Testable predictions question [Archive]

Alan

Jul21-04, 02:04 PM

Mike

Jul25-04, 10:32 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>Alan <info@optioncity.REMOVETHIS.net> wrote in message news:<KPednTCf-_9cMGPdRVn-oA-100000@adelphia.com>...\n> As an outside interested observer, it seems pretty clear\n> from some recent threads that if there are \'large\' extra dimensions,\n> then string theory predictions should be accessible to some upcoming\n> generation of colliders, cosmic ray experiments, or other mainstream\n> approaches.\n>\n> But, let\'s take the tougher scenario where the putative extra dimensions are\n> planck length scale. In that case, presumably these dimensions\n> were important and \'accessible\' by the processes occuring early after the\n> big bang.\n> Intuitively, this \'must\' lead to some signatures today. In other words, in\n> what observable ways is the universe different today, because of these\n> early extra-dimensional processes, than it would be if there were *no*\n> extra dimensions?\n>\n> I expect, of course, that there must not be an easy answer here because in\n> that case the theory would already be confirmed or disproved in some\n> sense. But I am interested in any speculation. For example, I would\n> consider a legitimate answer to be one that started, "travel to the\n> nearest Black hole star and do the following experiment, which uses\n> equipment that we can build today ..."\n\nAs another outside interested observer, let me point you to Georgi\nDvali\'s article, "Out of the darkness", in the February 2004 issue of\nScientific American. Page 75 lists several empirical tests of string\ntheory. Here are two.\n\n1. Further surveys of type Ia supernova should allow scientist to pin\ndown the transition from post big-bang deceleration to acceleration.\nThe various dark energy theories and graviton leakage make different\npredictions for this time so experimental data could eliminate some\nand support others.\n\n2. Alternative theories of gravity (to general relativity) modify the\ngravitational force in "a small but nonnegligible way". Graviton\nleakage is predicted to cause the moon\'s orbit to precess about a\ntrillionth of a degree on each go round. Eric Adelberger et all at\nWashington University propose using "more powerful lasers" bouncing\noff the mirrors left on the moon by the Apollo astronauts to look for\nthis predicted precession.\n\n"The mere fact that observers are talking about probing string theory\nis exciting". Yes indeed.\n\n--Mike\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>Alan <info@optioncity.REMOVETHIS.net> wrote in message news:<KPednTCf-_9cMGPdRVn-oA-100000@adelphia.com>...
> As an outside interested observer, it seems pretty clear
> from some recent threads that if there are 'large' extra dimensions,
> then string theory predictions should be accessible to some upcoming
> generation of colliders, cosmic ray experiments, or other mainstream
> approaches.
>
> But, let's take the tougher scenario where the putative extra dimensions are
> planck length scale. In that case, presumably these dimensions
> were important and 'accessible' by the processes occuring early after the
> big bang.
> Intuitively, this 'must' lead to some signatures today. In other words, in
> what observable ways is the universe different today, because of these
> early extra-dimensional processes, than it would be if there were *no*
> extra dimensions?
>
> I expect, of course, that there must not be an easy answer here because in
> that case the theory would already be confirmed or disproved in some
> sense. But I am interested in any speculation. For example, I would
> consider a legitimate answer to be one that started, "travel to the
> nearest Black hole star and do the following experiment, which uses
> equipment that we can build today ..."

As another outside interested observer, let me point you to Georgi
Dvali's article, "Out of the darkness", in the February 2004 issue of
Scientific American. Page 75 lists several empirical tests of string
theory. Here are two.

1. Further surveys of type Ia supernova should allow scientist to pin
down the transition from post big-bang deceleration to acceleration.
The various dark energy theories and graviton leakage make different
predictions for this time so experimental data could eliminate some
and support others.

2. Alternative theories of gravity (to general relativity) modify the
gravitational force in "a small but nonnegligible way". Graviton
leakage is predicted to cause the moon's orbit to precess about a
trillionth of a degree on each go round. Eric Adelberger et all at
Washington University propose using "more powerful lasers" bouncing
off the mirrors left on the moon by the Apollo astronauts to look for
this predicted precession.

"The mere fact that observers are talking about probing string theory
is exciting". Yes indeed.

--Mike