Geocentric Belief

Discussion in 'Astronomy, Exobiology, & Cosmology' started by StrangerInAStrangeLand, Jul 15, 2015.

  1. StrangerInAStrangeLand SubQuantum Mechanic Valued Senior Member

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    .
    Did most people truly believe planets, stars & everything circle Earth?
    Of course I realize I am in a very different situation from them but it seems to me obvious after enough naked eye observation that it is possible that such seems so due to movement of Earth & nearly obvious that it is due to Earth's movement.

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  3. Schmelzer Valued Senior Member

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    I disagree. The geocentric world view is quite consistent. For the Earth being a sphere there is sufficient evidence accessible with a naked eye, given the spherical shadow seen at lunar eclipses. For the rotation of Earth in comparison with the rotation of all the stars there is no such clear evidence, and the counterargument that this would cause a quite strong constant storm. But, of course, the theory of daily rotation of Earth - together with air - could be quite plausible. Here, Foucaults pendulum was an independent argument which has settled the issue for the population, but it was settled for scientists long before.

    But to explain the movement of a few small stars by introducing a movement of Earth around the Sun, given that this would lead to parallaxe effects for all other stars which nobody has seen, sorry, no, this is not even very plausible. Here one needs more, beyond naked eye observations. And it is not even clear if the simplifications of the model provided by Copernicus are sufficient - from point of view of modern positivism, this theory could have been simply ignored as an almost equivalent interpretation - without the improvements in accuracy provided by Kepler's model.
     
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  5. paddoboy Valued Senior Member

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    The geocentric model held favour for more than 2,000 years with the obvious help of passages from the bible [supporting that concept] and the preferred position of God's "perfect" creations to be the center of the Universe, as dictated by the church under threat of death.
    Galileo's observations of the phases of Venus, along with the moons of Jupiter showed evidence that this was not the case, although scientifically, the geocentric model did serve its purpose for limited scenarios and some predictions.eg: the rising and setting of the Sun each day.
    But obviously it failed at explaining easily observed retrograde motion of planets.
     
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  7. Russ_Watters Not a Trump supporter... Valued Senior Member

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    Yes.
    What observations, exactly, have you made? Did you observe Venus's back and forth motion and Mars's retrograde motion? It isnt clear to me if you are saying you believe heliocentrism or geocentrism.
     
  8. Trippy ALEA IACTA EST Staff Member

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    Measuring parallax is the first step on the ladder of cosmic distances...
     
  9. nebel

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    When we look at the background radiation, the deep survey, the picture seems to be very similar in all directions, perhaps a little skewed to one side, but we seem to be in the center of the universe, no wonder, we were once part of the small little big bang singularity, and everyone has expanded away from us more or less evenly. "From a distance" now. looking, radiating back at us.
     
  10. Schmelzer Valued Senior Member

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    Except that from all other points the picture would look similarly symmetric in all directions.
     
  11. paddoboy Valued Senior Member

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    The Universe has no center except the center of your personal observable universe.
    The Universe is also said to be Isotropic and homegeneous, meaning looking the same in all directions, and being the same where ever you are in the Universe. These are views over macroscopic scales.
     
  12. Schmelzer Valued Senior Member

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    5,003
    This is, by the way, an interesting point: The "expanding universe" picture suggests the existence of a center. The ballon picture has no center, but suggests another dimension - which is also a misleading suggestion, at least GR itself does not suggest such a thing.

    The shrinking rulers picture does not have these problems. Dried up earth with cracks nicely illustrates how such a shrinking creates inhomogenity in an initially homogeneous universe - without any center, without any additional dimensions.
     
  13. paddoboy Valued Senior Member

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    Not really, if one takes the time to look right into it. The BB is the accepted model of Universal evolution. The BB was an evolution of all space and time.
    All of spacetime was packed to within the volume of an atomic nucleus so it can be visualised that the BB occurred everywhere at once....not any particular place.
    The balloon analogy is a good analogy as long as one realises that all analogies do have limitations. The important point to remember is that the 2 D surface of the balloon, represents the 4D spacetime.
    The following reputable link explains it......
    http://math.ucr.edu/home/baez/physics/Relativity/GR/centre.html

    The shrinking ruler picture is very rarely used and is even more limited then the balloon model/analogy for obvious reasons.
    Any shrinking model has a limitation in how small it can get.
    And I believe we would be seeing blue shifts of distant galaxies.
    Also in the expanding universe model anything smaller than galactic clusters is not subject to expansion due to gravity overcoming DE. The shrinking ruler model cannot explain how or why the rulers in these situations would not be shrinking.
    In fact all I see with your proposal is another effort to try and invalidate the current cosmological picture which includes GR, to add some non existant credibility to your own hypothesis.

    Again, in answer to the question by nebel, "The Universe has no center except the center of your personal observable universe.
    The Universe is also said to be Isotropic and homegeneous, meaning looking the same in all directions, and being the same where ever you are in the Universe. These are views over macroscopic scales."
    And that is the accepted cosmological model.
     
  14. Fraggle Rocker Staff Member

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    No one realized that the moon, planets, sun and other stars are as big as they are. No one could have imagined the enormous distance just between here and the moon, much less the much larger distance to the sun, much less the amazingly larger distances to the stars. They just thought all those things were floating in the atmosphere, just a bit farther away than the tops of the tallest mountains. Yes, they could see that the sun and moon are not mere points of light, but if they were indeed floating in the atmosphere, they wouldn't be much larger than a gigantic monument on a mountain peak. As for the stars, as far as these people could tell, they actually are points of light.

    This is simply not enough evidence to wonder whether there are other earth-like objects out there, too small to see from a distance.

    Since the earth is obviously not moving (I don't feel any sense of motion, do you?) then it makes sense that everything that IS moving must be revolving around it. Obviously the outer planets have rather complicated orbits, but the aphorism, "God works in mysterious ways," can easily account for that.
    There's no consensus on that. If the universe sprang into being as a result of the Big Bang, then it's a sphere of matter and energy that have been radiating out from an actual center for several billion years--our Hubble Volume, it's called.
    There is no consensus on that either. The only halfway elaborated model of the birth of the universe is the Big Bang, and as I said above, it strongly implies an expanding sphere with the point where the B.B. occurred at its center.

    We obviously don't have any way to test these hypotheses (at least not yet), but the Big Bang model answers a lot more questions than the others.

    The Rule of Laplace reminds us that extraordinary assertions must be supported by extraordinary evidence before we are obliged to take them seriously. The Big Bang has a lot more supporting evidence than any competing assertion.
     
  15. paddoboy Valued Senior Member

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    The BB was not an explosion per se. It was an evolution of space and time, and as such it can be seen that there is no center.
    Invoking God or any other deity is a non scientific explanation.
    http://www.skyandtelescope.com/astronomy-resources/center-of-the-universe/

    http://math.ucr.edu/home/baez/physics/Relativity/GR/centre.html
     
  16. paddoboy Valued Senior Member

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    http://www.universetoday.com/111561/where-is-the-center-of-the-universe/

    Where Is the Center of the Universe?

    by FRASER CAIN on APRIL 28, 2014

    In a previous episode we hinted that every spot is at the center of the Universe. But why? It turns out, every way you look at it, you’re standing dead center at the middle of everything. And so is everyone else.

    We ended a previous episode with how the center of the Universe is everywhere, and then quickly moved on to “Thanks for watching” without providing any details other than a wink and a nod.

    Good news, here come your details. First, imagine the expanding Universe in your mind. You might be picturing an inflating ball pushing out in all directions. Perhaps you’re seeing some kind of giant expanding celestial pumpkin. Unfortunately, that idea is incorrect. But don’t feel bad, our thinking meat parts just aren’t built to do this sort of thing.

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    Hubble’s images might look flat, but this one shows a remarkable depth of field that lets us see more than halfway to the edge of the observable Universe. Credit: NASA/ESA.

    The region of space that we can see is the observable Universe. When we look in any direction, we’re seeing the light that left stars millions and even billions of years ago. When you get out to the 13.8 billion light year mile marker, you’re seeing the light that was emitted shortly after the Big Bang, when the Universe cooled down to the point that it became transparent. So the observable Universe is a sphere around you, it’s relative to your position.

    My observable Universe is a sphere around me, relative to my position. So if I’m 10 meters away from you, I can see a little further into the Universe in that direction. If you look behind you, you’re seeing the observable Universe a little further in the that direction.

    Imagine you’re standing in a dark room holding a candle. You can see out into a sphere around you. You’re at the center of your observable space. And if I’m in a different location, I’ll have a different observable sphere. This is why we say that everyone is at the center of their own personal observable Universe.

    This has hints of pedantry and it’s a little unsatisfying, so let’s dig a little deeper. Where is the actual center of the Universe, regardless of who’s observing it? Our Universe might be finite or it might be infinite. Astronomers don’t actually know for sure. Their most precise calculations say that the observable Universe is 93 billion light years across.

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    Representation of the timeline of the universe over 13.7 billion years, and the expansion in the universe that followed. Credit: NASA/WMAP Science Team.

    Remember that light from the Big Bang that took 13.8 billion light years to get to you? Well the expansion of the Universe has pushed that region out to more than 46 billion light-years away. Look as far as you can to the right and as far as you can to the left. Those two spots are currently 93 billion light-years away from each other. So we can’t see how big the Universe really is. It’s got to be larger than 93 billion light-years. Everything outside that region we just can’t see… yet. It might be infinite.

    If the Universe is infinite, then there’s an infinite amount of space in that direction and an infinite amount of space in that direction, and that direction. And we’re back where we started, literally. Once again, you’re at the center of the Universe. And so am I.

    But what if the Universe is finite? That’s where it gets tricky. Imagine the observable Universe as a tiny sphere inside the much larger actual Universe. Maybe it’s 100 billion light years across, or maybe a trillion, or a quadrillion. Whatever the size, it’s not infinite. Now you would think there’s a center, right?

    Well, astronomers think that the topology of a finite Universe indicates that if you travel in any one direction long enough, you’ll return to your starting point. In other words, if you could look far enough in any direction, you’d see the back of your head.

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    Imagine the universe as a sphere – Advanced Celestial Sphere (Wolfram Project). Credit: Jim Arlow

    We did a whole episode on this, and you might want to check it out. And you’ll really want to check out Zogg the Aliens’ in-depth explanation. As an analogy, consider an ant on the surface of a sphere. Should the ant choose to walk in any direction, it’ll return to its starting point. Take that concept and scale it up one dimension. Can’t imagine it? No problem. Like I said, our brains aren’t equipped or experienced. And yet, that extra dimension seems to be the nature of the Universe. Regardless of what direction you travel, if it takes you the same amount of time to return to your starting point. Well… you’re at the center of the Universe?

    See? No matter how you think about it and break it down, you’re at the center of everything. And so am I. What do you think? Is the Universe finite or infinite? Tell us why in the comments below.
     
  17. Schmelzer Valued Senior Member

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    5,003
    No, why?
    Certainly not.
    A "ruler" in the general sense would be anything hold together by the existing forces. Once the galaxy cluster is hold together by gravitational forces, it is simply the greatest example of a ruler. And shrinking together with all smaller rulers.
    If one looks at the coordinates cosmologists use to describe the "expanding" universe, one sees coordinates where all the galaxies remain at rest (relative to the FLRW coordinates). So, it is the "expanding universe" picture which is not used by cosmologists in their computations, and the "decreasing rulers" picture used in FLRW coordinates.
     
  18. paddoboy Valued Senior Member

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    I find your explanations baseless.
    You have any reputable references to back up your claims?
     
  19. paddoboy Valued Senior Member

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    The accepted model is an expanding Universe over large scales, with gravity overcoming DE over smaller regions, which the shrinking rulers do not explain.
    This may help you.

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    https://www.aip.org/history/cosmology/ideas/expanding.htm
     
  20. paddoboy Valued Senior Member

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    The best that can ever be said for the "shrinking ruler" analogy, is that it is an "alternative perspective" albeit faulty, on the accepted standard cosmological model, rather than an "alternative model"
    The FLRW scenario you mention is just another "red herring"by yourself for previous stated reasons. Physicists/cosmologists often use "changes in perspective" to make a particular illustration clearer and sometimes do chose other perspectives when convenient to do so.
    The fact remains that the accepted expanding homegenous isotropic Universe model is what mainstream cosmology operates under along with the BB and GR.
    A reason why such models are so powerful and readily accepted is that they compliment each other admirably.

    ps: Again the important reminder...Any shrinking ruler perspective does not explain the decoupling of smaller regions of spacetime, nor why we do not see blue shifts over larger regions, with of course the obvious limitation to how small anything can shrink before it goes poof!
     
  21. Schmelzer Valued Senior Member

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    It is an interpretational issue, thus, it is not about a different theory with different equations. Once the equations are the same, there is no base to assume that the physical predictions are different. Thus, there is no reason to expect any additional limitations, nor a blueshift instead of a redshift.

    The picture of dried up earth with cracks, caused by the shrinking of the pieces of earth if the water evaporates, gives a nice picture what happens if everything shrinks. http://de.depositphotos.com/2126080/stock-photo-dried-up-cracked-earth.html

    Part of this is that there will be some critical size of the pieces which hold together. Which depends on the particular physical forces in this particular situation. And it is quite clear that the free parts will become greater if the shrinking continues.
     
  22. Schmelzer Valued Senior Member

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    Yep. Your point being? I have used "picture", quite close to "perspective", instead of "model".
    Yep. And I think that in this case to have different perspectives is useful and helpful for laymen too.
    As if I had questioned in this thread standard mainstream cosmology.
    Note: It is clear that the physical predictions do not depend on the choice of coordinates, or, in other words, on the choice of the "perspective". Thus, the success of the mainstream cosmology in no way depends on this choice - even if one could argue that some results could have been reached earlier if they would have preferred other coordinates, this is speculation. But, of course, some coordinates are easier than others, and it is natural that the scientist will prefer those which make the computations as simple as possible. In this (very weak) sense, it makes even sense to talk about coordinates "preferred" by the scientists in their actual computations.

    Then, the fact is that these "preferred" coordinates are the FLRW coordinates, and these coordinates correspond to the "shrinking rulers" perspective: The spatial coordinates of all galaxies, in the whole universe, remain unchanged, what changes is the measured distance between them, measured by the function a(t).
     
  23. James R Just this guy, you know? Staff Member

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    As others have said, we don't feel any apparent motion of the Earth. And if the Earth was really rotating at a thousand kilometers per hour at the equator, wouldn't there be enormous winds there? The air isn't tied down to the ground, so as the Earth rotates it would make sense for the air to stand still, causing apparent winds.

    Also, everybody knows that the Moon, the Sun and the other heavenly bodies must be made of different stuff to the stuff down here on Earth. If they weren't, then the Moon, for example, would surely fall down and hit the Earth. Rocks don't just hang in the sky.

    It makes sense that the Moon, if it is a big rock-like thing, is embedded in a giant sphere that revolves around the Earth once a day or so. The same goes for the Sun. And the planets must have their own independent spheres because they move across the sky at different rates to the Sun and Moon.

    Everybody knows that there are four elements - earth, air, fire and water - and each has its natural place in the cosmos. Earthy things tend to move downwards. Fire tends to move upwards. But no fire seems to affect the Moon. Moreover, the stars are unchanging and fixed in their relative positions in the sky. For a star to keep burning, it can't be made of fire, because all fires eventually burn out. Stars must all be embedded in their own heavenly sphere, and they must be made of a fifth element - call it quintessence.

    So, we have the sublunar realm - everything below the Moon - where the familiar elements do what they do. Then, above the Moon we have the various crystalline spheres that carry the planets and the Sun around the Earth every day. Beyond Saturn - the furthest planet - there is likely some mechanism that keeps the whole system revolving - call this the prime mover. Since we know that God created all of this, it seems likely that God lives somewhere above the prime mover, with the angels and other heavenly beings.
     

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