If observing the universe affects its duration ? (recent Krauss Dent paper)

In summary, the highly speculative recent paper by Lawrence Krauss and James Dent suggests that recent observations of type Ia supernovae may have hastened the end of the universe. While the article is short, it contains several striking speculative ideas that may have important cosmological implications. Several interesting open questions are raised, including whether observing the cosmological configuration of our universe may ultimately alter its mean lifetime.
  • #1
marcus
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Highly speculative recent paper by Lawrence Krauss and James Dent.
Can't help suspecting there is some logical flaw or unjustified assumption.
In any case the paper is short (only 4 pages) and contains several striking speculative ideas, so some may want to check it out if only from curiosity.

http://arxiv.org/abs/0711.1821
The Late Time Behavior of False Vacuum Decay: Possible Implications for Cosmology and Metastable Inflating States
Lawrence M. Krauss (1,2), James Dent (2) ((1) Case Western Reserve University, (2) Vanderbilt University))
4 pages, submitted to PRL
(Submitted on 12 Nov 2007)

"We describe here how the late time behavior of the decaying states, which is predicted to deviate from an exponential form, while normally of insignificant consequence, may have important cosmological implications in the case of false vacuum decay. It may increase the likelihood of eternal inflation, and may help explain the likelihood of observing a small vacuum energy at late times, as well as arguing against decay into a large negative energy (anti-de Sitter space), vacuum state as has been motivated by some string theory considerations. Several interesting open questions are raised, including whether observing the cosmological configuration of our universe may ultimately alter its mean lifetime."

Thanks to Peter Woit for noticing this
http://www.math.columbia.edu/~woit/wordpress/?p=621

The senior author, Krauss, is a prominent and respected cosmologist (as well as a popular author). I don't recall ever seeing in his professional papers anything that seemed quite so apt to provoke controversy as this.
 
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  • #2
According to news reports, they have an article in the upcoming New Scientist claiming that we may have hastened the end of the universe by making observations of type Ia SNae the led to the inference of a small positive cosmological constant. Unless their article is being misrepresented or misunderstood, this is some serious disconnect. I can accept the quantum weirdness that says that observing a sub-atomic particle necessarily affects its state, but this? The news report just cannot be right.

http://www.news.com.au/adelaidenow/story/0,22606,22801758-5005962,00.html

It will be interesting to see what the article really claims, unfiltered through the popular press.
 
  • #4
Request clarification

turbo-1 said:
According to news reports, they have an article in the upcoming New Scientist

Hang on, are you saying they are themselves writing an article for NS :yuck:, or is their speculation at the end of the cited eprint being written about, no doubt with the maximum of hysteria, by an NS "reporter"?
 
  • #5
Chris Hillman said:
Hang on, are you saying they are themselves writing an article for NS :yuck:, or is their speculation at the end of the cited eprint being written about, no doubt with the maximum of hysteria, by an NS "reporter"?
More likely. The reporters grab the sensational stuff. Grab Wallace's link for comments by Krauss. It's still REALLY speculative to posit that observing photons from a supernova and inferring the existence of a cosmological constant can have a deleterious effect on the false vacuum from which such cc might arise.
 
  • #6
Yes, I'm following the other thread too. My understanding is that NS has announced (probably in one of their infamous "press releases"--- talk about involving yourself in the story, on in this case creating the "story"!) a forthcoming NS article by one of the their "reporters", not an NS article by Krauss and Dent.
 
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  • #7
turbo-1 said:
According to news reports, they have an article in the upcoming New Scientist claiming that we may have hastened the end of the universe by making observations of type Ia SNae the led to the inference of a small positive cosmological constant. Unless their article is being misrepresented or misunderstood, this is some serious disconnect. I can accept the quantum weirdness that says that observing a sub-atomic particle necessarily affects its state, but this? The news report just cannot be right.

http://www.news.com.au/adelaidenow/story/0,22606,22801758-5005962,00.html

It will be interesting to see what the article really claims, unfiltered through the popular press.
i don't think so either on a minute scale yes but on a universal scale classical physics apply
 
  • #8
andrewj said:
i don't think so either on a minute scale yes but on a universal scale classical physics apply
Really. If we had the ability to observe all the virtual particles of the false vacuum instantaneously (we don't and never will), we would still have to posit some kind FTL communication to make the claim that we have constrained the state of all those evanescent virtual particles simultaneously. Sakharov felt that experimentation in the field of the false vacuum should be severely limited. I sincerely believe that we are not alone in this universe and that we have no special universal leverage with our observations, and the fact that the universe exists is definitive proof that no other race has such leverage either. The universe is robust against our observations - our sphere of influence is appropriately modest.
 
  • #9
I agree with the generally skeptical tone of the comments and just have two things to say.

1. I didn't realize when I posted that someone else had already initiated discussion. There is another thread about this, as Wallace pointed out a few posts back, which seems to focus more on the popular media reaction (judging by links in the O.P.)

2. I respect Larry Krauss in general very much both as a scientist and as a writer.
One of his papers this year was called something like the Static Universe and the End of Cosmology----about what the late universe will look like according to the accepted LambdaCDM model. Beautiful and eye-opening paper.

Nevertheless a couple of sentences in the conclusion in the present paper totally do not make sense to me.

Krauss contributed a couple of brief posts to the other thread and Wallace rebutted.

==================

UPDATE
Krauss has revised the paper on arxiv. Hopefully this will make it less provocative and help damp the media reaction.

Here is the new abstract summary, so you can compare it with what is in the O.P.
==quote Krauss Dent abstract==
We describe here how the late time behavior of the decaying states, which is predicted to deviate from an exponential form, while normally of insignificant consequence, may have important cosmological implications in the case of false vacuum decay. It may increase the likelihood of eternal inflation, and may help explain the likelihood of observing a small vacuum energy at late times, as well as arguing against decay into a large negative energy (anti-de Sitter space), vacuum state as has been motivated by some string theory considerations. Several interesting open questions are raised, including whether observing the cosmological configuration of a metastable universe can constrain its inferred lifetime.
==endquote==

The last couple of sentences in the main body of the article are also toned down or perhaps tastefully obfuscated :

==quote==
...ensured, by measuring the existence dark energy in our own universe, that the quantum mechanical configuration
of our own universe is such that late time decay is not relevant? Put another way, what can internal observations of the state of a metastable universe say about its longevity?
==endquote==

there is still some sensational content but you have to stretch a little and dig more to get it.

KRAUSS THINKS HE HAS REMOVED ANY SUGGESTION OF CAUSALITY by changing the last two sentences, he says on Woit's blog
"... In any case, the last two sentences of the paper have been revised so that it should be clear to the press that causality will not be implied."
http://www.math.columbia.edu/~woit/wordpress/?p=621#comment-31045

In other words there is now supposed to be no suggestion that our observing the CC can have caused anything. In my humble, he is fooling himself and he will still have to revise further, before the paper is published, or perhaps eliminate the last two sentences.
 
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  • #10
After I wrote the above, about their changing the paper, Larry Krauss happened to show up and kindly pointed that out in the other thread:
lmkrauss said:
I have decided that indeed the final two sentences of the paper left the incorrect impression that causality was somehow involved. The purpose of these comments was to refer to work I have been discussing with Alan Guth related to this paper.. namely to what extent cosmological observations made today constrain the nature of the wavefunction and our quantum state in a way that may imply we are not in the late-decaying phase.. This is what I should have said, rather than leaving the incorrect impression that somehow actually making the measurement has a causal effect.. it does not.. it merely constrains our quantum state.. The new version of the paper with the last two sentences changed removes this ambiguity I hope, for all future journalists who look at it.

L. Krauss

So that's apparently settled now. The paper is NOT supposed to give people the idea that our observing the cosmo constant etc has any effect on universe future rates of expansion.

Hope they can get the word out so as to correct any earlier misinterpretation.
 
  • #11
marcus said:
The senior author, Krauss, is a prominent and respected cosmologist (as well as a popular author). I don't recall ever seeing in his professional papers anything that seemed quite so apt to provoke controversy as this.

[EDIT]Controversy is not necessarily a bad thing, and, in the right context, can be quite a good thing, as it generates much discussion. If no one pushes the envelope, science doesn't advance very far.[/EDIT

Krauss is also a co-author of the Phys. Rev. D accepted

http://www.arxiv.org/abs/gr-qc/0609024

which generated a bit of controversy controversy a few months ago.

The main (and controversial) point of the paper: *no* observer (hovering, freely falling, blasting away with a rocket *towards* the surface of the collapsing object, etc.) experiences an event horizon because there is no event horizon to experience.

From the paper: “Instead it may happen that the true event horizon never forms in a gravitational collapse ... The infalling observer never crosses an event horizon, not because it takes an infinite time, but because there is no event horizon to cross. As the infalling observer gets closer to the collapsing wall, the wall shrinks due to radiation back-reaction, evaporating before an event horizon can form. The evaporation appears mysterious to the infalling observer since his detectors don’t register any emission from the collapsing wall Yet he reconciles the absence of the evaporation as being due to a limitation of the frequency range of his detectors. Both he and the asymptotic observer would then agree that the spacetime diagram for an evaporating black hole is as shown in Fig. 9. In this picture a global event horizon and singularity never form. A trapped surface (from within which light cannot es cape) may exist temporarily, but after all of the mass is radiated, the trapped surface disappears and light gets released to infinity.”
 
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  • #12
marcus said:
After I wrote the above, about their changing the paper, Larry Krauss happened to show up and kindly pointed that out in the other thread:


So that's apparently settled now. The paper is NOT supposed to give people the idea that our observing the cosmo constant etc has any effect on universe future rates of expansion.

Hope they can get the word out so as to correct any earlier misinterpretation.
I really respect Dr. Krauss's responsiveness to our criticisms. Isn't that the kind of reaction a well regarded science forum should provoke?
 

1. How can observing the universe affect its duration?

The recent Krauss Dent paper suggests that the act of observation itself has an impact on the duration of the universe. This is based on the principles of quantum mechanics, which state that the act of measurement can change the state of a system.

2. What evidence supports this idea?

The paper presents theoretical arguments and mathematical models to support the idea that observation can impact the duration of the universe. However, this is still a highly debated topic and there is currently no concrete evidence to prove this hypothesis.

3. Does this mean that humans have the power to control the duration of the universe?

No, the impact of observation on the duration of the universe is still a theoretical concept and has not been proven. Even if it were true, the extent of human observation on the vastness of the universe would be minuscule.

4. How does this idea fit into our current understanding of the universe?

The idea that observation can affect the duration of the universe is still a controversial topic and not widely accepted by the scientific community. It challenges our current understanding of the laws of physics and the concept of a fixed and unchanging universe.

5. What implications does this have for the study of the universe?

If this theory were to be proven true, it would have significant implications for our understanding of the universe and the laws of physics. It could lead to a new understanding of the relationship between the observer and the observed, and potentially open up new avenues of research in the field of quantum mechanics and cosmology.

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