Mordred

Have you looked at the balloon analogy? Take a balloon draw some dots on it. Then inflate it. Don't concern yourself with what is inside or outside the balloon. Were only concerned with how the dots move. Notice how they seperate with evenly from each other with no change in angle between any of the dots. How galaxies move from each other works the same way as those dots.

Lol my post got split up by the other relevant comments guess we have some active members on this thread

By the way higher density is a requirement of a smaller universe in the past than it is today. This conforms to the thermodynamic laws. Google the term "ideal gas laws in Cosmology". If you wish further detail outside the material I provided. The links contain everything stated on this thread. Take the time to learn it. "I don't understand it" therefore don't accept it is plain wrong. Read the material and post specific questions on it. Include the article and page we can easily step you through it if you truly want to learn. It would be a pleasure. After all that is the only reason why I visit forums. To help others learn. I never ask questions. Why is simply due to buying and studying over 40 textbooks. As well as spending 15 years of self study. I come here to help others only... so please feel free to show us a willingness to learn. I would be more than happy to help with that proven willingness

If you want to understand it then take the time to read the material provided. The first section of links is no math or little math needed. In all honesty most of the material provided is entry cosmology level.

Well I'm glad to see the cosmic inventory included in your links. It's rather extensive and detailed. Judging by your calcs and what I recall its in the right range. For an approximation Though I am still unclear what you are presenting that is new.

As Strange mentioned the FLRW metric is an exact solution to the Eintein field equations. However showing how is a rather complex matter. The best article is a 995 page technical article. Unfortunately advanced. Outside of textbooks and the other articles on my free non profit website it is the best I can offer. The problem is this particular text requires a good understanding of math and differential geometry. Some of the other articles on my site less so however this is the one that answers specifically the GR to FLRW relation. It will take time to study I would recommend the FAQ Strange posted as well as working downward the links in my Sig prior to reading this link if you cannot afford a textbook. http://www.blau.itp.unibe.ch/newlecturesGR.pdf If you have a strong interest the best intro textbook I ever read out of 27 of them is Barbers Rydens "Introductory to Cosmology" followed by "Modern Cosmology" by Scott Dodelson to simplify the math Roads to Reality by Sir Roger Penrose. (This is a non specific model math breakdown at high school level text) This last part needs addressing as it is vital. First off we have to cover a few aspects. 1 expansion is homogeneous and isotropic. (No preferred location or direction. In other words uniform) Now the FLRW metric also includes the ideal gas laws. Treat every energy density contributor as a gas with a pressure contribution according to its equation of state (cosmology) Link added at the end. Now as expansion is uniform pressure exerts An equal uniform force upon those galaxies in all directions equally. So the galaxies themselves experience no greater force in a particular direction. Therefore they themselves gain no intertia or kinetic energy. Instead the cosmological constant aka dark energy can only affect the regions between galaxies or gravitationally bound objects. Sounds counter intuitive but it helps to think of energy density as pressure and the universe as an ideal gas. ,(this is how the FLRW metric is designed with GR added.) As stated start with the link Strange posted earlier. The tutorial on that site is excellent. Then read downward the links on my site. The articles were chosen to teach textbook cosmology for those that cannot buy textbooks http://en.m.wikipedia.org/wiki/Equation_of_state_(cosmology) Forgot to add one key concept to understand is that no galaxy gains inertia due to expansion. Instead the volume of space between galaxies simply increased so GR is not violated. Also as mentioned recessive velocity required a huge distance measurement between observer and object measured to show a distance dependant recessive velocity in excess of c. (Past Hubbled sphere)

[latex]{\small\begin{array}{|c|c|c|c|c|c|}\hline R_{0} (Gly) & R_{\infty} (Gly) & S_{eq} & H_{0} & \Omega_\Lambda & \Omega_m\\ \hline 14.4&17.3&3400&67.9&0.693&0.307\\ \hline \end{array}}[/tex] [tex]{\small\begin{array}{|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|} \hline a=1/S&S&T (Gy)&R (Gly)&D_{now} (Gly)&D_{then}(Gly)&D_{hor}(Gly)&V_{now} (c)&V_{then} (c) \\ \hline 0.001&1090.000&0.0004&0.0006&45.332&0.042&0.057&3.15&66.18\\ \hline 0.003&339.773&0.0025&0.0040&44.184&0.130&0.179&3.07&32.87\\ \hline 0.009&105.913&0.0153&0.0235&42.012&0.397&0.552&2.92&16.90\\ \hline 0.030&33.015&0.0902&0.1363&38.052&1.153&1.652&2.64&8.45\\ \hline 0.097&10.291&0.5223&0.7851&30.918&3.004&4.606&2.15&3.83\\ \hline 0.312&3.208&2.9777&4.3736&18.248&5.688&10.827&1.27&1.30\\ \hline 1.000&1.000&13.7872&14.3999&0.000&0.000&16.472&0.00&0.00\\ \hline 3.208&0.312&32.8849&17.1849&11.118&35.666&17.225&0.77&2.08\\ \hline 7.580&0.132&47.7251&17.2911&14.219&107.786&17.291&0.99&6.23\\ \hline 17.911&0.056&62.5981&17.2993&15.536&278.256&17.299&1.08&16.08\\ \hline 42.321&0.024&77.4737&17.2998&16.093&681.061&17.300&1.12&39.37\\ \hline 100.000&0.010&92.3494&17.2999&16.328&1632.838&17.300&1.13&94.38\\ \hline \end{array}}[/latex] See if this works here Nope guess not tried posting the cosmocalc in my Sig... works on other forums just not this one

Same here I would also take the time to study why a model states what it does before discounting it.

That is not what you are measuring. When we look further back in time we see a higher density. We see the thermodynamic laws that form the basis of big bang nucleosynthesis. We see the predicted quantities of elements in particular hydrogen and lithium. We see different stars type 1a that can only form as a result of a higher density. We see the CMB which is a prediction of the big bang model. We see a higher number of quasars which is a result of a higher energy density in the past. We see the redshift of the light from those objects. We SEE plenty of evidence that supports an expanding universe. You choose to ignore all of that evidence. You fail to take the time to study the tools that will teach you why we know the universe is expanding. Google Hubble for example. Remember he observed and measured galaxies moving away from each other. If you refuse to look at the info provided then believe whatever unicorns suit your fancy

It's amazing though I and others post numerous articles including peer reviews. My signature also contains free peer reviewed textbooks. As well as provides An expansion and redshift calculator. Yet you choose to ignore this wealth of information . The LCDM (hot big bang model with cold dark matter and the cosmological constant.). Is a model that is continously being tested by observations. That data set and model gets tested with every observation made every single day that provides new data. As mentioned there is also redshift. I already provided an article explaining in simple terms what that means. Please take the time to read the links I provided. Especially the one titled. "What we have learned from Observational evidence" http://arxiv.org/abs/1304.4446

You also aren't considering that the CMB is measured accurately. At 3000 Kelvin in the past. Then consider how the ideal gas laws work. A higher density means a higher temperature.

Think of it this way the further we look the more dense the universe becomes. Thus the universe also becomes hotter. Ie the CMB at 3000 Kelvin. Galaxies included. Remember baryonic matter is only a small contributor to the energy budget of the universe. The term recessive velocity and its superluminal measurement is very misleading. We're stuck with it but it's far more misleading than what it is worth. The term accelerating expansion is a result of recessive velocity. It is based on geometry. Take that 10 cm ruler. Let's apply simple numbers. Say there is a galaxy at each centimeter dividend. Now increase the distance between each galaxy by 1mm (10% the total volume) So second two has a total volume of 11 cm to start now add 10% for new total of 12.1 cm. Then add 10 % of that the next second and so forth. See how it has an accelerating exponential expansion. However per 1" divident the change remains 1mm per second per inch. Or 10% of each centimeter. Hope this helps. Keep in mind the space between each of the original coordinates all change equally in every direction. Ie if you did the same thing with two rulers to represent 2d or 3 rulers to represent ,3d with no change of angles between any of the galaxies or rulers Notice the rate of change remains 10% per volume. This is the same as Hubbles constant 70 km/sec/Mpc. However the rate of change in the recessive velocity will be accelerating. By 10% of the total volume between any two galaxies of the previous second.

You could add up the energy budget to check your numbers http://arxiv.org/pdf/astro-ph/0406095v2.pdf

Have a good sleep hopefully you can explain how your bubble model can possibly explain wave particle duality. Just a side note I found a handy animation on it. http://m.youtube.com/watch?v=Xmq_FJd1oUQ Might come in handy on the forum at some point Granted these types of simulations are numerous

Your welcome really makes you think

Lol this topic is beginning to remind me of whether or not virtual particles are real or not. The discussion on another forum went on and on for over 100 pages. No agreement was ever reached. Just a side note ( It was entertaining though as it involved roughly a dozen professors in the discussion)coincidentally also in a quantum mechanics forum

How could your spacetime bubbles show the wave particle duality is the other question. It could certainly be pointlike. How would it show the wave function. Particularly since the photon is defined as having only electromagnetic interactions.

Fair enough then what do you define as being physical? Is your definition that it must contain only matter particles? Ie take up space such as fermions? An infinite number of bosons can occupy the same volume where only one fermion can occupy a given volume. This seems to be the direction your going. English aside physics is the study of the physical universe. This does include energy. Granted English definitions are often cumbersome. So let's clarify what we define as physical in terms of this discussion. It certainly isn't going to change the accepted definitions in any dictionary or textbook lol The photon isn't a matter particle as it is a boson so in the sense of this post it wouldn't count as being a material. However it is a form of particle with measurable properties and energy. Does this mean it isn't physical? Then we would have to rewrite the definition of physical. Good luck with that.

This article has some interesting coverage on various QM myths Including wave particle duality. http://xxx.lanl.gov/abs/quant-ph/0609163 it's a good coverage definetely worth reading

Interesting discussion. The wording here seems to have caused some confusion.. though the intent was probably different. What is physical...well if you look at the definition of physical it includes anything studied in physics. Including all forms of matter and energy. There is for example the physical accoustics of sound. The physical properties of a wavelength. Etc. So according to the Webster dictionary of the term physical I would have to say a photon is physical. As we can measure its properties I would say it is real. As mentioned it depends on how you define the terminology. By the current definitions the photon is both real and physical

my two favourite articles covering distance measure and superluminal expansion is "Distance measures in Cosmology by David Hogg's http://arxiv.org/abs/astro-ph/?9905116 http://arxiv.org/abs/astro-ph/0310808:"Expanding Confusion: common misconceptions of cosmological horizons and the superluminal expansion of the Universe" Lineweaver and Davies

This math is still wrong. It does not account for expansion. You evidentally didn't read my post in regards to the Hubble sphere and cosmological event horizon ( observable universe) The proper distance to a stellar object is given by [latex]Proper distance =\frac{\stackrel{.}{a}(t)}{a}[/latex] a is the scale factor. The dot above represents the scale factor today. See my earlier posted articles for clarification. To clarify this we can see objects with an apparent recessive velocity at z=1090 of 3c . However the object is not moving at 3c . Recessive velocity is a distance dependant measurement. Hubble's law states " the greater the distance the greater the recessive velocity." [latex]v_{recessive}=H_oD[/latex] Locally light can overcome the rate of expansion 70 km/s/Mpc. At each Mpc divident the rate of expansion is no obstacle. Recessive velocity becomes greater than c past the Hubble sphere. However that measurement is total distance between us and the Hubble sphere. It is an apparent not an actual velocity. All of this is covered in the article I posted earlier. http://tangentspace.info/docs/horizon.pdf However as the universe is flat S(k)=0. You can use the 4d distance formula of the FLRW metric conniving distance equation. (In the notation from Barbara Ryden "Introductory to Cosmology" [latex]d{s^2}=-{c^2}d{t^2}+a{t^2}[d{r^2}+{Sk}{r^2}d\Omega^2][/latex] [latex]S\kappa r= \begin{cases} Rsin ,r/R & k=+1\\ r & k=0\\ Rsinh,r/R & k=-1 \end {cases}[/latex] See the universe geometry article below its 2 pages http://cosmology101.wikidot.com/universe-geometry The link to page two is http://cosmology101.wikidot.com/geometry-flrw-metric/ This breaks down the distance measures in 2d 3d and 4d with the FLRW metric. The first page describes what is meant by flat or curved universe geometry. The second page shows the metrics in each case. Flat, positive or negative curved. The difference between commoving and proper can be found here http://en.m.wikipedia.org/wiki/Comoving_distance You will note Another varient on the commoving distance formula both are compatible

To add to To the latter comments. Their is no mysterious substance such as the ether. Needed to explain the thermodynamic properties of the big bang theory nor in the popular LQC alternative. When you study thermodynamic history and observable measurements as well as combine that understanding with the SO(5) or SO(10) particle physics models. A greater sense of true understanding applies. The articles I posted is just a preliminary touching ground. The site in my link has a full manual though older roughly 5 years The info is provided the details come with how much you choose to study to truly understand

Here is a way to think of the distance light can travel and the size of the observable universe. First for clarity we need to define two regions. The Hubble sphere and the cosmological event horizon. The Hubble sphere is basically the distance light can travel multiplied by the age of the universe. The ccosmological event horizon represents the size of the observable universe. This is the age of the universe plus speed of light plus expansion The latter does not simply add up as expansion rates is exponenential. To keep extremely simple we will apply some numbers. Take a 12" ruler set 1" as one light year. In the former each year represents one year of light travel so the Hubble sphere equals the age of the universe in light years. The the case of expansion however it gets more complex. Take the same ruler look ahead one light year. Now each measurement point in that ruler has increased in distance by approx 70 km/Mpc/sec ( Hubble constant=rate of expansion at a specific moment in time constant everywhere only at a specified moment in time) Now what does this do.. The light has travelled one light year. However the distance between us and the light path is increasing as well as the distance already travelled So locally light has no problem travelling faster than the Hubbles constant. It's far faster than 70 km/Mpc/sec. However the distance between its current location and us also increases. This means it will take longer to close that added distance ( the FLRW metric takes this into account) However the space already travelled is also increasing. For the light path already travelled this has no effect other than to the observer. This increase of distance causes the wavelength of light to stretch (cosmological redshift)(part of the FLRW metric) As a result of expansion the cosmological event horizon is larger than the Hubble sphere. The cosmological event horizon is roughly 46 Gly in radius the age of the universe is roughly 13.78 years the Hubble sphere equals the age in Gly hope this helps if not my signature has a calculator which I assisted in development. As well as numerous articles under misconceptions. I would recommend reading Redshift and expansion which I wrote under the cosmology101 signature link as well as the Cosmological horizons article under misconceptions by Brian Powell a good friend and colleague of mine. He has years of exp answering forum questions and he wrote that article as a time saver. (I proof read and added some advise) (I also proof read his dissertation more on the grammar as his math ability far exceeds mine) http://cosmology101.wikidot.com/redshift-and-expansion http://tangentspace.info/docs/horizon.pdf Both articles require little math to understand they have simple formulas as a reference. I also recommend This FAQ style article http://arxiv.org/abs/1304.4446 *"What we have learned from observational cosmology" ( working from phone so ignore spell and grammar mistakes currently 50 km from true North pole)

In a sense how we we review relativity and redshift relies upon our interpretation of the data. Dang Schrodinger