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Frame Dragging by Earth Reconfirmed
smooth wombat writes "After 11 years of watching the movements of two Earth-orbiting satellites, researchers found each is dragged by about 6 feet (2 meters) every year because the very fabric of space is twisted by our whirling world.
The results, announced today, are much more precise than preliminary findings published by the same group in the late 1990s.
The researchers say their result is 99 percent of the predicted drag, with an error of up to 10 percent. The details are reported in the Oct. 21 issue of the journal Nature."
...to change from 'theory' it to The Laws Of Relativity?
If backward time travel is possible, it does not seem it would have any adverse effects. Physics does not care about your lineage. Assuming you shot your ancestor, the bullet would not mystically stop and the particles that make up your body would not mystically disappear.
It does not matter that you would not be born to go back in time. Physics does not care about you as a being. If your particles exist in a certain configuration at a certain time in the past, it does not matter that the original cause no longer exists. Physics does not care about timelines. It only cares about the instant immediately preceding the event. Only people care about unbroken chains of cause and effect, not physics.
All the confusion comes from people creating paradoxes by ignoring deterministic physics laws and imposing stupid irrelevancies.
What are you looking for? There's no such thing as "certain." In fact, this result is excellent--with 10% error bars, I'd be ecstatic to agree with predictions within 1%.
99% +/- 10% is far better than 99.9% +/- .01%
I already stated that. Physics is deterministic. It does not care about nice, logical, unbroken chains of cause and effect. All it cares about is taking the snapshot at one instant to transform it into the snapshot at the next instant.
Most theories with paradoxes are based on the idea that the universe will suddenly act strangely because it somehow notices there is no longer a cause for the particles to be in the place where they are now. Again, the universe does not care about cause, it's mechanistic (and a bit probablistic, but this doesn't harm my argument) and only does its job.
In a computer analogy, assume you have a computer in which one process starts another. You can travel back in time, and you flip the bits to make the child program execute at an earlier time. It terminates the parent program before the program is called. The child program doesn't suddenly stop. The computer, being mechanistic, does not care that it no longer has a cause.
In contrast to human laws, which just 'become' without any evidence in their favor (and then presented as absolute truths).
Yes, I've always known that mother nature is far better at creating sensible & logical constructs (and enforcing them)...
Disclaimer: i'm only the brother of an astrophysicist, and don't know much outside of what he's told me.
The idea of independent frames of reference only holds for velocity. Rotation of an object involves acceleration towards the center of that object. Each point on a rotating circle moves tangentially to the circle, but that velocity is changed (accelerated) as it goes, because the tangent to the circle is different at each point it moves through. Thus, there is no rotating frame of reference for the earth.
To test this idea in simpler terms: if you're in a zero gravity environment, and you're spinning, what happens when you pull your arms in? You start spinning faster, right (conservation of angular momentum and all that)? Well, if instead, you're stationary and the thing you're in starts spinning, what happens when you pull your arms in? Nothing! It's the rotating thing, not you, thus you have no angular momentum to conserve. If rotation was just another frame of reference, then to be consitant, when you pulled your arms in, the same thing would have to happen: the relative rotational speed would have to increase.
Incidentally, that's also why we can definitely say that we orbit the sun, not the other way around.
I hope that clears that up.
b.c
additionally, the moon and Sol's gravity would most likely be the second two things to be factored in, and cause perturbations far greater than 6 feet.
and the atmosphere and a few other more minor effects are what the Gravity Probe B people are critical of. However, it seems that the orbit of LAGEOS II is at 5,782 kilometers, according to NASA Spacelink at that altitude, the amount of atmospheric drag is greatly overcome by many other effects such as the radiation of the sun, which pushes the satelite slightly, the same way some people have speculated for years that we could use that same solar radiation to travel to other planets, using a solar sail.
My guess is that they would have checked most of the sources of error which you listed before going to press.
In the future, we will all be very smart or very stupid.
99% +/- 10% is far better than 99.9% +/- .01%
Not at all. That +/- 10% is there for a reason. The margin of error is just that--a margin within which error could have occurred. The true value could easily have been 92% or 105% the predicted value, but the error caused it to become closer to what was expected. I'd be more interested in the latter example, as deviations that small usually indicate that we're on the right path with minor reworking.
No comment.
Your question is a good one, but it has no answer. I'd like to explain why. It's a matter of philosophy.
You see, science (especially in popular consciousness) is seen as the discipline which endeavors to answer the question "why?" with respect to various observable phenomena. These questions have been at the center of human thought for well, ever. We created religion in its various forms to answer this very class of questions.
With the advent of science, it seemed as though we finally had a way to truly answer these questions, but unfortunately this stems from a fundamental misunderstanding of what science is. Science does not try to answer nor can it answer the why. The why has no answer.
Let me explain. Science (and specifically the scientific method) is designed to determine, through experiment and falsifiability of hypothesis, the way the world behaves and to model its behaviour. Because these theories often have far reaching consequences, laymen (and even scientists, unfortunately) often make the mistake of thinking that their theories explain the why. But they do not; they simply explain the how.
Let's explore this a bit. Newton's law of gravity did not explain why gravity exists. Why two bodies fall together is anyone's guess -- why, as a question, demands a reason. There may very well be a reason that two bodies fall together -- a popularly believed one is that some supernatural being designed it that way -- but physics does not, indeed, cannot, conjure up a reason by simply observing and modeling the way those two objects fall together.
An example of this in more human terms: suppose you have a batty friend, and everytime you say foo, he says bar, like clockwork. You would quickly observe this and would, in your mind, be able to construct a hypothesis based on this behaviour -- when the subject hears foo, he says bar. And you could construct a series of experiments that test this hypothesis -- perhaps you would find that in the presence of blondes, he utters baz instead. This knowledge would allow you to predict his behaviour in certain situations, but it would say nothing whatsoever about his reasons for it. Nor could any amount of observation ever explain the reasons.
Now, in physics this is obfuscated by the discipline's drive to isolate core phenomena. That is, it has been noted that often phenomena we observe are caused by smaller, less obvious phenomena. So, for example, attempts to make gravity fit into quantum mechanics have driven physicists to suggest that gravity as a force is mediated by a graviton, or what not. If this were ever demonstrated by experiment and became widely accepted, a laymen might ask, "why does gravity behave the way it does?" and a physicist might explain that it has to do with property xyz of gravitons. But this is not an explanation.
This is simply telling the listener that the macroscopic observable phenomenon of gravity is actually made up of several, less easily observable phenomena. This is all well and good, but you'll notice that it actually explains "how" gravity works. "Why does my house keep out the rain?" "Because it has a roof." It seems logical, but it isn't. Because the roof is how it keeps out the rain -- the reason it keeps out the rain is something much more subtle, like, "Because the designers felt that the house's inhabitants would rather not get wet."
Science answers the how of things, and it does this exceedingly well. It cannot (and for the most part, does not even attempt) to answer the why. But why and how are so muddled in the way people think that lots of folks (scientists included) are deluded into thinking that science will eventually explain the big questions like "why does the universe exist", and "why are we here."
If you've ever asked a scientist the latter question, you may have gotten something along the lines of "We're here as a result of abiogenisis, followed by billions of years of evolution, catelysed by Darwinian na
Then while you have a theory that has not been disproved, Ockhams Razor advises us to use the simplest one that explains all the data, and that's not yours.
You make an excellent point here, but not the one you think you do. Ockham's Razor, as you point out, advises us. It says that the least complicated explanation for observed behaviour is probably the correct one. It does not say that it is definately correct. It simply allows us to predict which of several explanations is most likely to be correct based on our past experience that things are usually simpler rather than more complicated. Ockham's Razor, four thousand years ago, would have had us believe that the stars were little point-sources of light floating just above the clouds. Certainly that was a more simple explanation of our observations than the idea that they were huge self-sustaining fusion reactions happening thousands of light-years across a limitless universe.
~Benjamin
As a long time science buff I'm pretty well read on the various "big" theories out there relating to how the universe works. Your explanation is a good one, and tends to follow the standard space-time is a fabric, blah, blah, blah. But the things that annoy me most about modern concepts are the big ambiguities that result of some simple explanations. For example, take the concept of the "stretching" of space-time. If we up all the dimensions by 1, going from a flat sheet to a volume. We would expect that the word "stretching" doesn't fit very well. We alrady have 3 dimensions of space and 1 of time. So basically what stetching means in 3 dimensional terms is "densities" of space. More precisely we find that when large masses are placed in a space-time fabric (volume) the space around it gets more dense. If space is more "dense" around large masses then that means there is "more space" within a given volume. But what volume? Gravity waves would be seen as simply variaitions in the densities of space-time.
This all seems very strange until you read up on some of the modern concepts of vacum physics. Space is not seen as being emtpy at all. Space is actually something. Where matter within space is simply some strange configuration of whatever space is. This is sort of like ice in water, where water can be viewed as space, and ice is the matter within it. If this is true, as in the way things actually work, then everything that exists is really just one thing...the stuff that space is made of. Apparently though, this "stuff" is non-continuous, becuase how can you stretch it otherwise? It seems to have a finiteness so that, like air pressure, it gets more dense the closer you get to a massive object. In my view, the Bekenstein bound, a model for the granularity of quantum events, seems to be linked to the finiteness of space-time. The Bekenstein bound proposes that any given volume of space can only have a finite number of states. This brings about the model of a computer screen where you only have a certain number of pixels within a given area. To expand further, based on the Bekenstien bound, it would be only possible to have a finite number of physical manifestations (objects) within a given volume of space-time. In the same way, you can only have a limited number of possible pictures viewable on a computer screen within a given resolution.
Does the universe actually work this way? If it does, then this suggests the possiblity that the volume of the entire universe is a large finite state machine. Within the lifetime of the universe, the machine is working out all the possible logical permutations of reality as time progresses. What we don't know is: Is the volume of the entire universe infinite? What would be the end result of the permutations?
The contrary argument would be that space-time could actually be continuous, but that there only exists so-called quantum interfaces at a certain level. Below the level of the interfaces, we cannot know about any of the other features of space-time. The interfaces block further exploration into space-time because our measuring devices only operate at the level of the interfaces. This model is very much like working with Legos(TM). Legos blocks are finite, and they allow you to build large numbers of possible devices (objects) within a given volume of space. But Legos can only interact at the connection level. Where there are no connections, Legos cannot be known.
The more I read, the more I'm finding that modern science is telling the above story over and over again as we come to understand things better. Do you guys read the same picture, or am I just reading the wrong books?
+1
Your example with the sheet of paper presupposes an outside force that causes the objects on the paper to slide towards the depression. To wit, um, gravity.
Without the force of gravity all the objects would remain where they were, regardless of the deformation of the paper. They wouldn't even stay on the paper, they would just float.
I know there's real, valid science behind relativity. I just would like to request a better metaphor. Or a better explanation. Or maybe just a turkey sandwich.
That is all
-tom
It breaks my pluginses, my precious!
That's two meters, of course, but you're right. On the other hand, it may be that the distance dragged is known more accurately than that but that the prediction is only accurate to 10%. But, I doubt it. (I haven't read the FA.)
The entire universe can be explained by the obvious 'That's the way it is.', but not the simpliest explanation at all, it's just the laziest one.
If corporations are people, aren't stockholders guilty of slavery?
I don't know... there's nothing silly, on the face of it, about unicorns. Why shouldn't there have been a horse with one horn at some point in time? It, like many other things, might just be extinct. Anyway, stranger creatures have walked this earth.
As for the Jessie Jackson bit, that truly is silly. But I think it's a different issue than the existance or non-existance of God, because your scenario serves no purpose. Don't you ever wonder why the universe exists? It all seems so perfect. I see the existance of benevolent white bearded super-being as the willfull creator of the universe as a bit of a stretch, granted. But I guess if someone were able to offer evidence that the universe had been somehow engineered, I wouldn't really be surprised. But I would just replace my "why does the universe exist" question with "why does God exist", which is equivalent. It's the whole "Unmoved mover" thing. My human belief in causality makes me wonder why things are, and anything which exists for no reason confuses me.
To me, "the universe exists for no reason" and "God created the universe for a reason, but God exists for no reason" are equivalently frustrating belief systems.
But I'll stay open-minded. I just wanted to underscore that I'm not against the notion of God in principle. I just don't think it's supportable.
A better analogy on how curved space can seem like a force is to look at two ships, both some distance apart at the equator heading north. For the sake of this argument, assume the Earth is totally cloud covered, and those on the surface are not aware of anything off of the surface.
The captains will see that their initial motion is parallel. They are both going in a straight line, along a longitude line, heading for the North Pole. On the surface of a sphere, as on any curved ( or uncurved) space, a straight line is defined as the shortest distance between two points. As the two ships head north, the captains will notice that they are getting closer to each other; finally colliding at the Pole.
After scratching their heads to figure out what happened, the will conclude that there was some force drawing the two ships together. From "outside" we can see that the collision was caused by the curvature of their space, but those whose motion, and vision is confined to the surface of a sphere, will give this force a name. Perhaps "gravity."
Maybe 'fried' instead?
No amount of precision will _prove_ the correctness of a theory. It will _support_, but not prove.
Theory - All pigeons are grey.
No number of grey pigeons can prove that theory true as if after that number of grey pigeons has been found an albino one is seen, then the theory is disproved.
Anything which can be later disproved can not have previously be said to be proved.
FP.
Also FatPhil on SoylentNews, id 863