Understanding the Cosmological Constant Problem (aka vacuum catastrophe)

There was a recent thread discussing the cosmological constant problem (aka vacuum catastrophe) and how it requires an extremely improbable fine-tuning of our universe. I want to try to explain the nature of this problem as clearly as possible and also offer one potential solution which doesn't require any fine-tuning. It all started when we looked at distant galaxies and discovered the universe was experiencing accelerating expansion, meaning the further away a galaxy is from us, the faster it is moving away from us. In order to explain what could be causing this expansion of space they had to introduce a new form of energy they called dark energy.

One idea developed to explain dark energy was the cosmological constant, a constant energy density filling the entire universe smoothly. Most theories of particle physics predict that empty space has an energy due to vacuum fluctuations and the Casimir effect is evidence that it really happens. So at this point scientists made a logical assumption, they said that the cosmological constant must be definable as vacuum energy, because vacuum energy would fill the entire universe and the energy density would never drop because when you create new space it also creates more vacuum energy along with it, meaning it cannot be diluted and it remains constant.

The idea is that dark energy must be vacuum energy, which is quite a clever and elegant theory with the potential to close many gaps in our understanding of the universe. The problem however, is that when you actually attempt to calculate how much vacuum energy must be contained in our universe it's more than 100 orders of magnitude too large, and if the cosmological constant were actually that large our universe would be expanding much faster. That is the cosmological constant problem. The generally accepted way of solving this problem is to introduce a new type of energy which cancels out most of the vacuum energy but leaves just the right amount to produce the expansion of the universe.

This cancellation process is where the fine-tuning comes into the picture. In order to exactly cancel out all the vacuum energy and leave just the right amount "would require fine-tuning of about 1 part in 10^60, which is 1 part in trillion trillion trillion trillion trillion times". Obviously this is a huge fudge factor to make the theory consistent, there is no explanation for what this huge opposite term needed to cancel out the vacuum energy could possibly be. In order to explain dark energy they've had to introduce some kind of "anti-dark-energy" which is even more mysterious than dark energy its self and requires a completely ridiculous level of fine-tuning to work.

Clearly there is something we are not understanding, this theory just doesn't hold up to scientific scrutiny, yet it remains the most widely accepted explanation of dark energy among the scientific community. That is why it's such a bad problem, most scientists know there's something deeply wrong with the theory, but they are stuck between a rock and a hard place because it's not easy to see where the theory goes wrong. We know what the cosmological constant should be because we know how fast the universe is expanding, and if the vacuum energy isn't responsible for the expansion of the universe then we need a new theory for explaining what dark energy is, which we don't have.

The evidence for dark energy is indirect but comes from three independent sources:

* Distance measurements and their relation to redshift, which suggest the universe has expanded more in the last half of its life.[9]
* The theoretical need for a type of additional energy that is not matter or dark matter to form the observationally flat universe (absence of any detectable global curvature).
* It can be inferred from measures of large scale wave-patterns of mass density in the universe.

en.wikipedia.org...

I want to focus on the 2nd point for a moment. We know the universe is flat based on CMB measurements and in order for the universe to come from nothing it must be flat because only a flat universe has an equal amount of positive and negative energy, so only a flat universe can have zero total energy. This is why theoretical physicists such as Krauss say the only mathematically beautiful universe is a flat universe. If dark energy contains negative energy it may help balance out all the positive matter in our universe. When you look at the nature of dark energy it does indeed have many properties that would be expected if it was negative energy.

It was once believed the universe would end in a "big crunch" because the gravity of all the mass in our universe would slow down the expansion and then reverse the expansion and eventually pull everything back into a singularity or some such thing. Dark energy behaves in the opposite way to normal energy/matter, it behaves as if it has negative gravity because it pushes the universe apart and causes it to expand. The gravity of positive matter pulls objects together, but negative energy has negative mass and therefore negative gravity. However, if we say vacuum energy is responsible for dark energy it doesn't help with the 2nd point and doesn't help balance anything out.

Vacuum energy is thought to consist of virtual particles, normal particles which only exist for a very short period of time, the particles are not believed to have a negative mass and so they wont contribute the negative energy required to get our zero energy universe. The reason for why positive vacuum energy is supposed to cause the universe to expand even though it's not negative energy with negative gravity is complicated and I get the feeling it's just another trick to make their theory work. What I believe is that dark energy is negative energy, it is exactly what it appears to be. But what exactly does it mean for something to have negative mass and negative gravity and why can't we see it?

I mentioned at the start of this thread that I would provide an answer to this problem. I recently created a thread titled Unmasking Dark Matter and Dark Energy which didn't get much attention so I'm giving it a plug here. It was a follow up on my earlier theory concerning Negative Energy & Negative Space. By interpreting dark energy as negative energy it's possible to solve the cosmological constant problem. Vacuum energy no longer plays any role because it's canceled out exactly by negative vacuum fluctuations, which is obviously the only logical solution, and it's nice because it eliminates the need for fine-tuning. Check out those two threads for more details on the theory I developed.

Just wanted to offer up this vid that goes into what is known as the constants that turn out to not really be constant at all but do have a relationship to one another .The speed of light is decreasing while Planks constant is increasing . I found it interesting and wanted to share . I will read over your post and take in what others have to say but I am just a learner in all this stuff . I do find it interesting though ..peace

a reply to: the2ofusr1

Just wanted to offer up this vid that goes into what is known as the constants that turn out to not really be constant

It's interesting that you should mention that, because the cosmological constant might not be constant, it could just change so slowly over time that we cannot detect the change, the Wikipedia page on dark energy mentions that possibility. In fact the solution I propose in those other threads actually predicts it is not a constant.

a reply to: ChaoticOrder

If this was a treatise in high school, then it would be marked as an A+. But if this was presented at conference you'd instigate a brawl.

The only constants that remain are the laws that already govern us. But Brian Schmidt and co proved that the universe is expanding at a faster rate so it's only natural for astrophysicists to include a variable such as dark energy, and those variables are only speculative at this point in time and have many interpretations.

The fabric of our universe is the key but we can't measure it at our current level of technology- it's taken billions of dollars and city encompassing accelerators to identify certain particles-and yet there is still even smaller building blocks that could exist, and It could take many decades to find them.

But we could also find them via indirect means.

originally posted by: Thecakeisalie
a reply to: ChaoticOrder

But if this was presented at conference you'd instigate a brawl.

Lol why is that?

But Brian Schmidt and co proved that the universe is expanding at a faster rate so it's only natural for astrophysicists to include a variable such as dark energy, and those variables are only speculative at this point in time and have many interpretations.

I never disputed the existence of "dark energy", the universe is clearly experiencing metric expansion. I'm just saying vacuum energy is not the culprit. Read my other threads.

Maybe the supermassive black holes at center of every galaxy are just pulling us along faster and faster as the billions of years have passed by. Kinda like how I on engines just keep going faster as long as they have fuel.

No need for magical invisible energies or dark matters or imaginary friends like gods. Each Galaxy is just propelling itself along. It's not like all galaxies are moving apart. In fact we are on collision course with Andromeda right now. No expansion there now is there?

The speaker in the vid I posted speaks about time . It (time) ,according to the speaker has it's own variable .2 atomic clocks do not give the same results and vary .One constant reconing of time we have that seems to have remained constant is the solar /lunar way of keeping time .But because of the de-acceleration of light and the atomic clock he thinks we can calculate the differences .Billions become thousands of years .I know it's a very complicate and controversial subject but the speaker does bring up some good points ..just saying ....peace a reply to: Thecakeisalie

a reply to: the2ofusr1

I know it's a very complicate and controversial subject but the speaker does bring up some good points

Yes it is a controversial subject, people don't like having their constants change. Personally I think it may be possible that big G changes but I'm more skeptical about the speed of light. However there was a controversial TED talk I liked which was titled the science delusion. In that talk Rupert mentions that in the past the speed of light has appeared to change and how scientists managed to fix that problem by defining the metre in terms of the speed of light. So even if the speed of light does change we wont notice it because the unit we use to measure it will change with it.

On the topic of G changing, this news came out last year:

Did gravity, the force that pins us to Earth's surface and holds stars together, just shift? Maybe, just maybe. The latest measurement of G, the so-called constant that puts a figure on the gravitational attraction between two objects, has come up higher than the current official value.

Measurements of G are notoriously unreliable, so the constant is in permanent flux and the official value is an average. However, the recent deviation is particularly puzzling, as it is at once starkly different to the official value and yet very similar to a measurement made back in 2001, not what you would expect if the discrepancy was due to random experimental errors.

It's possible that both experiments suffer from a hidden, persistent error, but the result is also prompting serious consideration of a weirder possibility: that G itself can change. That's a pretty radical option, but if correct, it would take us a step closer to tackling one very big mystery – dark energy, the unknown entity accelerating the expansion of the universe.

Str ength of gravity shifts – and this time it's serious

Very interesting read. I think that there should be much more work done on other potential shapes for the universe, considering that there are other shapes that would be consistent with the observed data. There are the possibilities of using a hyperbolic or spherical 3-manifold. The idea of a saddle-shaped universe just seems a bit odd to me, but that doesn't really mean anything. It is not as aesthetically pleasing as other spaces in my opinion. There are numerous possibilities that could be explored, so many that most probably haven't been toyed with. The flaws would likely be fairly evident in any particular model quite quickly, which would help. I remember reading about the idea of using Lie groups as well, although I do not recall whether this was referring to the actual shape of the universe, and I think what I am referencing had to do with mapping the known particles and forces using this particular geometry. There are just so many possibilities that could be fiddled with, although of course some look better than others. Positive as well as negative curvature/open or closed must also be considered. Although curvature beyond a certain point could be used to rule out certain models.

Anyway, we don''t really know the actual density of the universe, which is why we don't really know what the universe will do in the future. All of the possibilities relate to the density. If the density is above critical then the universe will eventually collapse back on itself. If the density equals the critical value then the universe will just barely continue to expand, but will expand forever...If the density is below the critical value the universe will expand forever. In the first case the curvature would be positive, which is basically like the curvature of a sphere. In the second case, where the density is close to the critical value, we would have a Euclidean or flat universe. In the last case, the curvature would be negative and the shape would be what I referred to earlier, hyperbolic or like the shape named after Picard, or what is often termed saddle-shaped. There are a great variety of 3-manifold possibilities.

If the mathematics themselves weren't difficult enough to grasp, at least for me, attempting to relate a mathematical concept to physical reality is something that I really struggle with. It is easier just to ignore the math and think of things strictly physically in my opinion. I've always had a problem with learning to do the work without actually grasping the meaning behind it, which is a horrible strategy, lol.

Anyway, I know there are potential ways to at the very least limit the possibilities. If you know the local geometry you can make inferences about the global geometry in some instances, but it depends on how much larger the global universe is when compared to the local universe. The local geometry basically refers to the curvature of the parts of the universe we can see, while the global geometry refers to the topology of the entire universe. As you might imagine there are potential problems that one could run in to if the universe is not symmetrical on all sides. What we see might look like it fits this description, but the global topology might be different from what is expected. If the observable universe was known to be the entire universe then things would be a bit easier.

The reason that the universe is thought to be Euclidean has to do with the data collected. The measurements that have been made, if accurate, suggest that the curvature is very close to zero, meaning the universe is flat. This is what I meant when I said that Euclidean space meant being close to zero, as the curvature is close enough to zero to be interpreted as being flat, although ideally zero would equal flat. It is close enough basically, but this relates to the local geometry. If you consider a balloon that is blown up, obviously it has curvature. But if you could blow that balloon up to the size of the universe, and then plop yourself down on it, everything would look flat to you. This is why I stated earlier that it would be easy to tell the curvature of the universe if the local geometry was equivalent to the global topology. Also, space can be flat while spacetime itself is curved, if the other stuff wasn't confusing enough. The entire idea of a finite or infinite universe is also wrapped up in the topology of the universe. Many of these ideas seem counterintuitive for sure, but often times it has to do with terminology. The concepts we are talking about here are a lot more intuitive than quantum mechanics for instance. Anyway, suffice it to say that I think it is a mistake to assume that the universe is flat, and that is the way it has to be.

The G subject is probably left to the mysterious world of Quantum . Reason being from my point is that nobody knows what gravity really is . I suspect it is something associated with a gyro but more then likely it's electrical magnetic in nature. That would explain the variables on our own surface . a reply to: ChaoticOrder

a reply to: the2ofusr1

I can tell you what gravity is. Gravity IS making my rear end hurt from sitting in this plane seat for 4 hours straight.

Wrong ...That is the effects of gravity lol a reply to: Xeven

a reply to: JiggyPotamus

The reason that the universe is thought to be Euclidean has to do with the data collected. The measurements that have been made, if accurate, suggest that the curvature is very close to zero, meaning the universe is flat. This is what I meant when I said that Euclidean space meant being close to zero, as the curvature is close enough to zero to be interpreted as being flat, although ideally zero would equal flat. It is close enough basically, but this relates to the local geometry. If you consider a balloon that is blown up, obviously it has curvature. But if you could blow that balloon up to the size of the universe, and then plop yourself down on it, everything would look flat to you.

There are more accurate ways to determine the curvature of the universe. We now know with a very high level of confidence that the universe is flat and most likely infinite. Only a flat universe can produce the patterns we observe in the CMB data, we don't need to measure the curvature of space over huge distances to know the universe is flat. Krauss actually has a good lecture where is explains how we are able to derive the shape of the universe from patterns in the CMB data.

Although the shape of the universe is still a matter of debate in physical cosmology, based on the recent Wilkinson Microwave Anisotropy Probe (WMAP) measurements "We now know that the universe is flat with only a 0.4% margin of error", according to NASA scientists.

The model most theorists currently use is the so-called Friedmann–Lemaître–Robertson–Walker (FLRW) model. According to cosmologists, on this model the observational data best fit with the conclusion that the shape of the universe is infinite and flat

en.wikipedia.org...