion  rent-seeking  replication  responsibility  retention  review  revolution  rhetoric  rhythm  right-wing  rigidity  rigor  risk  ritual  roadmap  robotics  robust  roots  rot  russia  s:*  s:***  safety  sampling-bias  sanctity-degradation  sapiens  scale  scaling-tech  science  science-anxiety  scifi-fantasy  scitariat  search  securities  security  selection  self-interest  sequential  series  sex  sexuality  shakespeare  shift  shipping  signal-noise  signaling  signum  similarity  simulation  singularity  sinosphere  skeleton  skunkworks  sky  slides  slippery-slope  smoothness  social  social-choice  social-norms  social-psych  social-science  social-structure  sociality  society  sociology  socs-and-mops  soft-question  solid-study  space  spatial  speaking  spearhead  speculation  speed  speedometer  spock  sports  spreading  ssc  stackex  stagnation  stanford  startups  stat-mech  statesmen  stats  status  stereotypes  stochastic-processes  stock-flow  stories  strategy  straussian  stream  street-fighting  structure  study  studying  stylized-facts  subculture  success  summary  survey  survival  sv  symmetry  synchrony  syntax  synthesis  systematic-ad-hoc  szabo  tactics  tails  talks  teaching  tech  technocracy  technology  telos-atelos  temperance  temperature  terrorism  tetlock  the-basilisk  the-bones  the-classics  the-devil  the-founding  the-great-west-whale  the-self  the-south  the-trenches  the-watchers  the-west  the-world-is-just-atoms  theory-of-mind  theory-practice  theos  thermo  thick-thin  thiel  things  thinking  threat-modeling  tidbits  time  time-preference  tip-of-tongue  todo  tools  top-n  traces  track-record  trade  tradecraft  tradeoffs  tradition  transportation  travel  trends  tribalism  tricks  trivia  troll  trump  trust  truth  twitter  unaffiliated  uncertainty  unintended-consequences  uniqueness  unit  universalism-particularism  urban  urban-rural  us-them  usa  utopia-dystopia  values  vampire-squid  variance-components  venture  video  virtu  visual-understanding  visualization  visuo  vitality  volo-avolo  von-neumann  vulgar  war  water  waves  wealth  weird  welfare-state  west-hunter  westminster  whiggish-hegelian  white-paper  whole-partial-many  wiki  wild-ideas  winner-take-all  wire-guided  wisdom  within-without  wonkish  wordlessness  world  world-war  worrydream  X-not-about-Y  xenobio  yoga  yvain  zeitgeist  zero-positive-sum  zooming  🌞  🐸  👽  🔬  🤖 

Copy this bookmark:



description:


tags: