| 1 Jack Sarfatti | Hawking's "Universe in a Nutshell" | vrijdag 9 november 2001 6:29 |
| 2 Nicholas Bada |
Re: Hawking's "Universe in a Nutshell" | vrijdag 9 november 2001 6:45 |
| 3 Gordon D. Pusch |
Re: Hawking's "Universe in a Nutshell" | vrijdag 9 november 2001 7:16 |
| 4 Buckler |
Re: Hawking's "Universe in a Nutshell" | vrijdag 9 november 2001 7:20 |
| 5 James Hunter |
Re: Hawking's "Universe in a Nutshell" | vrijdag 9 november 2001 17:13 |
| 6 Oriel36 |
Re: Hawking's "Universe in a Nutshell" | vrijdag 9 november 2001 17:44 |
| 7 Jack Sarfatti | Re: Hawking's "Universe in a Nutshell" | zaterdag 10 november 2001 4:01 |
| 8 Nicolaas Vroom | Re: Hawking's "Universe in a Nutshell" | zondag 11 november 2001 20:24 |
| 9 Phil Gibbs |
Re: Hawking's "Universe in a Nutshell" | maandag 12 november 2001 7:13 |
| 10 Tom Roberts | Re: Hawking's "Universe in a Nutshell" | dinsdag 13 november 2001 19:45 |
| 11 Stephen Speicher |
Re: Hawking's "Universe in a Nutshell" | woensdag 14 november 2001 8:21 |
| 12 Nicolaas Vroom | Re: Hawking's "Universe in a Nutshell" | woensdag 14 november 2001 13:31 |
| 13 Tom Roberts |
Re: Hawking's "Universe in a Nutshell" | donderdag 15 november 2001 3:50 |
This is Laputan. I see no point to it. I am remainded of Gertrude Stein's "Oakland".
David Gladstone wrote:
| > > | From E-Mails exchanged between Prof. Tachibana and Prof. Agassi On the |
| > |
Kyoto Prize Workshop:
"Takashima said that Popper's falsificationism raised a question: how can we recognize progress between the two theories both of which are incompatible and false? Popper did not solve this question by means of his theory of verisimilitude and of corroboration. His evolutionary theory is not successful. He made a pessimistic conclusion that scientific activity may be a Sisyphus. Popper commented: You are very skeptic but I have an idea of metaphysical realism, though metaphysical realism cannot save skepticism completely." All the inconsistency in a nutshell! |
Rather see Hawking's latest book "Universe in a Nutshell". Very good. Much better than his first. Lots of good pictures and the latest topics including Susskind's "world hologram", "branes", strong short range gravity, parallel universes etc. Hawking does contradict sci.physics faq that one should think of expanding universe galaxies as rigid coins glued to expanding surface of ballon rather than painted on. Hawking says painted on! Is this an error of the ghost writer? Does Hawking really write his books, or, is Hawking right? Are the sci.physics faq pundits wrong? Hawking also writes of "shallow humans" in "shadow branes". Is "shallow" a typo, or does he mean "shallow"? Some Borgesian literary mysteries to ponder here. :-)
Jack Sarfatti wrote in message
| > | Rather see Hawking's latest book "Universe in a Nutshell". Very good. |
Hawkings is challenged at:
http://www.prospect-magazine.co.uk/ArticleView.asp?Accessible=yes&P_Article=7269
[NOTE: 'Followup-To:' set to 'sci.physics.relativity']
Jack Sarfatti sarfatti@well.com wrote in message:
| > | Hawking does contradict sci.physics faq that one should think of expanding universe galaxies as rigid coins glued to expanding surface of ballon rather than painted on. Hawking says painted on! Is this an error of the ghost writer? Does Hawking really write his books, or, is Hawking right? Are the sci.physics faq pundits wrong? |
Hawking's analogy is a reasonable one. He is trying to provide an image to address the FAQ question, ``Why doesn't the Solar System expand if the whole Universe is expanding?''
http://www.astro.ucla.edu/~wright/cosmology_faq.html#SS
The ``Dots painted on a balloon'' analogy fails (as all analogies will do if you push them too far) because when the balloon expands, so do the dots --- which is exactly contrary to the actual behavior of gravitationally bound assemblages such as galaxies or star systems, which do not themselves expand in proportion to the expansion of the Universe. Hence, the ``Dots painted on a balloon'' analogy can be deeply misleading to those who make the error of taking it far too literally, and Hawking is trying to provide a modified analogy that does not fail quite as badly or as soon.
-- Gordon D. Pusch
perl -e '$_ = "gdpusch\@NO.xnet.SPAM.com\n"; s/NO\.//; s/SPAM\.//; print;'
On Fri, 09 Nov 2001 05:29:40 GMT, Jack Sarfatti sarfatti@well.com wrote:
| > |
This is Laputan. I see no point to it. I am remainded of Gertrude Stein's
"Oakland".
David Gladstone wrote: |
| >> > |
From E-Mails exchanged between Prof. Tachibana and Prof. Agassi On the |
| >> |
Kyoto Prize Workshop:
"Takashima said that Popper's falsificationism raised a question: how can we recognize progress between the two theories both of which are incompatible and false? Popper did not solve this question by means of his theory of verisimilitude and of corroboration. His evolutionary theory is not successful. He made a pessimistic conclusion that scientific activity may be a Sisyphus. Popper commented: You are very skeptic but I have an idea of metaphysical realism, though metaphysical realism cannot save skepticism completely." All the inconsistency in a nutshell! |
| > |
Rather see Hawking's latest book "Universe in a Nutshell". Very good. Much better than his first. Lots of good pictures and the latest topics including Susskind's "world hologram", "branes", strong short range gravity, parallel universes etc. Hawking does contradict sci.physics faq that one should think of expanding universe galaxies as rigid coins glued to expanding surface of ballon rather than painted on. Hawking says painted on! Is this an error of the ghost writer? Does Hawking really write his books, or, is Hawking right? Are the sci.physics faq pundits wrong? Hawking also writes of "shallow humans" in "shadow branes". Is "shallow" a typo, or does he mean "shallow"? Some Borgesian literary mysteries to ponder here. :-) |
Dr. Sarfatti, I must admit I've been one of those who have foung your theories specious, however, I also admit that I don't have the math background to verify this. Can you explain, in layman's terms, your theories?
Buckler
Jack Sarfatti wrote:
| > |
This is Laputan. I see no point to it. I am remainded of Gertrude Stein's
"Oakland".
David Gladstone wrote: Rather see Hawking's latest book "Universe in a Nutshell". Very good. Much better than his first. Lots of good pictures and the latest topics including Susskind's "world hologram", "branes", strong short range gravity, parallel universes etc. Hawking does contradict sci.physics faq that one should think of expanding universe galaxies as rigid coins glued to expanding surface of ballon rather than painted on. Hawking says painted on! Is this an error of the ghost writer? Does Hawking really write his books, or, is Hawking right? Are the sci.physics faq pundits wrong? Hawking also writes of "shallow humans" in "shadow branes". Is "shallow" a typo, or does he mean "shallow"? Some Borgesian literary mysteries to ponder here. :-) |
Since galaxies are obviously painted *into* the universe, this is simply one more reason why Hawking, Einstein, Newton, et.al, are not themselves shallow, but rather, as always recursive, but semi-useful MOOOOOOOOOOOOOOOROOOOOOOOOOOOOONS.
gdpusch@NO.xnet.SPAM.com (Gordon D. Pusch) wrote in message
| > |
Hawking's analogy is a reasonable one. He is trying to provide an image to address the FAQ question, ``Why doesn't the Solar System expand if the whole Universe is expanding?'' http://www.astro.ucla.edu/~wright/cosmology_faq.html#SS The ``Dots painted on a balloon'' analogy fails (as all analogies will do if you push them too far) because when the balloon expands, so do the dots --- which is exactly contrary to the actual behavior of gravitationally bound assemblages such as galaxies or star systems, which do not themselves expand in proportion to the expansion of the Universe. Hence, the ``Dots painted on a balloon'' analogy can be deeply misleading to those who make the error of taking it far too literally, and Hawking is trying to provide a modified analogy that does not fail quite as badly or as soon. |
Analogies normally relate to processes that we cannot observe,the water analogies in dealing with electricity is a good example,but generally where objects such as the expansion of galaxies with 3D mass are visibly observed there should be no need to resort to analogies let alone push the analogies to the limit.I notice that when a description of the evolution of the cosmos or the behavior or mass in 3D is requested,the all too familiar analogies are dragged out in turn that are neither helpful or coherent.
There is great mystery to the cosmos but on the other hand it does not mean that common sense has to be set aside.The dots on a balloon analogy is just another poor excuse for glaring errors that I'm certain will become harder to maintain.
"Gordon D. Pusch" wrote:
| > |
The following message is a courtesy copy of an article
that has been posted to sci.physics,sci.physics.relativity,sci.skeptic,sci.physics.particle,sci.astro as well.
[NOTE: 'Followup-To:' set to 'sci.physics.relativity'] Jack Sarfatti sarfatti@well.com writes: |
| > > |
Hawking does contradict sci.physics faq that one should think of expanding universe galaxies as rigid coins glued to expanding surface of ballon rather than painted on. Hawking says painted on! Is this an error of the ghost writer? Does Hawking really write his books, or, is Hawking right? Are the sci.physics faq pundits wrong? |
| > |
Hawking's analogy is a reasonable one. |
The issue here is that it appears to be in flat contradiction to the statements in the sci.physics faq.
| > | He is trying to provide an image to address the FAQ question, ``Why doesn't the Solar System expand if the whole Universe is expanding?'' |
Exactly.
| > |
The ``Dots painted on a balloon'' analogy fails (as all analogies will do if you push them too far) |
Good point
| > | because when the balloon expands, so do the dots --- which is exactly contrary to the actual behavior of gravitationally bound assemblages such as galaxies or star systems, which do not themselves expand in proportion to the expansion of the Universe. |
Take the painted dot model seriously for a moment to see where it might lead.
dR/dt = HR
For R = scale factor in Robertson-Walker cosmology time element
t is global "cosmic time"
Einstein-de Sitter solution has k = 0, i.e. spatially flat and
R(t) ~ t^2/3
dR/dt ~ (2/3)t^-1/3
H(t) ~ 1/t
The Planck time Tp is the quantum of time. Let's first suppose it is fixed without any possible hyperspace dilation from the universe's unseen dimensions.
Therefore
R(n)/R(n') ~ (n/n')^2/3
The universe is about 13 billion light years old in our epoch. This is about 10^17 sec, and the Planck time is ~ 10^-44 sec. Therefore n ~ 10^61. Let n' = 1 at the initial singularity itself. Therefore,
R(now)/R(Creation) ~ (10^61)^2/3 ~ 10^40
This does not include inflation however. But let's continue in this crude, naive toy model. We take it with a grain of salt for now. The electron today has a Compton wavelength 10^-11 cm. Divide this by 10^40 to get 10^-51 cm.
Lp^2/10^-51 ~ 10^-66 10^51 ~ 10^-15 cm
This is somewhat suggestive of a string duality between electron source and weak force boson masses. However, because of inflation, it may be that n' ~ 1 is not a good place to start. n' >> 1 more likely. Howmany chronons before electrons form. That will be the n' to use!
10^-11(cm) ~ (10^61/n')^2/3 L
where L is the initial size of the electron painted on the surface of the expanding balloon in terms of the metaphor.
The general idea is that
L(of object now) ~ L(creation of object)[10^61/n'(creation of object)]^2/3
Set of objects include
electron, proton, hydrogen atom, planet, star, solar system, galaxy.
The question here is how badly does the painted dot picture, compared to copper coins glued on picture, really fail?
BTW Hawking's exact words are:
"People (such as us) living on the brane, the surface of the bubble, would think the universe was expanding. IT WOULD BE LIKE PAINTING GALAXIES ON THE SURFACE OF THE BALLOON AND BLOWING IT UP. The galaxies would move apart ..." p.195
"
| > |
Hence, the ``Dots painted
on a balloon'' analogy can be deeply misleading to those who make the error
of taking it far too literally, and Hawking is trying to provide a modified
analogy that does not fail quite as badly or as soon.
-- Gordon D. Pusch |
I do not see how Hawking's actual words above justify your words here? Where in his text is the analogy modified?
The real question here is does Hawking mean what he literally is saying here, or is it a typo, something put in by the editors? That's why I began to speculate above. Perhaps the problem is not so simple. Perhaps Hawking really means what his words say here?
To be continued. Lot's of interesting ideas and lots of cutting edge questions raised by Hawking's latest book.
Gordon D. Pusch
Jack Sarfatti sarfatti@well.com writes:
Hawking does contradict sci.physics faq that one should think of
expanding universe galaxies as rigid coins glued to expanding surface of
ballon rather than painted on. Hawking says painted on! Is this an error
of the ghost writer? Does Hawking really write his books, or, is Hawking
right? Are the sci.physics faq pundits wrong?
Hawking's analogy is a reasonable one. He is trying to provide an image
to address the FAQ question, ``Why doesn't the Solar System expand if
the whole Universe is expanding?''
http://www.astro.ucla.edu/~wright/cosmology_faq.html#SS .
The ``Dots painted on a balloon'' analogy fails (as all analogies will do
if you push them too far) because when the balloon expands, so do the dots ---
which is exactly contrary to the actual behavior of gravitationally bound
assemblages such as galaxies or star systems, which do not themselves expand
in proportion to the expansion of the Universe. Hence, the ``Dots painted
on a balloon'' analogy can be deeply misleading to those who make the error
of taking it far too literally, and Hawking is trying to provide a modified
analogy that does not fail quite as badly or as soon.
The ``Dots painted on a balloon'' analogy I do not think is invented by
Hawking.
In the book Universe by Kaufmann 2 edition page 551 is written:
"As the balloon expands the amount of space between the coins
gets larger and larger.
In the same way, as the universe expands, the amount of space
between widely separated galaxies increases."
"As the balloon expands, you see all the coins moving away from you.
... the nearby coins are moving away from you slowly,
whereas the more distant coins are moving away more rapidly.
You find this relationship,
which is just like the Hubble law,
no matter which coin you decide to call home."
In the book "The Big Bang" by Joseph Silk page 98
he compares it with: "A raising pudding model of the Universe"
The two anologies are different.
IMO they prove nothing nor they explain anything.
At page 552 is written:
But does that mean that we are living on the surface
of a balloon ? No.
The balloon analogy gives the impression that we know
something, but this can be highly misleading.
Fred Hoyle in the book "Astronomy and Cosmology" does
not use the bolloon nor the raising pudding analogy.
Stephen Hawking in his lecture "A brane new world"
also uses the balloon analogy.
In my opinion it is much more realistic to compare
the Big Bang with an exploding star (supernova)
and to describe the differences between the two.
The edge of a supernova propagates with the speed of light.
The remnants of the exploding star (Cassiopeia A)
(at the center, where the exploding star was), a nebula,
grows at a much slower speed.
If you compare a small section of those remnants with our Universe
(as we observe it) than a comparison (maybe) is much
more realistic, except the difference in size.
In article
It was invented by Eddington in the 1920s or 1930s
Jack Sarfatti wrote:
If that is the extent of this passage, then you are clearly reading too
much into his words to distinguish between "dots painted on" and "coins
glued onto", which is the usual analogy. Dots painted on do not preserve
the sizes of the individual dots, while coins glued on do preserve the
sizes of the individual coins.
Hawking is obviously speaking very loosely here, and it is unwarranted to
read more into his words than he himself does.
Tom Roberts tjroberts@lucent.com
On Tue, 13 Nov 2001, Tom Roberts wrote:
If that is the extent of this passage, then you are clearly
reading too much into his words to distinguish between "dots
painted on" and "coins glued onto", which is the usual analogy.
Dots painted on do not preserve the sizes of the individual
dots, while coins glued on do preserve the sizes of the
individual coins.
Hawking is obviously speaking very loosely here, and it is
unwarranted to read more into his words than he himself does.
Indeed, just as he speaks throughout the rest of the book.
Hawking explicitly states that he seeks to convey just the "broad
ideas" of work which is otherwise very technical.
Note that Hawking ends the quoted paragraph with "Let's hope
there's no one with a cosmic pin to deflate the bubble." Would
Jack like to relate this to Hawking's singularity theorems? :(
Stephen
sjs@compbio.caltech.edu
Welcome to California. Bring your own batteries.
Printed using 100% recycled electrons.
Tom Roberts
If that is the extent of this passage, then you are clearly reading too
much into his words to distinguish between "dots painted on" and "coins
glued onto", which is the usual analogy. Dots painted on do not preserve
the sizes of the individual dots, while coins glued on do preserve the
sizes of the individual coins.
You are 100% correct by pointing out this difference but that does not
mean that either comparison is right or wrong.
You cannot say that the following sentence is true:
"In an expanding universe the size of each individual galaxy stays
the same (i.e does not expand)"
because:
"When you glue coins on a balloon and you inflate the balloon
only the size of the "space" between the coins increases
and not the size of each coin"
Where do you draw the line ? and why
The space
The most logical answer would be all space expands
and all objects are influenced.
(I am not saying that all objects themself expand)
Assuming H= 30km/sec/Mly
I doubt if that is excepted
This answer is inline with the dots painted on a balloon analogy.
IMO the only way to decide what is right is to improve observations.
and or maybe to come up with a completly different interpretation.
Tom Roberts tjroberts@lucent.com
Nicolaas Vroom wrote:
This is not any sort of argument, it is merely an _analogy_, and a not
very good one at that.
A better answer is that it depends upon what one means by "object". And
it depends upon what one means by "length".
Assume the world is well described by some total Lagrangian, in which
the Hilbert Lagrangian of GR is added in with the various Lagrangians
of the quantum fields of interest. The basic assumption is that the
inflation affects only the metric, and the form of the quantum field
Lagrangians remains unchanged. As the sizes of bound systems are
determined by this Lagrangian, and as the only effect of inflation is
in the metric tensor (which of course appears in the Lagrangian term
for each quantum field), it should be clear that the _ratios_ of the
sizes of bound systems remain constant. So if one defines "distance"
by using rulers, then the size of any bound system will remain constant,
independent of the inflation, because it is ultimately a ratio to the
length of another bound system: a meterstick.
So there is no "line" to be drawn: bound systems remain of constant size;
unbound systems need not. This is independent of the binding mechanism.
Tom Roberts tjroberts@lucent.com
Back to my home page Contents of This Document
>
[NOTE: 'Followup-To:' set to 'sci.physics.relativity']
> >
>
He writes:
" The raisins are scattered randomly through the pudding;
they individually represent clusters of galaxies.
The pudding swells steadily but the raisins do not expand"
"Just as the surface of the balloon has neither center
nor edge, our universe has no center or edge."
Does that answers the question:
if the universe has an edge, Yes or No ?
The next step is to compare the surface with a brane....
9 Hawking's "Universe in a Nutshell"
Van: Phil Gibbs
Onderwerp: Re: Hawking's "Universe in a Nutshell"
Datum: maandag 12 november 2001 7:13
>
The ``Dots painted on a balloon'' analogy I do not think is invented by
Hawking.
10 Hawking's "Universe in a Nutshell"
Van: Tom Roberts tjroberts@lucent.com
Onderwerp: Re: Hawking's "Universe in a Nutshell"
Datum: dinsdag 13 november 2001 19:45
>
BTW Hawking's exact words are:
"People (such as us) living on the brane, the surface of the bubble,
would think the universe was expanding. IT WOULD BE LIKE PAINTING
GALAXIES ON THE SURFACE OF THE BALLOON AND BLOWING IT UP. The galaxies
would move apart ..." p.195
11 Hawking's "Universe in a Nutshell"
Van: Stephen Speicher
Onderwerp: Re: Hawking's "Universe in a Nutshell"
Datum: woensdag 14 november 2001 8:21
>
Jack Sarfatti wrote:
> >
BTW Hawking's exact words are:
"People (such as us) living on the brane, the surface of the
bubble, would think the universe was expanding. IT WOULD BE
LIKE PAINTING GALAXIES ON THE SURFACE OF THE BALLOON AND
BLOWING IT UP. The galaxies would move apart ..." p.195
>
--------------------------------------------------------
12 Hawking's "Universe in a Nutshell"
Van: Nicolaas Vroom nicolaas.vroom@pandora.be
Onderwerp: Re: Hawking's "Universe in a Nutshell"
Datum: woensdag 14 november 2001 13:31
>
Jack Sarfatti wrote:
> >
BTW Hawking's exact words are:
"People (such as us) living on the brane, the surface of the bubble,
would think the universe was expanding. IT WOULD BE LIKE PAINTING
GALAXIES ON THE SURFACE OF THE BALLOON AND BLOWING IT UP. The galaxies
would move apart ..." p.195
>
Between the planets surrounding our Sun
Between the stars within our galaxy the Milky way.
Between the satelite galaxies surrounding our Galaxy
Between the galaxies in the Fornax Cluster
Between the individual Clusters.
r of Earth = 150*10^6 km
v(rad) of Earth = H*r= 5*10^-10 km/sec
This is very small.
However over a period of 5 Byears we get ("roughly")
an increase of:
v*dt = v*(5*10^9 year) = v*(15*10^16 sec) = 75*10^6 km
>
Hawking is obviously speaking very loosely here, and it is
unwarranted to
read more into his words than he himself does.
13 Hawking's "Universe in a Nutshell"
Van: Tom Roberts
Onderwerp: Re: Hawking's "Universe in a Nutshell"
Datum: donderdag 15 november 2001 3:50
>
You cannot say that the following sentence is true:
"In an expanding universe the size of each individual galaxy stays
the same (i.e does not expand)"
because:
"When you glue coins on a balloon and you inflate the balloon
only the size of the "space" between the coins increases
and not the size of each coin"
>
Where do you draw the line ? and why
The space
Between the planets surrounding our Sun
Between the stars within our galaxy the Milky way.
Between the satelite galaxies surrounding our Galaxy
Between the galaxies in the Fornax Cluster
Between the individual Clusters.
The most logical answer would be all space expands
and all objects are influenced.
(I am not saying that all objects themself expand)
Created: 15 November 2001