Does Space Expand? What Do You Think?

[alexg]

Don't be insulted I am just rattling some chains
If Einstein hadn't dropped out of high school and become a free thinker who knows where we would be with this right now

But he didn't. Where did you get the idea that he had?

He attended the Luitpold Gymnasium until he was 15, when his family left Germany.

He then attended the Aargau Cantonal School to complete his secondary schooling, and then the Swiss Federal Polytechnic in Zurich, where he got his degree.

 

[Drakkith]

#1 The theory is all wrong vacuums don't expand

A vacuum is an area of space devoid of matter. It cannot expand because it isn't "something". What is meant is that the geometry of space is set up in such a way that it causes two objects to get further apart as time goes on, yet neither of them are actually moving. This is very counterintuitive and there are many threads and posts dedicated to discussing it here on PF. A quick search or a look at the first few pages of the Cosmology forum will show a few.

#2 So comparing space to balloons or bread is foolish

No, assuming the bread or balloon analogy is actually the full description of the model is foolish. They are simply analogies developed to help people understand.

#3 Then an equation is created to explain what we see through our telescopes

All equations are created to explain a phenomena we observe or theorize. There is no other way to simplify our observations other than by developing equations to explain the underlying mechanisms for what we are observing. For example, if you wanted to explain what happens when someone throws a baseball, you could put together a monumental list with a verbal description of all possible throws and define a million different descriptions of how "hard" it is thrown, OR we can simplify the entire thing by using a simple mathematical equation and an explanation of how and when to use it. F=ma. This one equations let's us calculate almost any thrown ball.

#4 When that doesn't fit more equations are created to explain the faulty equations
because there isn't enough mater to explain movement and we add dark mater and dark energy and dark flow ignoring space itself the whole time

You are saying that we shouldn't attempt to explain phenomena because we don't have *all* the information? The we wouldn't be able to explain ANYTHING. It is not possible to have all knowledge of everything.

How do we know that space wasn't already here and mater and time was created by the negative energy of space and the space time distortion associated with mater is nothing more than surface tension.

You seem to be stringing a bunch of scientific words with no knowledge of what they actually mean or the context of where they are supposed to go. Current theories and models fully describe what we know and are backed up by large amounts of evidence for most of it. If you learned the theories you would know WHY we believe what we do.

Don't be insulted I am just rattling some chains

Who's chains are you rattling? Certainly not mine. The only thing you're doing is showing your ignorance of Cosmology and Science in general. I recommend not attempting to rattle anyone's chains until you know more about the subject under discussion. Continuing to post in this kind of attitude will only get you banned.

 

[GeorgeDishman]

Don't be insulted I am just rattling some chains ...

Nobody will feel insulted, all you are doing is publicising your ignorance of the subject. If you have an alternative explanation that works for cosmological redshift, the stretching of supernova light curves and the intensity of the CMBR that hasn't already been thought of and proven to be wrong, by all means lay it out.

 

[Whitewolf4869]

Your absolutely right and I am working on it.
It just seems to be that every time someone thinks outside the box there is always some one that has to protect there ego. I realize that a lot of people have spent many years studying and teaching this subject and my own (bizarre) notions are based on common theory but if we don't constantly question popular belief we are doomed to failure.

 

[Drakkith]

Your absolutely right and I am working on it.
It just seems to be that every time someone thinks outside the box there is always some one that has to protect there ego. I realize that a lot of people have spent many years studying and teaching this subject and my own (bizarre) notions are based on common theory but if we don't constantly question popular belief we are doomed to failure.

The problem is not that no one is thinking outside the box, or that people that are thinking outside the box are laughed at, it's that sooooo many people with only the vaguest idea of what the current theories say try to argue that they are wrong.

It would be like me arguing that Paton Manning or some other football star is the worst player ever just because I don't like him, I don't watch football and I saw 1 game where he did bad, or something similar.

My best piece of advice I can give you is to simply learn the theory. Learn why it is viewed as it is. Only then can you make an informed decision. This doesn't mean that you need to go to college for years and get into the math heavily, only that you look around at the various posts here on PF, sites on the internet, books available, and the countless other sources and get a good grasp on the basics. If you don't understand why something is viewed as it is, ASK. There are multiple people here willing to help you understand, and if they can't they can usually tell you where to find out.

 

[GeorgeDishman]

Your absolutely right and I am working on it.
It just seems to be that every time someone thinks outside the box there is always some one that has to protect there ego. ... if we don't constantly question popular belief we are doomed to failure.

There's nothing wrong with questioning the current model, people do that all the time, but when your question gets the answer that an aspect is based on some measurement, you have to then constrain your alternatives to also fit that observation. If the alternatives are ruled out, accept that part and move on. There are many areas where we simply don't have a model at all at the moment hence lots of scope for new ideas.

Look at what happened into Einstein's cosmological constant. Based on Hubble's observation at the end of the 1920's, he commented that it was his "biggest blunder", everyone asumed it had a value of zero, until 1998 when just a handful of measurements of distant supernovae overthrew seven decades of entrenched belief. People seem to think there is some establishment conspiracy to stifle new ideas but the opposite is actually the case, the groups that made those observations won the Nobel Prize for their discovery.

 

[Whitewolf4869]

Hears an alternative for you. Have you read any papers by William Tifft he and others found that c is not a constant.

 

[steve watson]

I'm coming in on the tail-end of this, so forgive me, but I am fascinated by the topic of your discussion.

I think that a fundamental problem regarding the question of whether space is expanding is the fact that we treat "space" as a "thing", "something", i.e., a planet, a dog, a grain of sand, an atom, etc., etc., etc., rather than "nothing", i.e., the absenceof "something".
If we viewed "space" as "nothing", theabsence of "something", which it must be, then "space", which is "nothing" cannot be expanding.

 

[Drakkith]

I'm coming in on the tail-end of this, so forgive me, but I am fascinated by the topic of your discussion.

I think that a fundamental problem regarding the question of whether space is expanding is the fact that we treat "space" as a "thing", "something", i.e., a planet, a dog, a grain of sand, an atom, etc., etc., etc., rather than "nothing", i.e., the absenceof "something".
If we viewed "space" as "nothing", theabsence of "something", which it must be, then "space", which is "nothing" cannot be expanding.

This is why understanding the context of the statement is important. When it is said that "space" is expanding, what is meant is that the geometry of space is set up in such a way that it causes objects to recede from each other at rate that increases with distance. Obviously trying to say that every time you want to talk about it is horribly inconvenient, so most people just say "Space is expanding".

 

[steve watson]

I know that understanding the context of a statement is of the utmost importance. And I said so when I posted my note. So my apologies again, I didn't mean to inconveience you. Still, first, words shouldn't be used so loosely. Words have meanings or they would be useless. And next, "space" not being "something" cannot cause "something" to happen. Who set "space" up? What does that mean? I"m not be sarcastic or cute, I am asking real questions and I am curious as to your answers.

 

[Drakkith]

I know that understanding the context of a statement is of the utmost importance. And I said so when I posted my note. So my apologies again, I didn't mean to inconveience you. Still, first, words shouldn't be used so loosely. Words have meanings or they would be useless. And next, "space" not being "something" cannot cause "something" to happen. Who set "space" up? What does that mean? I"m not be sarcastic or cute, I am asking real questions and I am curious as to your answers.

The problem is that while words may have specific meanings, the models themselves are NOT based on words. There is no word that describes the geometrical layout of a particular area of space. That requires math. So when you take the model and have to explain it verbally in english or other spoken language, it gets garbled and misunderstood.

What we mean when we talk about space is that when you set up objects in space and do certain things with them, they behave a certain way depending on how the underlying geometry is set up. Curvature of space is a good example. We often talk of an analogy of drawing a triangle on the surface of the Earth. If the surface were flat, all the angles would add up to 180 degrees. However, the Earth is a sphere and is curved. So as long as you make the triangle big enough to notice the curvature, you can measure the angles as adding up to MORE than 180 degrees.

Similarly space itself can be curved or be flat. Note that nothing anywhere describes what space "is". It only describes the way objects behave and interact. If I were to "draw" a huge triangle in space, and moved waaaay back and measure the angles and they added up to 198 degrees, then I would say that space is curved like a sphere. I'm not saying that space is made up of something, or anything about what space "is", I am only describing how my triangle and other objects behave.

 

[steve watson]

I understand, and I appreciate your response. These mathematical concepts trouble me. Math is trickey and can lead to strange and unverifiable notions and theories. My problem is with the nature of "space" and what it is or rather what it is not. Nobody seems to be able to give me a straight answer. But everyone seems to think "space" is a "thing" rather than "nothing". If "space" were "nothing" wouldn't that turn a lot of these theories upside down?

 

[Drakkith]

I understand, and I appreciate your response. These mathematical concepts trouble me. Math is trickey and can lead to strange and unverifiable notions and theories.

I don't think math is nearly as "tricky" as you think it is. The building blocks of any theory and model are mathematical formulas and equations that explain the way all the different pieces of the theory fit together. Many of these are simple equations that explain observed phenomena, while others are horribly complex to calculate, such as the Schrodinger equation in QM. Even so, the math itself must be shown to be correct and accurate.
Edit: Also, perhaps the most important thing, is that the theories themselves MUST be validated by observations and evidence. Without this a theory cannot be "accepted" fully. Hence why string theory is still not considered to be a mainstream accepted theory. It has no evidence beyond math.

My problem is with the nature of "space" and what it is or rather what it is not. Nobody seems to be able to give me a straight answer. But everyone seems to think "space" is a "thing" rather than "nothing". If "space" were "nothing" wouldn't that turn a lot of these theories upside down?

No, as no one is describing some underlying makeup of space itself. Any discussion about the shape of space, the geometry, or anything like that only describes how objects interact within it. Put simply, we don't know, and perhaps can't know, what space "is", if it is anything at all.

 

[steve watson]

Well you're way out of my league regarding math and the mathematical theories you speak of, but when you descirbe "space" as having a "shape", aren't the only things that have a "shape" things that exist? And if "space" has a "shape" doesn't that mean "space is a "thiing"?

 

[Drakkith]

Well you're way out of my league regarding math and the mathematical theories you speak of, but when you descirbe "space" as having a "shape", aren't the only things that have a "shape" things that exist? And if "space" has a "shape" doesn't that mean "space is a "thiing"?

Define "thing".

 

[steve watson]

anythat that exists: a planet, an atom, a needle, a haystack, a grain of sand, everythig except nothing, i.e., the lack of something. ...

 

[Drakkith]

anythat that exists: a planet, an atom, a needle, a haystack, a grain of sand, everythig except nothing, i.e., the lack of something. ...

All those are capable of being observed, measured, and interacted with. They follow certain rules and feel certain forces. Does space do this? Can we observe "space itself"? In my opinion the only force that space obeys is gravity. Except that gravity is a result of the curvature of space due to mass, not a "real" force. So maybe we can say that space is altered by mass. Does this count as observing space?

I don't know the answer, and many people have many different opinions on what space is. The simple answer is that we don't know. However the current theory that explains the behavior of the universe on the largest scales is General Relativity. In the context of GR space has geometrical structure that determine how objects interact. It says nothing about what space "really is".

So, when someone talks about space expanding, realize that within the context of the theory and model that we use to describe the universe, we only mean that two objects, far enough apart so that gravity is very weak between them, will recede from each other due to the geometric structure of spacetime. Whether space is being created, being stretched, or something else is up for debate and is merely an interpretation.

 

[steve watson]

Not sure, but at a mininimum, I think it counts as observing the relationship between "things", and, by implication, but to a much lesser degree, "space" itself. But i don't think there is much to reveal about space itself since it is "nothing"., i.e., there is nothign to reveal. On the other hand, I think it is of the utmost importance to understand the relationship between "things" and "space".

Most interesting, as I was under the impression that scientist today generally believed that space was something because howelse could it be curved. Nothing cannot be curved as there is nothing to be curved.

I understand, but doesn't the "big bang" theory (which i don't subscribe to) and other theories setting out the beginning of time proclaim "space" to be a "thing" .. and if it is a "thing" where does it end, when does it end (if this is even a sensical question when it comes to matter, i.e., "things" and if things have no end, i.e., infinite, then how come you can identify one thing from another thing?

 

[Drakkith]

I understand, but doesn't the "big bang" theory (which i don't subscribe to) and other theories setting out the beginning of time proclaim "space" to be a "thing" .. and if it is a "thing" where does it end, when does it end (if this is even a sensical question when it comes to matter, i.e., "things" and if things have no end, i.e., infinite, then how come you can identify one thing from another thing?

The Big Bang theory doesn't set out the beginning of time. It merely says that the universe was once in a hot, dense state and expanded from there, cooling off in the process as the density dropped. It is supported by what most would consider overwhelming evidence.

And I'm not sure what you are getting at about infinite. The universe may or may not be infinite, we do not know. If it is infinite in size that has no bearing on what space is as far as I know.

 

[GeorgeDishman]

Hears an alternative for you. Have you read any papers by William Tifft he and others found that c is not a constant.

I haven't but that's a good example. Here's his bio in Wikipedia:

http://en.wikipedia.org/wiki/William_G._Tifft

It discusses his involvement with the idea of quantised redshift but not variable c. Note that that work was about 35 years ago, before the Hubble and other space telescopes. It became apparent that redshift isn't quantised some years after that but the acoustic resonances in the early universe means there is a tendency for the clumping of matter to shows peaks which, with limited data, could look like quantisation.

Regarding variations in c, that is closely related to the fine structure constant. Observation of some variation in that was reported some years ago (2004) by a group using a telescope in the southern hemisphere and they concluded it might have changed over time. Their result was that it was smaller by 5 parts per million (ppm) 10 billion years ago (z~1.8).

In response to peer questions, they recently extended their observations in the northern hemisphere and found a similar degree of variation but in the opposite sense. Using a different telescope in the northern hemisphere, they find it was about 7 ppm higher 10 billion years ago.

Overall, the average change from that period is now 0.6ppm with an accuracy of ±1.6ppm which means the most likely conclusion is no change. They have had to change their hypothesis to now suggest there is no time-related variation but possibly a variation with position. On the other hand, since nearly all the results from one telescope are low while those from the other are high, it seems much more likely to be a problem of calibration.

The point of this is that measurements in 2004 might have agreed with Tifft's suggestion, though at a very low level, but the same measurements made by the same team using a second telescope and published in 2011 have eliminated that apparent trend. Observations are improving all the time and papers written just a few years ago may well be out of date.

This is the paper in question:

http://arxiv.org/abs/1008.3907

That's an excellent example of how things that can appear to be taken for granted are actually being questioned all the time.

 

[GeorgeDishman]

My problem is with the nature of "space" and what it is or rather what it is not. Nobody seems to be able to give me a straight answer. But everyone seems to think "space" is a "thing" rather than "nothing". If "space" were "nothing" wouldn't that turn a lot of these theories upside down?

It's not a trivial question. For example, if space is the absence of anything, how can it have a permitivity and permeability? What about the Casimir Effect, is that caused by "stuff in space" or is it a property of the vacuum itself? Space may not be a "thing" but it definitely seems to have measurable properties. You might also like to do a search for the term "substantivalism" (be careful with the spelling) and look at the Hole Argument just to get a flavour of this topic:

http://plato.stanford.edu/entries/spacetime-holearg/

Note that the Hole Argument is a problem for manifold substantivalism but perhaps not for metric substantivalism (which the SEP barely mentions).

You should also consider what gravitational waves (as indirectly measured by Hulse and Taylor) and "gravitational wave recoil" imply for the existence of the metric.

http://www.black-holes.org/explore2.html

 

[steve watson]

No, it's not a trivial question .. tks for your response and the website info .. it's not easy to understand ...

 

[Orion1]

Cosmology scale factor equation:
\frac{\lambda_0}{\lambda_t} = \frac{T_t}{T_0} = \frac{a(t_0)}{a(t)} = 1 + z
λCDM redshift at decoupling:
z = 1090.89
CMBR temperature at present:
T_0 = 2.72548 \; \text{K}
T_t = T_0 (1 + z) = 2.72548 \; \text{K} \times (1 + 1090.89) = 2975.92 \; \text{K}
Universe temperature at photon decoupling time t:
\boxed{T_t = 2975.92 \; \text{K}}

However, does the Cosmology scale factor equation also work this way?

Universe total observable radius:
R_u(t_0) = 4.399 \cdot 10^{26} \; \text{m}
\frac{R_u(t_0)}{R_u(t)} = \frac{a(t_0)}{a(t)} = \frac{T_t}{T_0} = 1 + z
\boxed{a(t_0) = 1}
R_u(t) = a(t) R_u(t_0) = 9.158 \cdot 10^{-4} \times 4.399 \cdot 10^{26} \; \text{m} = 4.028 \cdot 10^{23} \; \text{m}
Universe total observable radius at photon decoupling time t:
\boxed{R_u(t) = 4.028 \cdot 10^{23} \; \text{m}}
[/Color]
Reference:
Total amount of energy in the Universe - Orion1 #13
Lambda-CDM model - Parameters - Wikipedia
Scale_factor - Cosmology - Wikipedia
Redshift formulae - Wikipedia
Cosmic microwave background radiation - Features - Wikipedia
Recombination - Cosmology - Wikipedia
Timeline of the Big Bang - Photon epoch

 

[GeorgeDishman]

However, does the Cosmology scale factor equation also work this way?

Universe total observable radius:
\frac{R_u(t_0)}{R_u(t)} = \frac{a(t_0)}{a(t)} = 1 + z
\boxed{a(t_0) = 1}

Yes, in fact that is the definition of a(t). However, that only gives you the ratio of the present size to that at the time of emission. The values you quote of roughly 42 million and 46 billion light years respectively are correct but to get those, you need to find the lookback time first.

 

[Orion1]

Cosmology scale factor equation:
\frac{R_u(t_0)}{R_u(t)} = \frac{a(t_0)}{a(t)} = \frac{T_t}{T_0} = 1 + z

Universe total observable radius:
R_u(t_0) = 4.399 \cdot 10^{26} \; \text{m}

Cosmic neutrino background radiation temperature at present:
T_0 = 1.95 \; \text{K}

Cosmic neutrino background radiation temperature at neutrino decoupling time t:
T_t = 1 \cdot 10^{10} \; \text{K}

R_u(t) = R_u(t_0) \left( \frac{T_0}{T_t} \right) = 4.399 \cdot 10^{26} \; \text{m} \times \left( \frac{1.95 \; \text{K}}{1 \cdot 10^{10} \; \text{K}} \right) = 8.578 \cdot 10^{16} \; \text{m}

Universe total observable radius at neutrino decoupling time t:
\boxed{R_u(t) = 8.578 \cdot 10^{16} \; \text{m}}
[/Color]
Reference:
Total amount of energy in the Universe - Orion1 #13
Timeline of the Big Bang - Hadron epoch - Wikipedia
Neutrino_decoupling - Wikipedia
Cosmic neutrino background - Wikipedia
Red shift - Highest redshifts

 

[GeorgeDishman]

Universe total observable radius:
R_u(t_0) = 4.399 \cdot 10^{26} \; \text{m}[/Color]

That figure is for what is observable optically, i.e. the CMBR. We can't observe primordial neutrinos. However, your end result will still be a reasonable rough estimate.

 

[dtyarbrough]

The rate of expansion (hubble constant) of the universe is equivalent to the sun moving 3/4 of a mile farther away in 100 years. Do the math. The solar wind adds solar particles to the solar system and universe. This causes distant objects to appear ever more distant as space becomes more opague. Space is not empty as recent articles have stated.

 

[GeorgeDishman]

This causes distant objects to appear ever more distant as space becomes more opague.

That makes no sense, you need to explain why space becoming opaque would change the wavelength of a spectral line.

 

[Mark M]

The rate of expansion (hubble constant) of the universe is equivalent to the sun moving 3/4 of a mile farther away in 100 years. Do the math. The solar wind adds solar particles to the solar system and universe. This causes distant objects to appear ever more distant as space becomes more opague. Space is not empty as recent articles have stated.

This is so wrong, I have to question if you have a clue about what you're talking about.

First of all, recessional velocity on large scales requires a frame of reference. The distance from this FoR is then multiplied by a scale factor, Hubble's constant. This is shown by Hubble's law:

V=H_{0}D

Also, expansion only effects very large objects, such as galaxies or super clusters, not the Sun.

Second, Hubble's constant is estimated by WMAP to be 70.8 ± 1.6 (km/s)/Mpc.

So, an object that is very far away will appear to have an extremely high recessional velocity, your calculation was completely made up, and had no basis whatsoever.

Also, the cosmic microwave background provides conclusive evidence the universe is expanding and cooling.

 

[GeorgeDishman]

This is so wrong, I have to question if you have a clue about what you're talking about.

He doesn't, he is confusing reddening with redshift.

.. Hubble's law:

V=H_{0}D

Use 1AU for D to get V then multiply by a century and you might get the figure he quoted. Of course that ignores all orbital mechanics and doesn't seem to have any rational connection to the solar wind anyway.