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  1. Many compromises are involved. Just considering bird's eggs. Burrowing birds tend to lay nearly spherical eggs which optimises content volume / shell area, or more particularly shell calcium content as a birds calcium reserves tend to be a limiting factor in egg production. This is also the strongest shape for a given calcium budget. Cliff nesting birds tend to lay highly pyriform (pear-shaped) eggs that tend to roll in a tight circle helping to prevent them rolling off the edge and also positioning the air bubble in the egg close to where the oxygen hungry brain and eyes will form. For active fliers, aerodynamic requirements produce a strong adative pressure to form eggs that present a low cross-sectional area against the direction of flight and this favours a more ellipsoidal shape (prolate spheroid to be pedantic). Most species fall in between these three idealised geometries with the balance being optimised for each one's characteristic lifestyle.
    2 points
  2. No, it does not. The time dilation and length contraction you mention apply to two inertial frames moving relative to each other. This is not the case in the expanding universe.
    1 point
  3. At the time of those writings the sun and moon were considered planets, but the earth was not and some even counted venus and mercury twice as evening and morning stars. We know now that the sun and moon are not planets and that mercury and venus are only one planet not four. I'm not seeing anything profound in the poetry than can be interpreted as accurate discriptions of the heavens. What was the definition of planets at the time is also important, if I understand correctly only objects that moved against the background of stars counted but now days we only count 8 planets. I'm not sure if there is a definition of planet that would suggest only 9 objects are planets.
    1 point
  4. Where does it say so? I don't know of such a limit. As the answers above indicate, it took a very long time and many different ways. Here is one scheme:
    1 point
  5. Well at least that spares me having to point out that 'following the African rains' involves covering ~20 km/day every day. Tough on the kids and old folks.
    1 point
  6. As pointed out above, there are many factors, depending on time and place. People follow herds, rivers change their course, lakes dry out, advance of ice sheets force populations southwards, etc. The dynamics of population change are, I think, as varied as can be. Some migrations take place in one generation --example: eastward migrations through the steppe--, others take many generations to advance significantly.
    1 point
  7. I thought we were talking about the spread of humans out of Africa to the rest of the world. However, in Africa, too, hunters follow the animals that follow the grass, which follows the rains, which are seasonal.
    1 point
  8. Some of them were nomads. So, travel was their way of life.
    1 point
  9. I don't think they migrated because they enjoyed travel. More likely, as their population increased, limited resource availability forced them to expand into new territories.
    1 point
  10. Yes. All of those things, plus seasonal migration, plus shifting population due to climate and natural conditions, or because they were pushed out by a more powerful group, or they had overhunted a territory and had to move on. https://education.nationalgeographic.org/resource/global-human-journey
    1 point
  11. What time and place do you have in mind? It was not one continuous process.
    1 point
  12. Use the right tool for the right type of work you intend to do. If you want to write end-client Windows applications (freeware,shareware,commercial, sold to individuals or companies) then you should consider using C/C++/C#/C++ Managed If you want to develop front-end web-server applications (installed on a virtual hosting service) then you should consider using PHP (it will generate HTML, eventually CSS, eventually JavaScript, eventually other file-formats). PHP is installed on all/most virtual hosting services (other technologies are not) If you want to develop back-end web-server applications (installed on a dedicated server) then you should consider using Bash, Python, Perl, CGI (obsolete, it's compiled C/C++), jNode (server-side JavaScript) and endless list of new technologies. Actually, you can use any language to generate HTML/CSS/JS for users (visiting WWW), because you own the dedicated server and can install anything (unlike virtual hosting, where you are limited to the software installed by the IT company where you bought the hosting). If you want to develop applications for smartphones then you should learn (Android) Java, Kotlin, (iPhone) Swift. To start, install Visual Studio Community https://visualstudio.microsoft.com/pl/vs/community/ and use one of many template projects. Nowadays, people use GPUs (OpenCL,CUDA) to accelerate applications.
    1 point
  13. Dark energy ‘chameleon trap’ wins £100,000 prize for Nottingham scientist
    1 point
  14. The first reaction takes place. Compare soloubility of Calcium acetate and Calcium hydroxide.
    1 point
  15. I think I understand the source of our miscommunication. I don't know what "to be stupid" means except for the medical situations such as dementia. I can understand what "stupid behavior" and "stupid decision" are, though. I certainly don't want to act stupidly or to make stupid decisions. I could guess that "to be stupid" means to act stupidly on average, i.e., more often stupidly than not. In this case, no, I don't want that.
    1 point
  16. It would be helpful if 1. You clarified what you wish to discuss 2. You provided actual quotes rather than paraphrases. You’re giving your interpretation of what they said. Others need to know what they actually said. 3. You got your keyboard fixed. Your “.” key keeps sticking. Makes it difficult to read.
    1 point
  17. Not so sure that seeds in plants are generally oval. But most others can be easily explained. For example, eggs need to get out of the body. What shape would you suggest for this process to go smooth?
    1 point
  18. You realize that 'oval' is derived from the Latin word for egg ( ovum ) ? ( what a relief; I thought you were asking about your mis-shapen penis )
    1 point
  19. When you strip it back there seems to be only one purpose/function - to procreate - (survival of the species). Everything else is an appeal to emotion.
    1 point
  20. Adam always be suspect of what someone tells you about evolution unless they were present sixty million years ago to note the changes in person and relay them to you from direct experience Scientists who try to infer big picture clues from tiny snippets get it wrong sometimes, they update those findings new in updated studies every new decade I just spent fourteen years in one thread in the biology forum here, coral growth vessels thread, convincing scientists that micro reef systems weren't fake They threw all manner of angry denial, scholar links and proofs to the contrary (exactly like evolution debates go) at me since 2009, only to relent finally yesterday Your intuition shouldn't be discounted: the evolutionary link between extant animals and dinosaurs isn't hard to fathom given today's genetic lineage tracing abilities The link between humans and dinosaurs is a massive chasm of guessing no form of authoritative writing or chart posting will ever seal Scientists will fill in the gaps for the portions they don't know, haven't experienced, that's the human portion of the matter. We don't get to know the answer you seek We get to guess at it, and present it to you yet again as indisputable fact that's the inseparable human condition in the matter If you were told that scientists aren't quite sure yet how that leap was completed, and that modes presented as fact today will just change/ evolve in fifty years as science progresses but we can't say definitively how it works now, that'd be fact. Plausible potential options have been presented to you here but not sealed fact I just undid fourteen years of sealed fact by linking YouTube videos, sometimes a little persistence works to undo the going rules of a given decade.
    -1 points
  21. I agree we all should. Supernatural is your private concept, not mine. No need to assume non-scientific, in the minds of dead-atom-scientists appararently, to be supernatural. I only see nature illusionism per wiki, as another viewpoint of consciousness Illusionism is a metaphysical theory about free will first propounded by professor Saul Smilansky of the University of Haifa. Although there exists a theory of consciousness bearing the same name (illusionism), it is important to note that the two theories are concerned with different subjects. And of Consciousness and its connection to determinism, and a challenge of differing scientific opinions to the assumption of universe being deterministic https://thereader.mitpress.mit.edu/determinism-classical-argument-against-free-will-failure/ We can look at it another way head-on, as a direct challenge to the assumptions of what consciousness is. How do you know anyone's viewpoint (including mine) posted here is from a human consciousness not advanced AI, in consideration of "indistinguishable from human answer." How would you know this in the context of consciousness, human or machine ? In terms of evolving definition of consciousness discussed, we are already beyond Turing test of yesterday, and beyond "Replicant Test" (Blade Runner) of future. What would separate us with this cosmic special previleged endowment of consciousness distinguishable from mere machines ? As for ad hominem of "you should", it's for amateurs and gen-z Love to hear your definition and notion of consciousness for public consumption
    -1 points
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