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dgavin
2007-Oct-26, 02:13 PM
Something occured to me today aboout gravitational waves.

Seems to me that our own Sun might be a good source to use to try and detect them.

The core of the sun contracts and expands at an interval of about five minutes. Seems to me this would change the suns gravitational signature ever so slightly.

Would not a repeating expanding/contracting mass like a close star also be a source for gravitationalal waves that would match this frequency?

Ekim
2007-Oct-26, 02:26 PM
Would you have to add to decrease the mass of the sun rapidly to create gravitational waves?

antoniseb
2007-Oct-26, 02:34 PM
Would you have to add to decrease the mass of the sun rapidly to create gravitational waves?
No, just change the distribution of mass. The effect is subtle but potentially detectable. The problem for this case is that it would need a very spacious detector, since the wave size is large compared to the Earth.

Jerry
2007-Oct-26, 02:36 PM
Core fluctuations would have little change upon the net gravimetic field broadcast from the sun - the center of mass does not change. HOWEVER, there would be some variability in the Love number, and this would have second order effects that should translate as gravity wave modulations...good call.

So why no expectations of the detection of waves from the sun? I'm guessing, but they would get lost in the gross and not completely predictible changes already attributed to tidal variations.

StupendousMan
2007-Oct-26, 05:33 PM
Something occured to me today aboout gravitational waves.

Seems to me that our own Sun might be a good source to use to try and detect them.

The core of the sun contracts and expands at an interval of about five minutes. Seems to me this would change the suns gravitational signature ever so slightly.


The core of the Sun does not oscillate with a five-minute period, as far as I know. Perhaps you are referring to the oscillations of the outer layers of the photosphere, which contain much, much less mass.



Would not a repeating expanding/contracting mass like a close star also be a source for gravitationalal waves that would match this frequency?

No, not unless there was some sort of asymmetry in the shape of the expanding/contracting star.

Tim Thompson
2007-Oct-26, 05:34 PM
The core of the sun contracts and expands at an interval of about five minutes. Seems to me this would change the suns gravitational signature ever so slightly.
The 5-minute oscillations of the sun (http://adsabs.harvard.edu/abs/1970ApJ...162..993U) are a surface wave, and not an oscillation of the core. Those oscillations are so tiny as to be far below the limit of detectability for gravitational waves now, and for a long time to come. The technology for detecting gravitational waves is now centered around precision interferometers, i.e., ground based LIGO (http://www.ligo.caltech.edu/), which is now in operation, and space based LISA (http://lisa.nasa.gov/), which is tentatively planned to launch in 2015. But even those sensitive instruments can only detect big things, like colliding black holes & neutron stars or supernovae, a far cry from the measly wiggles of the sun. There has been no direct detection of gravitational waves reported so far (i.e., Sintes, et al., 2007 (http://adsabs.harvard.edu/abs/2007arXiv0710.4898S); AURIGA & LIGO, 2007 (http://adsabs.harvard.edu/abs/2007arXiv0710.0497A); B. Abbott, et al., 2007 (http://adsabs.harvard.edu/abs/2007PhRvD..76f2003A); LIGO, 2007a (http://adsabs.harvard.edu/abs/2007arXiv0709.0766L); LIGO, 2007b (http://adsabs.harvard.edu/abs/2007arXiv0708.3818L) & etc.).

trinitree88
2007-Oct-26, 05:45 PM
[QUOTE=Tim Thompson;1098170]There has been no direct detection of gravitational waves reported so far .

...except for the claims by Sulak et al from SN1987a. While many dispute the needed sensitivity for the claimed coincidences, a subsequent event seen by LIGO, LISA, and the wordwide neutrino detectors in operation today, like SNO, AMANDA, DUMOND....might shore up their claims. There should be no g-wave without a coincident neutrino event though, supernova or not. pete.

Tim Thompson
2007-Oct-26, 06:24 PM
There has been no direct detection of gravitational waves reported so far.
...except for the claims by Sulak et al from SN1987a.
I have never heard of this claim before. I looked, but can find no reference to Sulak looking for and/or detecting anything except neutrinos. Do you have a reference for the claim of detecting gravitational waves? I remember when Weber claimed to have detected gravitational waves with his bar detector, but his claim was eventually discounted as well (Physical Review Focus, 22 Dec 2006 (http://focus.aps.org/story/v16/st19)).

trinitree88
2007-Oct-28, 04:47 PM
I have never heard of this claim before. I looked, but can find no reference to Sulak looking for and/or detecting anything except neutrinos. Do you have a reference for the claim of detecting gravitational waves? I remember when Weber claimed to have detected gravitational waves with his bar detector, but his claim was eventually discounted as well (Physical Review Focus, 22 Dec 2006 (http://focus.aps.org/story/v16/st19)).

Tim. Professor Sulak spoke at the MIT Winter Course in Nuclear and Particle Physics, winter of 91-92...and verbally talked of it, claiming a confidence level of > three sigma, about a 1/10,000 chance of a fluke, and soon-to-be-published article in Il Nuovo Comento C. (Then). I searched his CV,and NASA Astrophysics Database, and did not find it, but a similar reference I can't open...see:http://adsabs.harvard.edu/abs/1990ICRC...10...40B

There is the article by Pizzella, Guido et al in Il Nuovo Cimento C...see; http://adsabs.harvard.edu/abs/1992NCimC..15..931P

dgavin
2007-Oct-28, 05:50 PM
Thanks for all the answers! Sounds like it's possible, but the wave length is so long that it it would take a large detector.

I dug deeper and the five minute interval I mentioned is indeed surface waves. The core has a cycle of over 2 hours for it's waves. Making it even harder to dectect and gravitation waves for it. Guess it would take an inferometer with a base line of over 2 light hours for that. Yikes.