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Natural Science Forum / Physics / Research / November 2007



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so, is it really true that observing dark energy hastens the end of    the Universe?

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robert bristow-johnson - 22 Nov 2007 13:25 GMT
first there was that weird Swiss ballot encryption thing:
http://www.smh.com.au/news/World/Swiss-to-use-encryption-voting-method/2007/10/1
3/1191696216022.html


now there is this weirder astronomers are hastening the end of the
universe thing:
http://www.theage.com.au/news/world/bscienceb-did-astronomers-hasten-end-of-the-
universe/2007/11/22/1195321929950.html


  "Incredible as it seems, our detection of the dark energy may
   have reduced the life-expectancy of the Universe," says
   Lawrence Krauss of Case Western Reserve University.

this really seems like crap.  in the former, i cannot understand how a
robust communications system cannot tolerate the loss of a photon, and
if it can, how it can differentiate a loss of a photon because of a
kink in the fiber-optics vs. someone observing the data.  in the
latter, the light from the distant galaxies has been emitted, some of
it absorbed by dark matter, eventually an obscenely small portion
arrives on this planet where an obscenely large portion is just
absorbed.  what difference to the Universe should it make as to what
state the neurons in the brains of some astronomers and physicists
are?  this is silly.

r b-j
Dirk Bruere at NeoPax - 22 Nov 2007 20:38 GMT
> first there was that weird Swiss ballot encryption thing:
>  http://www.smh.com.au/news/World/Swiss-to-use-encryption-voting-method/2007/10/1
3/1191696216022.html

[quoted text clipped - 19 lines]
>
> r b-j

Depends whether you believe that the collapse of the wavefunction only
occurs due to conscious perception.
http://en.wikipedia.org/wiki/Consciousness_causes_collapse

Dirk

http://www.transcendence.me.uk/ - Transcendence UK
Remote Viewing classes in London
Phillip Helbig---remove CLOTHES to reply - 23 Nov 2007 18:20 GMT
In article
<38f2eccb-f0c0-468f-9e36-4c698a2494d7@o6g2000hsd.googlegroups.com>,
robert bristow-johnson <rbj@audioimagination.com> writes:

> first there was that weird Swiss ballot encryption thing:
>  http://www.smh.com.au/news/World/Swiss-to-use-encryption-voting-method/2007/10/1
3/1191696216022.html

No mystery here.

> this really seems like crap.  in the former, i cannot understand how a
> robust communications system cannot tolerate the loss of a photon, and
> if it can, how it can differentiate a loss of a photon because of a
> kink in the fiber-optics vs. someone observing the data.  

It can't.  To quote from the article "Those that are lost - or
intercepted - become useless, Gisin said."  It doesn't matter.  The
point is that no-one can intercept the data, because the coherence is
then destroyed.  That doesn't mean that there are no other ways to
destroy the coherence.

> now there is this weirder astronomers are hastening the end of the
> universe thing:
[quoted text clipped - 3 lines]
>     have reduced the life-expectancy of the Universe," says
>     Lawrence Krauss of Case Western Reserve University.

> in the
> latter, the light from the distant galaxies has been emitted, some of
[quoted text clipped - 3 lines]
> state the neurons in the brains of some astronomers and physicists
> are?  this is silly.

I'll have to read the original article.  On the one hand, Krauss is
certainly not a crackpot and has been investigating the cosmological
constant for a long time, usually contributing something interesting.  
On the other hand, the account might be garbled somewhat, although that
seems unlikely if the quote is correct.

Things like this are what inspired Einstein to ask whether the moon is
really only there when he looks at it.

It's all down to the interpretation of quantum mechanics.  Many people
actually do believe that consciousness plays a real role in quantum
mechanics.  (Interestingly, Penrose a) believes that quantum mechanics
plays a real role in consciousness and b) his "interpretation" is not
really an interpretation since it is in principle possible to
differentiate it from other interpretations by experiments.)  My own
view is that the universe existed before we (or any other consciousness
did) and that its evolution is more or less independent of whether we
came into existence or not.

Let's look at the article in more detail:

  Until recently, a common idea was that the energy unleashed in the Big
  Bang happened when a "false vacuum" - a bubble of high energy with
  repulsive gravity - broke down into a safe, zero-energy "ordinary"
  vacuum.

I'm not sure what is meant by "common".  Although many people hold this
view, it is important to realise that it is not essential for the
general picture of the big bang, the expansion of the universe, the
acceleration of the universe etc.

  For one thing, cosmologists have discovered that the Universe is still
  expanding.

No surprise here.  What is probably meant is "still accelerating".

  Dark energy, goes the thinking, is a result of the Big Bang and is
  accelerating the Universe's expansion.

Well, what is NOT a result of the big bang?

  If so, the Universe is not in a nice, stable zero-vacuum state but
  simply another "false vacuum" state that may abruptly decay again -
  and with cataclysmic consequences.

Non-sequitur.  If the "dark energy" is a classical cosmological
constant (and there is NO evidence to indicate that it is not, despite
the fact that some folks have checked whether observations are more
compatible with something else), then there is no danger of "decay".

  The bad news is: the quantum effect, a truly weird aspect of physics
  that says whenever we observe or measure something, we reset its
  clock.

I'll have to read the original article to see what is really meant by
this statement.

  Krauss and colleague James Dent point to measurements of light from
  supernovae in 1998 that provided the first evidence of dark energy.

  These measurements may have reset the decay clock of the "false
  vacuum" back to zero, back before the switching point and to a time
  when the risk of catastrophic decay was greater than now, say Dent and
  Krauss.

  "Incredible as it seems, our detection of the dark energy may have
  reduced the life-expectancy of the Universe," says Krauss.

  "We may have snatched away the possibility of long-term survival for
  our Universe and made it more likely it will decay."

I agree with you that this is simply absurd.  Even assuming the effect
does exist, perhaps some other intelligence has already observed the
expansion.  In that case, our observation will make no difference, since
if "The energy shift from the decay would destroy everything in the
Universe, `wiping the slate clean'", then it will wipe it clean for them
AND us.
ebunn@lfa221051.richmond.edu - 25 Nov 2007 08:54 GMT
>   "Incredible as it seems, our detection of the dark energy may
>    have reduced the life-expectancy of the Universe," says
>    Lawrence Krauss of Case Western Reserve University.
>
>this really seems like crap.  

Indeed it does.  It's probably worth pointing out that this article
refers to work that will appear in New Scientist, which is not a
peer-reviewed scholarly journal and which, unfortunately, has jettisoned
its former status as a respectable science magazine by publishing
all sorts of pseudoscientific garbage in recent years.  See

http://golem.ph.utexas.edu/category/2006/09/a_plea_to_save_new_scientist.html

for instance.

(On the other hand, Krauss is a well-respected scientist.)  

-Ted

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[E-mail me at name@domain.edu, as opposed to name@machine.domain.edu.]

Phillip Helbig---remove CLOTHES to reply - 26 Nov 2007 19:49 GMT
In article <fi79ga$1da$1@bigbang.richmond.edu>,
ebunn@lfa221051.richmond.edu writes:

> >   "Incredible as it seems, our detection of the dark energy may
> >    have reduced the life-expectancy of the Universe," says
[quoted text clipped - 9 lines]
>
> http://golem.ph.utexas.edu/category/2006/09/a_plea_to_save_new_scientist.html

Has Krauss published anything similar in a more respected journal, or
discussed it at a well respected conference, or responded to criticism?
Does anyone else of repute seem to agree with him?
ebunn@lfa221051.richmond.edu - 26 Nov 2007 19:49 GMT
>>   "Incredible as it seems, our detection of the dark energy may
>>    have reduced the life-expectancy of the Universe," says
[quoted text clipped - 3 lines]
>
>Indeed it does.  

According to Peter Woit's blog (
http://www.math.columbia.edu/~woit/wordpress/?p=621 ), this New
Scientist article is referring to an arXiv preprint,
http://arxiv.org/abs/0711.1821 .  I haven't had a chance to check out
the New Scientist article yet, but for the moment I'm happy to take
Woit's word for it that the article is indeed about this preprint.  In
this case, Krauss and Dent seem to bear very little blame for the
silliness: the preprint is mostly about very reasonable-seeming stuff
(although I confess I haven't made the effort to follow all the
details), and New Scientist has blown up one or two sentences at the
end to make it sound sensational.

It's instructive to compare versions 1 and 2 of the preprint.  The
authors have changed the last couple of sentences to make them less
easy to exaggerate.  Version 2 was posted on November 24, with
"changes to abstract and concluding sentences to stem possible
confusions regarding observation and metastability" (according to the
arXiv Comments field).

Version 1 says

  If observations of quantum mechanical systems reset their clocks,
  which has been observed for laboratory systems, then by measuring
  the existence dark energy in our own universe have we reset the
  quantum mechanical configuration of our own universe so that late
  time will never be relevant?  Put another way, can internal
  observations of the state of a metastable universe affect its
  longevity?

Version 2 says

  Have we ensured, by measuring the existence dark energy [sic] 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?

-Ted

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ebunn@lfa221051.richmond.edu - 27 Nov 2007 05:00 GMT
I just submitted another post on this subject, pointing out the
arxiv preprint that this story is based on, and saying that
New Scientist is blowing a couple of sentences in the original
article way out of proportion.  One more thing I should have included
in that post: Lawrence Krauss posted a comment on Peter Woit's
blog clarifying what his paper is really about and making clear
that the New Scientist article is a misinterpretation:

http://www.math.columbia.edu/~woit/wordpress/?p=621#comment-31045

-Ted

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[E-mail me at name@domain.edu, as opposed to name@machine.domain.edu.]

 
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