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7 minutes ago, Bmpbmp1975 said:

Sorry this is the other wiki

WHICH OTHER WIKI?

Is this the Wikipedia that only exists inside your head and says all sorts of nonsensical and plainly false things?

Why not provide a link to whatever you are referring to?

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1 minute ago, Strange said:

WHICH OTHER WIKI?

Why not provide a link to whatever you are referring to?

Oops forgot to paste

also sorry for the confusion but everything I have read by Katie Mack states we are metastable

Edited by Bmpbmp1975

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1 minute ago, Bmpbmp1975 said:

Oops forgot to paste

Please quote the exact sentence where it says the cosmological constant is less than zero. (Because it doesn't.)

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55 minutes ago, Strange said:

Please quote the exact sentence where it says the cosmological constant is less than zero. (Because it doesn't.)

No that’s where it said metastable also my post was a reply to migl who I quoted to read that.

thank you for claryfiying things for me but for some reason I have been under the impression that we are metastable I universe and that’s  the comments in many articles and videos from Dr Mack. So I think we are really in a metastable universe.

Edited by Bmpbmp1975

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3 minutes ago, Bmpbmp1975 said:

thank you for claryfiying things for me but for some reason I have been under the impression that we are metastable

Then stop reading things you don't understand.

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1 hour ago, Strange said:

Please quote the exact sentence where it says the cosmological constant is less than zero. (Because it doesn't.)

No that’s where it said metastable

and also I believe the the lhc discovered the higgs   field also being metastable which can lead to vacuum decay

Edited by Bmpbmp1975

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1 hour ago, Bmpbmp1975 said:

No that’s where it said metastable

But again, no quotation of what it said. Why?

1 hour ago, Bmpbmp1975 said:

and also I believe the the lhc discovered the higgs   field also being metastable which can lead to vacuum decay

Nope.

But the measurement of the mass of the Higgs boson did put constraints on the stability of the vacuum.

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20 minutes ago, Strange said:

But again, no quotation of what it said. Why?

Nope.

But the measurement of the mass of the Higgs boson did put constraints on the stability of the vacuum.

20 minutes ago, Strange said:

But again, no quotation of what it said. Why?

Nope.

But the measurement of the mass of the Higgs boson did put constraints on the stability of the vacuum.

According to the new findings at lhc in 2012 thé Higgs bosom is unstable and the new changes show that vacuum collapse it can  happen at any time? So something changed recently to set it in this state

this is in almost every new article online

also not sure where you have seen that constraints have been put on it ?

Edited by Bmpbmp1975
iPhone spellcheck

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It's like trying to teach integral calculus to an 8 year old, Strange.

I'm starting to get the impression he's 'playing' us.

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30 minutes ago, MigL said:

It's like trying to teach integral calculus to an 8 year old, Strange.

I'm starting to get the impression he's 'playing' us.

I am not playing you, I have been reading news articles about metastable universe, what was found and lhc the Higgs, Katie Mack and vacuum Collapse for months now

also I have posted numerous articles about where I get my info. The only thing i get back is how I am wrong which I probably am but show me where I am wrong so I learn don’t just tell me

Edited by Bmpbmp1975

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12 minutes ago, Bmpbmp1975 said:

I am not playing you, I have been reading news articles about metastable universe, what was found and lhc the Higgs, Katie Mack and vacuum Collapse for months now

It may be a really good idea, if you straight up disregard news articles, interviews with scientists and other stuff that could be confusing. You also seem to like Katie Mack a lot, and maybe her research/ideas are very interesting, but wouldn't it be a good idea to first brush up your basic physics.

Start with the basics, explain things here, in detail, with specifics and references to where you found the information (exactly) and first verify if you understand the basics. It is very important that you are specific, because only by being specific can we talk about the same things, especially in science.

If you ask a question about anything, let's say metastability, maybe explain it. So we are all on the same page. Try to put care and thought in your explanation, as it will aid you in learning. I don't have much physics background and I would love to know what it is, just explain it for people that aren't as knowledgeable. If you can explain the concept and people here agree with your explanations, you move onto the next part, and the next. Until your question logically follows (or what regularly happens, you see that you have wrong assumptions and that is why you were confused about it in the first place).

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10 hours ago, Bmpbmp1975 said:

The only thing i get back is how I am wrong which I probably am but show me where I am wrong so I learn don’t just tell me

You have been repeatedly corrected with explanations about why you are wrong. But you just repeat the same incorrect statements over and over.

You also frequently claim that an article says something but when others read it they explain it doesn't say that. You insist it does but refuse to quote the bit where it says what you claim. So, effectively, you are making up stories about what the article says.

As you are unwilling to actually listen and learn anything, I will stop trying to correct you. It is a waste of time.

I will answer direct questions (when I can). But any incorrect statements will , from now on, just be met with "no".

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1 hour ago, Strange said:

You have been repeatedly corrected with explanations about why you are wrong. But you just repeat the same incorrect statements over and over.

Good point, I'll try another way to help by attempting to state the question OP seems to want to ask but is not able to state. @Bmpbmp1975 might want to understand the questions before the answers?

Begin

Due to interest in the concepts of metastability, false vacuum and vacuum decay* of the universe I've followed what's been published. After reading and trying to interpret a few articles** and papers, and there are two questions.
1:
In current mainstream physics is there a consensus regarding false vacuum and meta stability? Are there conclusive evidence in the observations to favour theories that universe is in a false vacuum at this time?

2:
If a false vacuum model is a correct way to describe universe and vacuum decay is theoretically possible, are there any reliable sources showing calculations of the probability of vacuum decay to happen in the observable universe (in a location in the universe were vacuum decay would affect us at some time from now)?
I have seen a few sources publish various numbers such as “it may happen once in a timespan many times the age of the universe” but I have not found where such calculations come from. I choose not to link to these sources since some seems to promote fringe or pet theories outside of the mainstream.

End

My own attempt at answering OP, given that above questions are valid, would be
1: I do not know. I any case AFIK there is no evidence or model stating that anything related to vacuum decay has changed or will happen any time soon. Universe seems to have been around pretty long without decaying.
2: If the probability is >0 (greater than exactly/mathematically zero) it means that it may happen at any time, not that it is bound to happen any time soon. I see no need to pursue these physical concepts as a reason to believe the end of the universe is approaching.

**)Katie Mack have published an interesting post. https://astrokatie.blogspot.com/2018/09/extra-dimensions-black-holes-and-vacuum.html. Here is the paper "Bounds on extra dimensions from micro black holes in the context of the metastable Higgs vacuum" discussed in the previous link:  https://arxiv.org/pdf/1809.05089.pdf

Edited by Ghideon
better formulation

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20 minutes ago, Ghideon said:

Good point, I'll try another way to help by attempting to state the question OP seems to want to ask but is not able to state.

Excellent approach.

21 minutes ago, Ghideon said:

1:
In current mainstream physics is there a consensus regarding false vacuum and meta stability? Are there conclusive evidence in the observations to favour theories that universe is in a false vacuum at this time?

There is not a strong consensus. From purely quantum considerations, the measurement of various constants (including the mass of the Higgs boson and the top quark) put constraints on whether we are in a false vacuum state and how close to being metastable the universe is. This is generally agreed, but the data is not precise enough to come to a definite conclusion one way or the other.

This is complicated by trying to take gravity into account. My understanding is that the presence of mass in the universe appears to make the possibility of the universe being in a metastable state much less likely. But we probably need a quantum theory of gravity to really understand that.

It is possible that the universe is in a metastable state and could, at some point decay to a lower (true vacuum) state. However, the probability of that happening is so low it is not likely to happen in the lifetime of the universe. After all, it hasn't happened yet.

It is also possible that the universe is not in a false vacuum state at all.

In summary, it is an interesting theoretical problem in physics but not something that needs to be worried about in any practical sense. (Apart from anything else, no one would ever know if it happened!)

For the second question, I would also refer to the False vacuum wikipedia page as a starting point.

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Thanks for the excellent response! That clarified* a few things. Especially the part about quantum theory of gravity; since there is not yet AFAIK any support for one specific theory it seems reasonable that it is really hard at this time to reach consensus. It also then makes sense when someone states "new physics will intervene"**. It is simply not fully known yet what a quantum theory of gravity will predict regarding false vacuum.

16 minutes ago, Strange said:

It is possible that the universe is in a metastable state and could, at some point decay to a lower (true vacuum) state. However, the probability of that happening is so low it is not likely to happen in the lifetime of the universe. After all, it hasn't happened yet.

A quick followup: When saying "lifetime of the universe" does "lifetime" account for a set of possible ways that our current models predict that universe may end?
I have read about for instance about heat death, big rip and big bounce. Without going into specific probabilities, is the following a reasonable assumption: Let's stay we would make a list of various ways the universe may end, placing more probable ones at the top. I assume current theories states that "vacuum decay" will be near the bottom of the list; one of the others are more likely to happen first.
(An of course, none of the entries in this fictive list is bound to happen any time soon)

*) I'm still kind of playing the role of OP here...

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10 minutes ago, Ghideon said:

A quick followup: When saying "lifetime of the universe" does "lifetime" account for a set of possible ways that our current models predict that universe may end?
I have read about for instance about heat death, big rip and big bounce. Without going into specific probabilities, is the following a reasonable assumption: Let's stay we would make a list of various ways the universe may end, placing more probable ones at the top. I assume current theories states that "vacuum decay" will be near the bottom of the list; one of the others are more likely to happen first.
(An of course, none of the entries in this fictive list is bound to happen any time soon)

If I had read it, I would probably recommend Katie Mack's new book on the subject

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Thank you all for clarifying what I was trying to say. And to answer a question asked before why I thought the constant has fallen below 0 this is what I read claiming that.

see below

This portion of the link you referenced has some good detail. https://en.wikipedia.org/wiki/Cosmologi ... _solutions So I'll add some comments numbered by the paragraph in the link.

1) The "anthropic arguments" are rejectable unless you embrace untestable multiverses. Let's not go there.
2) Modified gravity.... hmmm. Well ECSK has some interesting points in its favor in this regard I recall.
3) & 4) Unruh and Ellis are experts and challenge that there is a problem. OTOH Zeldovich started this industry of calculating the cosmological constant and is an expert too. As much as I admire Zeldovich this might really be a non problem. Ellis's suggestion that only deviations from the vacuum gravitate is quite appealing.
5) Might be technically correct but how to test whether it is true?

Now the whole business reminds me of the 19th century Ultraviolet Catastrophe https://en.wikipedia.org/wiki/Ultraviolet_catastrophe

Essentially there was a singularity in the black body radiation in the ultraviolet in classical electromagnetism that was only cured in quantum field theory (in the primitive form deployed by Max Planck). We should never forget that as wonderful as GR is it has singularities. These are cured in ECSK.

Nikodem J. Popl􏰀awski has calculated the cosmological constant after the manner of Zeldovich in ECSK gravity and the results are amusing.

https://arxiv.org/pdf/1005.0893.pdf

We present a simple and natural way to derive the observed small, positive cosmological constant from the gravitational interaction of condensing fermions. In the Riemann-Cartan spacetime, torsion gives rise to the axial-axial four-fermion interaction term in the Dirac Lagrangian for spinor fields. We show that this nonlinear term acts like a cosmological constant if these fields have a nonzero vacuum expectation value. For quark fields in QCD, such a torsion-induced cosmological constant is positive and its energy scale is only about 8 times larger than the observed value. Adding leptons to this picture could lower this scale to the observed value.

Well I think it would have been nice to do the calculation with leptons to begin with as opposed to aiming at the target with quarks, missing by a factor of 8 and then arguing that leptons would close the gap. It would make for better PR anyway. But there it is. Torsion coupling by the simplest nonlinear term to particle spins solves the problem.

Now this is a personal observation. If Poplawski is right then the equation of state of Dark Energy might fall out trivially. I'd expect it to be close to w=p/ρ=1w=p/ρ=−1 like the usual cosmological constant but the kinetic term would make it slightly larger than -1. As it turns out the measured value of w from the Planck data is -0.98 but with an error bar of 0.05. So beating down on the error might allow some interesting conclusions to be drawn.

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1 hour ago, Strange said:

It is possible that the universe is in a metastable state and could, at some point decay to a lower (true vacuum) state. However, the probability of that happening is so low it is not likely to happen in the lifetime of the universe.

Somehow this statement is difficult to understand, Strange. Surely if it happens, then it happens within the lifetime of the universe, not afterwards.

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47 minutes ago, Bmpbmp1975 said:

Thank you all for clarifying what I was trying to say. And to answer a question asked before why I thought the constant has fallen below 0 this is what I read claiming that.

Nowhere does that say anything about a value falling below zero.

It does say that the equation of state of dark matter energy (the pressure divided by the energy density) might be approximately -1. That is the only specific value I can see mentioned.

So why do you keep claiming that bits of text say things that they don't?

Edited by Strange
dark energy not matter

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On 2/14/2020 at 9:59 AM, Strange said:

The measured value has changed over time as better (more accurate) measurement methods have been found.

The source for a change in $$\Lambda$$ might be something like Barrow and Shaw "The Value of the Cosmological Constant", arxiv.org/abs/1105.3105.

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1 minute ago, taeto said:

Somehow this statement is difficult to understand, Strange. Surely if it happens, then it happens within the lifetime of the universe, not afterwards.

Good catch. I wasn't very clear what I was trying to say (even in my own head). Can I get away with saying I meant "a period of time equal to the current age of the universe"? No. Oh, well.

I was trying to remember a figure I saw that gave the probability in terms of a number of gigayears , but I don't know where that came from now.

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2 minutes ago, Strange said:

Good catch. I wasn't very clear what I was trying to say (even in my own head). Can I get away with saying I meant "a period of time equal to the current age of the universe"? No. Oh, well.

I was trying to remember a figure I saw that gave the probability in terms of a number of gigayears , but I don't know where that came from now.

But luckily for us, the probability that it happens during our own lifetime is exactly zero. Indeed it could only happen at its very end ☠️.

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17 minutes ago, Strange said:

Nowhere does that say anything about a value falling below zero.

It does say that the equation of state of dark matter (the pressure divided by the energy density) might be approximately -1. That is the only specific value I can see mentioned.

So why do you keep claiming that bits of text say things that they don't?

Isn’t that the same

16 minutes ago, Strange said:

Good catch. I wasn't very clear what I was trying to say (even in my own head). Can I get away with saying I meant "a period of time equal to the current age of the universe"? No. Oh, well.

I was trying to remember a figure I saw that gave the probability in terms of a number of gigayears , but I don't know where that came from now.

Not sure what you mean here

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20 minutes ago, Bmpbmp1975 said:

Isn’t that the same

Not really. Something having a value of less than 0 (approximately -1 in this case) is not the same as "falling below 0" because that implies it once had a value greater than 1.

If I am standing on the ground, it doesn't mean I have fallen from a ladder.

Quote

The equation-of-state parameter governs the rate at which the dark energy density evolves. For a perfect, unchanging vacuum energy, we have w=-1: the pressure is equal in magnitude and opposite in sign to the energy density. If w is a little bit greater than -1 (e.g., -0.9 or -0.8), the dark energy density will slowly decrease as the universe expands. ... If w is less than -1, the energy density of the dark energy is actually increasing as the universe expands.

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35 minutes ago, Strange said:

Not really. Something having a value of less than 0 (approximately -1 in this case) is not the same as "falling below 0" because that implies it once had a value greater than 1.

If I am standing on the ground, it doesn't mean I have fallen from a ladder.

What I meant was you keep saying dark energy but isn’t that the cosmos constant also, which is at minus 1

Edited by Bmpbmp1975

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