Slashdot Mirror
Gravitational Wave Detection Imminent?
Seumas Hyslop writes "The UK Telegraph is reporting that we may finally have equipment that are sensitive enough to measure gravitational waves, which are incredibly small and have evaded detection despite the theories that they are present as a way of explaining gravitational effects. Basically, a laser beam is split into two branches that are sent down two identical 2000 feet long tubes and back again via mirrors. Assuming the two arms remain exactly the same distance, they will cancel each other out. But the scientists think that the beams will interfere with each other owing to the effect of gravity, meaning the length of the branches is altered and a gravitational wave has been detected."
The word is imminent. immanent means something completely different.
How we know is more important than what we know.
If only it was imminent...it would be so much nicer.
Oh well. Maybe next week.
The gravitational waves! They're all in your mind!
The opinions stated herein do not necessarily represent those of anybody at all. Deal with it.
Bring out your gravity surfboard and roll on!
bash$
For some reason I was expecting a poll involving Cowboyneal to be associated with this story.
i won't even get into it.
anyways, the purpose of the interferometer is to measure the differential gravitational strain between two remote masses. as a gravity wave passes (supposedly), two masses will be driven to oscillate in quadrature with one another. that means that relative to some fixed point, one mass will be drawn closer, and at a right angle another mass will be pushed further away. IIRC.
luckily a michelson interferometer is a great way to detect these small changes, where the remote masses are mirrors. the extremely long beam paths increase the sensitity of the device. and two remote locations are needed for local error cancellation. if you have three locations (there is a LIGO opening in louisiana soon. uh, maybe) then you can actually do gravitiational wave astronomy.
probably some LIGO person will write a better explanation, but it's late.
m
I, for one, welcome our Gravity overlords!
Only the most diehard Slashdot moderators mark this kind of post with a lower score than an AC's FP. Do you dipshits not know what a troll is anymore? Offtopic, redundant, and possibly flamebait, sure - this one embodies those. It is not a troll. Obviously, the moderators are just as literate as the story submitters and editors are.
That sounds like a hellishly sensitive instrument. I wonder how they account for effects from tremors, temperature changes, or even the presence of local masses affecting the equipment.
Or are there webpages explaining the instrument in more detail?
To someone who only has had a year of general physics?
PayPal $$ if you sign up for free offers (eBay, cred cards, e
Gravitational Radiation - the cosmological reference, not the meteorology ones.
Some other gravitational wave detection projects
Some anomalies in gravity theory
and, of course, Einstein@Home
Mongrel News all the news that fits and froths
As I understand it, gravitational waves will compress/expand space along one "arm" of the split laser beam, causing interference when the beams are combined. OK, got that; no problem.
However, as stated in the article, gravitational waves are waves in space-time, not just space. Isn't it possible that the distortion in space and the distortion in time will exactly cancel out, thus rendering the wave indetectible via this method?
Both sites are asking for public help processing the data, via a special screensaver called Einstein@Home.
--Greg
is the first step towards bottling gravity up and selling it. I wonder how the porn industry will utilize this. Will we see gravity powered sex machines, or sex machines that utilize this stored gravity for dildo motion? If either of these are to ever be, their applications are limitless!
Obviously an exaple of Z-Shift at work (in reverse).
Huge litagurgical structures, like those at the Telegraph and Oxford University Press, can move the position of alphabetical characters...
Mongrel News all the news that fits and froths
It's obvious to anyone who's read this site for a while that an admin just burned 20 or 30 of his unlimited mod points to bitch slap all of the "you spelled it wrong" posts. It wasn't regular readers with mod points.
Interferometer? More like Interociter am I RITE or am I RITE?
I have no idea of what you just said, but I agree with you.
LIGO and other gravity detectors have been known about for quite some time. There's no news here. What might be even newer is the idea of using atom matter waves for ultra-precise detection of the same phenomena. This is where the Bose-Einstein condensates and similar things come in.
The interferometric GW detection systems have been under development for quite a while. These include the LIGO project in the US, the GEO in the UK/Germany, and Australia and I believe Japan and Italy have their own versions. LIGO started collecting data a couple of years ago. So now the guys in the UK turned on their instrument.
So what's the big deal?.. Well, there isn't one. Today's instruments are pretty damn bad. I don't remember the numbers, but you'd have to run them for quite a few decades in a row for a good chance to observe one event (it would have to be something big falling into a black hole somewhere relatively close to us, or a major supernova, or something equally rare.) Essentially, you are trying to measure a ludicriously small displacement (10^-16 cm) of a macroscopic object.
The good thing is, technology is continuing to improve, increasing the sensitivity. Furthermore, there's hope (subject to funding) of creating a space-based version of the experiment by bouncing laser beams between three satellites millions of kilometers apart. So is the GW detection imminent?.. Considering the scale and cost of the projects, it better be, but I (being a scientist and all) prefer to steer clear of that word. So provided the funding doesn't get cut, we'll very likely detect gravitational waves in a few years. But be prepared to wait.
For more deets, check out www.ligo.caltech.edu
Don't spout "I'm sure." I don't care if you're sure. Tell me when it actually happens.
I want results, not speculation. What was that about this being science again?
And how many times have we heard this before? Theory X is about to be proven. Then in the weeks, months and years to come, nothing more is heard and the media circus fades out of memory.
And even if this thing detects something, how do we know if it has actually detected what we think it has detected.
I remember hearing a story about some Experimental Physicists a while ago. They were doing some sensitive experiments and kept getting weird results; spent a lot of time trying to figure out what was wrong/checking theory/etc.
What it ended up being, is some Chemists refrigerator three floors up and at the other end of the building. The magnetics were interfering with the Physicists device.
So, who's to say that something similar might happen here. Possibly a passing train? Airplane maybe? If it even detects anything at all.
I'll wait for the real story. But, I'm certainly not going to hold my breath.
unless that headline is fixed.
with a machine like this paving a 4 lane highway at a mile a minute would be a snap!
This story is a few months old, at least back from June or July. There were even pictures, not mentioned in the article, one of which looked vaguely like multicolored magnetoscopic x-rays, although considering my expertise in the field and affinity for spotting pseudoscience and hoaxes, I'd say gravity was the last thing involved in those pictures.
I'm anxiously awating the next wave of 'your mom' jokes that come out of this device.
In that case, they should learn what their own mod points mean. :P
The greatest "your momma is so fat" joke will become a reality.
Who hired ScuttleMonkey? He's certainly no copyeditor, that's for sure. "Immanent" means "existing within". I think he meant to type "Imminent", meaning "soon to be realized".
Between the crackpot science and the bad copyediting, I hope Taco beats him upside the head with a raw ham...
I was on a lecture about gravity waves, once. This guy showed a lot of interesting stuff, like that a best gravity wave emitter is when you place four bodies each on a node of a square, and then squash/unsquash this fictional square. Then a strong wave is emitted in perpendicular direction.
also he said that some folks are trying to detect gravity waves by sending two laser beams through a very long tunnel, they bounce of mirrors and then interfere, so length of their way can be measured with high precision. Exactly like in the summary above.
And guess what? They got totally different results depending if there are clouds up in the sky or not. The beams were attracted to the clouds because of cloud's mass. Of course it means that they couldn't detect any gravity waves from far away - too strong local effects.
He also said that the only possible gravity wave detector should be placed in the space on lagrangian point.
#
#\ @ ? Colonize Mars
#
The parent post is simply wrong.
The detection rate for instruments such as LIGO is estimated to be much higher, around several per year. Certain rare events, such as supernovae, will be detected very infrequently, if at all. More common sources of gravitational waves, such as inspirals (basically one object inspiraling into another object, presumably a massive black hole) are expected to be very common. In fact, there is even an established "confusion limit"---the point at which the background gravitational wave noise from the countless inspirals occuring at any given time obscures any isolated signal. Anyway, the point is that the event rate is supposed to be about 1-10 per year, which isn't anywhere near what the parent suggested.
The parents also mentions a space-based version of this experiment, called LISA (Laser Interferometer Space Antenna). I worked with some of the people at JPL and Caltech working on LISA. LISA would be great, since it could measure very small displacements without having to deal with the seismic noise of the earth. However, try keeping your three spacecraft in formation to the 10^-16 cm level. That's, uh, hard.
Ok sounds nice and all, but heres some food for thought. In order for this to work you need both 2000ft arms to be the same EXACT length. If they are not EXACT then the whole thing wont work, but in that case how will you know? Or even better when they are making it, how do they know the gravity waves arent throwing off their measurements before its even built!
Taco: GRaaaaaaviton waves off the forehead!!!
ScuttleMonkey: OWOWWOOWWWW
Virginia Ham as a LART. I love it.
Soko
"Depression is merely anger without enthusiasm." - Anonymous
How do you guarantee that the two tubes are identical in length to begin with? If I would imagine that even the slightest difference will be a problem. Is there some form of callibration ?
In Soviet Russia gravitational waves measure YOU.
I've been listening to the Feynman Lectures on Physics on my ipod while working out at the gym. There's dozens of 50min lectures (each lecture is a nice 600+ calorie workout on the Precore machine). I've only taken introductory Physics but I've found I can understand quite a bit of what he's saying. It's kind of like speed reading a book.
Anyway, in the Special Theory of Relativity lecture (or maybe it was The Theory of Gravitation, not sure) he of course talks about how matter and energy are "two sides of the same coin" but it really resonated with me that when we talk about matter we're also talking about gravity since gravity is just a consequence of mass. So when you fly that super-spaceship at nearly the speed of light you become heavier but you're gravitational effect is accordingly stronger. It's important to understand phenomenon that seem totally unrelated but are actually the same thing. The effects of them are just measured in different ways. So one could say energy and matter and gravity are the same "thing".
(with props to Mickleson and Morley)
Jack
"It may just be that there is something fundamentally unworkable about government itself" -H. Beam Piper
I heard they only wanted 10^-12 m (picometer) resolution. And they aren't planning on keeping them fixed at that relative distance; that's impossible without breaking the experiment (if you don't know why, then you don't understand the experiment). The probes are going to be moving at a speed of order meters/second relative to each other. In any case, they don't have to keep the distance fixed so long as they keep track of where the probes are wrt each other. The engineers claim that the optics is the "easy part" (a friend of mine is working on one of the "hard parts"), though it seems anything but easy to me.
...
Also, keep in mind that our wonderful politicians want to build a wind farm next to Hanford since "there's nothing there anyway"
It sounds as if the system is set up to detect gravity waves by detecting microscopic changes in the distances between two mirrors and a third object. Yes?
Aren't there be lots of things that could cause a microscopic motion of one of the mirrors? (Sound? Seismic activity? Changes in temperature? The ground settling underneath the structure that supports a mirror?) How do you construct the apparatus to make sure that either (a) the mirrors move only if affected by a gravity wave, or (b) any motion due to another cause is clearly distinguishable?
Wouldn't that make the Moon the perfect place to set up a detector?
:-)
Vacuum at no cost, no tectonics(?)
I'm not considering travel expenses and room and board...
Thnaks to all teh braev suols who wer willign to bern kamra to piont out teh diferense btween "immanent" and "imminent". Othrewise we all wuold haev to RFTA and haev a maeningful dicsussion. Tihs is Slasdhot, and we ca'nt haev taht heer! (Stewpid atricles!)
What if some hungry and / or amorous rabbits are enjoying the beets near the pipes?
Seismic activity?
Temperature changes?
Planes flying overhead? (sound)
I am not sure how they can remove all this tiny tremors and vibrations and details from their detection equipment. I wish they would publish a 'how it works' that deals with stuff like that. It will be on my mind all day now.
please type the word in this image: buffets
random letters - if you are visually impaired, please email us at pater@slashdot.org
#hostfile 0.0.0.0 primidi.com 0.0.0.0 www.primidi.com 0.0.0.0 radio.weblogs.com
Actually thats just me. SLAINTÉ!
LISA satellites need to be stable to within 1 nm per root Hz of bandwidth. (It's been a while since I worked on it, so someone else is welcome to explain what exactly this means.) Suffice it to say that this is a tractable problem, and I would argue no more difficult than the Advanced LIGO designs currently being implemented. And you get more bang for the buck in sensitivity.
Please show me a good reference for LIGO expected detection rates. This is taken from a popular book, but the numbers agree with what I remember hearing from those working on LIGO.
Supernova (within our galaxy)
1 to 3 per century
Black Hole/Black Hole Merger (300 million light-years)
1 per 1,000 years to 1 per year
Neutron Star/Neutron Star Merger (60 million light-years)
1 per 10,000 years to 10 per century
Neutron Star/Black Hole Merger (130 million light-years)
1 per 10,000 years to 10 per century
Source: Einstein's Unfinished Symphony: Listening to the Sounds of Space-Time by Marcia Bartusiak
Oh yeah, the detection rates are given for LIGO I. LIGO II should improve the numbers dramatically. Which was my point in the original post.
immanent means something completely different.
So, is it right to say: "..And now time for immanent!"
doh, drop it, it's not funny that way.
I can think of a ton of other things that would affect such a test...
What about vibrations in the ground? 4000ft of tubing and NO vibrations? Unless the tubes were also a perfect vaccuum, the resulting pressure waves in the tubes would diffract the laser beams slightly and cause variation. (believe me, I worked for a company that makes laser imaging devices).
Ok... now heat/cold? The length of the tubes, the positioning of the mirrors, deforming of the mirrors, etc. will be affected by this. Over 2000 ft, it doesn't take much of a change to have noticable influence.
I think you'd have a very sensitive instrument, that would measure 200 different factors at the same time - how do you tell whats gravity and whats not?
MacCow
I used to have a sig, but I set it free and it never came back.
One thing that I always wondered about with this is whether or not the gravity waves are also affecting time space. If so then the speed of light could also be affected by the wave making detection rather difficult.
What I'm thinking is the following, We all know the speed of light is constant for a material (or vacuum). From our frame of reference we will not notice the distortion in spacetime. Our yardstick will shorten and lengthen with the compression and expansion of the waves. which would make it impossible to detect the changes. Of course, I'm probably just not knowledgeable enough to know what's going on here, but then again. I'm curious to see if this idea has been addressed.
If no one has thought of this idea yet, I just did and I claim it! :)
"The bass, the rock, the mic, the treble. I like my coffee black, just like my metal" - Mindless Self Indulgence
I've been looking for the Feynman lectures on physics for a while. Where did you get them from?
when do we get our impeller drives & Warchowski sails?
-- The Heineken Uncertainty Principle: You can never be sure how many bears you had last night.
Hell with that. How to they account for a change of exactly X wavelengths? if the length change is exactly on a wavelength it will look identical to no change. That is unless they are encoding data to the laser beam but I highly doubt that we have the capability to modulate data onto the standing wave of the laser light so that a single cycle of light would have data on it. Last I knew from fiberoptic technology we have been using Lasers in a CW on off on off primitive way.
so if a gravity wave comes along and changes the length of the detector by exactly 1 wavelength nothing will be detected.
Hundreds of scientists spend millions of dollars of money on an incredibly expensive
8 6.htm
method of detecting gravity waves when cheap ones somehow already exist.
Build your own gravity wave detector:
http://www.rexresearch.com/hodorhys/remag86/remag
Non sequitur: Your facts are uncoordinated.
If you can detect the passing Gravitational Wave then does this mean it has done work? If so then the waves should attenuate.
So in what form is the energy of a Gravitational Wave? With EM the energy travels in the form of a photon. Does this mean if we detect a gravitational wave that we have detected a graviton?
If so is it quantized? Also does this mean that somehow the graviton interacts with other mater? Wouldn't this unify gravitation into the EM force?
Well - I don't know enough physics to answer but I suspect that gravitational energy might actually be continuous.
However the mechanizm by which gravitational energy (which should have mass because E=MC^2 - except they are thinking "rest" mass and the rest mass may be zero) gets transfered from the gravitational wave into whatever it gets transfered into may have a consequence. If we have a pair of spinning black holes for instance then this may be a way for them to leak energy and thus they might slowly evaporate.
I seem to recall reading that NASA had sent up a bunch of satellites bearing very sensative equipment that were supposed to detect gravitational waves, though I don't think they were using this method of detection. Does anyone know what happened with that experiment? Do they have the results yet?
At any rate, I think I read about it on slashdot, so I suppose I could just wait a few months for a dupe.
Ok, so are these gravitational "waves" real or just a construct to explain gravity?
Essentially the trigger for this question is the whole sound/EM difference. EM is acutally the emission of "stuff" whilst sound is the propogation of energy through a medium and without the medium there is no sound just the vibration of the original source.
It's been a long time since I read any theoretical physics and so my head hurts a little when I think about this stuff, but the "dents in space time caused by mass as balls on a rubber film" metaphor help explain the "pull" of gravity really quite nicely, if it is even remotely true. But that model suggests a "medium" through which gravity acts.
"The first thing to do when you find yourself in a hole is stop digging."
The other replies are mostly right: you use more than one detector so you can look for a signal in both of them...
/.ers)
then you have the fact that the signal you look for has a very well known shape (it can be calculated in our teoretical framework)
you also expect to observe it toghether with other (indipendent) signatures:
a supernova for example would be observed by all astrophisics experiments sensitive to light (common visible light telescopes, radio/gamma telescopes) and by most of the neutrino experiments around (this is no sci-fi neutrino telescopes already "saw" a supernova a few years ago)
and finally every piece interferometer apparatus is contained in a vacuum tank and suspended at the end of many pendules designed in such a way that it is as decoupled as possible from external vibrations (bunnies humping, trains, earthqakes, everything mentioned by the other
So, the device sensitive enough to measure it consists of a laser doohicky and some 2000 ft tubes?
And people still wonder how nano-technology could be usefull...
"I used to have that really cool,funny sig
I'm so happy for the GEO600 crew if they are in fact getting close! I've actually seen the facility - pretty amazing stuff and a very good example of how far you can push things using much brain and relatively little dollar. For example, the article didn't mention this but the arms of the interferometer do not intersect at quite 90deg due to the fact that the arms are built along the borders of farm plots.. As for filtering out noise, they filter out everything above and below particular frequencies. It's all extremely sensitive work and I'm glad somebody else is doing it!
My hat's off to anybody in this business, they must have a lot of time and money and patience!
Ok, it has been decades now, and gravity waves seem to be just like dark matter - just so much phlogiston. I think or theories of gravity are way off. Nothing can move faster than light said einstein, except, says I, gravity, because gravity is actually geometry and hence everywhere instantly. No waves.
isnt it spelt?
If your neighbours roof is flying past your window, you know it's cyclone season.
>>BTW, whenever you here someone speaking of physics and using feets, you should doubt that s/he knows anything about the subject.
>>
As an engingeer, there's nothing I hate more than working with averdupois/English units, but it happens frequently, even with "physics" type problems. Ballistics, statics/dynamics, radiation... Ugh.
An amusing aside is that the USA officially adopted the metric system in 1893...and then we used it to better define the foot, the pound, etc. *sigh*
A preposition is a terrible thing to end a sentence with.
 "...and because, in all the Universe, they found nothing more precious than Mind..."
please type the word in this image:creature
You know it makes sense.
I feel the detection of these gravity waves pulling me closer to the answer. It was a slight tug at first when I first learned about gravity. It steadily grew stronger as I learned more. Now, the pull is so strong, I wonder if I could escape discovering these waves if I tried. It would take an enormous amount of effort to leave this research.
he has a very good point here. what if , in order to detect the gravity wave, you need two referencial systems??
IANAP, but I like to read books on science, esp. physics, astronomy, cosmology, evolutionary biology, etc. Some people read cheapie novels, I'll read the latest thing from Kaku, Green, Dawkins, Darling, etc. Not that they are necessarily the best books on any given subject at any given time, but for the most part they are fairly accurate. It seems that in string theory gravity is solved in higher dimensions, but the instruments to test that are some time off from development, and so, in terms of testability, we're stuck where we've always been - somewhere between Einstein (relativity) and Bohr (quantum theory). And while everything in terms of matter seems to favour Quantum theory, Relativity is still on top of gravity, as we have yet to find a gravity wave or even a graviton. Therefore, IMHO, we have to come to ask an interesting question: What If Quantum Theory Simply Doesn't Work With Gravity? String Theory might have an explanation, but we're a long way off from being able to test String Theory's ideas about gravity, and (most importantly) a failure of Quantum Physics on Gravity is not necessarily an indication of String Theory's notions. So, if it this test fails (like all the other Gravity Wave Detectors has) when will scientists give up and figure out a new understanding of gravity? This test seems like a good one, so what will happen if it fails? And furthermore, given its expense, how can it be repeatable outside of its own instrumentation? I'm not being a troll - just asking honest questions and trying to get a better conversation in this article beyond a bunch of juvenile carping about spelling errors. RS
Shoes for Industry. Shoes for the Dead.
Not offtopic, funny... whether or not it's intentional, really.
... a gravitational wave generator patented by the NSA. I guess reverse engineering all those UFOs paid off.
[ObDisclaimerForTheClueless: No, I don't really believe they reverse engineered UFOs. The patent's real though. Who knows, it might even work.]
Human/Ranger/Zangband
2000 feet long tubes
:-)
So I guess we're not going to see a portable one any time soon.
Coder's Stone: The programming language quick ref for iPad
Is it gravity waves, or a construction truck going by?
I remember that a similar experiment was done before Einstein's Theory of Relativity to determine the speed of light with respect to earth. It was called the Michelson-Morley Experiment.
The results were null. There was no noticeable fringe shift.
No need for fancy experiments. My wife detected a gravity wave using our car recently. One minute she was driving along minding her own business, next minute she was in a ditch after a rogue wave shifted the entire road out from under her.
Anyway, that's her story and she's sticking to it.
UNIX: 'cuz you can tattoo it on your knuckles!
I see a few posts saying, "Well, we haven't seen gravitational waves yet, so maybe they don't exist." To that, I have several responses:
1. There's no reason why we should have seen them yet; they're so weak that even LIGO I probably won't see them. (LIGO II probably will, if the equipment works as designed.)
2. Gravitational waves have already been detected indirectly: the 1993 Nobel Prize was awarded to Taylor and Hulse for this discovery. They observed a binary star system whose orbits were inspiralling at exactly the rate that general relativity predicts for a binary system that is losing energy via gravitational waves. That rate also gives the rate at which energy is leaving the system, and allowed them to infer the speed of gravitational waves: the speed of light, to within a few percent --- also as predicted by general relativity.
3. Even if general relativity in particular is wrong, pretty much any field theory compatible with special relativity contains wave solutions propagating at the speed of light, for demonstrable reasons of logical consistency. This holds for both classical and quantum theories (e.g. Maxwell's equations, general relativity, the Standard Model of particle physics, etc.), theories of quantum gravity like string theory, and so on. You basically have to throw out all of relativity and go back to Newtonian physics to get field theories without wave solutions.
IANAP (I am not a physicist) but it seems to me that the detection of an event is *relatively* pedestrian.
Sorting through the 'noise'and proving it was a gravitational wave that caused the movement seems to be the big trick. I expect that several budding young physicists who aren't even in college yet will have their PhDs before anything detected is conclusively PROVEN to be a gravity wave.
But hey: long-term experiments, indeterminate results, and long spans of analysis are what keeps the grant money flowing, right?
-Styopa
Yo Mamma so fat, the LIGO Gravitational Wave detection project uses her for calibration tests.
Some how geek Yo Mamma jokes are lacking I think.
Just as a point of information: mathematicians have defined "immanent" to be a certain generalization of the determinant (of a matrix).
http://planetmath.org/encyclopedia/Immanent.html
I've always thought it would make more sense to take a long steel pipe, entomb it in concrete and lead, and attach a highly sensitive and highly isolated pico-volt range voltmeter to either end. By my calculation, if a 500 ft pipe was thus situated in a vertical position, the earth's gravity would create a > 4,000 picovolt potential from end to end. I don't know what the limits of our voltage testing ability are, but if we can get precise enough, it seems to me that that's a more reliable (and more directional) way to detect gravity waves.
It also seems obvious that once we figure out how to detect the most infintesimal gravity waves (such as waves that we can also transmit), electromagnetic waves will start to become obsolete. Satellites-based communication will immediately become obsolete, because the same thing can be done cheaper with gravity waves, and without the satellite-induced delay, as gravity waves can take the direct path through the earth undisturbed (and, I suspect, faster than light).
If it is possible for gravity wave communication to replace EM wave communication, then it will. And if it does, then the EM communicating phase of humanity was a microscopic flash in the pan, and by extrapolation will probably be flashes in the pans in any extraterrestrial technological histories. Thus, I have long suspected that searching the skys for alien EM signals is probably pointless, but if the day comes that we can "hear" transmitted gravity waves, we will have plenty to listen to.
Will you armchair physicists just shut up and let the professionals do their job? Sheesh, get back to coding - that's what you get paid for, right??
I'm surprised I didn't see any references to this: http://www.cheniere.org/misc/index.html /.
I was so certain that there were more conspiracy theorists who frequent
According to Tom Bearden (physicist and retired Army Lt. Col.), the Soviets weaponized the artificial generation of gravitational waves in the mid-'70's and have been using it since then to screw with the weather. He wrote a book about it, about which you can find the details starting here:
http://www.cheniere.org/books/ferdelance/s1.htm
This article got me thinking:
If you can detect a gravity wave then doesn't that mean that some energy is being absorbed from it?
If energy can be absorbed from it, then doesn't it get weaker?
So if a gravity wave can be made weaker, then couldn't you theoretically build a gravity shield?
And if you scaled one up, could I stand on it and float off of the earth?
It doesn't seem right, so where am I going astray? Thanks Physicists!
...then it behooves them to offer alternative explanations for their results. "In experimental philosophy we are to look upon propositions iffered by general induction from the phenomena as accurately as or very nearly true, notwithstanding any contrary hypotheses that may be imagined, till such time as other phenomena occur, by which they may either be made more accurate or liable to exception." -- Isaac Newton, Rule IV of "Rules of Hypothesizing", in Mathematical Principles of Natural Philosophy (1687).
The experimental design is that of the Michealson-Morley experiments. That hypothesis still stands (ie. they failed to reject the null hypothesis, a very different thing than supporting the alternative hypothesis, and the beast of proving the null hypothesis is imaginary). If they get results, it'll be on them to show the effect is due to something other than that which has so far been unable to be detected but previously theorized and hypothesized as causing the same effect they expect to find.
Still awaiting the technology capable of testing it is the hypothesis that ether flows along the lines of a gravitational field, and so must be tested simultaneously parallel and perpendicular to gravity. Getting a vertical structure big enough but stable enough to do this is far harder than getting two perpendiculars.
Keep in mind that in science "out of favor" and "disproven" are not the same, but in peoples minds they are taken as such. Read "The Golem" by Collins & Pinch for many entertaining examples, including the M/M experiments.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
Gravitational Wave Detection Imminent? Well yea, remember Gravity Probe B? Finished collecting data a couple weeks ago after 40+ years in the making? I think /. even mentioned it. :shrug:
Do what thou wilt shall be the whole of the Law.
Everything -- that has mass and that moves -- generates a ripple in gravity. You do it, your mom does it, too. Heck, so does any movement of Earth (e.g., techtonic plate movement, oceanic changes due to El Nino, etc).
Straight line motion and spin will not produce gravitational waves. More complicated motion is required. The quadropole moment (or higher moment) must be changing in time.
IAAP
Does the fact that gravity (wave or whatever) exceeds the speed of light pose a problem?
h tml
http://www.ldolphin.org/vanFlandern/gravityspeed.
This brings up a favourite old argument of mine: Isn't the moon perfect for all sorts of interesting, first step in space things that humans would like to do? It's right next door, it's 80% of the energy distance to just about everywhere else in the solar system, and it contains a lot of it's own raw materials. Additionally, it'd be a great platform for observation of earth phenomena. wtf do we want w/ mars right away? 6 months travel, yeesh. phooey on it.
I'm on pins and needles here. I'm wondering if gravitational waves will be complicated enough to require
an application of the new theory of intelligent design.
A small point: both LIGO and GEO detectors have been turned on, as it were, for several years, and have participated in joint data runs previously to gather coincident scientific data. The difference this time is that the science run is 18 months (I believe) as opposed to ~1 month.
I'm sorry I wasn't clear.
I was merely answering your question about why spelling mistakes are different if a computer is reading than if a human is reading.
I know that you meant it as a rhetorical question, but I though that my answer was clear enough.
Apparently you didn't understand that seeing the difference in the effects of spelling mistakes is not the same as liking misspellings.
This isn't really meant to be as sarcastic as it reads to me, but I couldn't see a nicer way of saying it. Maybe I should just have ignored your misunderstanding, but I have a hard time ignoring people when they don't seem to understand me.
Exam 4/C again. Maybe I'll do better this time.