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originally posted by: intrptr
a reply to: FauxMulder
I believe the answer to this is that the gravitational waves the sun puts out are way too small for us to detect.
But hold our earth in orbit. How powerful is that influence of gravity compared to these 1 billion light year removed waves?
Galactic black holes hold billions of suns in their sphere of influence.
If gravity waves that far away are so intense as to outshine our suns gravity so much, they should have some impact on our orbit, ya think? Can't they tune this super sensitive device to read our own suns gravity 'waves'?
originally posted by: Bedlam
a reply to: intrptr
Water, air waves etc are qualitatively different from EM. EM radiation is not 'waves of photons' like water is a wave of water or sound is a compression wave of air.
But hold our earth in orbit. How powerful is that influence of gravity compared to these 1 billion light year removed waves?
So tiny that it only distorts light 1 / 10000 of the width of a proton.
originally posted by: FauxMulder
a reply to: intrptr
I like questions, they force you to challenge your own knowledge to be able to answer them or maybe even learn you were wrong about something in the process. That's why I like ATS, at least when it isn't people looking for an echo chamber though.
You don't need something to "wave" to have a wave. EM is composed of photons, but the "waves" are electric and magnetic fields. There are no particles "waving" like water and air waves.
ps the lcd you're looking at tells you they're transverse
"Einstein showed that energy and mass were related --- so in that sense, light does have inertial mass --- but it it still doesn't have rest mass; so it is indeed affected by gravity."
originally posted by: intrptr
Outstanding layman terms layout. Watching video....
Edit: If gravity travels in 'waves', can one assume that gravity is made of particles like waves of light, water and air? Does that mean they are looking for that 'graviton' (particle)?
Why are they waiting for these 'black hole events' to measure gravitons? Can't we get a close up of intense gravity measurement from our own sun?
Must be expensive to fire this mw laser, how do they know when the waves arrive from some billion year ago event, down to the 'tenth of a second?
Are they firing it continuously hoping they catch some distant merger of black holes, by accident?
originally posted by: intrptr
a reply to: FauxMulder
Thank you Mulder...
after a major upgrade, where LIGO was outfitted with extra-special noise-cancelling headphones, higher-power lasers, and larger mirrors, the Advanced LIGO detectors made their VERY FIRST OBSERVATION of gravitational waves on September 14, 2015, within days of becoming fully operational! This means either LIGO got lucky, or these kinds of events are relatively common.
Ummm hmm, and I am going to strike lotto the first time I buy a ticket. See my point? Something fishy here. Converging back holes are not that common.
What other 'undisclosed' purpose does this contraption have? I bore in on this because to me its seems such a delicate passage of such distant gravity waves would be out shined[/]i by the close source of gravity, our own sun. No...?
It also seems continuous firing of a mw laser is expensive, in the hopes of catching such rare events.
"When the two supermassive black holes [that exist in the center of each galaxy] [after Andromeda-Milky Way galaxys collide 4 billion years from now] come within one light year of each other, they will emit gravitational waves that will radiate orbital energy until they merge completely."
originally posted by: dogstar23
originally posted by: intrptr
a reply to: FauxMulder
Thank you Mulder...
after a major upgrade, where LIGO was outfitted with extra-special noise-cancelling headphones, higher-power lasers, and larger mirrors, the Advanced LIGO detectors made their VERY FIRST OBSERVATION of gravitational waves on September 14, 2015, within days of becoming fully operational! This means either LIGO got lucky, or these kinds of events are relatively common.
Ummm hmm, and I am going to strike lotto the first time I buy a ticket. See my point? Something fishy here. Converging back holes are not that common.
What other 'undisclosed' purpose does this contraption have? I bore in on this because to me its seems such a delicate passage of such distant gravity waves would be out shined by the close source of gravity, our own sun. No...?
It also seems continuous firing of a mw laser is expensive, in the hopes of catching such rare events.
I think the gravity waves of conveging black holes would be coming continuously over a LONG period of time (like cosmic long.)
But then, I'm no astrophysicist, so I I could easily be completely wrong. If it's a a quick burst (even if by "quick" we're talking hundreds, maybe even thousands of years long, then I agree, it might be an awfully fishy smelling scenario.
There is 0 chance of doing that with gravitational waves as far as we can tell. The individual graviton would induce such a negligible influence that it could not be detected one at a time, unlike photons.
Personally, I could imagine it happening only if we found some way of making large amplitude *high frequency* gravitational waves (GHz, THz, +++) so that the individual graviton would be much more energetic, but again, no known technological way to make that happen and no known natural source---i.e. pure magic at this stage.
I watched the same video a few days before your thread and some if it I knew but I didn't realize this part:
originally posted by: FauxMulder
I saw this great video yesterday on the Veritasium channel on YouTube.
The video explains why it's so powerful but then I got to thinking about conservation of energy as in where does this million watts go? Since energy is conserved it can't just vanish, so maybe it's converted into heat in the detection system and maybe they have some kind of cooling system in place to remove all that heat? I tried to search about 10 minutes for an explanation but I kept getting information about the energy from the black holes and not energy from the lasers but if someone happens to know where that million watts goes when they are done with it I'd be interested to know. I know how a car radiator removes heat from the combustion engine and maybe they have some kind of cooling system along those lines but it must be a big one to handle a million watts.
The laser uses 1 megawatt of energy. That's 1 MILLION watts. 1 MW hour can serve about 650 residential homes.
originally posted by: moebius
a reply to: Arbitrageur
I find it disturbing that they confuse power and energy.
Googling a bit shows the actual laser power output of 200W
This answers my question about how they dissipate the energy from 1MW (or 750 kW if that's the correct value and I'm not sure either value is correct), they don't. In this case it's not "smoke and mirrors", just mirrors without the smoke. 200 W or maybe a bit more is all that needs to be dissipated and that doesn't require anything special.
Power Boosted Laser
Length isn't the only design factor important to LIGO's sensitivity; laser power is too. While increasing length increases the interferometer's sensitivity to vibrations, increasing laser power improves the interferometer's resolution. The more laser photons there are moving through each arm and merging at the beam splitter, the sharper the resulting interference pattern becomes in the photodector, which in turn makes it 'easier' to recognize the signature flicker of gravitational waves.
But there's a problem here too. For LIGO to operate at full sensitivity, its laser has to shine at 750 kilowatts. But LIGO's laser enters the interferometer at 200 Watts. And just as it is impossible to build a 1120 km-long interferometer, building a 750 kW laser is also a practical impossibility. So how does LIGO boost the power of its laser 3750 times without actually using more power?
More mirrors! Specifically, "power recycling" mirrors placed between the laser source and the beam splitter. Like the beam splitter, the power recycling mirror is only partly reflective (a 'one-way mirror'). The figure at left shows schematically where such a mirror is located.
In a power recycling mirror, light from the laser passes through the transparent side of the mirror to reach the beam splitter where it is split and directed down the arms of the interferometer. The instrument's alignment ensures that nearly all of the reflected laser light from the arms follows a path back to the recycling mirrors rather than to the photodetector. Laser light coming from the arms is reflected back into the interferometer (hence 'recycling') where those photons add to the ones first entering. This process greatly boosts the power of the beam without needing to generate a 750 kW beam at the outset.