FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups 
 ProfileProfile   PreferencesPreferences   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Forum index » Science and Technology » Physics » Research
Detection of Gravitational Radiation
Post new topic   Reply to topic Page 1 of 1 [10 Posts] View previous topic :: View next topic
Author Message
Chalky
science forum beginner


Joined: 13 Jan 2006
Posts: 20

PostPosted: Wed Jun 07, 2006 3:20 am    Post subject: Detection of Gravitational Radiation Reply with quote

About 30 years ago, terrestrial GW detectors were only sensitive enough
to observe "hammer blow" radiation of indeterminate origin.

I would like to know; have modern detectors:

A) Established whether such "hammer blow" radiation is terrestrial
or extraterrestrial in origin?
B) Detected any expected (more sinusoidal varying) gravitational waves?

(I recall reading one story about g waves having been detected from our
galactic nucleus, but don't know whether this has been confirmed)

C
Back to top
Jonathan Thornburg -- rem
science forum beginner


Joined: 06 May 2005
Posts: 41

PostPosted: Thu Jun 08, 2006 8:06 am    Post subject: Re: Detection of Gravitational Radiation Reply with quote

Chalky <chalkyspam@bleachboys.co.uk> wrote:
Quote:
About 30 years ago, terrestrial GW detectors were only sensitive enough
to observe "hammer blow" radiation of indeterminate origin.

I would like to know; have modern detectors:

A) Established whether such "hammer blow" radiation is terrestrial
or extraterrestrial in origin?
B) Detected any expected (more sinusoidal varying) gravitational waves?

The (overwhelming) consensus among experts is that no gravitational
waves (of any waveform shape) have yet been directly detected.

Quote:
(I recall reading one story about g waves having been detected from our
galactic nucleus, but don't know whether this has been confirmed)

In the early 1970s Prof. Joseph Weber (U of Maryland) claimed to
have detected pulses of gravitational radiation, with some (weak)
evidence that they came from the general direction of the galactic
center. However, other researchers found various flaws in Weber's
data analysis, and (different) other researchers with much more
sensitive detectors were unable to detect such signals. The
(again, overwhelming) consensus among experts now is that Weber's
"detections" were artifacts of the data analysis.

There has been one very convincing, abeit rather indirect, "detection"
of gravitational radiation: The orbit of the pulsar PSR B1913+16 has
been found to be gradually shrinking, at a rate which matches precisely
(within the error bars of about 0.3%) the rate one would expect from
gravitational radiation emission.

There are no known sources of gravitational radiation powerful enough
to have accounted for the size of signals Weber claimed to have
detected. (Indeed, the *huge* amounts of energy involved were one
argument against the hypothesis that Weber's detections were geniune.)

There are major efforts currently under way to build, debug, and
fine-tune gravitational-radiation detectors sensitive enough to detect
the (very faint) signals from sources that we _do_ know to exist.

(There are also parallel theoretical efforts to try to estimate the
likely gravitational-radiation signals from various types of sources.
My own research lies in this area.)

ciao,

--
-- "Jonathan Thornburg -- remove -animal to reply" <jthorn@aei.mpg-zebra.de>
Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut),
Golm, Germany, "Old Europe" http://www.aei.mpg.de/~jthorn/home.html
"Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral."
-- quote by Freire / poster by Oxfam
Back to top
FearlessFerret
science forum beginner


Joined: 03 May 2005
Posts: 17

PostPosted: Fri Jun 09, 2006 7:17 am    Post subject: Re: Detection of Gravitational Radiation Reply with quote

Jonathan Thornburg -- remove -animal to reply wrote:

Quote:
The (overwhelming) consensus among experts is that no gravitational
waves (of any waveform shape) have yet been directly detected.

I've always been of the opinion that terrestrial GW detectors are a
complete waste of effort (except maybe as an interesting engineering
problem) when you can put one in space and make it millions of times
bigger without any noise problem.

Not that a space-based system could be built for the same cost, but here
on earth you're hamstrung by the signal-to-noise ratio.

/ff
Back to top
Jonathan Thornburg -- rem
science forum beginner


Joined: 06 May 2005
Posts: 41

PostPosted: Sun Jun 11, 2006 11:04 am    Post subject: Re: Detection of Gravitational Radiation Reply with quote

I wrote:
Quote:
The (overwhelming) consensus among experts is that no gravitational
waves (of any waveform shape) have yet been directly detected.

FearlessFerret <ff@repliestonewsgrouponly.com> wrote:
Quote:
I've always been of the opinion that terrestrial GW detectors are a
complete waste of effort (except maybe as an interesting engineering
problem) when you can put one in space and make it millions of times
bigger without any noise problem.

Not that a space-based system could be built for the same cost, but here
on earth you're hamstrung by the signal-to-noise ratio.

If gravitational-wave detector people had as much money to play with
as (say) the pentagon, they probably would build lots and lots of
detectors in space. Alas, in the real world you have to do the best
science you can within (very) finite budgets, and doing things in
space costs a *lot* of money.

Of the major ground-base GW detectors now running or almost-running:
* In (very) round numbers, the US spent around $300 million to build
the 2 LIGO detectors (ground-based).
* I'm less knowledgable about the budget of the French/Italian Virgo
detector, but I would guess it's on the order of 100 million Euros.
* The UK-German GEO600 detector was very cheap, perhaps 15 million Euros
(it's 1/5 the size of LIGO and Virgo, and used a lot of volunteer
labor to help keep costs down).
* I don't know the budget of the Japanese TAMA300 detector.

There is indeed a project underway to build a space-based GW detector.
It's a joint US-European project called LISA (Laser Interferometer Space
Array). It's designed to be sensitive to a much lower frequency band
than the ground-based detectors (milliHertz instead of 100s of Hertz).
LISA should be *very* sensitive, and do *great* science.

However, LISA won't be launched until 2015 at the absolute earliest,
and its total budget will probably be close to 1000 million dollars
or Euros. And alas, the most recent US budget proposals would *not*
provide funding for US LISA development in the next US fiscal year.
There are hopes that the US may have funding available starting in
their 2009 fiscal year.

See the LISA web sites
http://sci.esa.int/science-e/www/area/index.cfm?fareaid=27
http://lisa.jpl.nasa.gov/
http://www.lisa-science.org/newsletter
for more information.

I think we need *both* ground-based GW detectors (which are running
now, and can do excellent science at moderate cost) *and* space-based
detectors in the future.

[Conflict-of-interest disclosure: My institution operates GEO600,
and has a major role in LISA. My boss's boss is chair of the LISA
science working group.]

--
-- "Jonathan Thornburg -- remove -animal to reply" <jthorn@aei.mpg-zebra.de>
Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut),
Golm, Germany, "Old Europe" http://www.aei.mpg.de/~jthorn/home.html
"Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral."
-- quote by Freire / poster by Oxfam
Back to top
ebunn@lfa221051.richmond.
science forum beginner


Joined: 21 Sep 2005
Posts: 38

PostPosted: Mon Jun 12, 2006 9:20 pm    Post subject: Re: Detection of Gravitational Radiation Reply with quote

In article <4esq67F1gaf3gU1@individual.net>,
Jonathan Thornburg -- remove -animal to reply <jthorn@aei.mpg-zebra.de> wrote:
Quote:
I wrote:

FearlessFerret <ff@repliestonewsgrouponly.com> wrote:
I've always been of the opinion that terrestrial GW detectors are a
complete waste of effort (except maybe as an interesting engineering
problem) when you can put one in space and make it millions of times
bigger without any noise problem.

Not that a space-based system could be built for the same cost, but here
on earth you're hamstrung by the signal-to-noise ratio.

If gravitational-wave detector people had as much money to play with
as (say) the pentagon, they probably would build lots and lots of
detectors in space. Alas, in the real world you have to do the best
science you can within (very) finite budgets, and doing things in
space costs a *lot* of money.

Jonathan is exactly right. I just wanted to add one other point.
Even if a space-based experiment is ultimately necessary to get to the
science goals, it may be cost-effective to do the best you can from
the ground first, as a way of developing technology and working the
bugs out before mounting the space mission.

As an example, think of cosmic microwave background (CMB)
observations. The space-based missions (COBE and WMAP) were essential
-- no ground-based experiment could ever have done what they did.
(And we hope that we'll be able to say the same thing about future
satellite missions -- Planck soon and maybe someday a CMB polarimetry
satellite.) But COBE and WMAP could not have been as successful as
they were if they hadn't "stood on the shoulders of giants," namely
the incredible efforts of the ground-based and balloon-borne CMB
experiments.

Just to be clear, I am not saying that the suborbital CMB experiments
were *only* technology pathfinders for the space probes; on the contrary,
they returned very important science of their own.

CMB science is one area in which a space-based mission was clearly "the
right way to go," but it would have been utterly crazy to neglect
the suborbital experiments in favor of a space mission. The right
thing to do was to push hard on the suborbital program while
simultaneously trying to make the case for a space mission.
I don't know for sure that the same is true for the gravitational-wave
business, but I suspect that it is.

-Ted

--
[E-mail me at name@domain.edu, as opposed to name@machine.domain.edu.]
Back to top
Chalky
science forum beginner


Joined: 13 Jan 2006
Posts: 20

PostPosted: Thu Jun 15, 2006 4:39 pm    Post subject: Re: Detection of Gravitational Radiation Reply with quote

Jonathan Thornburg -- remove -animal to reply wrote:
Quote:
Chalky <chalkyspam@bleachboys.co.uk> wrote:
About 30 years ago, terrestrial GW detectors were only sensitive enough
to observe "hammer blow" radiation of indeterminate origin.

I would like to know; have modern detectors:

A) Established whether such "hammer blow" radiation is terrestrial
or extraterrestrial in origin?
B) Detected any expected (more sinusoidal varying) gravitational waves?

The (overwhelming) consensus among experts is that no gravitational
waves (of any waveform shape) have yet been directly detected.

(I recall reading one story about g waves having been detected from our
galactic nucleus, but don't know whether this has been confirmed)

In the early 1970s Prof. Joseph Weber (U of Maryland) claimed to
have detected pulses of gravitational radiation, with some (weak)
evidence that they came from the general direction of the galactic
center. However, other researchers found various flaws in Weber's
data analysis, and (different) other researchers with much more
sensitive detectors were unable to detect such signals. The
(again, overwhelming) consensus among experts now is that Weber's
"detections" were artifacts of the data analysis.

There has been one very convincing, abeit rather indirect, "detection"
of gravitational radiation: The orbit of the pulsar PSR B1913+16 has
been found to be gradually shrinking, at a rate which matches precisely
(within the error bars of about 0.3%) the rate one would expect from
gravitational radiation emission.

There are no known sources of gravitational radiation powerful enough
to have accounted for the size of signals Weber claimed to have
detected. (Indeed, the *huge* amounts of energy involved were one
argument against the hypothesis that Weber's detections were geniune.)

There are major efforts currently under way to build, debug, and
fine-tune gravitational-radiation detectors sensitive enough to detect
the (very faint) signals from sources that we _do_ know to exist.

(There are also parallel theoretical efforts to try to estimate the
likely gravitational-radiation signals from various types of sources.
My own research lies in this area.)

ciao,

--
-- "Jonathan Thornburg -- remove -animal to reply" <jthorn@aei.mpg-zebra.de
Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut),
Golm, Germany, "Old Europe" http://www.aei.mpg.de/~jthorn/home.html
"Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral."
-- quote by Freire / poster by Oxfam

The following response was sent to me direct by email. I would
appreciate informed comments on the points raised. As the respondent
clearly chose to respond to me privately, I have omitted name. However,
from my level of knowledge, his points appear interesting and
potentially worthy of further discussion. C

It would indeed appear that Weber's analysis was
faulty. Recent analysis indicates that resonance type
detectors (Weber pigs) and the current configuration
of LIGO are incapable of detecting gravitational
waves, if they exist at all. It has been argued that
theory shows that masses must be in relative motion to
enable them to detect a passing gravitational wave. I
refer you to the recent papers:

L. Borissova - "Gravitational waves and gravitational
inertial waves in the general theory of relativity: A
theory and experiments." Progress in Physics, Vol.3,
2005, www.ptep-online.com

D. Rabounski and L. Borissova - "Exact theory to a
gravitational wave detector. New experiments
proposed." Progress in Physics, Vol.2, 2006,
www.ptep-online.com

The papers can be downloaded from the Journal's site
free of charge.

Concerning the Taylor-Hulse pulsar, the interpretation
is dubious. The standard theoretical basis for
localisation of gravitational energy is erroneous. For
instance, one cannot use Einstein's pseudo-tensor to
substantiate gravitational waves since his
pseudo-tensor requires, by application of Euler's
theorem, the existence of a 1st order intrinsic
differential invariant depending only upon the
components of the metric tensor and their 1st
derivatives. However, the pure mathematicians Ricci
and Levi-Civita proved in 1900 that such an invariant
does not exist! Consequently, Einstein's pseudo-tensor
cannot substantiate anything. Deductions based upon
its validity are therefore inadmissible.
Back to top
FearlessFerret
science forum beginner


Joined: 03 May 2005
Posts: 17

PostPosted: Thu Jun 15, 2006 9:22 pm    Post subject: Re: Detection of Gravitational Radiation Reply with quote

ebunn@lfa221051.richmond.edu wrote:

Quote:
Jonathan is exactly right. I just wanted to add one other point.
Even if a space-based experiment is ultimately necessary to get to the
science goals, it may be cost-effective to do the best you can from
the ground first, as a way of developing technology and working the
bugs out before mounting the space mission.

I entirely agree and I should add that I did not intend to imply that anyone
working on LIGO or other ground-based projects is wasting their time. I was
merely expressing the perspective of someone keen on getting the highest quality
data.

This discussion prompted me to do a bit of research, which turned up the fact
that the LISA'06 conference (http://lisa6.gsfc.nasa.gov/conf/lisa6/index.html)
is right in my own backyard, so I managed to get myself registered and I'll go
see for myself how it's going.

/ff
Back to top
linearised@gmail.com
science forum beginner


Joined: 19 Jun 2006
Posts: 1

PostPosted: Mon Jun 19, 2006 8:50 pm    Post subject: Re: Detection of Gravitational Radiation Reply with quote

Chalky wrote:
Quote:
The following response was sent to me direct by email. I would
appreciate informed comments on the points raised. As the respondent
clearly chose to respond to me privately, I have omitted name. However,
from my level of knowledge, his points appear interesting and
potentially worthy of further discussion. C

It would indeed appear that Weber's analysis was
faulty. Recent analysis indicates that resonance type
detectors (Weber pigs) and the current configuration
of LIGO are incapable of detecting gravitational
waves, if they exist at all. It has been argued that
theory shows that masses must be in relative motion to
enable them to detect a passing gravitational wave. I
refer you to the recent papers:

L. Borissova - "Gravitational waves and gravitational
inertial waves in the general theory of relativity: A
theory and experiments." Progress in Physics, Vol.3,
2005, www.ptep-online.com

D. Rabounski and L. Borissova - "Exact theory to a
gravitational wave detector. New experiments
proposed." Progress in Physics, Vol.2, 2006,
www.ptep-online.com


Full disclosure: I am a former employee of LIGO and currently work on
LIGO-related research.

I will say Progress in Physics is, errm, not a highly regarded journal,
to put it mildly. I didn't read the paper in detail but consider this
section of the second one (near the top of page 37):

[begin quote]
New experiment for a free-mass detector: A free-mass detector,
where two mirrors are suspended and vibrating so that they
have free oscillations with respect to each other or along par-
allel (vertical or horizontal) lines. With the mirrors oscillating
along parallel lines, such a system moves with respect to the
local space (v(0) = 0), while with the mirrors oscillating with
respect to each other the system has non-stationary relative
displacements of the butt-ends ((0) = 0, (0) = 0). Accord-
ing to the exact theory of a free-mass detector given above,
a falling gravitational wave produces a relative displacement
of the mirrors, that may be registered with a laser range-
finder (or similar system). Moreover, as the theory predicts,
a time shift is produced in the mirrors, that may be registered
by synchronized clocks located with each of the mirrors: their
asynchronization implies a gravitational wave detection.
[end quote]

Even if their calculations for their claimed relative displacement are
correct, the idea that you could possibly detect it with "laser range
finding" is just out of the question, as is the suggestion that you
could detect a loss of synchronization between clocks! Displacements
from gravitational waves are orders of magnitude too small to be
measured this way, which is why LIGO uses interferometry. That the
authors seem unaware of this does not enhance their credibility.

Moreover, many people other than Weber have done very careful analysis
of the linearised Einstein equation and shown that one can find
wave-like solutions, and that this is not merely a coordinate effect.
There are even exact solutions of the full Einstein equations which are
wavelike. Bernard Schutz's book "A First Course in General Relativity"
has a very clear explanation of this.

Philip
Back to top
tessel@um.bot
science forum addict


Joined: 20 Sep 2005
Posts: 60

PostPosted: Wed Jun 21, 2006 11:42 pm    Post subject: Re: Detection of Gravitational Radiation Reply with quote

On Mon, 19 Jun 2006, linearised@gmail.com wrote:

Quote:
Moreover, many people other than Weber have done very careful analysis
of the linearised Einstein equation and shown that one can find
wave-like solutions, and that this is not merely a coordinate effect.
There are even exact solutions of the full Einstein equations which are
wavelike. Bernard Schutz's book "A First Course in General Relativity"
has a very clear explanation of this.

Actually, while this textbook offers one of the best discussions of
weak-field gravitational radiation, Schutz doesn't discuss exact
gravitational wave solutions to the fully nonlinear EFE. But some other
textbooks do discuss such solutions, e.g. Stephani, General Relativity,
briefly mentions pp waves, Clarke, Elementary General Relativity discusses
plane waves, and (saving the best for last) Misner, Thorne & Wheeler,
Gravitation offer an excellent discussion of perhaps the most important
new phenomenon which occurs when you pass to fully nonlinear solutions,
the appearance of a kind of "background" which can be put down to the
gravitational effects of the energy carried by the wave. Another
interesting phenomenon is the optical distortion of constellations or
whatever viewed through the wavefronts of a departing gravitational wave
(but not, of course, an -approaching- wave).

In any case, I agree that the paper cited by Chalky's correspondent is
highly dubious, so much so that in an ideal world it would not have been
published.

Information resources like Google, the arXiv, and the Wikipedia can be
effective in bringing science to the masses, but unfortunately, it seems
that the masses often fail to recognize that not all journals are created
equal, nor that not all authors of research papers are equally
knowledgeable, insightful, careful, or reliable. I see a huge and largely
unmet need to teach the public some methods which can be used to make a
reasonable guess, without being an expert, about which assertions by
putative "experts" are likely to be unreliable. Similarly, I see a huge
unmet need to teach schoolchildren about the many ways in which
information provided in the media (both traditional mass media and
blogs/websites/wikipedia) is often grossly distorted by misinformation and
disinformation.

At the risk of getting even more OT:

Quite a few fringe physicists have been caught editing the Wikipedia in
order to present their theories as mainstream or established fact. Some
of these efforts seem to reflect thoughtlessness; others have constituted
determined and insidious disinformation campaigns. Also, I note that quite
a few biographies of (often rather obscure) academics in the Wikipedia
turn out to be have been written by the subject! (These can often be
recognized by the fact that they read like a C.V.)

Another problem with Wikipedia is that its scientific coverage is very
uneven: some important mainstream topics are not even mentioned, but quite
a few fringe scientists have written several articles dealing with their
own cranky notions. The result is that noisy self-promoters gain a
disproportional coverage, which then generates more discussion at web
sites and then generates even -more- coverage in the Wikipedia because of
Wikipedia's rather bizarre notion of "notability", which governs what
topics can be suitable subjects of a Wikipedia article.

For example, see

http://www.arxiv.org/abs/gr-qc/0505099
http://www.arxiv.org/abs/gr-qc/0603033

and then google for mention of "Felber, antigravity", "ESA, antigravity"
in websites, blogs, etc. Here, Felber seems to be an assiduous
self-promoter; the Tajmar and Matos paper OTH has been apparently promoted
by uncritical "electrogravity" fans (amateurs, not scientists) who insist
that "ESA" has "confirmed" Podkletnov. Nonetheless, despite their explict
disavowal of this connection in their paper, Tajmar and Matos are not
without blame for the ruckus on the web concerning their latest eprint.
For example, an earlier paper by Tajmar and Matos

http://www.arxiv.org/abs/gr-qc/0003011

gives a good example of how "coy" writing coupled with failure to cite
previous work (on fully nonlinear GEM, in this case) can lead to being
celebrated on the crankweb, probably not something to be desired by anyone
who wants to be taken seriously in physics.

(For the record, the above citations are intended merely as examples used
to illustrate a general point; I am definitely -not- trying to flame any
individuals here. But specific examples can be very helpful in this kind
of discussion, so I don't think it is inappropriate to offer a few.)

One of the problems I see which derives from the rise of the arXiv (which
is overall of course a tremendously Good Thing) is that many or most
scientists still haven't grasped that they must write with the expectation
that their paper may well be read by nonscientists, particularly if it
deals with something which might be taken to suggest a "new energy" scheme
(or a number of other topics which attract attention from fans whose
enthusiasm greatly exceeds their knowledge and critical ability). It
would be a serious mistake to assume that such readers enjoy even a modest
appreciation of the laws of thermodynamics, the role played by
approximation in physics, or even the notion of a physical "theory" and
how theory relates to experiment in physics.

Then there is the problem of the increasing politicization of coverage of
topics such as global warming, evolution, "creationist" cosmology, medical
controversies like the anti-vaccination movement, and so on and on and on.

Proponents of pseudoscientific and even fraudulent "new energy" schemes
also pose a threat to the integrity of information presented in the
Wikipedia, because many self-styled inventors are constantly seeking
private investment and consequently have a financial incentive to slant
Wikipedia articles in their favor. Some attempts to do just that have in
fact been noticed by alert Wikipedians. It is important to understand
that some very dubious "protoscientific" [sic] endeavours -have- on
occasion attracted private monies allegedly running into the millions, so
these financial incentives can be considerable.

No doubt this kind of self-serving manipulation of information is
precisely the result one would expect given human nature and the fact that
anyone can edit the Wikipedia, but it seems that the increasingly large
number of persons, including young students, who use the Wikipedia as an
information resource, often simply do not consider such possibilities
(unless they are themelves writing hoax articles, of course).

Unfortunately, the Wikipedia sociopolitical "governance" system has been
very slow to respond to these issues. I understand that Paul Ginsparg of
arXiv fame may discuss some of them in an invited address to an upcoming
Wikipedia conference.

Going back to research papers in journals or the arXiv, I note a marked
tendency by many authors of research papers to shamelessly "oversell"
their paper (in abstract and discussion section), apparently in the belief
that if they don't do this, their peers will conclude they don't believe
in the value of their own work! If so, I think they could not be more
wrong, in fact, as a reader I am always -far- more impressed by an author
who has taken the trouble to anticipate and counter some possible
objections to or misunderstandings of his work than by an author who brags
shamelessly and without foundation. Be this as it may, this tendency
poses a problem for the general public and policy makers, who lack the
expertise to see when a researcher is blowing hot air. IMO, authors of
research papers should remember that they are supposed to be scholars, not
salesmen. The best way to ensure the success of your paper, IMO, is to
write it honestly and well (and of course, you need to have something to
say which is truly worth saying).

Policy makers: as current scientific "best practice and belief" (or more
often than not, poor practice and misunderstanding) increasingly becomes
the basis for major policy decisions in most areas of government, the need
to render transparent all known -deficiencies- in scientific work becomes
ever more essential. Increasingly, I believe, when it comes to matters of
policy, professional politicians are becoming merely mediators between Big
Science and the general public. This is why it is so important that
scientists recognize that contributing to the understanding of science
good and bad by both local and national politicians is a huge part of the
their professional and civic responsibility, as is combating scientific
misconduct.

The disparity in penalties for scientific fraud and other white collar
crime with respect to minor drug infractions (in the U.S.) is really
scandalous, given the fact that something like the Vioxx scandal directly
affects far more people than any one marijuana peddler, bank robber, or
terrorist.

"T. Essel" (making waves?)
Back to top
tessel@um.bot
science forum addict


Joined: 20 Sep 2005
Posts: 60

PostPosted: Wed Jun 21, 2006 11:42 pm    Post subject: Re: Detection of Gravitational Radiation Reply with quote

I wrote:

Quote:
Unfortunately, the Wikipedia sociopolitical "governance" system has been
very slow to respond to these issues. I understand that Paul Ginsparg
of arXiv fame may discuss some of them in an invited address to an
upcoming Wikipedia conference.

I forgot to add: Wikimania 2006, Aug 4-6, Harvard Law School campus

http://wikimania2006.wikimedia.org/wiki/Program

"T. Essel" (making waves?)
Back to top
Google

Back to top
Display posts from previous:   
Post new topic   Reply to topic Page 1 of 1 [10 Posts] View previous topic :: View next topic
The time now is Sat Jun 24, 2017 10:28 am | All times are GMT
Forum index » Science and Technology » Physics » Research
Jump to:  

Similar Topics
Topic Author Forum Replies Last Post
No new posts Gravitational redshift wgilmour@i-zoom.net Research 5 Mon Jul 17, 2006 3:44 pm
No new posts Einstein interpretation of gravitational redshift is misl... mluttgens@wanadoo.fr Relativity 64 Thu Jul 13, 2006 12:46 pm
No new posts Do Rindler horizons emit Bekenstein-Hawking radiation? frank_k_sheldon@yahoo.co. Relativity 7 Sat Jul 08, 2006 9:57 am
No new posts "Defining Inertial and Gravitational Accelerations 5" Lij Relativity 0 Fri Jul 07, 2006 1:20 pm
No new posts "Defining Inertial and Gravitational Accelerations 4" Lij Particle 0 Fri Jul 07, 2006 1:19 pm

Copyright © 2004-2005 DeniX Solutions SRL
Other DeniX Solutions sites: Electronics forum |  Medicine forum |  Unix/Linux blog |  Unix/Linux documentation |  Unix/Linux forums  |  send newsletters
 


Powered by phpBB © 2001, 2005 phpBB Group
[ Time: 0.0367s ][ Queries: 16 (0.0052s) ][ GZIP on - Debug on ]