Notices
Results 1 to 47 of 47

Thread: Expanding Universe Question

  1. #1 Expanding Universe Question 
    Forum Sophomore
    Join Date
    May 2009
    Location
    South Africa
    Posts
    131
    If the universe is expanding at the speed of light and the light reaches us 13+ billion years late doesn't that make the universe, older than what it actually is we perceive it as?(basically the outer edge would be further than what it is as we see it now) or is my perception of space and the dimensions of the universe different to what the normal perception is

    Just a bit confused I guess on the dimensions of the universe and where we are in it

    Any thoughts, would be interesting


    Edit: Does no one know the answer or is it just a silly question that I am not fully grasping... Even a few links would be cool


    Just here to Learn =)

    Not Thinking is a sign of laziness, everyone has to make a choice at some point in their lives, either they reach a degree of non thinking where being stupid is just easier or they start thinking and enjoy the life they have now
    Reply With Quote  
     

  2.  
     

  3. #2 Re: Expanding Universe Question 
    Forum Professor
    Join Date
    Nov 2007
    Posts
    1,114
    Quote Originally Posted by Always.Asking
    If the universe is expanding at the speed of light and the light reaches us 13+ billion years late doesn't that make the universe, older than what it actually is we perceive it as?(basically the outer edge would be further than what it is as we see it now) or is my perception of space and the dimensions of the universe different to what the normal perception is

    Just a bit confused I guess on the dimensions of the universe and where we are in it

    Any thoughts, would be interesting


    Edit: Does no one know the answer or is it just a silly question that I am not fully grasping... Even a few links would be cool
    The BBT is a puzzle that is unsolvable.

    The question of size is one problem. How do you incorporate the 'megaparsec into this expansion?
    Officially, the BB is expanding at a rate of 75 kms per second. This expansion is happening at a 'uniform' rate.
    So is the BB expanding at 75 kms/s or is the megaparsec expanding at 75 kms/s?

    IMO, there is no solution to this problem.

    Cosmo


    Reply With Quote  
     

  4. #3  
    Suspended
    Join Date
    May 2008
    Posts
    1,096
    The Hubble constant is about 14 miles per second over a million light years. This means that if you have two small objects a millions light years apart, every second they will be 14 miles further from each other. Of course, it is just a coincidence that the maximum speed (186,282 mps) divided by 13,700 (units of one million light years) comes out to about 14.

    The big bang idea has some serious faults with it so maybe not true. The idea is that the universe expands like dots on a balloon so everything gets further away from everything else (except where local gravity is sufficient to overcome expansion). In this way, though expansion is fairly slow locally, since it is happening everywhere, the universe has expanded to maybe 158 billion light years across in just 13.7 billion years.

    Since light is so slow on a cosmic scale, we are looking back in time when we look at distant objects. If we look at something 13 billion light years away, then it is as it was 13 billion years ago, just 700,000,000 years after the big bang.

    However, I suspect we are living in a steady state universe which is not expanding. unfortunately we effectively live in a photo where on a cosmic scale, galaxies will not move noticeably in our lifetime, so we cannot know if expansion is a correct interpretation of effects or not.
    Reply With Quote  
     

  5. #4  
    Forum Sophomore
    Join Date
    May 2009
    Location
    South Africa
    Posts
    131
    Quote Originally Posted by Cyberia
    In this way, though expansion is fairly slow locally, since it is happening everywhere, the universe has expanded to maybe 158 billion light years across in just 13.7 billion years.
    how do we know that the universe is 158 billion light years u make it sound as well like we are not sure "maybe".

    and how can we see something 13.7 billion years ago, if its 158 billion light years away.
    Just here to Learn =)

    Not Thinking is a sign of laziness, everyone has to make a choice at some point in their lives, either they reach a degree of non thinking where being stupid is just easier or they start thinking and enjoy the life they have now
    Reply With Quote  
     

  6. #5  
    Suspended
    Join Date
    May 2008
    Posts
    1,096
    Put dots on a balloon and blow it up and they all move away from each other, so without breaking the cosmic speed limit, the universe can be very big in little time. It is estimated it is between 96 and 158 billion light years across.

    However, I do not believe in the big bang and have no idea how big the universe might really be since I don't think it is expanding. I can see several miles to the north from my house but on a misty morning, my view might stop at just half a mile. Because we live such short lives, we effectively see a photograph of the universe where very distant objects never move. It is possible that what is called the CMB is nothing more than a distance haze, caused by tens of billions of trillions of stars doing what stars do over untold billions of years.
    Reply With Quote  
     

  7. #6  
    Forum Sophomore
    Join Date
    May 2009
    Location
    South Africa
    Posts
    131
    Quote Originally Posted by Cyberia
    Put dots on a balloon and blow it up and they all move away from each other, so without breaking the cosmic speed limit, the universe can be very big in little time. It is estimated it is between 96 and 158 billion light years across.

    However, I do not believe in the big bang and have no idea how big the universe might really be since I don't think it is expanding. I can see several miles to the north from my house but on a misty morning, my view might stop at just half a mile. Because we live such short lives, we effectively see a photograph of the universe where very distant objects never move. It is possible that what is called the CMB is nothing more than a distance haze, caused by tens of billions of trillions of stars doing what stars do over untold billions of years.
    I have heard the balloon analogy before but I was not impressed with it.

    I heard that the expansion of the universe is like the balloon example except happening in a 3-D expansion

    it just confuses me how something could theoretically expand like that except in all directions and if it were to expand like that there are some questions that again crop up and the more time I spend reading the more I realize that there are no real answers

    if the big bang was a form of expansion, in a complete vacuum why would somethings move faster than others and what would make something like a galaxy form in the first place, I think we would get reverse creation(do the experiment with a balloon and imagine how small the big bang was at the beginning, so its kind of like saying well everything was really dense in the early universe then as everything came further and further apart things started coming back together to form galaxys etc)I know this is blamed on other forces but then why were those forces not there in the early expansion

    and as for the continuous accelleration I can understand this because its a 4-D object that were talking about with time included, so that would mean that things move away in particular ways.... but I don't understand how our visible universe would of formed under those circumstances, but on another side note we should still get a deceleration somewhere else maybe its just out of our visible view or something...by this I mean if everything expanded out from a single point in all directions then on the other side of the expansion we would be seeing deceleration
    or accelleration away from us but it would be deceleration in terms of the direction we are traveling

    and the acceleration (well what it appears from our perspective) why would we not hit the speed of light after several billion years(I think I know the answer to this just not sure about it) relative velocity is based on what we perceive u need something to compare to in order to measure velocity...if everything was moving at the speed of light would the speed of light be twice the speed of light and if not why not(and if u want to give an answer don't just say its a constant explain why its a constant)

    Just a few thoughts to ponder on

    Note: I am not making any claims here about anything, I am just stating my thoughts on the matter, and its all in all mostly disprovable pretty easily I would just like to learn a bit more.

    I would like to say as well that I use to believe in the big bang, but this forum and the stuff I have been reading lately(definitely more reading than writing on the forum and elsewhere) I no longer believe it so just wanted to say thanks to all that make this forum so interesting

    and thats everyone from Dish in this section, to Archy in the religious section.

    when a view is changed the whole world becomes more dynamic
    Just here to Learn =)

    Not Thinking is a sign of laziness, everyone has to make a choice at some point in their lives, either they reach a degree of non thinking where being stupid is just easier or they start thinking and enjoy the life they have now
    Reply With Quote  
     

  8. #7  
    Suspended
    Join Date
    May 2008
    Posts
    1,096
    The balloon analogy needs a 4D hypersphere. That is four physical dimensions, where the universe is the 3D skin. What would be inside is anybody's guess. What would happen if a 4D explosion punctured the 3D skin is anybody's guess but it sounds like the end of the universe.

    You are right in that there are no real answers. We are expected to believe that space expanded from quantum size to maybe over a hundred billion light years across without changing in any way. Doh!

    If you trace the big bang back, you eventually come to a density equivalent to a black hole, and it becomes a zillion times denser. Basic astronomy tells us that black holes (call them singularities if it makes you happier) don't expand or inflate so there is an impossibility.

    Expansion is at a crawl, around 15 miles per second per million light years.

    The speed of light is a constant. In theory if you were travelling at light speed and held a torch in front of you, the beam would be unable to leave the torch since it could go no faster. I suspect that what we call space is the limiting factor, that it is limited because of gravity's speed (rather than gravity's attraction).

    I don't believe in the big bang either but will give the info and other info so people can judge for themselves.
    Reply With Quote  
     

  9. #8  
    Suspended
    Join Date
    May 2008
    Posts
    1,096
    The balloon analogy needs a 4D hypersphere. That is four physical dimensions, where the universe is the 3D skin. What would be inside is anybody's guess. What would happen if a 4D explosion punctured the 3D skin is anybody's guess but it sounds like the end of the universe.

    You are right in that there are no real answers. We are expected to believe that space expanded from quantum size to maybe over a hundred billion light years across without changing in any way. Doh!

    If you trace the big bang back, you eventually come to a density equivalent to a black hole, and it becomes a zillion times denser. Basic astronomy tells us that black holes (call them singularities if it makes you happier) don't expand or inflate so there is an impossibility.

    Expansion is at a crawl, around 15 miles per second per million light years.

    The speed of light is a constant. In theory if you were travelling at light speed and held a torch in front of you, the beam would be unable to leave the torch since it could go no faster. I suspect that what we call space is the limiting factor, that it is limited because of gravity's speed (rather than gravity's attraction).

    I don't believe in the big bang either but will give the info and other info so people can judge for themselves.
    Reply With Quote  
     

  10. #9  
    Forum Sophomore
    Join Date
    May 2009
    Location
    South Africa
    Posts
    131
    Quote Originally Posted by Cyberia
    The balloon analogy needs a 4D hypersphere. That is four physical dimensions, where the universe is the 3D skin. What would be inside is anybody's guess. What would happen if a 4D explosion punctured the 3D skin is anybody's guess but it sounds like the end of the universe.

    You are right in that there are no real answers. We are expected to believe that space expanded from quantum size to maybe over a hundred billion light years across without changing in any way. Doh!

    If you trace the big bang back, you eventually come to a density equivalent to a black hole, and it becomes a zillion times denser. Basic astronomy tells us that black holes (call them singularities if it makes you happier) don't expand or inflate so there is an impossibility.

    Expansion is at a crawl, around 15 miles per second per million light years.

    The speed of light is a constant. In theory if you were travelling at light speed and held a torch in front of you, the beam would be unable to leave the torch since it could go no faster. I suspect that what we call space is the limiting factor, that it is limited because of gravity's speed (rather than gravity's attraction).

    I don't believe in the big bang either but will give the info and other info so people can judge for themselves.
    Is the expansion constant and is that a velocity or a acceleration
    Just here to Learn =)

    Not Thinking is a sign of laziness, everyone has to make a choice at some point in their lives, either they reach a degree of non thinking where being stupid is just easier or they start thinking and enjoy the life they have now
    Reply With Quote  
     

  11. #10  
    Moderator Moderator Dishmaster's Avatar
    Join Date
    Apr 2008
    Location
    Heidelberg, Germany
    Posts
    1,624
    Quote Originally Posted by Cyberia
    The speed of light is a constant. In theory if you were travelling at light speed and held a torch in front of you, the beam would be unable to leave the torch since it could go no faster.
    Careful with what you are saying. The speed of light is the same for everyone. For somebody watching the torch carrier as well as the torch carrier himself. This means, the latter would not notice anything particularly strange. He would still see a very normal torch with a very normal cone of light leaving it with a very normal velocity that is the speed of light.
    Reply With Quote  
     

  12. #11  
    Moderator Moderator Dishmaster's Avatar
    Join Date
    Apr 2008
    Location
    Heidelberg, Germany
    Posts
    1,624
    Quote Originally Posted by Always.Asking
    Is the expansion constant and is that a velocity or a acceleration
    The Hubble constant describing the expansion of the universe is a velocity per length unit. In the usual units, it is about 74 km/s per Mpc. This means that the expansion velocity increases by 74 km/s every megaparsec. One megaparsec is 1 million parsec, and one parsec is 3.086 x 10^16 metres. For a comparison, the currently valid distance estimate to the Andromeda galaxy is about 780 kiloparsec or 0.78 megaparsec.

    So, in that sense, expansion is a velocity. But this velocity can change. The Big Bang standard theory postulates a short era of very rapid and accelerated expansion immediately after the Big Bang that quickly slowed down to a constant velocity. Current measurements also seem to indicate that the expansion is accelerating again. So, it is really not an explosion. Something else is driving it.
    Reply With Quote  
     

  13. #12  
    Moderator Moderator Dishmaster's Avatar
    Join Date
    Apr 2008
    Location
    Heidelberg, Germany
    Posts
    1,624
    Moderator mode:
    I could bet that someone had to hijack this thread again to bring forward the antithesis of the non expanding universe. And I'm disappointed that I was right in that matter.

    To be clear: If you want to discuss alternative theories of cosmology, feel free to start a new thread, and we can discuss them. This thread is about the consequences of the commonly accepted theory - which does not mean that it is correct. It has been stated many times in this forum that no other theory is more consistent with all the evidence that had been found over the decades.

    So I encourage you, Two Socks, to delete your post and use it to open a new thread.

    Thank you,
    Dishmaster (Moderator).
    Reply With Quote  
     

  14. #13  
    Suspended
    Join Date
    May 2008
    Posts
    1,096
    Dishmaster. The big bang idea has some very serious problems with it and relies on a number of impossibilities and ideas. The few things given as evidence for it have alternative explanations. Why should posts which only agree with the opening topic be allowed on a thread? That isn't debate.



    In my example, I said someone was travelling at light speed (an impossibility of course) which would mean that light could go no faster so no beam would leave the torch in the direction of travel.
    Reply With Quote  
     

  15. #14  
    Universal Mind John Galt's Avatar
    Join Date
    Jul 2005
    Posts
    14,168
    Quote Originally Posted by Cyberia
    Dishmaster. The big bang idea has some very serious problems with it and relies on a number of impossibilities and ideas. The few things given as evidence for it have alternative explanations. Why should posts which only agree with the opening topic be allowed on a thread? That isn't debate..
    This is a science forum where we follow the consensus views of science when answering basic questions from persons ignorant in that particular sphere. If anyone wishes to pursue unorthodox concepts they are free to do so in a thread of their own creation. Don't **** up someone new to the subject with views stemming from your personal incredulity.
    Reply With Quote  
     

  16. #15  
    Moderator Moderator Dishmaster's Avatar
    Join Date
    Apr 2008
    Location
    Heidelberg, Germany
    Posts
    1,624
    Quote Originally Posted by Cyberia
    Dishmaster. The big bang idea has some very serious problems with it and relies on a number of impossibilities and ideas. The few things given as evidence for it have alternative explanations. Why should posts which only agree with the opening topic be allowed on a thread? That isn't debate.
    I welcome debate. But not in every thread. The first post contained a question based on the concept of the Big Bang theory. If you had followed my posts closely, you would have recognised that I agree that there are problems. But this is not what the OP wanted to know. We should respect that. I consider it his thread, because he opened it.

    Quote Originally Posted by Cyberia
    In my example, I said someone was travelling at light speed (an impossibility of course) which would mean that light could go no faster so no beam would leave the torch in the direction of travel.
    I understand. And I repeat that this is wrong. The torch does not know that it travels with the speed of light. Neither do the photons emitted. Anyone travelling along with the torch would not see anything special. He would still see a totally normal torch with light emitted with the speed of light. However, an external observer would see something else, namely something you describe, because he would also see light travelling with the speed of light. But since the light source has the same velocity, he would never get to see the beam.
    Reply With Quote  
     

  17. #16  
    Administrator KALSTER's Avatar
    Join Date
    Sep 2007
    Location
    South Africa
    Posts
    8,231
    The balloon analogy needs a 4D hypersphere. That is four physical dimensions, where the universe is the 3D skin. What would be inside is anybody's guess. What would happen if a 4D explosion punctured the 3D skin is anybody's guess but it sounds like the end of the universe.
    You keep getting this analogy wrong. The analogy is a standard 3D inflating sphere, with the dots on the surface getting further apart as in inflates. But only what happens on the surface is directly analogous to a model of the real universe. There is no consideration for the inside of the balloon. The expansion of our universe produces the same sort of effects in 3D as one sees on the 2D surface of the balloon. The universe is not a 4D hypersphere.

    The analogy provides a way to envisage the inflation of the universe where only the 3D version of the 2D surface exists, but according to observations the universe is probably more sort of a 3D saddle shape or hyperbolic. Look HERE for an explanation on the three possibilities (all of them only 3D, or 3-manifolds).

    If you trace the big bang back, you eventually come to a density equivalent to a black hole, and it becomes a zillion times denser. Basic astronomy tells us that black holes (call them singularities if it makes you happier) don't expand or inflate so there is an impossibility.
    Wrong. A black hole is not simply a singularity, but the singularity along with an event horizon. If you deflate the universe you get a point mass, or a singularity with no surrounding space. A singularity has infinite density. Just because we have never seen a singularity expand does not mean it cannot happen. We simply don't know exactly how something like that can happen. Models of the big bang also does not go as far back as t = 0.

    and the acceleration (well what it appears from our perspective) why would we not hit the speed of light after several billion years
    AFAIK it actually does. The farthest galaxies we can see have receding velocities approaching light speed.

    but I don't understand how our visible universe would of formed under those circumstances, but on another side note we should still get a deceleration somewhere else maybe it’s just out of our visible view or something...by this I mean if everything expanded out from a single point in all directions then on the other side of the expansion we would be seeing deceleration
    or acceleration away from us but it would be deceleration in terms of the direction we are travelling
    The farthest we can see is about 13.7 billion light years. It is this far, because that is the amount of time light has had a chance to get to us. If the universe were to stop expanding, then in another billion years we would be able to see things that were there the whole time 14.7 billion light years away. The universe did undergo a rate of inflation in which the expansion was at apparent superluminal speeds and then it did slow down. It has now started to accelerate again from observations.

    Remember to think of the universe as the surface of the balloon, where expansion means that a round trip would take longer as it expanded. You could be at any point in the universe and everything would still be expanding away from you.

    All of this is only AFAIK though.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

    "Gullibility kills" - Carl Sagan
    "All people know the same truth. Our lives consist of how we chose to distort it." - Harry Block
    "It is the mark of an educated mind to be able to entertain a thought without accepting it." - Aristotle
    Reply With Quote  
     

  18. #17  
    Forum Professor marcusclayman's Avatar
    Join Date
    Mar 2009
    Posts
    1,702
    "If the universe is expanding at the speed of light and the light reaches us 13+ billion years late doesn't that make the universe, older than what it actually is we perceive it as?(basically the outer edge would be further than what it is as we see it now)"

    There is no edge, also.

    The balloon analogy is flawed in the sense that it makes you think the balloon is the edge of the universe, and what is in the balloon, is the universe. I don't know if this is how other people first thought of it, but I had that misconception fro quite some time, and still my brain has a hard time wrapping around the truth.

    I like using the raisin bread analogy(as shown on wiki if you do a search for the expansion of space) instead of the balloon. As the bread is baked the raisins all move further apart, even though the ingredients never change(ignoring of course, for the sake of simplicity, the air)

    This is, in essence, the same as the balloon, but I think the added touch of "no added ingredients" helps folk understand it all easier.
    Dick, be Frank.

    Ambiguity Kills.
    Reply With Quote  
     

  19. #18  
    Forum Professor marcusclayman's Avatar
    Join Date
    Mar 2009
    Posts
    1,702
    There is no question that some of the universe will never be seen by us, unless it stops expanding, and even then it will take some time for us to see it all. By the time we see the furthest objects in the universe in such a situation, everything we CAN see, won't exist.
    Dick, be Frank.

    Ambiguity Kills.
    Reply With Quote  
     

  20. #19  
    Universal Mind John Galt's Avatar
    Join Date
    Jul 2005
    Posts
    14,168
    Quote Originally Posted by marcusclayman
    This is, in essence, the same as the baloon, but I think the added touch of "no added ingredients" helps folk understand it all easier.
    Each to their own. A loaf of bread has boundaries, the surface of a balloon does not. A loaf has a centre. The surface of a balloon does not. I've never seen a difficulty with the analogy since the key word is surface.
    Reply With Quote  
     

  21. #20  
    Forum Professor marcusclayman's Avatar
    Join Date
    Mar 2009
    Posts
    1,702
    That's true John. But I think some people are in the same boat as me, and the first time they heard the balloon analogy it was not explained very well. I heard it when I was very young and it shaped the way I imagined the universe, even though I know it is wrong, I wonder if I would be better at imagining such things if I had a different example. And the bread seems to be that example that would have given me the proper mental image...

    It is however, my own circumstances that lead me to think this. As you say, to each their own, and it would probably be best to give multiple examples, to eliminate misunderstanding, unless your especially good at describing, and/or are teaching an exceptionally gifted student.
    Dick, be Frank.

    Ambiguity Kills.
    Reply With Quote  
     

  22. #21  
    Universal Mind John Galt's Avatar
    Join Date
    Jul 2005
    Posts
    14,168
    Of course the real way to understand it properly is to understand the maths and that, regretably, is beyond me.
    Reply With Quote  
     

  23. #22  
    Administrator KALSTER's Avatar
    Join Date
    Sep 2007
    Location
    South Africa
    Posts
    8,231
    Quote Originally Posted by John Galt
    Of course the real way to understand it properly is to understand the maths and that, regretably, is beyond me.
    Me too. Ususally when I try to figure out the math my eyes turn into spirals and I start walking into walls and tripping over furnature.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

    "Gullibility kills" - Carl Sagan
    "All people know the same truth. Our lives consist of how we chose to distort it." - Harry Block
    "It is the mark of an educated mind to be able to entertain a thought without accepting it." - Aristotle
    Reply With Quote  
     

  24. #23  
    Forum Sophomore
    Join Date
    May 2009
    Location
    South Africa
    Posts
    131
    Quote Originally Posted by KALSTER
    You keep getting this analogy wrong. The analogy is a standard 3D inflating sphere, with the dots on the surface getting further apart as in inflates. But only what happens on the surface is directly analogous to a model of the real universe. There is no consideration for the inside of the balloon. The expansion of our universe produces the same sort of effects in 3D as one sees on the 2D surface of the balloon. The universe is not a 4D hypersphere.
    I was saying it using time as the 4th dimension, not a 4D object
    Just here to Learn =)

    Not Thinking is a sign of laziness, everyone has to make a choice at some point in their lives, either they reach a degree of non thinking where being stupid is just easier or they start thinking and enjoy the life they have now
    Reply With Quote  
     

  25. #24  
    Administrator KALSTER's Avatar
    Join Date
    Sep 2007
    Location
    South Africa
    Posts
    8,231
    Quote Originally Posted by Always.Asking
    Quote Originally Posted by KALSTER
    You keep getting this analogy wrong. The analogy is a standard 3D inflating sphere, with the dots on the surface getting further apart as in inflates. But only what happens on the surface is directly analogous to a model of the real universe. There is no consideration for the inside of the balloon. The expansion of our universe produces the same sort of effects in 3D as one sees on the 2D surface of the balloon. The universe is not a 4D hypersphere.
    I was saying it using time as the 4th dimension, not a 4D object
    Sorry, I was rsponding to Cyberia there. I should have labeled them.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

    "Gullibility kills" - Carl Sagan
    "All people know the same truth. Our lives consist of how we chose to distort it." - Harry Block
    "It is the mark of an educated mind to be able to entertain a thought without accepting it." - Aristotle
    Reply With Quote  
     

  26. #25  
    Forum Professor
    Join Date
    Nov 2007
    Posts
    1,114
    Before I say anything, I would like to explain my absence for a few days.
    Believe it or not, but microsoft has entered my computer without my knowledge and restructured my XP OS to keep me from accessing the internet to post my comments. It has also blocked most all my documents for my personal formatting.
    So I have a real problem here that may require legal action.


    Now to get back to the thread question?

    My own opinion is that the BB is NOT expanding. So the size is mute except for my original post here that this is not possible to solve.

    Cosmo
    Reply With Quote  
     

  27. #26  
    Forum Freshman
    Join Date
    Nov 2007
    Location
    San Diego, California
    Posts
    96
    Quote Originally Posted by Cosmo
    My own opinion is that the BB is NOT expanding.
    Cosmo
    My question to you (and Cyberia also, if you care to answer) is what is your explanation of the evidence that supports the BBT? For example, SN1a redshift data or the cosmic microwave background radiation. I think Cyberia said that there were other explanations (that presumably have not yet been refuted) and I was wondering what they were.
    Reply With Quote  
     

  28. #27  
    Time Lord
    Join Date
    Mar 2007
    Posts
    8,035
    My theory is that space is dragged inward toward objects that have gravity, which forces it to expand in other areas. So, it contracts near a star or planet or black hole, and then expands in the lagrange points between them.

    But I don't mean that it discreetly only contracts or expands at exactly those locations. More like, the effect tapers continuously from the expansion point to the contraction point. Under that theory, light would tend to undergo redshift after it's been traveling a long time in deep space, because it's been traveling through areas that are expanding.

    Another possibility would just be a universal expansion that's cancelled by local contractions.
    Reply With Quote  
     

  29. #28  
    Forum Freshman
    Join Date
    Nov 2007
    Location
    San Diego, California
    Posts
    96
    The problem with that is that you cannot have more expansion than contraction and still have a SS universe. You can look at it as a summation on a universal scale.
    If you want the universe to not expand in your theory, then the local anisotropies in spacetime caused by gravity wells and potentials would necessarily have to cancel each other out, ie, they would have to be equal. Given the homogeneity of the universe on large scales, we would not see any shift in the spectrum of distant galaxies in this case. Since we do, there would have to be more expansion than contraction and the universe would be expanding overall.
    Reply With Quote  
     

  30. #29  
    Forum Sophomore
    Join Date
    May 2009
    Location
    South Africa
    Posts
    131
    Quote Originally Posted by kojax
    My theory is that space is dragged inward toward objects that have gravity, which forces it to expand in other areas. So, it contracts near a star or planet or black hole, and then expands in the lagrange points between them.

    But I don't mean that it discreetly only contracts or expands at exactly those locations. More like, the effect tapers continuously from the expansion point to the contraction point. Under that theory, light would tend to undergo redshift after it's been traveling a long time in deep space, because it's been traveling through areas that are expanding.

    Another possibility would just be a universal expansion that's cancelled by local contractions.
    Hi kojax, that is definitely an interesting theory and in my opinion it sounds very similar to something else I have heard before

    If I may make the comparison:

    the earth does not grow or shrink, yet continents still move apart at pretty much a constant rate(I think it was 1 cm per yer or something like that, I know some move apart others move towards each other but most of it is apart and I think the same occurs in the reality of space), we get things moving towards each other and apart from each other, we just say most of it is apart and dismiss the rest

    at the middle of these movements we get new surface "space" appearing and at the continents (stars, planets, black holes etc) we get subduction space vanishing.

    I cannot really find a flaw in such an argument and u might just turn out to be right who knows, but since currently we have no force to do that to our universe it is likely that such theories will be dismissed pretty quickly

    if we had a better understanding the universe and perhaps a multi-dimensional view of it, this type of hypothesis would be clearer either to prove or dismiss.

    For a long time after the theory was developed there was no proof to back it up, and I think with our current technologies I would go as far as to say that it is up to future generations to find that proof

    I do not believe in the big bang at the moment(trying to dig into the evidence for it and trying to reinterpret what we are seeing) at least not in the traditional sense of it, thank you for sharing ur alternative view.

    I think the universe is way BIGGER than what we see

    I think our view of the universe is so small if I may use another analogy here

    "If the earth was a peach, we are skimming the fuzz on the peach"
    this was used to describe earth orbits in the early parts of the space race

    Our view of space is just that the fuzz on the peach
    and my explanation for the expansion is it is a local breeze blowing though the area of space we call everything...

    Its like a ancient society saying the blue sky and atmosphere is all that there is, because they cant imagine things further away even though they can see the stars, they are "pinholes above the sky" I could say the same for our interpretation of the background radiation, its there we all know that, but the speculation comes from our interpretation of it, and currently I think it is very wrong...

    and as yet not many would come forward to look at alternative reasons or causes for it
    Just here to Learn =)

    Not Thinking is a sign of laziness, everyone has to make a choice at some point in their lives, either they reach a degree of non thinking where being stupid is just easier or they start thinking and enjoy the life they have now
    Reply With Quote  
     

  31. #30  
    Time Lord
    Join Date
    Mar 2007
    Posts
    8,035
    Hubble observations could be seen as the observation of a wave traveling through the ocean part of that analogy, but not across the continents. If it hits a continent it stops, and has to be re-emitted.

    One possibility would be that space expands at a constant rate throughout, except near objects of mass, where it contracts instead. But that could still mean that all of the contractions cancel out the expansions. Maybe the need to enforce this ratio places a limit on how much matter there is out there?
    Reply With Quote  
     

  32. #31  
    Suspended
    Join Date
    May 2008
    Posts
    1,096
    Quote Originally Posted by KALSTER
    You keep getting this analogy wrong. The analogy is a standard 3D inflating sphere, with the dots on the surface getting further apart as in inflates. But only what happens on the surface is directly analogous to a model of the real universe. There is no consideration for the inside of the balloon. The expansion of our universe produces the same sort of effects in 3D as one sees on the 2D surface of the balloon. The universe is not a 4D hypersphere.
    Of course, the universe is only a mile thick and a zillion light years across. Doh! Expansion only works out with a hypersphere where the 3D skin has depth for us 3D beings but not for a 4D structure. Do read up on the fourth dimension sometime.


    The analogy provides a way to envisage the inflation of the universe where only the 3D version of the 2D surface exists, but according to observations the universe is probably more sort of a 3D saddle shape or hyperbolic. Look HERE for an explanation on the three possibilities (all of them only 3D, or 3-manifolds).
    So it's a saddle now? What happened to the trumpet, the cones, and all the other weird shapes these know-nothing clowns keep coming up with?

    Wrong. A black hole is not simply a singularity, but the singularity along with an event horizon. If you deflate the universe you get a point mass, or a singularity with no surrounding space. A singularity has infinite density. Just because we have never seen a singularity expand does not mean it cannot happen. We simply don't know exactly how something like that can happen. Models of the big bang also does not go as far back as t = 0.
    BS alert! BS alert! A singularity is a stupid idea that there is no evidence for. Even Hawking has disowned them. If something has infinite density, then it is infinitely stable, forever. Science don't come more basic than that! The only way your singularity IDEA is going to work is if an all powerful God is there to make it happen, because he doesn't give a damn about the laws of science.
    Reply With Quote  
     

  33. #32  
    Suspended
    Join Date
    May 2008
    Posts
    1,096
    Quote Originally Posted by marcusclayman
    I like using the raisin bread analogy(as shown on wiki if you do a search for the expansion of space) instead of the balloon. As the bread is baked the raisins all move further apart, even though the ingredients never change(ignoring of course, for the sake of simplicity, the air)

    The raisin bread analogy has a definite point of origin, so we could point in X direction and say that the big bang began there.

    There is also the point that the universe has supposedly expanded from quantum size to over a hundred billion light years in diameter. Anyone who thinks the structure of space has not changed out of all meaning in that time is living in lala land. It would also have an ever lower energy so whereas at BB + one year, a cubic light year of space might be bulling with zillions of virtual particles, the same area now would probably only contain a few virtual particles if that.

    But it all boils down to density as to how something a trillion times black hole density expands. Answers on a postcard to Santa Claus, North Pole.
    Reply With Quote  
     

  34. #33  
    Suspended
    Join Date
    May 2008
    Posts
    1,096
    Quote Originally Posted by Feifer
    My question to you (and Cyberia also, if you care to answer) is what is your explanation of the evidence that supports the BBT? For example, SN1a redshift data or the cosmic microwave background radiation. I think Cyberia said that there were other explanations (that presumably have not yet been refuted) and I was wondering what they were.

    SN1a are NOT standard candles. Spin them a little faster and you can have double the mass, so a much greater explosion, so an appearance of being much further away. Being in an area where there is gas (notably hydrogen) and dust works too. The elemental content of thee matter coming from a larger star is important too. And so on.

    I think the redshift is down to a sea of gravity which pervades the entire universe. It is a drag on photons. Whereas photons redshift strongly in just a mile, leaving a neutron star, they redshift strongly over billions of years, travelling through space.

    The CMB? Why is it at 2.7K and why not at around 3,000K? Do we look at stars 13 billion light years away and say that their surface temperature is only a few degrees above absolute? How did the CMB cool so quickly? We should be able to measure a graduated scale of cooling space from the CMB at around 3,000K to a point maybe a billion light years closer where it finally is around 2.7K.
    Reply With Quote  
     

  35. #34  
    Forum Masters Degree Numsgil's Avatar
    Join Date
    Jan 2009
    Posts
    708
    Quote Originally Posted by Cyberia
    I think the redshift is down to a sea of gravity which pervades the entire universe. It is a drag on photons. Whereas photons redshift strongly in just a mile, leaving a neutron star, they redshift strongly over billions of years, travelling through space.

    The CMB? Why is it at 2.7K and why not at around 3,000K? Do we look at stars 13 billion light years away and say that their surface temperature is only a few degrees above absolute? How did the CMB cool so quickly? We should be able to measure a graduated scale of cooling space from the CMB at around 3,000K to a point maybe a billion light years closer where it finally is around 2.7K.
    You just answered your own question. Wether from the expansion of space (doppler shift), or a gravity sea causing photon drag, energy is lost. That lost energy makes distant things look cooler. THe more distant, the cooler they get. So that 3000K background radiation from the surface of last scattering (ie: the moment the universe because transparent to light), has experienced "drag", which takes energy from it.

    The BR looks uniform in temperature everywhere we look because the surface of last scattering is the same distance from us in every direction (because all points in the universe are the center of the universe...)
    "A witty saying proves nothing." - Voltaire
    Reply With Quote  
     

  36. #35  
    Administrator KALSTER's Avatar
    Join Date
    Sep 2007
    Location
    South Africa
    Posts
    8,231
    Expansion only works out with a hypersphere where the 3D skin has depth for us 3D beings
    Dude, one of the 3 dimensions are depth. Once again, in the sphere analysis, only the 2D surface is analogous to 3D space, not the rest of the sphere. We have three dimensions, which are plenty (assuming string theory is incorrect).

    So it's a saddle now? What happened to the trumpet, the cones, and all the other weird shapes these know-nothing clowns keep coming up with?
    You really are confident for someone that doesn't have any idea what he is talking about and lacks any kind of training that would lend credibility to his flippant dismissals of complicated theories.

    BS alert! BS alert! A singularity is a stupid idea that there is no evidence for.
    It is a prediction of current theories. Care to try and explain why they are so stupid, other than you simply not liking the idea?
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

    "Gullibility kills" - Carl Sagan
    "All people know the same truth. Our lives consist of how we chose to distort it." - Harry Block
    "It is the mark of an educated mind to be able to entertain a thought without accepting it." - Aristotle
    Reply With Quote  
     

  37. #36  
    Forum Freshman
    Join Date
    Nov 2007
    Location
    San Diego, California
    Posts
    96
    Quote Originally Posted by Cyberia
    Quote Originally Posted by Feifer
    My question to you (and Cyberia also, if you care to answer) is what is your explanation of the evidence that supports the BBT? For example, SN1a redshift data or the cosmic microwave background radiation. I think Cyberia said that there were other explanations (that presumably have not yet been refuted) and I was wondering what they were.

    SN1a are NOT standard candles. Spin them a little faster and you can have double the mass, so a much greater explosion, so an appearance of being much further away.
    I'm sorry, this sounds backwards. Wouldn't this make it look closer, not further away?

    Whether or not it's possibile that a SN1a can be larger than normal seems beside the point to me since they can NOT be any smaller than about 1.4 solar masses for a non-rotating white dwarf. Obviously, dust is not evenly distributed in the universe, so how do you make them all look further away by the same proportion? A team like the High-z Supernova search is taking data from hundreds of SN and there is a definite correlation between z and apparent magnitude. Not to mention that at closer distances they've been proven reliable by cepheid variables. In other words, yes, SN1a ARE standard candles.
    Reply With Quote  
     

  38. #37  
    Suspended
    Join Date
    May 2008
    Posts
    1,096
    Quote Originally Posted by Numsgil
    You just answered your own question. Wether from the expansion of space (doppler shift), or a gravity sea causing photon drag, energy is lost. That lost energy makes distant things look cooler. THe more distant, the cooler they get. So that 3000K background radiation from the surface of last scattering (ie: the moment the universe because transparent to light), has experienced "drag", which takes energy from it.

    The BR looks uniform in temperature everywhere we look because the surface of last scattering is the same distance from us in every direction (because all points in the universe are the center of the universe...)

    I accept that photons do lose energy over time of travel, so redshift. I argue about the cause as I do not believe that space can stretch.

    As I have pointed out elsewhere, if the CMB is 3,000K, then we would be told that it was 3,000K. No one looks at a cluster thirteen billion light years away and tells us that it's stars are almost as cold as the intergalactic medium. Allowances are made for redshifting.

    Imagine a universe X billion years old. For tens of billions of years, trillions of trillions of stars have been pouring out radiations and solar winds. These are now fairly evenly scattered so their past emissions are virtually uniform across the universe.
    Reply With Quote  
     

  39. #38  
    Suspended
    Join Date
    May 2008
    Posts
    1,096
    Quote Originally Posted by KALSTER
    Dude, one of the 3 dimensions are depth. Once again, in the sphere analysis, only the 2D surface is analogous to 3D space, not the rest of the sphere. We have three dimensions, which are plenty (assuming string theory is incorrect).

    A 3D expansion gives us a definite centre away from which everything is expanding.


    You really are confident for someone that doesn't have any idea what he is talking about and lacks any kind of training that would lend credibility to his flippant dismissals of complicated theories.

    The complicated theories as in the shape of the universe changes regularly, so maybe not correct? I favour the universe being a sphere.

    It is a prediction of current theories. Care to try and explain why they are so stupid, other than you simply not liking the idea?

    A singularity would be ultimately stable. Every ultra-dense object would have an event horizon. Like DM, they are given whatever properties are needed at the time. Even Hawking dumped them (pg 50, A Brief History of Time).
    Reply With Quote  
     

  40. #39  
    Suspended
    Join Date
    May 2008
    Posts
    1,096
    Fiefer. Yes you are right. Closer. I shouldn't watch TV while on a forum. Dust can make them appear fainter, so further. It is wrong to label all stars, even super-novae as though they were 100% the same and that there could be no outside factors changing details (like a very large planet falling into a star).


    http://www.skyandtelescope.com/commu.../24314749.html


    .
    Reply With Quote  
     

  41. #40  
    Administrator KALSTER's Avatar
    Join Date
    Sep 2007
    Location
    South Africa
    Posts
    8,231
    A 3D expansion gives us a definite centre away from which everything is expanding.
    If you take the cookie dough analogy literally, which you shouldn't. Remember that since the big bang is purported to be the start of all space, time and matter, it means that the image of a sphere you have in your mind is impossible. The sphere you see in your mind is only possible if it has something to expand into, which the early universe did not.

    Here is again where the balloon analogy is supposed to help, but has given you entirely the wrong idea. On the surface of a balloon you could start at any point and then take off in any direction and would walk the same distance before ending up from where you started. This is where the analogy ends. You take that and apply it to our 3D universe to get an idea of what happened. It means that you can start at any point and take off in any direction and you would end up where you started after the same distance (if expansion stopped before you trip). From our vantage point everything looks as if it is moving away from us and indeed the same would be true for any point in the universe you chose to start your journey from. There is no center of the universe, since every point is the center.

    The complicated theories as in the shape of the universe changes regularly, so maybe not correct?
    There always was more than one possibility for the shape of the universe and as better understandings of relativity and better observations have been made, the data has started to point towards one shape.

    A singularity would be ultimately stable. Every ultra-dense object would have an event horizon. Like DM, they are given whatever properties are needed at the time. Even Hawking dumped them (pg 50, A Brief History of Time).
    Stephen Hawking has an idea about the big bang that does not necessarily include a singularity, but he has no problem with singularities in black holes. Singularities are predicted by relativity and quantum mechanics where an object with a certain mass and size will inevitably collapse into a singularity, since there is no known force that can keep it from happening. From what I have found out it looks as if this collapse will always start while no event horizon exists yet. An event horizon, remember, is the imaginary barrier at which the escape velocity is equal to C. Theoretically if you could compress the earth to a small enough diameter it would form a black hole (maybe even without a singularity), but the earth does not have enough matter for this to happen on its own. So if you were to start adding matter to the earth it would start the final inevitable collapse before the event horizon can form. Singularities are not given any properties willy-nilly. Trying to find out exactly what happens under the extreme environments of a black hole and around the singularity might yield a few out-there ideas, but these are quite often simply that, ideas, and by no means are intended to be taken as fact. Under these extreme conditions relativity and QM breaks down and it becomes difficult to make sure predictions. None of this speculation though takes away from the fact that singularities are pretty much accepted throughout.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

    "Gullibility kills" - Carl Sagan
    "All people know the same truth. Our lives consist of how we chose to distort it." - Harry Block
    "It is the mark of an educated mind to be able to entertain a thought without accepting it." - Aristotle
    Reply With Quote  
     

  42. #41  
    Time Lord
    Join Date
    Mar 2007
    Posts
    8,035
    Quote Originally Posted by Feifer
    The problem with that is that you cannot have more expansion than contraction and still have a SS universe. You can look at it as a summation on a universal scale.

    If you want the universe to not expand in your theory, then the local anisotropies in spacetime caused by gravity wells and potentials would necessarily have to cancel each other out, ie, they would have to be equal. Given the homogeneity of the universe on large scales, we would not see any shift in the spectrum of distant galaxies in this case. Since we do, there would have to be more expansion than contraction and the universe would be expanding overall.
    (continuing my cancellation theory --- this is not orthodox science)

    Just because the universe is homogeneous doesn't mean the light we see has passed through a homogeneous area. You don't see light if it runs into an object of mass. It disappears and gets re-emitted or converted into another kind of energy.

    The area near a star would be experiencing quite a lot of contraction (especially a lot of contraction per unit area of space). The areas far away from a star would experience much less expansion per unit area of space. (But the fact there's a lot of area makes up for it).

    So, the contractions are very concentrated, and the expansions are very spread out, and light traveling between us and a distant galaxy doesn't usually venture anywhere near the contractions.
    Reply With Quote  
     

  43. #42  
    Moderator Moderator Dishmaster's Avatar
    Join Date
    Apr 2008
    Location
    Heidelberg, Germany
    Posts
    1,624
    Quote Originally Posted by kojax
    The area near a star would be experiencing quite a lot of contraction (especially a lot of contraction per unit area of space). The areas far away from a star would experience much less expansion per unit area of space. (But the fact there's a lot of area makes up for it).

    So, the contractions are very concentrated, and the expansions are very spread out, and light traveling between us and a distant galaxy doesn't usually venture anywhere near the contractions.
    But wouldn't the structure of the CMBR be correlated with visible matter then? This is not observed. Another thing is: If the path is long enough, any photon would pass an area of matter eventually. The line of sight is limited for any point in space.
    Reply With Quote  
     

  44. #43  
    Time Lord
    Join Date
    Mar 2007
    Posts
    8,035
    Quote Originally Posted by Dishmaster
    Quote Originally Posted by kojax
    The area near a star would be experiencing quite a lot of contraction (especially a lot of contraction per unit area of space). The areas far away from a star would experience much less expansion per unit area of space. (But the fact there's a lot of area makes up for it).

    So, the contractions are very concentrated, and the expansions are very spread out, and light traveling between us and a distant galaxy doesn't usually venture anywhere near the contractions.
    But wouldn't the structure of the CMBR be correlated with visible matter then? This is not observed. Another thing is: If the path is long enough, any photon would pass an area of matter eventually. The line of sight is limited for any point in space.
    I'm sure many photons do pass through areas of matter, but none of those are part of the Hubble observations. Hubble measurements are taken from objects that we have an un-obscured line of sight to see, which means the light isn't passing near any material objects before it reaches us.

    As for the CMBR, I'm not sure it actually needs to be explained. The BBT predicted a CMBR before it was observed, but that doesn't necessarily prove that the CMBR has to be a product of the Big Bang.
    Reply With Quote  
     

  45. #44  
    Forum Professor
    Join Date
    Nov 2007
    Posts
    1,114
    To All

    Had to use a different OS to get on to this Forum!

    With the 2 dimentional analogy, this makes the BBT full of hot air and repeats the Flat Earth idea that we all see.

    BUT, we all know that we live in a 3 dimentional universe since we got airplanes flying above and space telescopes observing in all directions.

    So 3 dimentional space it is .

    Cosmo
    Reply With Quote  
     

  46. #45  
    Suspended
    Join Date
    May 2008
    Posts
    1,096
    KALSTER. The cookie dough is a 3D expansion. The balloon is a 4D expansion where the universe is the 3D skin. Both are expanding away from a centre but with the 4D expansion, we cannot detect it.

    The skin of the balloon is only 2D to a 4D being. To us it is 3D, with "endless depth". As you say, everything would be moving away from us on our 3D scale as the "skin" expanded.

    The obvious shape would be due to gravity as in a 3D sphere.

    Enough matter in a small enough area and whatever you call it, you have a black hole with an event horizon. We have neutrons existing at an escape velocity of 2/3 light speed. I cannot see why fundamental particles (electrons, quarks, etc) should break down at c, and think we would have a perfect spinning sphere of them of definite size inside a black hole. I think the insides would be perfectly predictable and that science does not break down just because of high figures.
    Reply With Quote  
     

  47. #46  
    Suspended
    Join Date
    May 2008
    Posts
    1,096
    Quote Originally Posted by Dishmaster
    But wouldn't the structure of the CMBR be correlated with visible matter then? This is not observed. Another thing is: If the path is long enough, any photon would pass an area of matter eventually. The line of sight is limited for any point in space.

    Isn't the CMB supposed to be full of matter as in hydrogen, helium and a little lithium since temperature has dropped sufficiently so that matter can now exist?
    Reply With Quote  
     

  48. #47  
    Moderator Moderator Dishmaster's Avatar
    Join Date
    Apr 2008
    Location
    Heidelberg, Germany
    Posts
    1,624
    Quote Originally Posted by Cyberia
    Quote Originally Posted by Dishmaster
    But wouldn't the structure of the CMBR be correlated with visible matter then? This is not observed. Another thing is: If the path is long enough, any photon would pass an area of matter eventually. The line of sight is limited for any point in space.

    Isn't the CMB supposed to be full of matter as in hydrogen, helium and a little lithium since temperature has dropped sufficiently so that matter can now exist?
    I think that is exactly the debate here. Either what we are calling CMBR is radiation redshifted by the hypothetical maze of changing expansion rates (as was suggested in previous posts), or it is a general redshift just caused by the global expansion of the entire universe. The original radiation is of indeed thought to originate from the era, when the universe became transparent and only consisted of these atomic species. This hot gas emitted the photons that we now measure as the CMBR, just redshifted.
    Reply With Quote  
     

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •