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Hang no more.http://www.bbc.co.uk/news/science-environment-35524440
Am I correct in my understanding that the premiss of detecting these gravitational waves involves sending light beams at an angle down hollow tubes that are lined with mirrors, where the light bounces around, and that the waves of gravitational energy pass through into the hollow tubes and cause the light to detectably 'shift' very slightly?
But even so... on the basis that this experiment is subject to a gravitational wave, shouldn't some form of 'shift' occur in the light itself though?
Ah, but I was not thinking about the gravitational wave bending the light beam, I was considering the premiss of gravitational redshift being synonymous to the expansion of the universe.Any change in the 'gravitational' field should cause a gravitational shift in the light. Being as this shift is distance related, and perhaps 'this' is where I've been getting it all wrong, but if I'm right, it would most definitely have an effect on the interference patterns, logically speaking... (rubs chin) ... whether the mirrors had moved or not...But it would really be very hard to believe that they had been searching for proof that distance is subject to change in a gravitational field, and to have forgotten about the gravitational shifting of light... so I daresay they have accounted for the effect in some way, or that I have made a mistake in my thinking.
Well its all certainly food for thought, and that's always good news in my book. . It does also occur to me that gravitational waves might well cause very slight seismic activity, so to take readings based on the movement of objects of mass 'may' be suspect in any case.In my mind, a study on how the gravitational energy is effecting the gravitational shift of light would be the logical approach.
Any change in the 'gravitational' field should cause a gravitational shift in the light.
Gosh... My 'visual' on this experiment has morphed again!So... presumably the arms must be vertically oriented, do they go into the ground?
Ah, Colin. I was considering a gravitational 'shift' in light, that the light would be subject to, both horizontally, and vertically, in the event of a gravitational wave.
Evan at one point there was a discussion about gravitons outside the event horizon of a black hole. Can you remember which thread that was in?
How far does this result tip the balance in favour of the existence of the graviton?
Quote from: jeffreyH on 12/02/2016 13:27:28Evan at one point there was a discussion about gravitons outside the event horizon of a black hole. Can you remember which thread that was in?I have found that the search tool within TNS forum is not always great, but that searching google using some of the terms you're looking for as well as the names of likely posters will often lead to the right place.I found these using that method:http://www.thenakedscientists.com/forum/index.php?topic=47582.0http://www.thenakedscientists.com/forum/index.php?topic=20014.0
the events have a combined signal-to-noise ratio (SNR) of 24
The gravitational wave signal is more intense in the last couple of days of a merge process that can take millions of years
you need to be "lucky" in the timing
Only the (two) LIGO detectors were observing at the time of GW150914. The Virgo detector was being upgraded, and GEO 600, though not sufficiently sensitive to detect this event, was operating but not in observational mode.
fairly "close" to Earth (in astronomical terms)
Quote from: jeffreyHHow far does this result tip the balance in favour of the existence of the graviton?If gravitons exist (as many physicists believe), this experiment will not detect them; it is looking for coherent graviton waves.Just like someone seeing coherent light waves from a laser pointer will not detect individual photons with their eyes.However, this measurement was able to place some constraints on the characteristics of the graviton: Wavelength > 1013km (ie very big)Mass < 10-22 eV/c2 (ie very low mass; perhaps massless?)
Are there any local sources nearer (than the one detected by LIGO)?
the Earth/Moon system must be generating some
and the effect on us are quite apparent.
How about a pair of tethered 1000Kg satellites rotating at 10hz 1000km away would they generate enough power to be detectable?
Viewed as a communication receiving device what is the bandwidth of LIGO?
The power radiated in Gravitational waves for two orbiting bodies is:P=dE/dt=-(32/5)*(G4/c5)*(m1m2)2*(m1+m2)/r5A few examples:System Mass1 (kg) Mass2 (kg) Radius (m) Power (W)Earth orbiting Sun: 5.97E+24 1.98E+30 1.5E+11 193
Quote from: evan_au on 13/02/2016 02:26:26The power radiated in Gravitational waves for two orbiting bodies is:P=dE/dt=-(32/5)*(G4/c5)*(m1m2)2*(m1+m2)/r5A few examples:System Mass1 (kg) Mass2 (kg) Radius (m) Power (W)Earth orbiting Sun: 5.97E+24 1.98E+30 1.5E+11 193Now that's 20 times the power of the transmitter on the Mars Rover, so should be detectable on Mars! Time to launch an experimental physicist on a one-way mission. Do I need a visa?
(200W of gravitational wave power from the Earth orbiting the Sun is) 20 times the power of the transmitter on the Mars Rover, so should be detectable on Mars!
Is there a polarization component to gravitational waves ?
The LIGO installations consist of two horizontal tubes at right angles would a third vertical tube albeit expensive to construct provide useful information?
I also wondered about the speed of the (gravitational) wave
three 10-kilometer arms arranged in the shape of an equilateral triangle rather than an L. That configuration would help it pinpoint the sources of gravitational waves on the sky