In the voids, time would be faster than in the inertial frame of reference of the galaxies. I would think that time distortion would follow the same inverse square law as gravity. Or has this been accounted for in the calculations?

Ever since I first read about the experiments to measure the expansion, this bit about relativity and time distortion near masses has been bugging me, but unlike cosmologists, my math skills are nowhere near good enough to work out Einstein’s field equations for myself.

Am I noggin-grasping the concept with this (layman’s and very rudimentary!) analogy?

I have a blue marble on a 15-degree-right-inclined plate \o, and a green marble on a 15-degree-left-inclined plate o/. The blue and green marbles are rolling toward each other, yet the plates are separating; the plates are moving farther apart faster than the marbles are rolling toward each other, thus netting the universal expansion result above. IIUC, that involves only one local reference frame (a point on an equivalent plane to the plates) vs two (the former point, plus a point on an equivalent plane as the marbles) from which to deduce the theory.

ATM, I’m at a loss to better explain what I hope to further understand. Fascinating, all!

It seems to me that if you want to know about what is causing an expansion of a body (say creation itself) it would only make sense to know what that body is expanding into. To me it seems that the Universe is expanding because the area its expanding into is well…..nothing. If that is the case isn’t it possible that its expanding due to wanting to have equilibrium? As for acceleration its accelerating due to the surface area that needs to expand is constantly growing. As the universe grows so does the surface area that is bordering the nothingness and hence the acceleration increases.

Its a simplistic approach to the topic but one I wanted to at least throw out for debate.

I’m not entirely convinced on this “theory” of an expanding universe.

Well, lucky for you it ain’t a theory. It’s a conclusion. A conclusion drawn by logical reasoning from hard data.

Even proponents of the “steady-state” universe (such as Fred Hoyle, who coined the term “big bang” as a derogatory nickname for the theory that the universe had a beginning) accepted that the universe was expanding. Why? Because the measurements are irrefutable.

An analogy would be a nat sitting on the south end of a north bound elephant, trying to explain the trunk. As we all are aware, light can be deceptive.

Er, no. Not when one understands general relativity.

Your analogy fails, because the trunk is not expanding, and is not covered in sources of information that are sending that information to the gnat.

Hey…wait till we discover that there are multiple unverses (perhaps billions) out there. That will put a whole new perspective on things. Just a thought.

And, until there is evidence on which to base some conclusions, your “just a thought” will remain a piece of idle speculation.

I have no answer for that, other than the immortal words of Hazel O’Connor:

What’s done has been done
And I won’t be the one
Who despairs in the wheelchair
At the sight of “if only”

So I’ll stand up again, and I’ll run
I’ll jump up ’til I touch the sun
Because I won’t be the one to be bound
By the sound of “if only”.

Now if only we could synthesize quantum theory with relativity theory!

There’s hope, though. Here’s what Tom Siegfried says in his book Strange Matters; Undiscovered Ideas at the Frontiers of Space and Time (I hope this quote falls under Fair Use laws, or at least that Tom and his publisher will permit me this indulgence, purely for educational purposes or as free advertising for the book — read it, people!). This is from his exposition on Unity and Harmony and “the unreasonable effectiveness of mathematics”:

“Poincaré understood how this process works. Imagine, he says, a chart depicting all ‘the variations of the world.’ At each point in time everything in the universe is in a particular arrangement. At the next instant the arrangement will be slightly different. (The differences from one instant to the next would be the result of the combined operations of all the laws of physics.) A graph of those changes over time would take the shape of a curve. A good mathematician could figure out an equation to describe that curve.”

“But earthbound mathematicians can never see the whole curve. Human theories are always based only on one arc, one piece of the universal curve. Two theories based on different arcs might deduce different equations to describe the whole curve. (Quantum mechanics and general relativity describe different aspects of reality exquisitely well, for example, while appearing to be incompatible.)

“However, Poincaré notes, a greater intellect, or a similar intellect with a wider field of view, could perceive the region between these two arcs and construct a better equation. That equation could describe not only both arcs but also the part of the curve in between. And sometimes human scientists can figure out that better equation before they see the whole curve. If they get the right equation, it will then tell them things about regions of the curve that have not yet been measured.”

Science is about filling in the missing points on that larger universal curve, one tiny dot at a time. It is the epitome and acme of being human, of what makes us intelligent beings.

Oh, DrBB, FYI: Cheer up, we don’t all have to be mathematicians or specialists to grasp concepts, general ideas or principles — as long as they’re presented clearly (an uncommon occurrence, I know, yet a treasure when found).

Seconded.

I have at least some understanding of such theories as quantum mechanics and Big Bang cosmology, despite never having got involved with the maths (the closest I came was when I was in a 3rd-year Chemistry lecture at Uni – my “major” being biochemistry – and when the lecturer mentioned ab initio molecular orbital calculations, several of the chemistry majors groaned and dropped their heads to the desk). But in that instant I became aware of two things I had not previously known – first, that it is possible in principle to calculate (as opposed to measure) the behaviour of electrons in a molecule; and, second, that it is fiendishly difficult even for a molecule of hydrogen, and may be impossible for very complicated molecules.

I appreciate your notes of acknowledgement. Nice to get that now and then. And good to know that reasoned minds are in the fight for truth and higher understanding.

Oh, DrBB, FYI: Cheer up, we don’t all have to be mathematicians or specialists to grasp concepts, general ideas or principles — as long as they’re presented clearly (an uncommon occurrence, I know, yet a treasure when found).

Thanks for your very lucid explanations throughout, and @111 (in response to a query of mine, once removed) in particular. The quotation does seem to confirm in a more detailed and accurate way what I was imagining the relation between dark energy, the BB and the expansion of space-time to be. I’m never going to get beyond the For Dummies stage with this stuff–defeated by the math, alas–but I like to have a reasonably sound lay-person’s grasp of it. Fascinating stuff.

What a poor legacy we leave for future brilliant minds, if we insist that the BBT is the only valid explanation of how and why we are here!

Why?

Cosmologists know it is, at best, incomplete. They are seeking better theories. However, inflationary BBT is better than all of its predecessors. It at least accounts for pretty nearly all the observed facts.

Thus, we can be fairly confident that BBT is a pretty good approximation for how the universe began, even if aspects of it are wrong. If it were wrong in any major way, we would already know by now.

It is far better to stick with observable evidence and admit we don’t know the how, where and why of the universe, than to, like the AGW folks, dismiss all sceptisism, be saying “the science is settled”

OK, I’ll bite.

Which climate scientist(s) said that the science is settled? When and where did they say it? And is there a wider context than you are providing?

I think you’ve got it wrong. Science is never truly “settled” or written in stone. (Engineering or a piece of technology might be considered “settled” based on the fact that it works, but theoretical and experimental science is always open to better data.)

While scientists may speak with confidence about a certain theory that’s backed up by solid evidence, if they’re truly scientific then they know that’s just the current best understanding based on the available evidence, but that it’s always subject to revision should we get better data. Sometimes new evidence leads us to whole knew ways of looking at things. When that happens scientists alter their view to match the evidence. Science is ALWAYS about gaining more data and refining our understanding based on evidence. Certainly we must form theories to explain the evidence, but that’s what “understanding” means. We may have wrong theories; honest scientists recognize this and stay open to new ideas. But those ideas or theories must fit the observed facts.

Other times new evidence confirms or reinforces the existing theories. This has been the case with the Big Bang theory. An enormous amount of evidence from many different fields converges independently upon the same conclusion. Yet there are many scientists who would love for something to come along that disproves the Big Bang. The BB theory was in fact only accepted reluctantly in the first place, as the best explanation that fit the observed data — many scientists fought hard to find some alternative because they did not want to believe such an outlandish idea as a universal Big Bang. Now, of course, we have ultra-high-energy particle accelerators that can duplicate the energies of the very early moments of the (hypothetical) Big Bang, and we have a map of the cosmic background radiation which is essentially a picture of the fireball left over from the Big Bang, and we understand nuclear processes and stellar formation and galaxy dynamics, and we can measure red shift (as well as blue shift in galaxies we know are moving toward us, so there is some good evidence that red shift is a function of velocity), and we can see the gravitational effects of something in the universe that we can’t otherwise detect and so we give it a name, dark matter. All this converging data and the theories built up around them fits together and can be extrapolated back to within a millisecond of the Big Bang with 99% confidence, according to cosmologists (the 10^-36 figure is purely speculative, the millisecond figure is based in actual measurements of particle energies and the like).

So of course our models of the universe are incomplete! Of course we try to stick to observable evidence and admit that we don’t know it all. But we don’t dismiss our best understanding BECAUSE we don’t know everything. Science is an unfolding process. We operate on what we have in front of us now, while staying open to better ideas in the future. That’s why we speak of the Big Bang theory AS IF it were true, because our best evidence points us there. We didn’t WANT to go there, the universe dragged us there kicking and screaming.

So it’s not arrogance. It’s actually humility. Those who deny the evidence and instead operate on speculation or dogmatic belief — I’d say that’s arrogance.

Those who arrogantly tell us they know what was happening at 10^-36 sec after the big bang, when the BB theory itself is a fudged theory make me laugh!

The emperor has no clothes!

A lot relies on the “red shift” doppler effect but if we have the arbitrarily invoked “dark matter, and “dark energy” dominating the universe and it has yet to be observed or explained, who’s to say that light travelling through dark matter and dark energy isn’t red-shifted for other reasons than velocity?

Expanding space is also consistent with shrinking matter!

Given enough invoked unobservable factors, mathematics can be cobbled to fit any theory, but it is admitted by most experts, that all our present models of the universe are incomplete.

Beware of “fudge factors”.

It is far better to stick with observable evidence and admit we don’t know the how, where and why of the universe, than to, like the AGW folks, dismiss all sceptisism, be saying “the science is settled”

What a poor legacy we leave for future brilliant minds, if we insist that the BBT is the only valid explanation of how and why we are here!

If the tectonics analogy is apt then there should be somewhere where spacetime is being ‘subducted’- black holes. The question then becomes where does it come out again? And how?

Jess Tauber

Okay, I stand corrected. However, in my defense I was merely trying to point out the common lay person’s fallacy of applying simple linear math to nonlinear phenomena, while steering clear of technical complexities and terminology which are unfamiliar to most — and which are more confusing than clarifying, especially when left undefined (as, unfortunately, is the jargon you used…sorry). Consequently I left a great deal out of my cursory explanation.

Of course, I suppose I am not as up-to-date and deeply immersed in current cosmology theory as are some. So forgive my indiscretion.

My advice for people who want real answers: Study actual research results and read quality books on the relevant subjects, don’t rely on word-of-mouth sound bites or comment postings.

It would seem unlikely that the Big Bang was the beginning of the universe. The total mass of the universe had to already exist or there could not have been anything to explode.

Er, no.

First, this looks like an argument from personal incredulity. It may seem unlikely to you, but that is neither here nor there.

Special relativity has demonstrated the equivalence of mass and energy, so the entire mass of the universe would have arisen from its initial energy. We do not know exactly from whence the energy came, because our best theories can only look back as far as 10^-36 sec after the big bang.

Additionally, it did not explode, because that implies it had something to explode into, but – as far as we can tell – space itself came into existence at the big bang.

If the collapse of an expended star can create a black hole from which nothing can escape, how could a black hole with all the mass of the universe possibly explode and release all the mass and energy in the universe? These two theories would certainly appear incompatible.

Stephen Hawking worked out that black holes evaporate (nearly 40 years ago! Get with the programme). Although the BB started from a spacetime singularity, it was not necessarily a black hole.

Also, the universe can still be considered to be a black hole, but I do not understand this interpretation. Here I have to trust the experts to know what they’re doing.

We should expect that all mass from an explosion will move radially away from the original position without a non-radial vector. How can we explain the collision of galaxies if this is true?

First, it was not an explosion.

Second, when an artillery shell on Earth explodes, how come the fragments all fall to Earth afterwards? The answer to this question is the same as the answer to your question – gravity.

How do we explain that all proposed velocities of observed stars in all directions are essentially the same and places Earth at the center of the explosion? It would seem highly improbable that this would be the case.

This is not the case. BBT does not require this to be the case. The space between objects is expanding, regardless of the individual velocities of those objects.

There are some proposals that the outer reaches of the universe is expanding faster than the speed of light. That would seem highly unlikely with the laws of physics of our local solar system. It is worrisome that it is proposed that the laws of physics that apply to our local solar system may be different elsewhere. What physical evidence would justify this?

Some preceding comments have answered this already.

From our frame of reference, distant objects may be receding at velocities exceeding c. But those objects are not exceeding c in their movement locally through space. The space between us and those objects is expanding rapidly enough for their recession velocities to exceed c.

Why do we observe stars in all stages of their lifetimes if the universe was originated all at the same time?

Because star formation takes time, and requires the right conditions to occur. Most stars that we observe are third-generation stars (i.e. they contain enough elements heavier than He that we know they cannot be primordial stars). Why would you expect stars to all be the same age?

We can verify that the Doppler effect is valid as a sonic frequency because we can observe it from both sides. Since there are few observations from stars coming toward us there is no verification there is a similar effect on the light in the universe.

First, this is wrong. Some local galaxies are moving towards us, and their light is indeed blue-shifted. Second, there are plenty of ways in which we can verify the Doppler effect for light here on Earth, in exactly the same type of experiment as you might use to verify it for sound.

Trying to visualize the geometrical configuration that should be associated with the Big Bang is more difficult. If it is assumed that the Big Bang occurred 13 or so billions of years ago, then the furthest stars have been traveling away from us all that time and the light observed from them has been traveling toward us for an equal amount of time. Why would it be assumed that the light was generated at the beginning and we were already separated by that distance?

The galaxies’ redshift in relation to the cosmic microwave background tells us what proportion of the time since the big bang has passed in the journey time of that light. This would apply irrespective of when the big bang occurred.

What exactly is the problem here?

Why not look for an energy or velocity loss mechanism for light as it passes through an ill-defined medium for eons that could cause the red shift to a lower energy light spectrum? This concept, if somehow validated, might possibly resolve some of the inconsistencies listed above.

Who’s to say that people have not already sought such things?

It seems that you are not familiar with exactly how red-shift is measured, because a little more understanding of the details would clear up some of your issues immediately.

When red-shift is measured, it refers not to the peak emission of the galaxy’s spectrum, but to the atomic absorption lines within that galaxy’s spectrum. These lines form distinctive patterns, so it is always possible to identify the absorbance lines for (say) Hydrogen by how far apart from one another they are in the spectrum. Where in the spectrum those lines occur (relative to where they occur in static experiments on Earth) tells us the amount by which the light has been red-shifted.

Here on Earth, there are only two things that can cause light to red-shift : gravity and the Doppler effect. Since these two components can completely account for the red-shifting of the spectral lines we observe, there is no need to invent something else unknown in the intergalactic medium to account for it.

The “inconsistencies” you describe are not inconsistencies in the theory, but in your understanding of what it states.

Don’t you all suddenly feel a lot younger!

Luckily Branes come in rolls- help yourself.

This means that much of the contents of our universe today would have long ago traveled beyond the ability of its light to reach us, and would be outside our visible light sphere.

As to some other posters’ continuing confusion about an edge to the universe (or a center), I addressed this in my earlier posting (#47), the last paragraph. Rather than repeat myself, I would refer you back to there. Admittedly this is a counterintuitive concept (as is pretty much all of modern cosmology), yet it’s what we’ve been able to figure out.

So hold on for the ride, the Cosmic Carnival is full of strange and weird surprises!

Observations of Some Inconsistencies of the Big Bang Theory of the Universe

It would seem unlikely that the Big Bang was the beginning of the universe. The total mass of the universe had to already exist or there could not have been anything to explode.

If the collapse of an expended star can create a black hole from which nothing can escape, how could a black hole with all the mass of the universe possibly explode and release all the mass and energy in the universe? These two theories would certainly appear incompatible.

We should expect that all mass from an explosion will move radially away from the original position without a non-radial vector. How can we explain the collision of galaxies if this is true?

How do we explain that all proposed velocities of observed stars in all directions are essentially the same and places Earth at the center of the explosion? It would seem highly improbable that this would be the case.

There are some proposals that the outer reaches of the universe is expanding faster than the speed of light. That would seem highly unlikely with the laws of physics of our local solar system. It is worrisome that it is proposed that the laws of physics that apply to our local solar system may be different elsewhere. What physical evidence would justify this?

Why do we observe stars in all stages of their lifetimes if the universe was originated all at the same time?

We can verify that the Doppler effect is valid as a sonic frequency because we can observe it from both sides. Since there are few observations from stars coming toward us there is no verification there is a similar effect on the light in the universe.

Trying to visualize the geometrical configuration that should be associated with the Big Bang is more difficult. If it is assumed that the Big Bang occurred 13 or so billions of years ago, then the furthest stars have been traveling away from us all that time and the light observed from them has been traveling toward us for an equal amount of time. Why would it be assumed that the light was generated at the beginning and we were already separated by that distance?

Why not look for an energy or velocity loss mechanism for light as it passes through an ill-defined medium for eons that could cause the red shift to a lower energy light spectrum? This concept, if somehow validated, might possibly resolve some of the inconsistencies listed above.

SR velocity addition is not appropriate to describe the Hubble flow. Galaxies are not flying through space apart from one another, but rather space is expanding between them. In this case > c recession velocities are possible and are seen. See:

http://arxiv.org/abs/astro-ph/0310808

“Expanding Confusion: common misconceptions of cosmological horizons and the superluminal expansion of the Universe”

We use standard general relativity to illustrate and clarify several common misconceptions about the expansion of the Universe. To show the abundance of these misconceptions we cite numerous misleading, or easily misinterpreted, statements in the literature. In the context of the new standard Lambda-CDM cosmology we point out confusions regarding the particle horizon, the event horizon, the “observable universe” and the Hubble sphere (distance at which recession velocity = c). We show that we can observe galaxies that have, and always have had, recession velocities greater than the speed of light. We explain why this does not violate special relativity and we link these concepts to observational tests. Attempts to restrict recession velocities to less than the speed of light require a special relativistic interpretation of cosmological redshifts. We analyze apparent magnitudes of supernovae and observationally rule out the special relativistic Doppler interpretation of cosmological redshifts at a confidence level of 23 sigma.