Why wouldn't we start S6 search right now?

Stranger7777
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That's great! But the

That's great! But the question is still on: why not to wait when the most sensitive instrument will be designed, installed and turned on and then start to work on this enough informative data. Why would we now proccess this rough enough data that comes from LIGO, GEO e.t.c. if we all know, that we will surely not find any evidence of GW on the current level of sensitivity? I don't want to change the project this time, because I'm fond of astronomy for about 7 years already, but I need arguments to talk to people who are not in any project yet, or who had dissapointed by other projects. So? Does anybody have a key answer that will return things on their places?

tullio
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I understand your sense of

I understand your sense of frustration, but think of the thousands people (myself included) crunching SETI data without the faintest hope of finding an alien signal. If you want to take part in a project which will certainly give some result I suggest you try QMC@home or LHC@home or some other biology and medicine oriented project. On the home page of LHC@home there is a link to a paper describing how distributed volunteer computing was useful in building the LHC accelerator, a very big scientific project with leading edge technology.
Tullio
In the same paper I found this interesting paragraph:
"An important discovery made with CPSS, and confirmed with LHC@home, is that different Intel and Intel compatible PC processors can return different results, even when a 32-bit static linked absolute binary executable is used. This problem was tracked down to the evaluation of elementary functions such as exponential and logarithm, A solution was found in the elementary function library CRlibm from ENS Lyon which not only provides identical results, but guarantees to provide the correct rounded double precision results."

Bikeman (Heinz-Bernd Eggenstein)
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RE: That's great! But the

Message 71064 in response to message 71062

Quote:
That's great! But the question is still on: why not to wait when the most sensitive instrument will be designed, installed and turned on and then start to work on this enough informative data.


"Most sensitive" is not a fixed thing. There will always be a more sensitive instrument, someday in the future. There's only a most-sensitive-available-now, which is LIGO S5.

Quote:
Why would we now proccess this rough enough data that comes from LIGO, GEO e.t.c. if we all know, that we will surely not find any evidence of GW on the current level of sensitivity?


GW astronomy is mostly unknown terrain. You can never know for sure what can be found, because there might be unknown stuff out there. The only way to find out is to actually search the data. It would not make sense to build those really expensive observatories, operate it , and then send the data to /dev/null because there will be more sensitive versions of the instruments in the future ;-). If you are only looking for things you expect to find, you'll never find something new.

Also, I think the sensitivity of S5 isn't that bad after all. For some known pulsars, the upper limit on GW radiation levels that are derived from LIGO and those derived from theory (a pulsar with a given history of spin-frequency is not likely to produce more GW radiation than the level explaining the observed loss of energy as its spin frequency is decreasing) are quite close. And we know only those pulsars which happen to emit EM radiation in our direction. There could be an unknown one next door.

CU

H-BE

Bikeman (Heinz-Bernd Eggenstein)
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For a discussion of the

For a discussion of the possibility of Einstein@Home finding something even with Initial Liga at full design sensitivity (reached in S5), see this short paper, for example:

http://arxiv.org/pdf/gr-qc/0511152

Quote:

Quote:

Future searches, using sophisticated hierarchical analysis techniques, together with the
computing power of Einstein@home will allow the deepest pulsar searches, and thus initial
LIGO at full sensitivity will have some chance of observing a continuous gravitational wave
signal.

So this is far from hopeless :-).

CU
H-BE

Nothing But Idle Time
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RE: RE: ...Future

Message 71066 in response to message 71065

Quote:
Quote:
...Future searches, using sophisticated hierarchical analysis techniques, together with the computing power of Einstein@home will allow the deepest pulsar searches, and thus initial LIGO at full sensitivity will have some chance of observing a continuous gravitational wave signal.

So this is far from hopeless :-).

Experiences differ, but in my experience when someone says "will have some chance" it means the chances are disparagingly low but not zero, so there is hope as you say. Yet, each individual needs to ask themselves whether donating cpu cycles and its related cost to Einstein versus, say, Rosetta (which I believe has a better chance at producing something useful to mankind and sooner) is where you want to donate your money. Personally I like cosmology and physics and science since my college degree is chemistry, but I will try to have both worlds and donate to Rosetta, Einstein and Cosmology projects. Afterall, pure research is just as important as applied research, one leads to the other.

Bikeman (Heinz-Bernd Eggenstein)
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RE: RE: RE: ...Future

Message 71067 in response to message 71066

Quote:
Quote:
Quote:
...Future searches, using sophisticated hierarchical analysis techniques, together with the computing power of Einstein@home will allow the deepest pulsar searches, and thus initial LIGO at full sensitivity will have some chance of observing a continuous gravitational wave signal.

So this is far from hopeless :-).
Experiences differ, but in my experience when someone says "will have some chance" it means the chances are disparagingly low but not zero, so there is hope as you say. Yet, each individual needs to ask themselves whether donating cpu cycles and its related cost to Einstein versus, say, Rosetta (which I believe has a better chance at producing something useful to mankind and sooner) is where you want to donate your money. Personally I like cosmology and physics and science since my college degree is chemistry, but I will try to have both worlds and donate to Rosetta, Einstein and Cosmology projects. Afterall, pure research is just as important as applied research, one leads to the other.

OK, so here's a source that uses less ambiguous language:

PDF Presentation: Einstein@Home Hierarchical Search by R. Prix (you'll see his name appear in some of the debug output where authors for source files are automatically inserted.

On Page 2:

Quote:


What is Einstein@Home?

Search for GWs from spinning neutron stars with unknown
sky-position, frequency & spindown: λ =
{α, δ, f , f_dot }

Maximize available computing power
Cut parameter-space λ in small pieces ∆λ
• Send workunits ∆λ to participating hosts
• Hosts return finished work and request next

* Public distributed computing project, launched Feb. 2005
* Currently ∼160,000 active participants, ∼80Tflops
* runs on GNU/Linux, Mac OSX, Windows,..
* Search for isolated neutron stars f ∈ [50, 1500] Hz
* Aiming for detection, not upper limits
* Analyzed data from S3, S4, currently S5

Stranger7777
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Thanks a lot for links. I

Thanks a lot for links. I started to read them yesterday, but haven't enough time even to finish the first PDF. But I try to do it this evening.
I just remembered the story from the 1998 (that year we won the "Odissey of The Mind" competition in Holland) and a new question has arised :)
So... the story
Sometime ago, when I studied applied mechanics and mathematics in South Urals State University in Chelyabinsk (Russia) we learned to solve non-linear tasks with 3 or more parameters. That time we used MathCad to solve the task with for e.g. 16 elements. These days we have enough computing power to solve huge tasks with huge number of elements and this gives us a big progress in some tasks that can not be solved any other way than this.
And there is one more question: this is an extensive way to sold the task and it should be used only if we haven't any other ways (mathematical, not computational). Are there no ways to solve this task to estimate the size, form and level of the GW we are looking for?

Bernd Machenschalk
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RE: Are there no ways to

Message 71069 in response to message 71068

Quote:
Are there no ways to solve this task to estimate the size, form and level of the GW we are looking for?


Of course these parameters depend on the parameters of the source of GW, which is what we are looking for.

We have some idea what objects could emit GW and some models how the resulting GW would look like, but we don't know what and where the sources actually are and which models are right until we found a GW.

We think (or actually just hope) that some of the pulsars we know from radio astronomy are emitting not only radio signals, but GW, too, but most of them are too far away for our current sensitivity.

However the fascinating thing about GW (for me) is that they are something entirely different from the electromagnetic waves (light, radio, x-ray, etc.) that is currently the only source of all information we have about the universe. There may be GW sources that we don't know anything about, because they're not emitting electromagnetic waves, and the further we can "look" into space, the more likely it becomes that some GW sources are within reach of our instruments. So we are simply pushing the sensitivity and thus the reach both of our detectors and search algorithms further and further.

BM

BM

tullio
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There are also cosmic rays

There are also cosmic rays and neutrinos. I have some newspaper articles about the 1987 supernova which state that it coincided with a burst of neutrinos in the Monte Bianco tunnel detectors and a possible GW detected by the supercold resonant mass instrument in Frascati. But I don't have any scientific paper about this event.
Tullio

Stranger7777
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So, we are looking with more

So, we are looking with more and more sensitivity deeper and deeper into the sky each day. But! We are looking for electromagnetic waves, because we assume that weak interactions (like GW) will produce by the way electromagnetic waves. So, supposing this, we use usual mathematical analisys in wide frequency and time range.
Now, imagine yourself, what happend if we will stay near a huge GW source (black hole, neutron star, or even two or more colliding galaxy cores or BHs.
We have so strong gravitation there, that even the light can't come out there.
We see only X-Rays that comes from that region while accretion (not sure how to write it, correct me, please) of matter on the border of events (not sure too) or on the surface of these bodies.
Now I have to suppose that we don't see black holes and sure will not see any form of GW just because the curvature of time-space there is so strong that the original electomagnetic form of any signal is deformed so strong that it doesn't even look like original waveform. So, I suppose, we see only some distorted impulses that originaly was the part of the original GW. That's why our eyes see black holes (not eyes, instruments) but not a shiny objects. They are not ready for this.
I suppose that we should use reverse analysis to look for the parts of waveforms, just like in signals in accoustic systems with high frequency 1 bit encoding that comes right after Digital-Analog conversion. If try to look for these impulses and soon will try to combine them together, may be, in some future we will know what is the real color of the Black Holes and what form GW consist of.
Is it interesting idea?

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