View Full Version : String theory proved in telescopes?
Lubos Motl
Dec16-04, 08:44 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>David Goss pointed an article in New Scientist to me.\n\nhttp://www.newscientist.com/channel/fundamentals/mg18424781.400\n\nUnfortunately I can\'t get the full version right now. But it seems that\nthe article claims that someone has observed double images of galaxies\nthat look like images from a fundamental string stretched to become a\nlarge cosmic string - and some strange quasar is another part of the\nevidence. I could not decode what\'s the rest. ;-)\n\nIf you happen to have something more meaningful to say about this article\nthan me ;-), don\'t hesitate to reply! I hope that you will forgive me that\nI chose a rather provoking subject for this posting. ;-)\n_______________________________________________ _______________________________\nE-mail: lumo@matfyz.cz fax: +1-617/496-0110 Web: http://lumo.matfyz.cz/\neFax: +1-801/454-1858 work: +1-617/384-9488 home: +1-617/868-4487 (call)\nWebs: http://schwinger.harvard.edu/~motl/ http://motls.blogspot.com/\n^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>David Goss pointed an article in New Scientist to me.
http://www.newscientist.com/channel/fundamentals/mg18424781.400
Unfortunately I can't get the full version right now. But it seems that
the article claims that someone has observed double images of galaxies
that look like images from a fundamental string stretched to become a
large cosmic string - and some strange quasar is another part of the
evidence. I could not decode what's the rest. ;-)
If you happen to have something more meaningful to say about this article
than me ;-), don't hesitate to reply! I hope that you will forgive me that
I chose a rather provoking subject for this posting. ;-)
__{_______________________________________________ _____________________________}
E-mail: lumo@matfyz.cz fax: +1-617/496-0110 Web: http://lumo.matfyz.cz/
eFax: +1-801/454-1858 work: +1-617/384-9488 home: +1-617/868-4487 (call)
Webs: http://schwinger.harvard.edu/~motl/ http://motls.blogspot.com/
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Robert C. Helling
Dec17-04, 05:20 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>On Thu, 16 Dec 2004 21:44:42 -0500, Lubos Motl <motl@feynman.harvard.edu> wrote:\n> David Goss pointed an article in New Scientist to me.\n>\n> http://www.newscientist.com/channel/fundamentals/mg18424781.400\n>\n> Unfortunately I can\'t get the full version right now. But it seems that\n> the article claims that someone has observed double images of galaxies\n> that look like images from a fundamental string stretched to become a\n> large cosmic string - and some strange quasar is another part of the\n> evidence. I could not decode what\'s the rest. ;-)\n>\n> If you happen to have something more meaningful to say about this article\n> than me ;-), don\'t hesitate to reply! I hope that you will forgive me that\n> I chose a rather provoking subject for this posting. ;-)\n\nThis rumor came across Cambrigde, UK, already a couple of months\nago. There have been no follow-ups since but already at that time\nthere was the gossip that the WMAP people were prompted to look in the\nsame direction and it is not ruled out (to say it carefully) that they\nsee a pattern in the CMB repeating as you would expect given the\ndouble imaging of a cosmic string.\n\nI cannot access the New Scientist article either, but maybe one should\nsay that gravitational lensing of \'point like\' objects produces\nan odd number of images (as can be shown using Morse theory, see for\nexample section 3.3 of\nhttp://relativity.livingreviews.org/Articles/lrr-2004-9/index.html\nVolker Perlick\'s living review on gravitational lensing) so a double\nimage is quite special. Still it could be that the third image is\nsomehow hidden. Or that it is not a pointlike object that does the\nlensing (remember that in 3+1d the gravitational effect of a string is\njust a deficit angle).\n\nSeasons greetings\nRobert\n--\n..oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oO o.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oO\nRobert C. Helling School of Science and Engineering\nInternational University Bremen\nprint "Just another Phone: +49 421-200 3574\nstupid .sig\\n"; http://www.aei-potsdam.mpg.de/~helling\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>On Thu, 16 Dec 2004 21:44:42 -0500, Lubos Motl <motl@feynman.harvard.edu> wrote:
> David Goss pointed an article in New Scientist to me.
>
> http://www.newscientist.com/channel/fundamentals/mg18424781.400
>
> Unfortunately I can't get the full version right now. But it seems that
> the article claims that someone has observed double images of galaxies
> that look like images from a fundamental string stretched to become a
> large cosmic string - and some strange quasar is another part of the
> evidence. I could not decode what's the rest. ;-)
>
> If you happen to have something more meaningful to say about this article
> than me ;-), don't hesitate to reply! I hope that you will forgive me that
> I chose a rather provoking subject for this posting. ;-)
This rumor came across Cambrigde, UK, already a couple of months
ago. There have been no follow-ups since but already at that time
there was the gossip that the WMAP people were prompted to look in the
same direction and it is not ruled out (to say it carefully) that they
see a pattern in the CMB repeating as you would expect given the
double imaging of a cosmic string.
I cannot access the New Scientist article either, but maybe one should
say that gravitational lensing of 'point like' objects produces
an odd number of images (as can be shown using Morse theory, see for
example section 3.3 of
http://relativity.livingreviews.org/Articles/lrr-2004-9/index.html
Volker Perlick's living review on gravitational lensing) so a double
image is quite special. Still it could be that the third image is
somehow hidden. Or that it is not a pointlike object that does the
lensing (remember that in 3+1d the gravitational effect of a string is
just a deficit angle).
Seasons greetings
Robert
--
..oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo. oOo.oOo.oOo.oOo.oOo.oOo.oOo.oO
Robert C. Helling School of Science and Engineering
International University Bremen
print "Just another Phone: +49 421-200 3574
stupid .sig\n"; http://www.aei-potsdam.mpg.de/~helling
Lubos Motl
Dec17-04, 04:27 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>I\'ve seen the article already. An abstract is here:\n\nhttp://motls.blogspot.com/2004/12/astronomers-prove-string-theory.html\n\nAstronomers prove string theory?\n================================\n\nDavid Goss has pointed out the following article in the future issue of\nNew Scientist to me.\n\nhttp://www.newscientist.com/channel/fundamentals/mg18424781.400\n\nAs far as I understand the article, a quirky quasar combined with double\nimages of galaxies that look like if they originate from a cosmic string\nactually lead some astronomers to believe that\n\n* a huge macroscopic heterotic or type II string is stretched across\nour galaxy\n\nThat\'s of course too cool and one is naturally skeptical. I am doubly\nskeptical because New Scientist has not been a terribly serious journal in\nmy eyes in the last 5 years. Nevertheless I think it\'s fun to bring your\nattention to this article because observing a string in the telescope is\nthe favorite scenario of many leaders of our field how string theory\nshould eventually be proved. ;-)\n\nOK, let me now pretend that I believe this stuff. The cosmic superstrings\nwere recently studied - and "predicted" :-) - by Joe Polchinski et al.,\nsee his following paper\n\n* hep-th/0410082\n\nand its citations and references. The paper explains how the cosmic\nsuperstrings can be distinguished from other, more ordinary types of\ncosmic strings. (Not sure whether the journalist in New Scientist knows\nthis stuff haha.) Those who have read The Elegant Universe by Brian Greene\nalso know that a string observed in the telescope is also Edward Witten\'s\nfavorite scenario how string theory will eventually be proved - because\nnothing would settle the question whether the strings exist so cleanly.\n\nNews:\n\nBefore I read the whole article, Joe Polchinski wrote me that he had been\ninterviewed, and he believes that the discovery may have been related to\nthe following Russian-Italian observation by Mikhail Sazhin et al.:\n\n* astro-ph/0407055\n\nThe authors keep the coordinates of the object in secret and they want to\nget a telescope time before someone else studies it. Joe Polchinski is\nskeptical whether the object is a cosmic string, but Henry Tye is more\nconfident because the tension seems to be much bigger than the upper bound\nallowed for pulsars. However Eanna Flanagan claims that the pulsar bound\nis wrong.\n\nThe team has observed a pair of galaxies 10 billion light years away and\ngravitational lensing is supposed to be the origin. The angular separation\nof the pair is roughly 2 arc-seconds. OK, now the unusual part:\n\nGravitational lensing, as Andy Neitzke explains me, usually produces an\nodd number of images. This is a consequence of the Morse theory. Moreover,\nthese images have typically very different intensities. The\nRussian-Italian pair is special because\n\n* no candidate galaxy whose gravity would be the source of the lensing\nhas been seen\n* exactly two (even number) of images have been observed\n* their intensity is equal\n\nTom Kibble from London believes that these things together indicate a\npresence of a cosmic string. In fact, I have not told you the main\ninteresting observation yet:\n\n* the team of Sazhin has now found 11 pairs of double images in the\n16-arc-second square around their original object CSL-1\n\nA galaxy as the source of gravitational lensing is statistically expected\nto create 2 images (pairs) in average, while the cosmic strings would give\nyou something in between 9 and 200; note that 11 belongs to this interval.\n;-) The main skeptics\' explanation is that the double images are just\nrandom pairs of galaxies etc. that happen to be similar to each other.\n\nThe oldest double image\n\nThe first gravitational lensing was observed in 1979 by the Jodrell Bank\ntelescope, the UK. It\'s a double quasar Q0957+561A,B. Normally, the\noscillations of one image are mimicked by the other image 417 days later.\nBut recently they observed some 100-day-long oscillation in intensity\nwhich was repeated by both images without any time delay. OK, something is\nmoving in between us and the quasar. For reasons that I don\'t quite\nunderstand, they say that it should be a cosmic string. However, what\nseems more comprehensible is that they can measure how this object\n(string?) is moving, and it is moving by the velocity 0.7c across our line\nof sight. OK, at any rate, they believe that this string is oscillating,\nand the smooth period of 100 days of the oscillation is translated to the\nradius comparable to 1000 astronomical units - and the string should be in\nour galaxy, 10,000 light years from the Sun!\n\nNote that this old double-imaged quasar is at a different location than\nCSL-1, so it would probably be an artifact of a different cosmic string,\nif I understand it well.\n\nMore tests to be done include the spectral analysis of CSL-1 to determine\nwhether they\'re really identical images, as well as the attempts to find\nmore examples in the skies. Joe Polchinski explains why the emission of\ngravitational waves is an interesting signal - a signal that can be seen\nby LIGO and/or VIRGO, as Damour and Vilenkin pointed out. Only the last\nparagraph of that article is dedicated to the fact that we still have no\nidea whether these cosmic strings are generic field-theoretical cosmic\nstrings, or fundamental strings (or D-strings) from string theory.\n\nFinally, let me say that the article looks much more serious and\npotentially exciting than what I expected. And don\'t get me wrong: the\nobservation of cosmic strings, even if they\'re not the known strings from\nstring theory, is a Nobel-prize-scale insight, I think.\n__________________________________________ ____________________________________\nE-mail: lumo@matfyz.cz fax: +1-617/496-0110 Web: http://lumo.matfyz.cz/\neFax: +1-801/454-1858 work: +1-617/384-9488 home: +1-617/868-4487 (call)\nWebs: http://schwinger.harvard.edu/~motl/ http://motls.blogspot.com/\n^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>I've seen the article already. An abstract is here:
http://motls.blogspot.com/2004/12/astronomers-prove-string-theory.html
Astronomers prove string theory?
================================
David Goss has pointed out the following article in the future issue of
New Scientist to me.
http://www.newscientist.com/channel/fundamentals/mg18424781.400
As far as I understand the article, a quirky quasar combined with double
images of galaxies that look like if they originate from a cosmic string
actually lead some astronomers to believe that
* a huge macroscopic heterotic or type II string is stretched across
our galaxy
That's of course too cool and one is naturally skeptical. I am doubly
skeptical because New Scientist has not been a terribly serious journal in
my eyes in the last 5 years. Nevertheless I think it's fun to bring your
attention to this article because observing a string in the telescope is
the favorite scenario of many leaders of our field how string theory
should eventually be proved. ;-)
OK, let me now pretend that I believe this stuff. The cosmic superstrings
were recently studied - and "predicted" :-) - by Joe Polchinski et al.,
see his following paper
* http://www.arxiv.org/abs/hep-th/0410082
and its citations and references. The paper explains how the cosmic
superstrings can be distinguished from other, more ordinary types of
cosmic strings. (Not sure whether the journalist in New Scientist knows
this stuff haha.) Those who have read The Elegant Universe by Brian Greene
also know that a string observed in the telescope is also Edward Witten's
favorite scenario how string theory will eventually be proved - because
nothing would settle the question whether the strings exist so cleanly.
News:
Before I read the whole article, Joe Polchinski wrote me that he had been
interviewed, and he believes that the discovery may have been related to
the following Russian-Italian observation by Mikhail Sazhin et al.:
* http://www.arxiv.org/abs/astro-ph/0407055
The authors keep the coordinates of the object in secret and they want to
get a telescope time before someone else studies it. Joe Polchinski is
skeptical whether the object is a cosmic string, but Henry Tye is more
confident because the tension seems to be much bigger than the upper bound
allowed for pulsars. However Eanna Flanagan claims that the pulsar bound
is wrong.
The team has observed a pair of galaxies 10 billion light years away and
gravitational lensing is supposed to be the origin. The angular separation
of the pair is roughly 2 arc-seconds. OK, now the unusual part:
Gravitational lensing, as Andy Neitzke explains me, usually produces an
odd number of images. This is a consequence of the Morse theory. Moreover,
these images have typically very different intensities. The
Russian-Italian pair is special because
* no[/itex] candidate galaxy whose gravity would be the source of the lensing
has been seen
* exactly two (even number) of images have been observed
* their intensity is equal
Tom Kibble from London believes that these things together indicate a
presence of a cosmic string. In fact, I have not told you the main
interesting observation yet:
* the team of Sazhin has now found 11 pairs of double images in the
16-arc-second square around their original object [itex]CSL-1
A galaxy as the source of gravitational lensing is statistically expected
to create 2 images (pairs) in average, while the cosmic strings would give
you something in between 9 and 200; note that 11 belongs to this interval.
;-) The main skeptics' explanation is that the double images are just
random pairs of galaxies etc. that happen to be similar to each other.
The oldest double image
The first gravitational lensing was observed in 1979 by the Jodrell Bank
telescope, the UK. It's a double quasar Q0957+561A,B. Normally, the
oscillations of one image are mimicked by the other image 417 days later.
But recently they observed some 100-day-long oscillation in intensity
which was repeated by both images without any time delay. OK, something is
moving in between us and the quasar. For reasons that I don't quite
understand, they say that it should be a cosmic string. However, what
seems more comprehensible is that they can measure how this object
(string?) is moving, and it is moving by the velocity .7c across our line
of sight. OK, at any rate, they believe that this string is oscillating,
and the smooth period of 100 days of the oscillation is translated to the
radius comparable to 1000 astronomical units - and the string should be in
our galaxy, 10,000 light years from the Sun!
Note that this old double-imaged quasar is at a different location than
CSL-1, so it would probably be an artifact of a different cosmic string,
if I understand it well.
More tests to be done include the spectral analysis of CSL-1 to determine
whether they're really identical images, as well as the attempts to find
more examples in the skies. Joe Polchinski explains why the emission of
gravitational waves is an interesting signal - a signal that can be seen
by LIGO and/or VIRGO, as Damour and Vilenkin pointed out. Only the last
paragraph of that article is dedicated to the fact that we still have no
idea whether these cosmic strings are generic field-theoretical cosmic
strings, or fundamental strings (or D-strings) from string theory.
Finally, let me say that the article looks much more serious and
potentially exciting than what I expected. And don't get me wrong: the
observation of cosmic strings, even if they're not the known strings from
string theory, is a Nobel-prize-scale insight, I think.
__{_______________________________________________ _____________________________}
E-mail: lumo@matfyz.cz fax: +1-617/496-0110 Web: http://lumo.matfyz.cz/
eFax: +1-801/454-1858 work: +1-617/384-9488 home: +1-617/868-4487 (call)
Webs: http://schwinger.harvard.edu/~motl/ http://motls.blogspot.com/
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Anthony Campbell
Dec18-04, 08:08 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>On 2004-12-17, Lubos Motl <motl@feynman.harvard.edu> wrote:\n\n> I\'ve seen the article already. An abstract is here:\n>\n> http://motls.blogspot.com/2004/12/astronomers-prove-string-theory.html\n>\n> Astronomers prove string theory?\n>\n> David Goss has pointed out the following article in the future issue of\n> New Scientist to me.\n>\n> http://www.newscientist.com/channel/fundamentals/mg18424781.400\n>\n> As far as I understand the article, a quirky quasar combined with double\n> images of galaxies that look like if they originate from a cosmic string\n> actually lead some astronomers to believe that\n>\n[snip]\n\nFrom a naive standpoint, could I ask for clarification about the\nconnection, if any, between the tiny strings posulated to exist at the\nsubatomic level and these cosmic strings? The New Scientist article says\nthat strings are supposed to exist at all possible sizes, so they are\nall the same kind of thing. Is this correct? (As the article is written\nby Marcus Chown, I imagine it is.)\n\nIf the above is correct, I suppose it would be an example of what\nBrian Greene describes in _The Fabric of the Cosmos_:\n\nPerhaps cosmic expansion can stretch the imprints of even\nshorter-scale processes or features - the physics of strings, or\nquantum gravity more generally, or the atomized structure of\nultramicroscopic spacetime itself - and spread their influence,\nin some subtle but observable manner, across the heavens. Maybe,\nthat is, the universe has already drawn out the microscopic\nfibers of the fabric of the cosmos and unfurled them clear\nacross the sky, and all we need do is learn how to recognize\nthe pattern.\n\nAnthony\n--\nUsing Linux GNU/Debian - Windows-free zone\nhttp://www.acampbell.org.uk (book reviews,\nAssassins, homeopathy, and skeptical articles).\nEmail: replace "www" with "ac@"\n\n\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>On 2004-12-17, Lubos Motl <motl@feynman.harvard.edu> wrote:
> I've seen the article already. An abstract is here:
>
> http://motls.blogspot.com/2004/12/astronomers-prove-string-theory.html
>
> Astronomers prove string theory?
>
> David Goss has pointed out the following article in the future issue of
> New Scientist to me.
>
> http://www.newscientist.com/channel/fundamentals/mg18424781.400
>
> As far as I understand the article, a quirky quasar combined with double
> images of galaxies that look like if they originate from a cosmic string
> actually lead some astronomers to believe that
>
[snip]
From a naive standpoint, could I ask for clarification about the
connection, if any, between the tiny strings posulated to exist at the
subatomic level and these cosmic strings? The New Scientist article says
that strings are supposed to exist at all possible sizes, so they are
all the same kind of thing. Is this correct? (As the article is written
by Marcus Chown, I imagine it is.)
If the above is correct, I suppose it would be an example of what
Brian Greene describes in _The Fabric of the Cosmos_:
Perhaps cosmic expansion can stretch the imprints of even
shorter-scale processes or features - the physics of strings, or
quantum gravity more generally, or the atomized structure of
ultramicroscopic spacetime itself - and spread their influence,
in some subtle but observable manner, across the heavens. Maybe,
that is, the universe has already drawn out the microscopic
fibers of the fabric of the cosmos and unfurled them clear
across the sky, and all we need do is learn how to recognize
the pattern.
Anthony
--
Using Linux GNU/Debian - Windows-free zone
http://www.acampbell.org.uk (book reviews,
Assassins, homeopathy, and skeptical articles).
Email: replace "www" with "ac@"
Lubos Motl
Dec18-04, 08:23 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>On Sat, 18 Dec 2004, Anthony Campbell wrote:\n\n> From a naive standpoint, could I ask for clarification about the\n> connection, if any, between the tiny strings posulated to exist at the\n> subatomic level and these cosmic strings? The New Scientist article says\n> that strings are supposed to exist at all possible sizes, so they are\n> all the same kind of thing. Is this correct? (As the article is written\n> by Marcus Chown, I imagine it is.)\n\nDear Anthony, yes! The microscopic strings inside the elementary particles\n- those that we call "fundamental strings" - are made of the same stuff as\none type of cosmic strings. When we quantize string theory to find the\nspectrum of particles, we are looking for low-energy excitations\n(vibrational patterns) of an actual object - the string. But this string\ncan have any shape and size. If it\'s very large, then it\'s also very heavy\n- and classical physics of this string starts to be a good description\n(this always happens if things become "large" in some sense).\n\nYou should imagine that a string is like a quantum harmonic oscillator -\nthe elementary particles correspond to the first, low-energy states of\nsuch an oscillator. The macroscopic cosmic strings correspond to very\nexcited states of a harmonic oscillator for which you may forget about\nquantum mechanics and you are allowed to think classically.\n\nThe fundamental strings are not the only types of cosmic strings that may\nexist in the Universe. String theory predicts other types of strings -\nnamely D-strings, for example, but also "field-theoretical cosmic\nstrings", something that does not require you to use string theory to see\nthem - the pointlike-particle quantum field theory is enough.\n\nEven if the observations were cosmic strings - which would be terrific -\nso far there is no evidence that could distinguish which type of cosmic\nstrings they are (the fundamental strings would be the most exciting ones,\nof course!). Read Polchinski\'s recent paper\n\nhttp://arxiv.org/abs/hep-th/0410082\n\nto see how to distinguish between different types of cosmic strings that\ncan arise in agreement with string theory. (I\'ve finally read the whole\narticle, and it\'s definitely worth your time.) Also, I recommend you a\nrecent, less-stringy review by T.W.B. Kibble "Cosmic strings reborn?"\n\nhttp://arxiv.org/abs/astro-ph/0410073\n\nSazhin\'s et al. observations of the strange gravitational lensing CSL-1 is\ndiscussed here:\n\nhttp://arxiv.org/abs/astro-ph/0302547\nhttp://arxiv.org/abs/astro-ph/0406516\n\n> If the above is correct, I suppose it would be an example of what\n> Brian Greene describes in _The Fabric of the Cosmos_:\n>\n> Perhaps cosmic expansion can stretch the imprints of even\n> shorter-scale processes or features - the physics of strings, or\n> quantum gravity more generally, or the atomized structure of ...\n\nThis is indeed the relevant portion of Brian\'s book that talks about these\npossibilities. They\'re not completely new - they just became popular again\nrecently, and some of the reasons are explained in Kibble\'s and\nPolchinski\'s articles. Brian also talks about his line of research that is\nmeant to discover imprints of strings on the cosmic microwave background,\nbut the same chapter should also talk about the cosmic strings. Either in\nthe Fabric of the Cosmos, or in The Elegant Universe, he also mentions\nthat "seeing a cosmic string in a telescope is Witten\'s favorite scenario\nhow string theory should be proved because nothing would settle the\nquestion as cleanly as a string seen in your telescope".\n_____________________________________ _________________________________________\nE-mail: lumo@matfyz.cz fax: +1-617/496-0110 Web: http://lumo.matfyz.cz/\neFax: +1-801/454-1858 work: +1-617/384-9488 home: +1-617/868-4487 (call)\nWebs: http://schwinger.harvard.edu/~motl/ http://motls.blogspot.com/\n^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>On Sat, 18 Dec 2004, Anthony Campbell wrote:
> From a naive standpoint, could I ask for clarification about the
> connection, if any, between the tiny strings posulated to exist at the
> subatomic level and these cosmic strings? The New Scientist article says
> that strings are supposed to exist at all possible sizes, so they are
> all the same kind of thing. Is this correct? (As the article is written
> by Marcus Chown, I imagine it is.)
Dear Anthony, yes! The microscopic strings inside the elementary particles
- those that we call "fundamental strings" - are made of the same stuff as
one type of cosmic strings. When we quantize string theory to find the
spectrum of particles, we are looking for low-energy excitations
(vibrational patterns) of an actual object - the string. But this string
can have any shape and size. If it's very large, then it's also very heavy
- and classical physics of this string starts to be a good description
(this always happens if things become "large" in some sense).
You should imagine that a string is like a quantum harmonic oscillator -
the elementary particles correspond to the first, low-energy states of
such an oscillator. The macroscopic cosmic strings correspond to very
excited states of a harmonic oscillator for which you may forget about
quantum mechanics and you are allowed to think classically.
The fundamental strings are not the only types of cosmic strings that may
exist in the Universe. String theory predicts other types of strings -
namely D-strings, for example, but also "field-theoretical cosmic
strings", something that does not require you to use string theory to see
them - the pointlike-particle quantum field theory is enough.
Even if the observations were cosmic strings - which would be terrific -
so far there is no evidence that could distinguish which type of cosmic
strings they are (the fundamental strings would be the most exciting ones,
of course!). Read Polchinski's recent paper
http://arxiv.org/abs/http://www.arxiv.org/abs/hep-th/0410082
to see how to distinguish between different types of cosmic strings that
can arise in agreement with string theory. (I've finally read the whole
article, and it's definitely worth your time.) Also, I recommend you a
recent, less-stringy review by T.W.B. Kibble "Cosmic strings reborn?"
http://arxiv.org/abs/http://www.arxiv.org/abs/astro-ph/0410073
Sazhin's et al. observations of the strange gravitational lensing CSL-1 is
discussed here:
http://arxiv.org/abs/http://www.arxiv.org/abs/astro-ph/0302547
http://arxiv.org/abs/http://www.arxiv.org/abs/astro-ph/0406516
> If the above is correct, I suppose it would be an example of what
> Brian Greene describes in _The Fabric of the Cosmos_:
>
> Perhaps cosmic expansion can stretch the imprints of even
> shorter-scale processes or features - the physics of strings, or
> quantum gravity more generally, or the atomized structure of ...
This is indeed the relevant portion of Brian's book that talks about these
possibilities. They're not completely new - they just became popular again
recently, and some of the reasons are explained in Kibble's and
Polchinski's articles. Brian also talks about his line of research that is
meant to discover imprints of strings on the cosmic microwave background,
but the same chapter should also talk about the cosmic strings. Either in
the Fabric of the Cosmos, or in The Elegant Universe, he also mentions
that "seeing a cosmic string in a telescope is Witten's favorite scenario
how string theory should be proved because nothing would settle the
question as cleanly as a string seen in your telescope".
__{_______________________________________________ _____________________________}
E-mail: lumo@matfyz.cz fax: +1-617/496-0110 Web: http://lumo.matfyz.cz/
eFax: +1-801/454-1858 work: +1-617/384-9488 home: +1-617/868-4487 (call)
Webs: http://schwinger.harvard.edu/~motl/ http://motls.blogspot.com/
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Hi,\n\nafter reading this thread and part of Joe Polchinskis article, the\nfollowing question came to me: The surviving cosmic strings found\nshould be of infinite length, at least at the beginning. Infinite\nlength means that they have to be in a noncompact direction of\nspacetime. But the noncompact directions vary with the cosmological\nsolution, for example S3xR has only one, but R4 has four. I assume that\nall other extra dimensions are compact. So shouldn\'t this influence the\ncosmic string density observed?\n\nRené.\n\n____________________________ __________________________________________________ _\nWeb page of SPS: http://schwinger.harvard.edu/~sps/\nPosted via: http://groups.google.com/groups?group=sci.physics.strings\n^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Hi,
after reading this thread and part of Joe Polchinskis article, the
following question came to me: The surviving cosmic strings found
should be of infinite length, at least at the beginning. Infinite
length means that they have to be in a noncompact direction of
spacetime. But the noncompact directions vary with the cosmological
solution, for example S3xR has only one, but R4 has four. I assume that
all other extra dimensions are compact. So shouldn't this influence the
cosmic string density observed?
René.
__{_______________________________________________ ______________________________}
Web page of SPS: http://schwinger.harvard.edu/~sps/
Posted via: http://groups.google.com/groups?group=sci.physics.strings
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Lubos Motl
Dec20-04, 06:45 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>On Sun, 19 Dec 2004, Rene wrote:\n\n> after reading this thread and part of Joe Polchinskis article, the\n> following question came to me: The surviving cosmic strings found\n> should be of infinite length, at least at the beginning. Infinite\n> length means that they have to be in a noncompact direction of\n> spacetime. But the noncompact directions vary with the cosmological\n> solution, for example S3xR has only one, but R4 has four. I assume that\n> all other extra dimensions are compact. So shouldn\'t this influence the\n> cosmic string density observed?\n\nI find your comments about the dimensions kind of difficult to understand\nand perhaps unphysical. You seem to count both spatial dimensions as well\nas time, and you count how many of them are compact. I see no significance\nof such counting. If you talk about the whole spacetime, a string (even a\ncosmic one) is described by its worldsheet which is two-dimensional. If\nJoe says that some strings are infinite, it\'s reasonable to expect that he\ntalks about the spatial extension only. So it would be more comprehensible\nto me if you removed the time coordinate from your discussion.\n\nMoreover I don\'t think that he really means "literally infinite" - in a\ncompact Universe, he probably means strings that are stretching across the\nwhole Universe, so for S3 x R it\'s OK if the string network covers the\nwhole S3 even though the total length is finite. Sorry if I misunderstood\nyou. All the best, Lubos\n___________________________________________ ___________________________________\nE-mail: lumo@matfyz.cz fax: +1-617/496-0110 Web: http://lumo.matfyz.cz/\neFax: +1-801/454-1858 work: +1-617/384-9488 home: +1-617/868-4487 (call)\nWebs: http://schwinger.harvard.edu/~motl/ http://motls.blogspot.com/\n^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>On Sun, 19 Dec 2004, Rene wrote:
> after reading this thread and part of Joe Polchinskis article, the
> following question came to me: The surviving cosmic strings found
> should be of infinite length, at least at the beginning. Infinite
> length means that they have to be in a noncompact direction of
> spacetime. But the noncompact directions vary with the cosmological
> solution, for example S3xR has only one, but R4 has four. I assume that
> all other extra dimensions are compact. So shouldn't this influence the
> cosmic string density observed?
I find your comments about the dimensions kind of difficult to understand
and perhaps unphysical. You seem to count both spatial dimensions as well
as time, and you count how many of them are compact. I see no significance
of such counting. If you talk about the whole spacetime, a string (even a
cosmic one) is described by its worldsheet which is two-dimensional. If
Joe says that some strings are infinite, it's reasonable to expect that he
talks about the spatial extension only. So it would be more comprehensible
to me if you removed the time coordinate from your discussion.
Moreover I don't think that he really means "literally infinite" - in a
compact Universe, he probably means strings that are stretching across the
whole Universe, so for S3 x R it's OK if the string network covers the
whole S3 even though the total length is finite. Sorry if I misunderstood
you. All the best, Lubos
__{_______________________________________________ _____________________________}
E-mail: lumo@matfyz.cz fax: +1-617/496-0110 Web: http://lumo.matfyz.cz/
eFax: +1-801/454-1858 work: +1-617/384-9488 home: +1-617/868-4487 (call)
Webs: http://schwinger.harvard.edu/~motl/ http://motls.blogspot.com/
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
=?iso-8859-1?B?UmVu6SBNZXllcg==?=
Dec22-04, 05:37 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Thats just what seemed reasonable too me too. But if its like this, we\ncould theoretically through the observation of cosmic string decay\nrates get some information about the geometry of the spacial part of\nspacetime. But at all, it was just an idea, and maybe he just meant\nliterally infinite. Rene.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Thats just what seemed reasonable too me too. But if its like this, we
could theoretically through the observation of cosmic string decay
rates get some information about the geometry of the spacial part of
spacetime. But at all, it was just an idea, and maybe he just meant
literally infinite. Rene.
DavidBowman
Dec27-04, 04:01 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>> the article claims that someone has observed double images of\ngalaxies\n> that look like images from a fundamental string stretched to become a\n> large cosmic string\n\nNone of us has enough information now to know whether this is true, but\nI don\'t think it is for one (only slightly tongue-in-cheek) reason: a\nheuristic which has served me well many times. It doesn\'t always hold,\nof course, but that\'s when the REALLY cool things happen.\n\nEarly in this century (oops) early in the last century, before we knew\nwe were one of many galaxies, it was hypothesized that the universe is\ncurved and closed. Someone observed that maybe the Andromeda nebula\n(as it was called then), was actually our universe seen in the\ndistance, like seeing the back of your head through a telescope that\ncan see around the world.\n\nA lot of people got very excited for a while, and understandably so;\nthat would have been REALLY cool! But sadly, it was "too cool to be\ntrue" ...which is the heuristic.\n\nREALLY cool things are actually discovered with far less frequency than\nthings which turn out not to be. Cold fusion, martian microbes, and a\nvariety of quasi-paranormal phenenomena come to mind. You can HOPE\nthey turn out to be real, but really big discoveries in science like\nQM, relativity, and evolution are very few and far between.\n\nST proven? Cosmic strings? COOL!\nBut sadly, I\'ll disbelieve it until I see it.\n\n=[ d\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>> the article claims that someone has observed double images of
galaxies
> that look like images from a fundamental string stretched to become a
> large cosmic string
None of us has enough information now to know whether this is true, but
I don't think it is for one (only slightly tongue-in-cheek) reason: a
heuristic which has served me well many times. It doesn't always hold,
of course, but that's when the REALLY cool things happen.
Early in this century (oops) early in the last century, before we knew
we were one of many galaxies, it was hypothesized that the universe is
curved and closed. Someone observed that maybe the Andromeda nebula
(as it was called then), was actually our universe seen in the
distance, like seeing the back of your head through a telescope that
can see around the world.
A lot of people got very excited for a while, and understandably so;
that would have been REALLY cool! But sadly, it was "too cool to be
true" ...which is the heuristic.
REALLY cool things are actually discovered with far less frequency than
things which turn out not to be. Cold fusion, martian microbes, and a
variety of quasi-paranormal phenenomena come to mind. You can HOPE
they turn out to be real, but really big discoveries in science like
QM, relativity, and evolution are very few and far between.
ST proven? Cosmic strings? COOL!
But sadly, I'll disbelieve it until I see it.
=[ d
serg271
Dec27-04, 07:41 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>REALLY cool things are actually discovered with far less frequency than\nthings which turn out not to be. Cold fusion, martian microbes, and a\nvariety of quasi-paranormal phenenomena come to mind. Yep. And the proof\nof the Fermat\'s Last Theorem\n\n[Moderator\'s note: I hope that it\'s OK after the Xmas that this posting\nsurvived. Happy Holidays, L.M.]\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>REALLY cool things are actually discovered with far less frequency than
things which turn out not to be. Cold fusion, martian microbes, and a
variety of quasi-paranormal phenenomena come to mind. Yep. And the proof
of the Fermat's Last Theorem
[Moderator's note: I hope that it's OK after the Xmas that this posting
survived. Happy Holidays, L.M.]
Tom McCurdy
Jan17-05, 05:32 PM
I am searching for any other articles related to this... if anyone finds one please post.
TimothyChase
Jan17-05, 05:33 PM
I found a number of more technical articles regarding this (oddly enough, by the same author -- although earlier), but this article fairly well summarizes what seems to be going on.
Possible Observation of Cosmic String - October 18, 2004
http://quarks.inr.ac.ru/proceedings/Astroparticle/sazhin.pdf
As the article is in PDF form, I will summarize a little bit. Essentially, a cosmic string will create two images (and sometimes three) when it acts as a cosmic lense, but unlike all other forms of gravitational lensing, these images will be identical to one-another. The reason being: cosmic strings are non-magnifying and non-distorting -- they simply bend light in accordance with a constant deficit angle (where the deficit angle may of course differ from cosmic string to cosmic string). Normally, the most distant parts of an image created through gravitational lensing will be blurred and otherwise distorted in shape, but not in the case of cosmic strings. And apparently, not in the case of CSL-1. (In fact, the only alternative which would seem to fit would be if these were identical galaxies with identical spectra (with a 99 percent match) which would seem so unlikely that it can virtually be dismissed.)
I will look up the other more technical articles and post links to them a little later as they cover details not dealt with in this more recent article. (Unfortunately, I saved and renamed the PDFs.) In all honesty, though, I was still a bit skeptical until I saw the above-linked article. Interestingly, a cosmic string moving through randomly seeded matter will tend to create a sheet-like clumping, so it would seem that a cosmic string (which may no longer exist) might explain the Great Wall as well.
RAD4921
Jan17-05, 05:36 PM
I just got done reading the article in New Scientist Mag. I am somewhat ignorant on string theory but I found on page 31, it says:
"Contrary to what to what we used to think, fundamental strings need not be ultra-tiny." says Tom Kibble.
Is this new news? Can strings be of the microscopic and macroscopic universe?
I find this to be very interesting.
Robert
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