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  1. J

    Animal Homing

    I have been reading about the theory of magnetoreception which may partially explain the homing ability of pigeons. Many studies are inconclusive, so I am wondering if I can extend this theory to other animals, specifically to the Beech Marten (aka Stone or House Marten, Martes foina). This...
  2. J

    IQ distribution curve

    What does the distribution curve of IQ in the world population look like? If the average IQ for all countries is 90 (Richard Lynn and Tatu Vanhanen “IQ and the Wealth of Nations”), with an average IQ for sub-Saharan Africans of 70, I suppose that the distribution curve is higher on the downside...
  3. J

    Blue Disk illusion

    The following picture has been posted in the Astronomy section (by Dave C426913). https://www.physicsforums.com/file:///C:/Users/John/AppData/Local/Temp/msohtml1/01/clip_image001.jpg [Broken] Source: http://www.space.com/4643-incredible-comet-bigger-sun.html Why does the comet fluctuate in...
  4. J

    Collision of massive star with black hole

    I saw somewhere a thread about a cow falling into a black hole. I don’t know why a cow, perhaps the OP was thinking about the Milky Way. With the cow example it is not clear to me what we are supposed to see when an object falls towards the event horizon. If time slows to infinity, does the...
  5. J

    Distribution of Iron

    I have 2 related questions about Earth-like planets and solar systems: First question: - I don’t understand why the Earth has so much iron. - How much iron is blown off by the typical supernova in proportion to other metals? - If the proto-solarsystem was a rotating gaseous disk, should most...
  6. J

    What controls heartbeat?

    I thought that the brain, specifically the medulla in the lower brain stem, controls heatbeat. But according to what I am reading, heartbeat is caused by electrical impulses in the heart which cause the heart muscles to contract. What is the source flow of this electricity? Does it come from the...
  7. J

    Am I conscious of my prefrontal cortex or is my prefrontal cortex me?

    I would like to know what my 'consciousness' does which my prefrontal cortex does not. Which circumstances show me that I have a 'consciousness' function? .
  8. J

    What causes onset/disappearance of claustrophobia?

    As a child between 5 and 12 I sometimes couldn’t get to sleep because I saw the walls of the room closing in on me. It was very frightening. I suppose it was claustrophobia, but I didn’t have any other similar problems, for example I could climb up monuments and castles with very narrow winding...
  9. J

    Why did it take so long to produce us?

    I am trying to understand why, if the first life on earth appeared so soon after the Hadean between 4 and 3.5 billion years ago, its development since then has been so slow. The fact that life appeared so soon, suggests that the prevailing conditions were favorable. So why didn’t those...
  10. J

    Age versus Size of the Universe

    I have learned a lot about cosmology on this forum, but I’m still behind on the logic. So far I have understood that, since the universe is everything, it cannot have a center nor a boundary. But it does have an expansion and that’s when my problems start. I would like to concentrate on a...
  11. J

    Curvature of Spacetime on Earth

    I am trying to improve my understand of the basic elements of GR. I have read that the earth orbits the sun because spacetime between the earth and the sun is warped, mainly due to the sun’s mass. The earth follows a geodesic, which is the equivalent of a straight line in curved space...
  12. J

    Flow rate of water dropping out of a pipe

    I need to figure out the best way to improve drainage of spring water flowing through my property. The water from my neighbour’s spring flows 10m through a pipe into a manhole on my side. The water level in this manhole is always 10-20 cm higher than the in and out pipes. The water then flows...
  13. J

    Framing versus Streaming

    Is it correct that all visual displays are frame based and all audio players deliver output in streaming format? What is the reason why we do not or cannot present visual displays in streaming format and we do not or cannot have frame based audio players? If you stop a film or a video monitor...
  14. J

    What does time mean in the context of BB theory?

    I would like to understand more about time. I am studying amongst other things, reality. If BB theory is the standard explanation for the start of everything then I would like to know how it explains the start of time. We link time to space and to events (entropy) and we measure time in...
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