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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."
derr... my brain thought "what? frame dragging? story about networks or something?"
-You're wasting your time. Alfador only likes me.
What one of the recent satelites was sent up to do?
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
The researchers say their result is 99 percent of the predicted drag, with an error of up to 10 percent
I think my head just exploded
....I can't find the @!#% TV remote. Time to diet, I guess.
Table-ized A.I.
I was under the impression that there has been experimental evidence for the existence of Spin Distortions in Lense Thirring effect?
This would mean that inward spiralling matter observed near black-hole like phenomenon were indeed valid physically.
But as the Nature article points out, the accuracy of Ciufolini's work not yet certain, since the value is not absolutely the same as that predicted by relativity (only 99%, with an error of upto 10%). And anyway, the last major prediction of GR -- gravity waves -- is not yet done.
So until then, three cheers for experimental physics!
Hmmm... I read this earlier because CNN jumped on it, but there are questions (noted in the Nature article) about its actual accuracy. There's some concern that the original gravity field maps that this method used weren't accurate enough.
This is a good step forward, but I think until we call the frame dragging prediction confirmed we should wait to see what Gravity Probe B comes up with.
Alito: A vote for Alito is a punch in the eye to put that bitch back in her place!
...to change from 'theory' it to The Laws Of Relativity?
The original linked article IS CNN's writeup. Read the Nature article. CNN may have beat them to the punch, but there's some question as to the accuracy of these findings that CNN conveniently didn't mention.
Alito: A vote for Alito is a punch in the eye to put that bitch back in her place!
Comment removed based on user account deletion
Read up the history of this project sometime. This is the longest running single project in the history of the federal government, it took like 50 years to complete because they kept getting stalled and most of the work was being done by grad students. In order to do this experiment they had to build what are, more likely than not, the two most perfectly round objects in the entire universe and then spinning them really really really quickly in a vacuum in outer space.
Crazy shit.
You're thinking of NASA's Gravity Probe B. That one isn't finished yet.
Tysons Equation explains this:
ch/(c - ke^n)
Where c is speed of light, of course, h is a coefficient representing the fabric and this is a quotient where k is a coefficient to the constant e (~ 2.7) and raised to n which is a variable for mass or changing objects in space.
Sanders developed a corollary for this saying:
f-r/e^d
where f is the temperature in space in farenheight and r is the change, divided by e, again, to the d, which is similar to n, but loses its delta value.
It's a lot to grasp if you don't know physics well, but what they say is that objects do indeed get entangled in the fabric of space time and move, due to gravity. Neat stuff...really. Hehehe.
"If you are a dreamer, a wisher, a liar, A hope-er, a pray-er, a magic bean buyer
"lol.. kind of sad really.
Read this hours ago on CNN, doesn't seem too interesting yet."
Where did you think the submitter got the story, you insentive clod!
This idea of this drag was originally proposed by Einstein. Almost fifty years ago, the idea of how to experimentally verify this effect was proposed; however, it required the launch of a very accurate gyroscope. That gyroscope, which is the center-piece of the longest running NASA project ever, was just recently launched into space. More info about it (Gravity Probe-B) and a good description of this drag can be found at http://einstein.stanford.edu. Yes, the article is describing a different project than GP-B; however, it references the skeptism that the folks at GP-B have expressed at this latest experiment, and the GP-B folks are considered the experts in the field. Check out their site, it's fascinating.
From the CNN article:
"Ciufolini's team analyzed millions of laser signals bounced off two satellites, called LAGEOS and LAGEOS 2. Both are highly reflective spheres not designed to do any work of their own. They look like 2-foot-diameter (0.6m) golf balls and contain no batteries or electronics."
Space Balls?
My framerate has been dragging too but I don't see the relevance of satellites to this issue. I've got cablemodem so satellite internet latency cannot be the problem.
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
Basically (acc. to the theory of relativity), gravity is not really a pull from one object to the other. What it is is a distortion in the fabric of space-time. What does this mean? Well think about a sheet stretched out very flat. On this sheeta are a number of very light objects. Now think of a lead weight placed in the center of the sheet. The sheet will bend into an inverted cone shape and all the items will slide towards the weight. Ta Da! Gravity!
Gravity is an extremely pervasive force. While it is the weakest of the defined forces, it permeates every area of our universe and, overall, has the largest impact. It is even powerfull enough to warp light. Again, just think of light as travelling along the surface of the sheet, the depression in the middle will warp the ligh as it travels.
What this article is describing is a secondary gravitational effect. Now, not only does this lead weight cause things to fall towards it, but if the lead weight was spinning, it will create another path/pull of gravity. In the sheet example. think of the lead weight as shaped like a corkscrew. Now imagine what would happen if you started turning that corkscrew. Not only would the sheet be weighed down in that area but it would also become wrapped around the corkscrew, causing further twisting in the fabric of the sheet. This is the effect that is currently trying to be proved.
Black holes are essentially very very very heavy weights. They create an extremely big "depression" in the fabric of the sheet. Many black holes also spin on their axis, much as the earth does. This spinning again distorts the sheet but, given how heavy the black hole is, it causes very large distortions.
This is all predicted by the theory of relativity. For this theory to be considered valid, it must make certain predictions that can be (eventually) proven. If this experiment is, in fact, true then this is yet another proof that relativity is the real deal. And there you have it.
Actually, now that I think about it. This pattern that they describe with the black hole looks exactly like a spiral galaxy (ie. the milky way) - with large "waves" coming out on all sides. It has been theorized that there is an enormous black hole at the center of the galaxy - could this be evidence of it?
No. Scientific theories don't get promoted to laws. Laws are observations of things that appear to hold true. For example, the law of gravity ("what goes up, must come down"), Snell's Law, Ohm's Law, the Law of conservation of Mass/Energy, the Laws of Thermodynamics, etc. A theory is an *explanation* that models some observed phenomena and which has the power to predict other phenomena. Theories are either falsified (i.e. proven wrong), or are confirmed (i.e. shown to be consistent with some new observation.) Theories are never proven true; rather, they are simply confirmed to a greater and greater degree. No matter how well a theory is confirmed, it can always be falsified by a new experiment testing some as-yet-untested prediction. In this case, the theory is either revised to account for the new observation, or it is simply discarded.
For those of you like me who didn't have a clue what this article is about check out the Wikipedia entry for frame dragging.
Your local junior high science fiction club would be a good place.
Plus, they say that the drag is about 6 feet or 2 meters? Not quite. I must nitpick.
2 meters is about 6'7", or 6 feet is about 1.82 meters. So which is it?
The metric system strikes again, I guess.
I couldn't fail to disagree with you less.
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.
it's really a sad state of affairs when a glorified weblog isn't able to report news faster than a multibillion dollar media corporation with reporters stationed all over the globe.
Not to be pedantic, didn't we learn that conversions in spacecraft need to be more precise?
Sincerely,
The Mars Climate Orbiter (AC to avoid karma whoring and giving away my location)
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.
Frame dragging IS the simpler explanation :)
frame dragging was predicted in the early 1900s by the various equations that make up relativity. if we were to observe that it wasn't happening and some other effect were causing it, then that would be very odd indeed, as that would imply that all the equations which have been right in so many other ways are wrong in this one little regard making things much much more complicated.
The simplest possible explanation for this is frame dragging.
Also, the gravity effects you mention would not affect the sattelite in this way, a downward pull has no effect on the horizontal motion of a satellite and the moon and suns gravity can easily be accounted for. Also, imagine the root cause was the moon and suns gravity, then that would imply there is something fundamentally new about the gravitational laws we do not yet understand, which again is very interesting and much more complicated than frame dragging.
http://notanumber.net/
Newton's laws have not been proved, they are just very likely. And there are some problems with them. So why not extend this naming to relativity?
I could say "My theory includes everything in General Relativity, except for a small sphere four miles wide in the center of Andromeda, where light travels twice as fast."
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.
Yes, this makes truly proving anything in the physical world basically impossible.
Which is why it is not a good idea for us to require theories to be "proven" before becoming "natural laws". We call a proven "theory" a "theorem".
This post written under Gentoo-linux with an SCO IP license.
You're not recognizing just how sensitive and sophisticated measurements and calculations of Earth's gravitational field have become. It's been well over a decade now since I read of how a satellite was used to create new and detailed maps of the ocean floor by measuring local variations in sea level; because rock is more dense than water, a seamount a mile below the ocean's surface creates a slight increase in the local gravitational pull, causing the ocean to hump up slightly above the mount.
The article doesn't say, but I would hope that the satellites were launched to orbit with Earth's rotation, so that frame dragging would accelerate them in their orbit, which would rule out atmospheric drag. I'd guess, though, that after 40+ years of satellite tracking such drag can probably be predicted to several significant digits, as can the gravitational effects of the Moon and Sun.
And, BTW, general relativity is a very physical theory. Last I heard, it's still the best explanation of why Mercury wobbles back and forth instead of being firmly tide-locked.I figure by 2030 or so my 6-digit UID will be something to brag about.
Bzzt, wrong.
If the whole idea of superstrings and 10-N dimensions are correct, then there are an infinite universes. The superset of these universes would include every possible random quantum event, and every effect from each.
In order to travel from one time to "another", you actually would guide to a universe very close to your diversion rate. You could kill off everybody, and it wont effect you at all. Then again, returning back to "your" time is impossible, as you can only approach your universe as a infinite limit (yeah, fun).
- If the earth's spin warps space around the planet what else is created by others planets or, what's a galaxy's effect arounds or inside itself ?
- Will this fabric help us to travel farther without a conventional energy ?
- Is the actual space station fullproof against anykind of fabric ripples ??
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)...
From the CNN article: Black holes [are] typically much more massive than Earth.
I took a course on the philosophy of modern physics at university and on the our text books was Einstein's own called Relativity : the Special and General Theory fairly informative and yet accesible. It is available for free from Project Gutenberg. Just click on the first link.
Your CPU is not doing anything else, at least do something.
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.
My favorite one of all time is: Yo Mama's so fat when she jumps up in the air she gets stuck.
The grandparent has pieces of truth ("theories are never proven true"), but doesn't seem to have it quite right (since laws are never "proven true", either). Hope that helps clarify things. I can address the grandparent post more thoroughly if this post was too vague.
Steven N. Severinghaus
Could it be something else that they haven't thought of? Like possibly due to inductive friction caused by the interaction of earth's magnetic field and non-ferrous metals in these satellites?
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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!
The moon doesn't move into the depression. The moon , like every other object, keeps traveling in a straight line until it collides with something. All the depression does is change the shape of a straight line. Any object in "free fall" is travelling in a straight line through curved space. Yes, satellites in orbit are falling unhindered in a straight line - that looks like a circle due to the curvature of space.
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.)
You're missing the OP's point. His computer analogy obviously doesn't hold literally; he's trying to explain that causality doesn't have much sway in Modern Physics. While we may be unable to send our entire bodies back in time, particles do it essentially all the time. It seems as though our current understanding of physics (both on the macroscopic general relativity scale and on the microscopic quantum scale) not only allows but actually encourages this kind of bizarre behaviour.
The confusion comes from classical mechanics, where we typically would model real-world behaviour parametrically -- and time was the parameter. So for example, we would explain the movement of a particle as vector function of time. This works fine, most of the time. But it isn't general enough.
Relativity showed that time is not a parameter anymore than classical dimensions could be considered a parameter, it's just that we perceive it that way. Time is actually a quantity much like space. It doesn't behave exactly the same way, but that's a result of the metric of the spacetime continuum (see Lorentz transforms in Special Relativity for an example of this).
So, now we have a particle occupying a position (x,y,z,t) instead of occupying a position (x,y,z) at a particular time t. In the same way that we accept that a particle can retrace its path when moving along the x axis, we must accept that a particle can move backwards on the t axis (it just isn't thermodynamically efficient to do so).
Let's talk about you and your grandfather. Your grandfather is at point (x,y,z,t) and you are at point (x',y',z',t'), presumably with t' > t. You time travel back to time t, and kill him. He ceases to exist at (x,y,z,t).
Now, because time is a positional coordinate, if you will, and not a parameter, you have not "arrested his movement". People like to wrap their heads around this by imagining that in changing the past you have "forked" the universe and that this new forked version will never produce you, but you aren't destroyed because you come from a different version of the future.
The point is that physics doesn't care why you came into being, only that you came into being. You exist; you will not cease to exist just because the thing that "created" you was destroyed. This leads philosophers to suggest that everything exists inherently, and that we just pick our way through a myriad of decision universes. It's a way of making our logic apply to physics. At the moment there's no evidence for it.
The "kill your grandpa" paradox was used in the old days to explain why time travel was impossible; and yet time travel is manifestly possible, even if harnessing it poses an engineering problem. It happens at the particle level all the time (positrons are electrons moving backwards in time, says Feynman). This suggests, then, that our starting principle is flawed (reducto ad absurdum). The "fall guy" in this case is causality. Causality doesn't matter. We hold on to it because we have memory. But cause can follow effect, etc... I mean, it's a bizarre world we live in.
I don't think so. Legislation is not the answer to every problem.
Sincerely,
Pan Tarhei Hosé, PhD.
"Homo sum et cogito ergo odi profanum vulgus et libido."
So, apparently, they had to take into account the non-uniformity of the earth's gravity in order to make accurate measurements. Turning that around, the non-uniformity of the earth's gravity caused a corresponding non-uniformity in the frame-dragging of the satelites.
Consider measuring the non-uniformity of frame-dragging of a black hole. If there is any, that would imply a non-uniformity in the matter in the black hole. Through this, we can determine something about the nature or distribution of the matter inside of the black hole, even though we cannot directly observe it (without being spaghettied).
So, you CAN get information back out of a black hole after all! (Although string theory already tells us that.)
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."
Most of people in this thread seem to be very confused, so please let me explain the most basic terms, using the most relevant quotes taken from several Wikipædia articles.
Axiom in epistemology is a self-evident truth upon which other knowledge must rest, from which other knowledge is built up. To say the least, not all epistemologists agree that any axioms, understood in that sense, exist.
Axioms in mathematics are not self-evident truths. They are of two different kinds: logical axioms and non-logical axioms. Axiomatic reasoning is today most widely used in mathematics.
The word axiom comes from the Greek word axioma, which means that which is deemed worthy or fit or that which is considered self-evident. The word comes from axioein, meaning to deem worthy, which in turn comes from axios, meaning worthy. Among the philosophers of the ancient Greeks an axiom was a claim which could be seen to be true without any need for proof.
Laws of logic and mathematics describe the nature of rational thought.
Law of nature or physical law in science is a statement that describes regular or patterned relationships among observable phenomena. It is a scientific generalization based on empirical observations. Laws of nature are conclusions drawn from, or hypotheses confirmed by, scientific experiments. The production of a summary description of nature in the form of such laws is the fundamental aim of science. Laws of nature are distinct from legal code and religious Law, and should not be confused with the concept of natural law.
Often, those who understand the mathematics and concepts well enough to understand the essence of the physical laws also feel that they possess an inherent intellectual beauty. Many scientists state that they use their perception of this beauty as a guide in in developing hypotheses, since there seems to be a connection between beauty and truth.
Physical laws are distinguished from scientific theories by their simplicity. Scientific theories have many of the same properties as laws, but are generally more complex than laws; they have many component parts, and are more likely to change as the body of availabe experimental data and analysis develops.
Theory in mathematics is a set of statements closed under logical implication. In mathematical logic, "theory" is the term for a set of well-formed formulae consisting of certain axioms and all theorems provable from said axioms. Gödel's incompleteness theorem states that no theory (formalized using a consistent set of axioms in First-order logic), that defines the concept of natural numbers, can include all true statements.
Theory in sciences is a model or framework for understanding. In physics, the term theory generally is taken to mean mathematical framework derived from a small set of basic principles capable of producing experimental predictions for a given category of physical systems. An example would be "electromagnetic theory", which is usually taken to be synonymous with classical electromagnetism, the specific results of which can be derived from Maxwell's equations.
The term theoretical to describe certain phenomena often indicates that a particular result has been predicted by theory but has not yet been observed. For example, until recently, black holes were considered theoretical. It is not uncommon in the history of physics for theory to produce such predictions that are later confirmed by experiment, but failed predictions do occur. Conversely, at any time in the study of physics, there can also be confirmed experimental results which are not yet explained by theory.
For a given body of theory to be considered part of established knowledge, it is usually necessary for the theory to characterize a critical experiment, that
Sincerely,
Pan Tarhei Hosé, PhD.
"Homo sum et cogito ergo odi profanum vulgus et libido."
You're thinking too deeply for the popular metaphor, which is for use by people who don't want to think deeply.
Here's a better metaphor, but still stopping short of the math. I've asked a PhD general relativist for commments: he didn't seem happy but had no direct objections.
Imagine the upper surface of your glass of Coke. The bubbles pucker the water around them. The bubbles tend to fall together and stick together. It's the water's springiness that's forcing them together: the water is "seeking" the configuration where it is least strained by the total amount of puckering.
Think of objects as bubbles of carbon dioxide, the dimples around them as their gravity fields, and the Universe as a vast glass of Coca-Cola :-)
wanna bet the next few episodes of star trek enterprise are gonna talk about how "the frame dragging around us is warping the space time continuum!" it'll probably be the nazis fault too...