E@H. This great endeavor
11 Aug 2008 18:26:54 UTC
Topic 193846
(moderation:
E@H. This great endeavor. I cannot write about the science of E@H, I have yet to truly engage with the science. Yet to be part of a quest like this - how marvelous that our human race is the way we are.
Be there anyone who would strike a note of pessimism - remember: we speak, to a lesser or greater degree from our own perceptions. Oh that we truly engage with the other's point of view. Our imagination helps us in this. Though what is in imagination is not ipso facto, another fact. (A lesson for myself rather than a particular other, I find this fora delightfully co-operative.)
E@H. This great endeavor
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I'm seriously quizzing myself. I find the post pompous. So be it. I do suffer from schizophrenia - perhaps that is the reason. (?)
[edit: I stand by my first post. end edit]
Well, pompous or not, you
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Well, pompous or not, you can't help to step back once in a while from the discussion of DCF and credits and SSE2 and whatever and look at what we are trying to do here:
I mean think of it:
The idea is that there are some extremely dense stars, out there, many lightyears away, roughly the size of a city , rotating at up to a few hundred times a second, which would cause ripples in space-time so that the distance between some test masses here on earth will change by a fraction of the size of a proton in the rhythm of this rotation...and our humble PCs would be part of the process of measuring this. Now if this isn't mind boggling, what is?
CU
Bikeman
EDIT: it's space-time, not time-space... :-)
RE: Well, pompous or not,
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I remain persistently boggled, ever since my first involvement. Not just the overall picture but also the detail of the incredible level of technology being applied at the IFO's to drive down the noise, combined with the likes of E@H to 'amplify' the signal.
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
RE: The idea is that there
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Wow, what a great description! Consider my mind boggled.
Rod
RE: Now if this isn't mind
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The idea that I arrived at my desk some 10 minutes early today... ;-)
Ripples in space-time in
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Ripples in space-time in theory affect distances. Is there a similar effect on clocks? Would a clock "skip" a beat as a gravity wave passed? I don't think I have seen any mention of an affect on time. Just curious.
RE: Ripples in space-time
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Good question, but I don't think so ~ in the example of a binary system that's producing detectable waves (or any periodic source like a rotating neutron star that has an uneven distribution of mass around the axis of rotation), the frequency of the signal at the detectors will be the same as the orbital period of the binary system (or the same as the rotational period for a single-object source), and there should be no missing beats in the timing...
RE: RE: Ripples in
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Actually the frequency of the signal should be twice the frequency of the spinning. That's why the Crab Pulsar (approx 30 rps) would generate a signal near the 60Hz "dent" in sensitivity of LIGO caused by EM interference.
Anyway, I think this link to einsteinathome.org should answer your question, right?
CU
Bikeman
RE: RE: RE: Ripples in
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Ah, thanks Bikeman, you're absolutely right. I should've remembered from doing the “Hands-on Gravitational Wave Astronomy� student worksheet (in this thread from Dan G.) Sure enough, for a circularized binary system, P_orbit (t) = 2P_gw (t) (see equation 4 in the worksheet). Hmmm, trying to imagine what it would be for a system with elliptical orbits ~ that would give a wobble to the signal received at the detectors? Almost like two separate [undulating?] chirp waveforms but slightly out of phase (and with differing amplitudes)? Would it even sound like a chirp at all?
But an elliptical orbit would become circularized over time, wouldn't it? Similar to the way that the time-varying amplitude of a standard (circularized binary) chirp waveform changes with time?
[edit] – the link to the worksheet given in the other thread doesn't work anymore, but here's a link to the Center for Gravitational Wave Physics, Classroom Activities page itself ,which has the link for the worksheet and also links for downloading the data plots: Hands-on Gravitational Wave Astronomy: Extraction of Astrophysical Information from Simulated Signals
That's a good exercise to do, and for me a good one to review – I still struggle with the fact that a decreasing orbital period means an increasing frequency in the signal, but it makes sense when you think it through. Thanks again, Bikeman :)
Hello folks and greetings
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Hello folks and greetings from Spain!!
This is my first post here after being logged-in for almost one year for this great project....Shame on me!
My backgrounds in Physics are only those from High School but as you can see, this world of science and Physics has trapped me since then. Participating in this great endeavour and helping with some CPU time/work from home cannot be wrong. Formation/education is very important: not everybody is like Einstein!
Cheers and thanks!