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Newton's Second Law, Revisited

eldavojohn writes "Dust off your fundamental physics books, an aspiring astrophysicist by the name of Alex Ignatiev has published a paper that proposes testing special cases of Newton's Second Law on earth's surface. His goal is sort of ambitious. The time he has to test his theory is only 1/1000th of a second, twice each year, in either Greenland or Antarctica. What would he look for? Spontaneous motion. From his interview with PhysOrg: 'If these experiments were to take place, Ignatiev says that scientists would look for what he calls the SHLEM effect. This acronym stands for static high latitude equinox modified inertia and would be noticed in a condition where the forces of the earth's rotation on its axis, and of the orbital force of the earth as it moves around the sun, would be canceled out ... In the end, if Newton's Second Law could be violated, he would be forcing physicists to reevaluate much of what we understand derived from that law — which is quite a bit.'"

171 comments

  1. A bit early for April Fools? by lecithin · · Score: 5, Interesting

    Or is it?

    Reminds me of what Patrick Moore did:

    Stolen from

    http://en.wikipedia.org/wiki/Patrick_Moore

    Eccentric personality

    Due to his long-running television and xylophone playing career, eccentric manner, distinctively rapid speech delivery and in later years his ever-present monocle, Moore is widely-recognised and well-respected in the United Kingdom, even by those with no interest in astronomy. This was used to great advantage for a 1976 April Fool's joke on BBC Radio 2, when Moore announced that at 9.47 am a once-in-a-lifetime astronomical event was going to occur: Pluto would pass behind Jupiter, temporarily causing a gravitational alignment that would reduce the Earth's own gravity. Moore informed listeners that if they could jump at the exact moment that this event occurred, they would experience a temporary floating sensation. The BBC later received hundreds of phone calls from listeners claiming to have felt the sensation.

    Moore joined the Flat Earth Society as an ironic joke though many have taken this seriously.

    --
    It could be worse, it could be Monday.
    1. Re:A bit early for April Fools? by Anonymous Coward · · Score: 0

      Everybody now!

      Patrick Moore plays the xylophone
      Patrick Moore plays the xylophone
      Patrick Moore plays the xylophone
      Pa-Pa-PaPaPaPat-rick!

    2. Re:A bit early for April Fools? by Poltras · · Score: 1

      I certainly fail to see what Patrick Moore has to do with this issue... Nice Markov though.

    3. Re:A bit early for April Fools? by junglee_iitk · · Score: 1

      Hey! Where is the GNU GFDL accompanying the text?

      Eh? Eh?

      Just kidding... you know slashdot I love you :-)

  2. No exceptions by edwardpickman · · Score: 5, Funny

    Law breakers should be punished to the fullest extent of the physical law.

    1. Re:No exceptions by orkysoft · · Score: 1

      It doesn't look like they're going to settle...

      --

      I suffer from attention surplus disorder.
  3. I KNEW IT by heptapod · · Score: 0, Offtopic

    Spending $1000 on these plans for the Dean drive weren't a waste of my money! Take that science!

    1. Re:I KNEW IT by Anonymous Coward · · Score: 0

      OH MY SCIENCE!

  4. I often wonder about by Nybble's+Byte · · Score: 0

    who formulated Cole's Law, especially when eating ribs.

  5. violate what law? by Chris+Chiasson · · Score: 1

    So, what law is this person using to calculate the cancellation of the forces?

    1. Re:violate what law? by demeteloaf · · Score: 5, Informative

      Currently, there is a discrepancy between the rotations of galaxies, and what newtons law says should happen. If you look at large galaxies, at a bunch of different radii, all the stars orbits are at about a constant orbital velocity, which since there is less force acting on them from gravity, shouldn't happen.

      The most common physical explanation of why this happens is that there is a ring of dark matter around the galaxies that is also producing a gravitational force, and that when you add in the force from the dark matter, the equations work out, and you calculate that the orbital velocities should be constant.

      However, there are some physicists who don't like the idea of dark matter, and in order to explain how galaxies orbit, introduced a new version of newton's second law. F = m * f(a/a0)*a, where a0 is a new fundamental constant describing a small acceleration level where these new Newtonian dynamics hold. and f(x) is a function that equals x when x > 1. This theory describes the constant angular orbit speed of galaxies without the need for the existence of dark matter, however, the theory has problems when applied to relativistic systems.

      What it looks like this new paper proposes to do is find a place on earth where the acceleration from the coriolis effect, the centripital acceleration and the acceleration from the sun will all cancel out, and then create a really small force and see if the modified second law works for a very small absolute acceleration.

      --
      If there's anything more important than my ego around, i want it caught and shot now.
    2. Re:violate what law? by GryMor · · Score: 1

      Uhmm... what acceleration from the sun? Or does this hypothosis thats attacking Newton forget that Newton allready fell to GR? How would this not be dominated by the 1g acceleration of the ground pushing up on you?

      --
      Realities just a bunch of bits.
    3. Re:violate what law? by loganrapp · · Score: 1
      What it looks like this new paper proposes to do is find a place on earth where the acceleration from the coriolis effect


      Everyone knows it's the cornwallis effect. Pfft.

    4. Re:violate what law? by Plutonite · · Score: 1

      an interesting question to ask would be: even if the said forces "cancel out" in a particular coordinate plane somewhere on earth, forces acting in directions other than those considered(e.g gravitational curvature) would interfere with his oh-so-delicate measurements, no? Indeed, it would seem a NASA investigation during a space-mission would be even better, but I think it would be hard to convince NASA to get it's astronauts to do a 10-min off-course acceleration with a shuttle in some pointless direction, all for the love of science. Oh well.

    5. Re:violate what law? by Mateo_LeFou · · Score: 1

      "forces acting in directions other than those considered(e.g gravitational curvature) would interfere with his oh-so-delicate measurements, no?"

      Well, yeah, but as I understand it their order of magnitude would be such that measurements would remain meaningful, which is not the case when the major nearby forces are acting on the system.

      --
      My turnips listen for the soft cry of your love
    6. Re:violate what law? by zero_offset · · Score: 1

      Bah. Everyone knows it's really the clanwallace effect.

      --

      Slashdot quality declines as the number of hot grits posts decreases. - Provolt's Law, Apr-09-2005

    7. Re:violate what law? by mstahl · · Score: 1

      Newton's second law of motion, not Newton's law of gravitation. General relativity won out against Newton, yes, but nobody's yet disproven that F=ma./P.

    8. Re:violate what law? by Ambitwistor · · Score: 1

      However, there are some physicists who don't like the idea of dark matter, and in order to explain how galaxies orbit, introduced a new version of newton's second law. F = m * f(a/a0)*a, where a0 is a new fundamental constant describing a small acceleration level where these new Newtonian dynamics hold. You're describing Modified Newtonian Dynamics (MOND), which can equally (and more justifiably) be interpreted as a new version of Newton's law of gravity (see here). In particular, relativistic versions of MOND are interpretable as modified gravity and not as modified inertia.
    9. Re:violate what law? by jZnat · · Score: 1

      You mean F = dp/dt. Just imagine how hard it would be to calculate the acceleration of an object whose mass is changing (e.g. anything that burns fuel to provide energy).

      --
      'Yes, firefox is indeed greater than women. Can women block pops up for you? No. Can Firefox show you naked women? Yes.'
    10. Re:violate what law? by mabraham · · Score: 1

      "see if the modified second law works for a very small absolute acceleration" The whole point of Galilean relativity is that there is no sense in which you can measure an absolute acceleration. All you can do is measure one relative to a frame of reference.

    11. Re:violate what law? by Anonymous Coward · · Score: 0

      However, there are some physicists who don't like the idea of dark matter

      Racists.

    12. Re:violate what law? by BungaDunga · · Score: 1

      Jeez, acceleration != force. I feel a "1g" _force_ standing at sea level (from the earth) but I am not accelerating relative to the earth, because the support force on me by the ground is acting in the opposite direction with equal magnitude. There's obviously acceleration caused by the sun- acceleration is change in velocity, velocity includes direction, and the earth is orbiting the sun.

  6. Finding holes in the theory... by RyanFenton · · Score: 4, Interesting

    Yes, it only takes one demonstration to a render invalid a scientific theory. But that does not validate any other theories by doing so, unless they can accurately carry the same predictive weight as the previous theory, plus comply with the improved observations.

    A hole in Newtons second theory in any case doesn't mean scientists throw out their physics books, it generally means they add and exception to the theory and work on finding a more unified algorithm to describe the newly revised observations. Here's hoping this somewhat exotic set of observations leads eventually to a stronger set of theories, rather than just more false controversy about 'mavericks' and 'closed minded skeptics' - everyone's a skeptic AND a maverick, closed minded and radical - focusing only on the extremes of that, especially in terms of science sort of ignores the whole point of science, to use biased viewpoints to paint a larger picture.

    Ryan Fenton

    1. Re:Finding holes in the theory... by Anonymous Coward · · Score: 1, Insightful

      Actually, even 1 failed experiment probably won't invalidate a theory - I'm fairly certain you'd have to demonstrate that the failure is repeatable given certain conditions. Otherwise there's no guarantee that you're equipment wasn't measuring properly or whatnot.

  7. LIES! by smthngcrprt726 · · Score: 0

    i always had a sneaking suspicion that my physics textbook was wrong... and now the funny thought is what if this somehow magically is correct... then can i light my textbook on fire because it will all be wrong and we'll have to start over from scratch?

  8. the era precision cosmology by bcrowell · · Score: 4, Interesting

    I think it's odd that MOND's enthusiasts are so eager to push it as an alternative to dark matter, now that we've entered the era of high-precision cosmology. We know a hell of a lot about cosmology that we didn't know ten years ago. We know the age of the universe to two significant figures. We know that the universe is expanding at an increasing rate. We know the spectrum and angular distribution of the cosmic microwave background to high precision. We've found out that neutrinos have mass. I can see how MOND would have some appeal back in 1981, when it was first proposed, but so much has changed in the last 26 years. The evidence has accumulated that we live in a universe that's much stranger than we'd believed. I think that's cool.

    1. Re:the era precision cosmology by amRadioHed · · Score: 2, Insightful

      The evidence has accumulated that we live in a universe that's much stranger than we'd believed. I think that's cool. And what about that rules out MOND?
      --
      We hope your rules and wisdom choke you / Now we are one in everlasting peace
    2. Re:the era precision cosmology by bcrowell · · Score: 4, Informative

      And what about that rules out MOND?
      It doesn't rule out MOND, but it shows that what MOND was trying to avoid -- dark matter -- is an intrinsic part of an extremely successful cosmological model, which has passed a variety of high-precision tests. The Wikipedia article on MOND also discusses some empirical tests that MOND (and TeVeS) seems to have failed.

    3. Re:the era precision cosmology by friedman101 · · Score: 0

      We know the age of the universe to two significant figures.

      Eh, I know the number of animals on earth to about 1 significant figure. (~1 googol)

    4. Re:the era precision cosmology by Anonymous Coward · · Score: 0

      We know the age of the universe to two significant figures.

      6000?

    5. Re:the era precision cosmology by Anonymous Coward · · Score: 0

      With the way you've written that number, it's ambiguous how many significant figures there are.

    6. Re:the era precision cosmology by 3waygeek · · Score: 1

      The evidence has accumulated that we live in a universe that's much stranger than we'd believed.

      Haldane figured that out 80 years ago, without benefit of modern cosmology.

    7. Re:the era precision cosmology by DjReagan · · Score: 1

      I bet you just looked that up on google.

      --
      "When I grow up, I want to be a weirdo"
  9. Hammer, Feather, Freefall on the Moon: Revisited by Anonymous Coward · · Score: 5, Interesting

    "Fall heavy towards the moon, and the moon falls also towards you." -- Nietzsche

    Hammer and feather are dropped simultaneously from equal heights (as measured by distance from the center of the moon), separated laterally by a distance substantially less than the moon's diameter. Both hammer and feather experience force from the moon's gravity proportional to their mass, and hence both accelerate at the same rate. Meanwhile, the moon is also accelerating towards the other two objects, but unevenly so: the hammer exerts a greater gravitational pull due to its greater mass. The moon is therefore subject to a torque, causing it to accelerate more rapidly towards the hammer.

    The hammer is first to hit the ground.

    Anyone who denies this truth is a spatially absolutist lunocentric whose refusal to recognize the validity of hammer/feather mechanics places him wholly beyond the help of Galilean metaphysics. Such hammer/feather rejectionists ought to be banished from planetary space, for their own good and for the good of not only hammers and feathers but all subjugated smaller objects, everywhere, who find themselves victims of this scientifically perpetrated emassculation.

    --
    a756f345ec354225c08ff1a10a43162a

  10. Laws should be brok... err, de-law'd by Essequemodeia · · Score: 4, Funny

    Maybe he's wrong, maybe he's not right. But damned if I don't admire a scientist who is willing to destroy a potentially promising career over a tiny hunch. Maybe god will take pity and alter gravity for just such an instance. I think he's getting bored with Iraq.

    1. Re:Laws should be brok... err, de-law'd by Anonymous Coward · · Score: 0

      It shouldn't destroy his career. Many scientists work on fairly "out there" stuff, braneworlds in higher dimensions and string theory spring to mind. What he's doing is good science, testing a hypothesis, and it shouldn't cause him any real trouble - he might find it harder to get a job because there aren't many research groups he'd fit into, but he's now slightly famous which always helps...

  11. This is actually a well known phenomenon by Anonymous Coward · · Score: 1, Informative

    http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/cr ls.rxml

    The link above explains the Coriolis force. Among other things, this is the force that causes water to spiral down the drain in different directions on different sides of the equator. It also manifests itself such that if you fly at sufficient speed travelling past 63 deg. North Latitude, you will feel a slight bump. This is easily measured and confirmed by placing an accelerometer on the aircraft. There is almost always a slight acceleration. Of course, the accelerometer is subject to the vibration of the aircraft and to rapid changes in altitude due to air currents so the bump is often lost in the noise floor but it's there nevertheless.

    The phenomenon cited above is not limited to any particular time and is somewhat south of 80 deg. North Latitude but I suspect that Ignatiev is probably talking about the same thing. He should check his math.

    1. Re:This is actually a well known phenomenon by Alex+Belits · · Score: 1

      No. Coriolis force exists. Phenomena you have mentioned don't.

      --
      Contrary to the popular belief, there indeed is no God.
    2. Re:This is actually a well known phenomenon by julesh · · Score: 1

      The link above explains the Coriolis force. Among other things, this is the force that causes water to spiral down the drain in different directions on different sides of the equator.

      Erm, yes. But the Coriolis force (actually not a force at all, but an effect of inertia in an accelerating reference frame) is (a) perfectly consistent with newton's second law, (b) not what the author of the paper, which you clearly didn't even look at the abstract of, was talking about and (c) doesn't cause water to spiral down the drain in different directions in different hemispheres, unless you can somehow produce a bowl of water with virtually zero angular momentum to start with (hint: you can't).

    3. Re:This is actually a well known phenomenon by Anonymous Coward · · Score: 0

      >The link above explains the Coriolis force. Among other things, this is the force that causes water to spiral down the drain in different directions on different sides of the equator. It also manifests itself such that if you fly at sufficient speed travelling past 63 deg. North Latitude, you will feel a slight bump.

      Who modded the parent "Informative"? The correct mod is "Funny". People, in all but the most carefully controlled experiments the direction of water spin down a drian is governed by the shape of the bowl/drain, the direction of the water entering the bowl/drain, and/or any initial spin, however slight, of the water before being drained. As for the "slight bump" at while flying past 63 deg. north latitude, pure and utter BS, but, yes, quite funny. ;)

      Suggested reading,

      Mechanics, Landau/Lifshitz
      Newtonian Mechanics, A.P. French
      An Introduction to Mechanics, Kleppner/Kolenkow
      And Introduction to the Coriolis Force, Stommel/Moore

  12. A big IF by Ibag · · Score: 5, Insightful

    "In the end, if Newton's Second Law could be violated, he would be forcing physicists to reevaluate much of what we understand derived from that law -- which is quite a bit.'"

    In the end, if the second law of thermodynamics [or any other law of physics] could be violated, it would force physicists to reevaluate much of what we understand derived from that law - which is quite a bit. However, given that what we have derived from our laws generally fits with experimental observation (which is why we call them laws), the odds of him disproving Newton's second law with this experiment are about as good as me disproving the second law of thermodynamics by accidentally building a perpetual motion device.

    Experiments disproving longstanding laws have happened before. People don't have reason to care about them until afterwards, though.

    1. Re:A big IF by blank+axolotl · · Score: 3, Insightful

      The key is that our experimental observations only cover the cases we have thought to test - he would be testing the law in a new way.

      In fact, we already know that newton's second law is wrong from special and general relativity, but you only see so at high velocities/high curvature of space. It was only once we had the theory that we knew how to test it properly. Here he is testing the law in the case of very small accelerations, based on a theory which tries to explain an astrophysics observation that is not well understood. Who knows, he might find something.

      In addition, we already know that our theory from general relativity is incomplete because it does not match up to quantum mechanics, so there is surely still something to be discovered there somewhere.

    2. Re:A big IF by Ibag · · Score: 4, Insightful

      A few quick comments. First, relativity does not conflict with Newton's second law. It only needs to be changed from F=mA to F=dp/dt where p is momentum. Second, nobody said that general relativity was the pinnacle of physical theories. People have been trying for a while to find a grand unified theory that incorporated all the known forces in the universe and worked at both small and large scales. This appears to have nothing to do with the article, though. Third, while our experimental observations may only cover the cases we have thought to test, our laws are further verified every time the world behaves like we expect it to, every time we use GPS satellites with relativistic corrections, and every time we use devices that rely on quantum effects to work. The odds that everything holds except for 2/1000 of a second each year in two places on earth is unlikely. Maybe the experiment will work. That is science. However, it doesn't hurt to be skeptical until the experiment is done. I'm not saying that it won't happen, just that it seems premature to talk about rewriting textbooks just yet.

    3. Re:A big IF by blank+axolotl · · Score: 1

      As I replied elsewhere, I think relativity does conflict with newton's law with all the variables defined as they were. If you redefine momentum to something new, sure, I agree. But newtonian mechanics *is* wrong after all.

      As for the rest.. I actually know almost nothing about MOND, and I can't tell whether this experiment is worthwile. But my point was that universal laws have been shown wrong before, even when most observations seemed to support them.

    4. Re:A big IF by Anonymous Coward · · Score: 0

      A few quick comments. First, relativity does not conflict with Newton's second law. It only needs to be changed...
      Wow.

    5. Re:A big IF by Anonymous Coward · · Score: 0

      I would say that the relativity universe is incompatible with the Newton universe and that the Newton universe is the limit case of the relativity universe when the speed of the particle is low $(u\llt c)$ and the gravity field in the region of motion is weak ($g_{\mu\nu}\approx diag(-1,1,1,1)$). The Newton universe was revised with Maxwell findings and the assertion that the propagation speed of forces is bounded by the speed of light was added; originally the propagation speed was infinite.

      The mathematical definitions of the force and momentum are just that: mathematical definitions. The physical theory behind them gives them physical meaning, and in the case of the special relativity universe the momentum of Newton is replaced with $\gamma m u$, $\gamma = \frac{1}{\sqrt{1-\beta^2}}, \beta = \frac{u}{c}$; in the case of general relativity the force field of gravity is replaced with the curvature of the space, which depends on the stress-energy tensor, according to the Einstein field equations, so the trajectory of a particle (which is what the 2nd Newton law is used for) depends on the curvature of the local region it traverses in addition to the force that is being exerted on it.

      Concluding, I would say that physically you are wrong; maybe the mathematical resemblance of some equations is confusing you. Also, future theories have to take into consideration general relativity, as it is unanimously regarded as simple and experimentally proven. About your conclusion on the article, I fully agree.

    6. Re:A big IF by Ibag · · Score: 1

      Replace "changed" with "restated as" and you preserve my meaning while getting rid of your nitpick.

  13. Does this mean... by AaxelB · · Score: 5, Funny

    that Newton's Laws are actually just flawed theories? In that case, sign me up for the new "Intelligent Force" theory. Everything accelerates because something smarter than me decided it would, and there's no point asking questions. No more physics equations for me!

    1. Re:Does this mean... by amRadioHed · · Score: 5, Funny

      They prefer to call it "intelligent falling", but yeah you got the gist of it.

      --
      We hope your rules and wisdom choke you / Now we are one in everlasting peace
    2. Re:Does this mean... by Anonymous Coward · · Score: 0

      There *is* a point to asking questions, to satisfy your own curiosity and knowledge. Ask them all you want, no law (faith or otherwise) says you cannot, though sometimes it feels that way. BUT, when you take a theory and teach it consistently as fact when it's still a theory (and thus mislead others by your own flaws), that crosses the line. Hence all the controversy and debate and etc.

    3. Re:Does this mean... by TheManifold · · Score: 2, Interesting

      Newton's laws are just very very good approximations of reality. Einstein's theories of general/special relativity are still even more accurate versions of reality.

      An article in the New Scientist talks about 'Quantum Reality', where everything we see is just an approximation of the quantum world. I won't elaborate further, but I hope you get my gist.

    4. Re:Does this mean... by Anonymous Coward · · Score: 0

      May the Intelligent Force be with you.

    5. Re:Does this mean... by Anonymous Coward · · Score: 0

      Your post is indeed funny and I agree that intelligent design theories are worthy of mockery, however the part about contrasting the will to investigate the laws of physics with the existence of someone smarter than man is simply wrong. If someone smarter than you decided that things should be a certain way and he allows you to investigate them, I don't see a reason why you shouldn't be able to. By the way, I study physics because I like to, and that's the main point in asking the questions you refer to, in my point of view. Why is there no point in asking questions if someone more intelligent exists? I don't understand this, except if you refer to whether the existence of the more intelligent being might suggest that there are things that are more significant than knowledge in life.

    6. Re:Does this mean... by AaxelB · · Score: 1

      Eh, it was a joke. I actually love physics and thinking about the laws that govern nature, although I'm not studying it. If those laws were just set by some higher power or whatnot then you're right, they're still laws worth investigating, and the presence of a being smarter than man just gives us something to aspire to, I suppose.

      However, the summary (I didn't RTFA) suggests that some of the most basic laws of physics we hold so dear are flawed to the point where sometimes they simply aren't true. Some could (as in the ID debate) assert that all physics is then subjective to the whim of a higher power (another reply mentioned Occasionalism, which is this idea exactly, apparently) in which case (they could claim) it would be silly to try to make sense of everything using laws and rules, because that more intelligent being is beyond our comprehension and may change its mind every now and then.

    7. Re:Does this mean... by Anonymous Coward · · Score: 0

      I see that your intentions were noble, unlike many other posts, so I must agree with you. I wish that people would just stop confusing science with religion, something that happened a lot in other posts. Also, in my belief, the being we are talking about has given the human full command of the universe, so the rest of the conversation is redundant.

      I apologize if my comment came out as pedantic or too harsh and thank you for your response.

    8. Re:Does this mean... by Anonymous Coward · · Score: 0

      Um... Newton's Laws *are* flawed theories, relativity replaced them long ago as the more accurate theory. However, they are still very useful and accurate approximations for the vast majority of human-scale experience. We also know that relativity isn't absolutely correct either because it doesn't take into account QM effects, but it approximates to a very high degree of accuracy that which we can currently observe (so far as we understand it).

      QM and Relativity will probably always stand as useful approximations but they are almost certain to undergo refinement in the future into even more accurate and encompassing theories.

  14. Speed of Light Breaks it Already, Doesn't It? by BlackGriffen · · Score: 4, Interesting

    I mean, NSL only applies in the case of slow moving/low acceleration objects because it assumes infinite propagation speed of the force carrier.

    If he finds this it will be interesting not because of NSL concerns but because it would be an observation of the finite propagation speed of gravity. A fact that would serve as indirect (or perhaps direct) evidence of gravitational waves.

    1. Re:Speed of Light Breaks it Already, Doesn't It? by Plutonite · · Score: 1

      Speed of Light Breaks it Already, Doesn't It? Yes, many of us have pointed this out, but apparently the man is proposing that relativistic form of the equation be revisited, which is a whole-nuther story. We're just nitpicking to be frank with you ;)

      If he finds this it will be interesting not because of NSL concerns but because it would be an observation of the finite propagation speed of gravity. I haven't done enough gravity to touch on advanced things like G waves, so I don't follow you. What I do know, as I posted somewhere below, is that cornerstone relationships like E=mc2 would very much go to hell, and quantum electrodynamics would have to be written from scratch. Relativity still holds as a mathematical/logical principle, but some fundamental axioms from which relativistic effects derive current relations will need to be modified, which is terrifying. I think he is wrong, but I wish him luck.
  15. Would it even be wrong? by ameyer17 · · Score: 1

    Perhaps there's a force that hasn't been taken into account in his calculations...

    1. Re:Would it even be wrong? by SEWilco · · Score: 1

      Did he include the force of enough money for him to vacation at lovely polar locations?

    2. Re:Would it even be wrong? by devnulljapan · · Score: 1

      Perhaps there's a force that hasn't been taken into account in his calculations...
      What kind of force? A bangy force? A pushy force? A growy force? A forcy force force? A magic man dunnit.

  16. troll toolbox by Anonymous Coward · · Score: 1, Insightful
    Template #183
    Category: Instant karma
    For: new scientific theory proposed

    Yes, it only takes one demonstration to a render invalid a scientific theory. But that does not validate any other theories by doing so, unless they can accurately carry the same predictive weight as the previous theory, plus comply with the improved observations.

    A hole in $SCIENTIFIC_THEORY in any case doesn't mean scientists throw out their $SCIENTIFIC_FIELD books, it generally means they add and exception to the theory and work on finding a more unified algorithm to describe the newly revised observations. Here's hoping this somewhat exotic set of observations leads eventually to a stronger set of theories, rather than just more false controversy about 'mavericks' and 'closed minded skeptics' - everyone's a skeptic AND a maverick, closed minded and radical - focusing only on the extremes of that, especially in terms of science sort of ignores the whole point of science, to use biased viewpoints to paint a larger picture.

    1. Re:troll toolbox by Anonymous Coward · · Score: 0

      I love you.

  17. Re:Hammer, Feather, Freefall on the Moon: Revisite by Anonymous Coward · · Score: 0

    Suppose the hammer and the feather were dropped in superposition along the same axis. They would both hit the moon at the same time.

  18. sounds like a free trip by r00t · · Score: 2, Funny

    Think it'd be cool to visit Greenland?

    1. be a prof
    2. propose theory that must be tested in Greenland
    3. profit

    1. Re:sounds like a free trip by Anonymous Coward · · Score: 0

      Oh, yeah... Vacation time in Greenland or the Antartic! I'm sure he's dying to visit either of those tropical paradises and vacation wonderlands and just cooking up the excuse of seeing if Newton's second law can be violated to allow him to catch some relaxation.

      Now, if such were the case, and it was me that was proposing the experiment, I'd claim that the Carribean was the location where conditions were ideal- especially in the middle of a five-star resort hotel. I'd also up the duration necessary to measure the effect to a year.

      Now, that's profit!

    2. Re:sounds like a free trip by Anonymous Coward · · Score: 0

      I think all the kewl people will stop at Iceland

    3. Re:sounds like a free trip by Anonymous Coward · · Score: 0

      Visiting Groenland should be *cool* in the real sense of word...

    4. Re:sounds like a free trip by d0nju4n · · Score: 1

      You forgot a key step. It should be:


      1. be a prof
      2. propose theory that must be tested in Greenland
      3. ???
      4. profit

  19. Why Not in Space? by vertigoCiel · · Score: 2, Interesting

    Am I missing something, or would this be a hell of a lot easier to do in space? From TFA I gather that he's looking for an instance of no outside force, and, since orbit is essentially free-fall, this would be easily accomplished on the ISS. Granted, I might be missing the point entirely, or I don't get his strange "I've got to do this on the surface of the Earth!" fetish.

    1. Re:Why Not in Space? by Logarhythmic · · Score: 1

      The only reason anything stays in orbit is because it's being acted on by a gravitational force (always pulling toward the center, thereby creating the sensation of "falling"). He's trying to find a time and place when forces cancel out. This does seem odd to me, however, because there's a mention of "absolute" force, which has little or no meaning in physics. Lacking an absolute frame of reference, everything has to be relative. It seems that he is counting on the cancellation of the known major contributing forces (somehow omitting the Earth's gravity) to make the experiment accurate.

      --
      "Before criticizing someone, first walk a mile in his shoes. Then, you'll be a mile away... and you'll have his shoes."
  20. IN SOVIET RUSSA by Forrest+Kyle · · Score: 0

    Mass Equals Force Times Acceleration!

    1. Re:IN SOVIET RUSSA by Anonymous Coward · · Score: 0

      Either that was a really lame attempt at an "In Soviet Russia" joke, or you're a bit confused...
      F = m * a

    2. Re:IN SOVIET RUSSA by SageMusings · · Score: 1

      Lorentz factor, anyone? Why do people always forget that?

      --
      -- Posted from my parent's basement
  21. Very nice. May be important. by Animats · · Score: 1

    That's a cute little paper. If other physicists think it makes sense, that little experiment is worth doing, even though some people will have to go up to the northern tip of Greenland to do it.

    1. Re:Very nice. May be important. by Anonymous Coward · · Score: 0

      That's cute little comment you have there. If other readers agree, it should be worth reading, otherwise it should be moderated down as offtopic.

  22. Dangerous? by Plutonite · · Score: 2, Insightful

    Newton's law underwent some serious revisiting in 1905 when a chap called Einstein realised that masses are not constant/absolute but in fact relative, and this is why the modern relativistic notation differs quite a bit from the original F=ma. Now if this new guy is not joking (Russian timezones, April 1st, bit early..etc) then not only is our understanding of momentum going to be radically different, but in fact E=mc2 might have to be revisited as well (must read part 10 of this historical paper by Einstein to understand). That happens to be a very ground breaking idea if it were true, and would change lots of things we supposedly know about fundamental physics.

    1. Re:Dangerous? by julesh · · Score: 1

      Now if this new guy is not joking (Russian timezones, April 1st, bit early..etc)

      The paper was published in December. That's a lot early.

    2. Re:Dangerous? by DiamondGeezer · · Score: 1

      Newton's law underwent some serious revisiting in 1905 when a chap called Einstein realised that masses are not constant/absolute but in fact relative, and this is why the modern relativistic notation differs quite a bit from the original F=ma.

      Not so. Even in Einstein's relativity, mass is invariant.

      --
      Tubby or not tubby. Fat is the question
    3. Re:Dangerous? by eyewhin · · Score: 1

      Newton's Second Law did not undergo any changes. It was, and always will be, F=dp/dt. The problem was the Newton had no way to test a change in momentum. There were no rocket engines, for instance. Having a running horse lose mass while shitting and then comparing the results before and after would have been difficult, to say the least.

      David

    4. Re:Dangerous? by Plutonite · · Score: 1

      Indeed, but Newton did not realise that mass varied with the energy content of a body, and therefore his version of the equation could simply be written as F = m dv/dt. The m is factored out because it is constant. When we consider what is called relativistic mass (which depends on a velocity relative to a particular system), it becomes necessary to include the m inside the differential. Newton would have never thought of that, because mass was an absolute and invariant concept to him. Like anything dealing with time, the equations needed to be re-written to take into account the relativity of "time".

    5. Re:Dangerous? by Plutonite · · Score: 1

      Read the notes you linked to carefully (they are some of the best on the web). Mass/inertia is no longer invariant when a body is moving with respect to a frame. This is why the term "relativistic" mass is used. Invariant mass is the so called "rest" mass which results from the mass being stationary with respect to a frame of reference, and this is the typical, implicit nomenclature for non-relativist applications. Because we need to consider the relative mass in moving systems, F=ma (which is just m*dv/dt)must be written as F=dp/dt, where the change in mass is accounted for with respect to velocity.

    6. Re:Dangerous? by XchristX · · Score: 1

      A few conceptual corrections. The concept of "relativistic mass" is an entirely unnecessary construct designed to make Einstein's famous "E=mc^2" look simple (actually, it's better stated as E^2=p^2c^2+m^2c^4 where m is the so called "rest mass"). If we do away with the redundant concept of "relativistic mass" altogether and only stick to the Lorentz-invariant "rest mass", then there is no need to muck about with the whole "mass depends on velocity" stuff. Relativity remains perfectly consistent without that claim. Now, all we need to say is "mass" , not "rest mass" or "relativistic mass" since there is no such thing as "relativistic mass".

      Einstein's student P. Bergmann avoided the concept of relativistic mass altogether in this manner, as do most particle physicists I know.

      --
      l'Homme n'est Rien l'Oeuvre Tout: Gustave Flaubert to George Sand
    7. Re:Dangerous? by Plutonite · · Score: 1

      actually, it's better stated as E^2=p^2c^2+m^2c^4 where m is the so called "rest mass" Yes, now may I ask what the "p" in that equation represents? It is (Lorentz factored)momentum, which incorporates the concept of relativism in mass. The word relativistic mass is not merely a simplification of the equation by substitution - it is a real effect of energy content on the inertial mass of the body (it's resistance to an accelerating force). When bodies gain energy (through motion or otherwise) they also gain "mass" by a factor of L/c^2, and the same for energy loss. Hence when bodies are travelling with a certain velocity relative to a frame, they are more difficult to accelerate in that particular direction than the same bodies at rest in the frame, because "p" in your equation above is GREATER than m*v for the same body of mass m at rest. And when they reach speed c, they become impossible to accelerate.

      You are correct in that there is in fact a difference between mass m that is intrinsic to the structure of the body, and the percieved mass M which differs due to changes in space-time itself.

      Finally, to quote Einstein:
      "Under this theory mass is not an unalterable magnitude, but a magnitude dependent on (and, indeed, identical with) the amount of energy."
    8. Re:Dangerous? by XchristX · · Score: 1

      [quote]
      Yes, now may I ask what the "p" in that equation represents? It is (Lorentz factored)momentum, which incorporates the concept of relativism in mass.
      [/quote]

      I disagree. Momentum can be defined irrespective of mass. Momentum is simply the generalized velocity derivative of the Lagrangian, or the generator group of the group of all possible motions (remember that photons have momentum but no mass)

      Momentum and mass are 2 different and largely unrelated ideas.

      [quote]
      The word relativistic mass is not merely a simplification of the equation by substitution - it is a real effect of energy content on the inertial mass of the body (it's resistance to an accelerating force)
      [/quote]

      Igor Bogdanoff is that you? /ducks

      I can't say that I agree. The above seems like a concatenation of physics terms that (to shamelessly copy the words of Jacques Distler), are "syntactically correct, but semantically meaningless". "Resistance to an accelerating force"??? What does that even mean? Who's doing the "resisting", God? Such ideas are entirely anthropomorphic in nature, and are little more than bad physics. We can explain this so-called "resistance to an accelerating force" simply through causality arguments. We do not need to bring any mythical "relativistic mass" into it at all. Read Bergmann's book on relativity. It was the pedagogocal standard where I did my undergrad. As long as we stick to the idea that the only mass that has any objective meaning is the rest mass (which is Lorentz invariant) then we don't need to explain the effects of "energy" in this way at all.

      Regarding the perceived increase in "inertia" (I hate that term) of the guy in the rocket frame:

      Applying your methods of argument to another case, the perceived increase in inertia in accelerated frames (non-relativistic) can be "defined" a "non-inertial mass" to explain the effects there (engineers do that already, except they call it "pseudoforce", Sheesh!). We don't need pseudoforce to explain accelerated frames (technically we don't even need regular force, which, itself, is an anthropomorphic construct and doesn't really exist) and, in the same way, we don't need this "relativistic mass" either.The perceived effects of pseudoforce in an accelerated frame are as "real" as perceived increase in "relativistic mass" in relativity. We don't need either to form a complete formalism.

      Physicists should be stingy with ideas. If we don't need it to get the correct results, off with it's head I say.

      [quote]
      Finally, to quote Einstein:
      "Under this theory mass is not an unalterable magnitude, but a magnitude dependent on (and, indeed, identical with) the amount of energy."
      [/quote]

      Einstein wasn't right about everything (remember his views concerning Quantum mechanics and the cosmological constant)?

      I am not a particle physicist, but I have taken a large number of courses in Particle Physics (graduate requirement, can't help it), and none of my particle physics profs say or use "relativistic mass". Not once, not ever. They only use "rest mass" and they don't even call it "rest mass", just "mass". Some students objected to that based on the argument you supplied and our Prof pooh-poohed it off as a redundancy.

      --
      l'Homme n'est Rien l'Oeuvre Tout: Gustave Flaubert to George Sand
    9. Re:Dangerous? by XchristX · · Score: 1

      [quote]
      When bodies gain energy (through motion or otherwise) they also gain "mass" by a factor of L/c^2, and the same for energy loss

      [/quote]

      Sorry I forgot to add in my last post that mass-energy equivalence is not destroyed if we abandon the concept of relativistic mass. Rest mass itself can be "converted" to photons (as happens in nuclear fission and decay processes). You go to a frame when the nucleus is at rest (so p=0) and you get E=mc^2 where m is the "rest mass" and, when the nucleus breaks off into to constituents and photons then 4-momentum is still conserved.

      --
      l'Homme n'est Rien l'Oeuvre Tout: Gustave Flaubert to George Sand
    10. Re:Dangerous? by torako · · Score: 1
      Actually, F=dp/dt is the way to state Newton's 2nd Law (and it is the way he stated it originally) not only because of relativity but also because of rockets, for example, i.e. anything that has a changing mass. A rocket would just be the example that's most often used.

      Also, while I agree with what you said about the distinction between relativistic and invariant mass, one should note that whenever physicists talk about "mass", they always refer to the rest mass of a body. Modern physics has completely eliminated the use of the so called relativistic mass.

    11. Re:Dangerous? by Plutonite · · Score: 1

      I disagree. Momentum can be defined irrespective of mass. Momentum is simply the generalized velocity derivative of the Lagrangian, or the generator group of the group of all possible motions (remember that photons have momentum but no mass) Ah, and therein the confusion lies. This is a great chat by the way, the issue has been debated formally in journals before. I agree perfectly with what you've said in both posts, it's just that classicaly the concepts of momentum and mass have been tied together, and that is why people use terms like "relativistic mass" to account for the variation in the time component of the four vector, which is very different from the "actual" or "rest" mass. Books still have F = d(mv)/dt, even though the m here is very different from mass in classical concepts. Which brings us to the other issue of:

      Resistance to an accelerating force"??? What does that even mean? Alright, you got me there :) Again, classical issues. It used to be that the percieved acceleration of a body in response to "force" was proportional to the invariant property of "mass". Whereas today we define (real, rest, invariant)mass only through energy equivalence, the "percieved resistance" to motion is still used with the aforementioned and equally confusing "percieved mass". As you pointed out, neither is necessary, we don't need all this nonsense with new formalisms!

      About Einstein's quote, he wasn't wrong methinks. He just stated it a little roughly, adding the "percieved" or relativistic stuff to the intrinsic, and we must remember this was written long before the current formulation of momentum..etc was made. He is quoted elsewhere shying away from the description of (relativistic mass" (i.e M = m/(1-beta) ) by one of the guys who responded to my OP. Also, concerning QM Einstein was not alone in his skepticism. In fact, only Bohr digested the stuff with a good stomach. Everybody else, including Hiesenberg (who caused the whole commotion in the first place) did not believe the "uncertainty" in a realistic sense when he got older. Everybody was trying to find ways to understand this probablistic reality that was proposed, and until today nobody has managed a satisfactory philosophical interpretation. Read Max Born's Nobel prize lecture. That guy had an amazingly mature understanding of things, and the more I study (I am not a Prof yet either) the more I see what he was trying to portray.
    12. Re:Dangerous? by XchristX · · Score: 1

      So the consensus is that concepts like "relativistic mass" are constructs largely directed towards a popular audience that likes to "perceive" human behaviour in natural phenomena (ie anthromorphism), and comes about as a result of historical associations between mass and momentum (very historical, since the Poynting Vector was discovered in 1884, and that alone shows momentum without mass).

      [quote]
      Whereas today we define (real, rest, invariant)mass only through energy equivalence
      [/quote]

      There are several problems with that statement.

      1.Since Energy is not a defined concept but an intuitive one, neither is mass.I have a hard time accepting that mass can be "defined" (or energy for that matter) without delving dangerously into anthropomorphic ideas. Mass and energy are like infinity, determinate but not defined.

      2.(Rest) Mass-energy Equivalence follows ipso-facto from Einstein's Equation. Using it to "define" mass creates the informal fallacy of petitio principii (begging the question), since you had to determine mass to write Einstein's equation.

      --
      l'Homme n'est Rien l'Oeuvre Tout: Gustave Flaubert to George Sand
    13. Re:Dangerous? by Plutonite · · Score: 1

      1. This is the reverse of the infinite/inifitismal - the infinite is defined but undetermined, not the other way round. You can define an infinite set, but you will never be able to "determine" all it's elements. It is rather dangerous playing with infinity also, because it can be argued that the lack of determinism is axiomatic i.e the definition is the lack of determination. Scary stuff, and not really relevant.

      2. Yeah, I thought about the circular definition issue for a while. The problem is that if you disregard the intertial notions (i.e mass as related to the kinematic response of a "stationary" body to applied "force", in the precise direction of the application force) then what do you have left? What is mass? It is incorrect, in my perhaps uninformed opinion, to say mass cannot be defined, because we consistently measure mass (i.e assign values to massive objects) and it makes no sense to measure what we do not comprehend. This is not a matter of anthromorphism, but simple science. We need to know what mass means.

      If mass can only be determined, then how do you determine it?

  23. Re:Hammer, Feather, Freefall on the Moon: Revisite by Whiteox · · Score: 1

    Ever hear of Force Vectors?
    The moon would be pulled towards both objects at the same rate.

    --
    Don't be apathetic. Procrastinate!
  24. Re:MOD THE TROLL DOWN!!! by Anonymous Coward · · Score: 5, Funny

    Done.

  25. Re:Hammer, Feather, Freefall on the Moon: Revisite by Anonymous Coward · · Score: 0

    The force pulling the moon towards the hammer is greater than the force pulling the moon towards the feather, as each one's gravitational force is proportional to the height of the object. Therefore (unless F=ma is no longer an accurate law, couldn't figure out TFA) the acceleration towards each will be that force divided by the moon's mass, and obviously the acceleration towards the hammer will be much higher, meaning the mon and hammer will collide sooner than the moon and feather.

  26. Wonder how much testing this is worth by ThanatosMinor · · Score: 2, Interesting

    So for this thousandth of a second in a remote location at 80 degrees of latitude, is he proposing that we build an entire testing facility to see if an uncharged particle wiggles a little bit for some reason by some mechanism that no one has really figured out?
    Are we also to believe that because the mathematical calculations work out such that all first- and second-order gravitational forces are cancelled, if we observe some motion, that motion is a clear violation of Newton's Second Law by assuming that there is zero force on the particle?
    Wouldn't it be just as reasonable to claim that there were another force involved rather than saying that the Law has been debunked?

    1. Re:Wonder how much testing this is worth by toby34a · · Score: 1

      It seems that he's got ideas for mobile testing locations. Now, 80 degrees N/S doesn't seem like that great of a place to go, but it's somewhere where we don't have to put it on a rocket, which would require more funding. The materials (from TFA) that he proposes wouldn't be too terribly expensive to cart to Greenland/Antartica versus launching it onto the ISS.

      Again, it's probably worth setting up some theoretical physicists up on top of a glacier just for the hilarity of it. But most of them are probably Russians, and used to the cold...

  27. One thing about this... by Nom+du+Keyboard · · Score: 1

    One thing about this is at least it can be tested for, and right here on Earth. But even if it's observed, that doesn't automatically prove his theory true. It would only add evidence to it.

    --
    "It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
    1. Re:One thing about this... by fatphil · · Score: 1

      If he claims to have tested it positively, but the situations under which it can be tested are so rare, he's set up a claim that can never be debunked.

      He may as well say "god did it" if he's going to be that much of a cheat. He should just bite the bullet (nebula), and admit he's bullshitting us.

      --
      Also FatPhil on SoylentNews, id 863
  28. Oh yeah? by HardCase · · Score: 4, Funny

    You can take my gun from me...oh, wait, wrong 2nd law...

  29. Laws aren't exactly "broken" in physics by thrawn_aj · · Score: 4, Interesting
    What laypersons should realize is that when a flaw is discovered in a well-established physical theory, it usually reduces the domain of validity of the theory, but RARELY makes that theory useless as a calculational tool (it just tells us when the theory will break down, as ALL current theories eventually do - the triumph of modern physics is to push those breakdown points to the farthest reaches of the imaginable). In this, physics has been an unqualified success - a fraction of the predictive power that we have today would have been enough to condemn several "soothsayers" to a grisly demise at one point in history :P. To digress for a moment here, it amuses me greatly that people can be obsessed with psychics and the contemptible Nostradamus while taking such exquisitely detailed predictions as tomorrow's weather for granted. It's rather like being impressed with a mythical flying superman while thinking of an airplane as mundane.

    An example to illustrate the breakdown of theories: the Special theory of Relativity modified Newtonian mechanics on a fundamental level. However, for speeds much less than the speed of light (which is what most of us experience in daily life), it is STILL Newtonian mechanics that we use, even in several cutting edge research fields. The rule of thumb in research is: never use a full model when an approximate one is just as accurate in the domain of interest. In much the same way, even if MOND were true, any deviations from Newton would kick in at EXTREMELY LOW accelerations (of the order of 10^-20 m/s^2 which is about 10^-21 g, something next to impossible to duplicate in a lab because of ambient vibrational noise which is usually MUCH higher (say, about 10^-9 g is a VERY quiet environment)). This is the reason why the paper (which attracted our group's attention a few weeks ago) proposes an experiment at such well-defined times and locations. To put it bluntly, this is an ad-hoc modification in the sense that there is just no justification for the modification. Of course, I don't even think MOND would replace the Dark Matter hypothesis. One might even argue that this modification is simply a way of expressing the effect of Dark Matter (just a thought).

  30. Perpetual motion machine by Khyber · · Score: 0, Offtopic

    idea for ya.

    The universe blows up, expands, shit forms, eventually everything comes back, collapses, and another big bang happens. Repeat countless cycles, yet it keeps happening.

    If you want to get into it, I'd argue that the universe, as open as it is, is a closed system without energy loss. But, this only works with the Big Bang theory.

    As it stands, we'll NEVER know in our lifetimes. So, I just present something for you to think of - the perpetual motion machine could exist, but it's on such a scale that even galaxies of competent and intelligent life coudn't figure it out before the universe collapses upon itself from it's own gravity and wipes us all out.

    --
    Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
  31. Re: Relativistic 2nd Law by Svartormr · · Score: 2, Informative

    ...Newton's second law is wrong from special and general relativity...
    Not if you state it in the form:

    F = dp / dt where F is the force on an object, p is the momentum of the object, and t is time; ie. the force is the time differential of the momentum. (And for completeness, p and F can be vectors.) Only with classical simplification do you get "F = ma".
  32. Not peer reviewed yet... by gb · · Score: 5, Insightful

    It's worth pointing out that this paper is only publihed on a preprint server - that means it has not been through peer review, so needs to be treated with a lot of caution. There's an awful lot of totally crazy stuff on preprint servers. Not that I'm saying it's totally crazy - whilst I'm a physicist, I do condensed matter not astro - amd wouldn't describe myself as qualified to have a definitve opinion. But I would be both cautious and skeptical until proven oherwise.

    1. Re:Not peer reviewed yet... by Dr_Mic · · Score: 2, Informative
      Indeed, it is quite a stretch to say that putting a paper up on arXiv.org is "published" in any normal sense (say onethat would be accepted by a tenure review committee). However we do have

      Is Violation of Newton's Second Law Possible? A. Yu. Ignatiev Phys. Rev. Lett. 98, 101101 (2007)

      as well as

      Mirror dark matter and large scale structure A. Yu. Ignatiev and R. R. Volkas Phys. Rev. D 68, 023518 (2003)


      Geophysical constraints on mirror matter within the Earth A. Yu. Ignatiev and R. R. Volkas Phys. Rev. D 62, 023508 (2000)

      and others.

      The author has a real publication record. For phys rev and especially phys rev lett, the crank filters are a little more effective. As with the parent, this is not my field. However, my initial knee jerk reaction (crank!) has abated somewhat.
    2. Re:Not peer reviewed yet... by gb · · Score: 1

      For phys rev and especially phys rev lett, the crank filters are a little more effective. Indeed, one would hope so. Especially if one is published in PR* :-)
    3. Re:Not peer reviewed yet... by Anonymous Coward · · Score: 0

      Er, that's simply not true, it has just been published in a highly prestigious journal (PRL).

      http://dx.doi.org/10.1103/PhysRevLett.98.101101

      However, IAAC (cosmologist), and despite this being a refereed paper, most of the community aren't taking MOND seriously any more, so I doubt this will garner much attention. The evidence for dark matter is simply too strong.

    4. Re:Not peer reviewed yet... by fatphil · · Score: 1

      It's not a stretch at all to say it's been published. This thing has been published in every sane definition of the word. Publishing is about the making available of information to the public. That has been done.

      It's not been reviewed by a suitable panel, that's all.

      Your conflation of the two concepts would make me worry about your ability to critically review anything written in the English language.

      --
      Also FatPhil on SoylentNews, id 863
  33. These theoretical astrophysicists are getting good by Phroon · · Score: 3, Interesting

    These theoretical astrophysicists are getting good at what they do.

    The submitter of this article (and the populace of Slashdot as a whole) doesn't get the point of this article. Ignatiev isn't suggesting this experiment out of thin air, he's suggested a novel earth-based experiment to help explain the anomaly in galactic rotation (ie. Dark Matter). To explain this anomaly some theoretical astrophysicists modify Newtonian dynamics in a small way so that the galactic rotation calculations come out correct. Others introduce Dark Matter, or alter gravitation itself.

    He basically wants to observe an object smaller than 7 cm x 40 cm x 40 cm at the precise moment and the precise location on the earth such that it would experience an acceleration that is much smaller than the extra acceleration it would experience as proposed by the modified Newtonian dynamics. So any extraneous acceleration observed at this moment had to have come from modified Newtonian dynamics.

    The interesting thing about this article is that it isn't just a wild claim by a crackpot scientist, it's the proposition of an extremely accurate measurement using the most advanced technologies we have available. Of particular interest to me was that the proposed effect was two orders of magnitude larger than that observable by LIGO, a gravitational wave detector, suggesting that such an experiment is actually possible.

  34. Take with a grain of salt by Anonymous Coward · · Score: 0

    PhysOrg doesn't tend to have very high standards when it comes to the articles they post. Similarly, their forum is overrun with nutjobs and crackpots.

    Though I haven't fully read the article, based on what I know of physics, this sounds like just another physics loony. I'd take this article with a grain of salt.

    - Dave

  35. Re:Hammer, Feather, Freefall on the Moon: Revisite by zippthorne · · Score: 1

    You could do this as a 3-body problem, and then you'd be correct that they fall at different rates, but you'd have quite a difficulty measuring the difference, since the feather and the hammer are orders of magnitude of orders of magnitude less than the mass of the moon.

    The other point you've mentioned is actually quite the physical puzzle. There's no reason why gravitational mass and inertial mass need to be the same, yet to our ability to measure so far, they are.

    --
    Can you be Even More Awesome?!
  36. Re: Relativistic 2nd Law by zippthorne · · Score: 1
    The actually stated in the article,

    Using momentum in the terminology (which would never have occurred to Newton) is a latter-day revision of the law to bring it into correspondence with special relativity.
    But after reading that, I'm left wondering where the heck the rocket equation came from. and fluid dynamics. And whether a smart man is trying to blow smoke where smoke does not belong in the hopes of appearing even smarter for the purpose of getting grant money.
    --
    Can you be Even More Awesome?!
  37. Re: Relativistic 2nd Law by blank+axolotl · · Score: 5, Interesting

    You're right that you can still use an equation that looks like F = dp/dt in GR, but I still think the original second law is wrong with all the quantities defined as they were. Writing it your way, it is then the definition of momentum which is wrong (or going on, the definition of velocity as dx/dt not dx/dTau). (Also in GR F= dp/dTau, not dp/dt if t is the time coordinate). The symbols in GR just happen to look and act quite like the newtonian symbols, but are interpreted differently.

    Anyway, it is the error in predicted motion that is interesting here, where 'F=ma' gives the newtonian motion,
    but this becomes like 'F = ma + m Gamma Vi Vj' in GR. You can't clearly see the different motions each theory gives in F = dp/dt.

  38. Wind your calendar by Marko+DeBeeste · · Score: 1

    Day early, dollar short.

    --
    Faith: n. -- That human impulse that drives them to steal appliances when the power goes out
  39. Re:A bit early for April Fools? - Already proved.. by Anonymous Coward · · Score: 0

    ...by the rocks that move in the desert...

    http://mmmgroup.altervista.org/e-rocks.html

  40. Signal : Noise Ratio? by Anonymous Coward · · Score: 0

    Erm,
    Could this minute fluctuation in forces over a 1ms time-period be drowned out by any other fluctuation? Physical vibration? Magnetic flux? Gravitational flux? Noise in the measuring devices?

    At least either way both sides will be able to deny that the result proved them wrong.

  41. SHLEM by Anonymous Coward · · Score: 0

    SHLEM stands for `helmet' in the Russian language.

  42. I disagree by khallow · · Score: 2, Insightful

    We know the spectrum and angular distribution of the cosmic microwave background to high precision.

    This is the only statement that is correct since it is the only conclusion derived directly from observation. A lot depends on how accurate our models of the universe and physics are. I think MOND is unlikely to last, but the theory is yet viable. Your claims about the age of the universe, mass of neutrino, etc are likely to be correct, but it would be embarrassing if these observations turn out to be dependent on assumptions that are incorrect. Eg, perhaps Type IA supernovas are different in the early universe than they are now (even though physical law is the same, there are substantial differences like elemental composition), perhaps we're incorrect about our local gravity environment (eg, we're deeper in a gravity well) and this effects our perception of the temperature of the cosmic background, or perhaps a more accurate model of the universe involves oscillating yet massless neutrinos.
    1. Re:I disagree by Ambitwistor · · Score: 2, Informative

      This is the only statement that is correct since it is the only conclusion derived directly from observation. No, you could introduce weird mechanisms that distort the true spectrum of the CMBR, which is about as plausible as the other scenarios you put forth.

      perhaps Type IA supernovas are different in the early universe than they are now (even though physical law is the same, there are substantial differences like elemental composition) You would then have to explain how these different supernovas still manage to produce the same characteristic light curves as modern supernovas. Possible in principle, but not plausible.

      perhaps we're incorrect about our local gravity environment (eg, we're deeper in a gravity well) and this effects our perception of the temperature of the cosmic background The temperature of the cosmic background isn't really that important in this context, and moreover, I can't imagine what kind of "gravity well" you could think that we were in that would distort all our measurements of distant galaxies equally and in all directions, without simultaneously distorting local observations.

      or perhaps a more accurate model of the universe involves oscillating yet massless neutrinos Only if you want to basically throw out all of relativity and quantum mechanics, since you can't get flavor oscillations without mass in any theory that obeys both; flavor and mass are complementary observables.
    2. Re:I disagree by khallow · · Score: 1

      No, you could introduce weird mechanisms that distort the true spectrum of the CMBR, which is about as plausible as the other scenarios you put forth.

      No "weird mechanism" (aside from some sort of NASA hoax) is going to change the fact that the observation was made and very precise data was collected. Nor does that statement depend on any observer biases that might be present.

      The temperature of the cosmic background isn't really that important in this context, and moreover, I can't imagine what kind of "gravity well" you could think that we were in that would distort all our measurements of distant galaxies equally and in all directions, without simultaneously distorting local observations.

      The deeping in the well you are, the hotter the rest of the universe appears because it is blue-shifted by the drop down the gravity well. This would be an easy way to underestimate the age of the universe, for example, and the distance of things that are outside the gravity well.

      Only if you want to basically throw out all of relativity and quantum mechanics, since you can't get flavor oscillations without mass in any theory that obeys both; flavor and mass are complementary observables.

      Well, quantum mechanics (via quantum field theory) is a crude approximation on the scale of subatomic physics that grows worse as the scale shrinks. And general relativity doesn't apply at all. So that isn't a stretch. That is my point. For example, the mass of the neutrino may not be described sufficiently well by the mass operator in quantum chromodynamics (eg, maybe due to curvature of space which does modify the d'Alembert operator or an unknown interaction between the neutrino and the graviton). So the mass that actually describes the neutrino may commute with its flavor even though the mass as described by current theory does not.

      I think I'm going way overboard as a devil's advocate here, but my point is that I don't think we have good reason to be so confident about phenommena either that we haven't directly observed, is based on very recent data, or depends on models that we already know aren't entirely valid in the regime in which the phenomena are observed.

    3. Re:I disagree by Ambitwistor · · Score: 1

      No "weird mechanism" (aside from some sort of NASA hoax) is going to change the fact that the observation was made and very precise data was collected. Nor does that statement depend on any observer biases that might be present. You can say the same about the CMBR temperature. Yet you propose some kind of global gravity well that distorts our measurements and causes us to infer the wrong things from it. The same can be said of the CMBR angular power spectrum: there could be some astrophysical phenomenon out there distorting everything in some unknown way. You can't criticize CMBR temperature measurements for being potentially distorted by unknown processes, and at the same time insist that the CMBR angular power spectrum is a "true observation".

      The deeping in the well you are, the hotter the rest of the universe appears because it is blue-shifted by the drop down the gravity well. This would be an easy way to underestimate the age of the universe, for example, and the distance of things that are outside the gravity well. Like I said, I can't imagine what kind of "gravity well" you could think that we were in, that would distort all our measurements of distant galaxies equally and in all directions, without simultaneously distorting local observations. And it would screw up redshift-luminosity curves to make them inconsistent with the CMBR, barring fine-tuning — but they are consistent.

      Furthermore, the age of the universe is not determined by the CMBR temperature.

      Well, quantum mechanics (via quantum field theory) is a crude approximation on the scale of subatomic physics that grows worse as the scale shrinks. And general relativity doesn't apply at all. So that isn't a stretch. No, it is a stretch. A large stretch.

      Quantum theory is not a "crude approximation" which "grows worse as the scale shrinks". Quantum theory holds exactly at every scale we have tested. All proposed replacements for quantum field theory that I can think of (e.g., string theory) are also quantum theories. General relativity is irrelevant; you don't need it in order to derive mass/flavor uncertainty relations. You only need the Lorentz causal structure of special relativity.

      For example, the mass of the neutrino may not be described sufficiently well by the mass operator in quantum chromodynamics (eg, maybe due to curvature of space which does modify the d'Alembert operator (I assume you mean electroweak theory, not QCD.) QFT in curved spacetime has been worked out and doesn't change flavor oscillations.

      or an unknown interaction between the neutrino and the graviton). The graviton couples universally to all mass-energy; there's really only one way it can consistently couple.

      I will concede that it might be possible to have some weird coupling of neutrinos to matter that can mimic flavor oscillations. I have no idea how it could be done, though.
    4. Re:I disagree by Ambitwistor · · Score: 1

      I think I'm going way overboard as a devil's advocate here, but my point is that I don't think we have good reason to be so confident about phenommena either that we haven't directly observed, is based on very recent data, or depends on models that we already know aren't entirely valid in the regime in which the phenomena are observed. Which models do we know aren't valid in the regime in which they're being applied?

      By the way, here is a blog post with a slide from a talk by Roger Blanford listing "radical possibilities" for ways in which our cosmological inferences could be wrong. (I think most of them are very unlikely, although still more likely than "we're in a giant but unknown gravitational well".)
    5. Re:I disagree by khallow · · Score: 1

      Which models do we know aren't valid in the regime in which they're being applied?

      The regime in question is subatomic scale and smaller with considerable precision and gravity. We already know QCD as it is for starters, and most other QFTs don't apply at this scale especially when gravity is taken into account. Perhaps when we've mapped out the full series of QCD (assuming the current perturbation theory approach to constructing QCD terms works) and glued it somehow to relativity, this will change. String theories might be applicable. We don't know yet.

      By the way, here is a blog post with a slide from a talk by Roger Blanford listing "radical possibilities" for ways in which our cosmological inferences could be wrong. (I think most of them are very unlikely, although still more likely than "we're in a giant but unknown gravitational well".)

      Thanks for the link to Blanford. Unfortunately, he only partially address my key concern. Namely, tthat we're too confident (at the moment and IMHO) in our understanding of the universe. There's still the possibility that key answers may change either because of hidden bias in our observations or improved models. Nothing really complicated. But he just lists rival theories. I'm not really worried that MOND is correct as opposed to the current theory. I'm concerned that we'll find that our observations have been in error for the past ten or twenty years because there was one or more hidden biases in our web of observations or just because we use a new model that makes the funniness go away.

      For example, we don't need to be in a "giant but unknown" gravity well. We already know we're in a giant gravity well (the Virgo Supercluster, right?). The problem is that we may be wrong about how far down we are inside that well. And the concept of "dark energy" is subsumed into the cosmological constant.

      Let me go way back to a quote from your original post.

      I think it's odd that MOND's enthusiasts are so eager to push it as an alternative to dark matter, now that we've entered the era of high-precision cosmology. We know a hell of a lot about cosmology that we didn't know ten years ago.

      Consider a historical example, the speed of propagation of gravity. We are almost certain that gravity has to propagate at the speed of light because that is an implication of general relativity which fits quite well at the macroscopic scale. Yet 90 or so years after the creation of the general relativity theory, you don't see similar claims of certainty despite 90 years of no proof to the contrary and plenty of confirmation in the theory of general relativity and no genuine violation of the speed of light (ie, as of yet no information propagates faster than the speed of light). In comparison, we are claiming after a decade or two of observation, that we are confident that the universe has positive cosmological constant or that the neutrino has nonzero mass. My take is that some caution is warranted and that historically physicists have exercised this level of caution.
    6. Re:I disagree by Ambitwistor · · Score: 1

      The regime in question is subatomic scale and smaller with considerable precision and gravity. We already know QCD as it is for starters, and most other QFTs don't apply at this scale especially when gravity is taken into account. QFT does too apply at those scales; you don't even need to do QFT in curved spacetime (which you can do if you want). The Planck scale of quantum gravity is not relevant for any of the questions you've mentioned; at best it could be relevant to very early-universe cosmology.

      Perhaps when we've mapped out the full series of QCD (assuming the current perturbation theory approach to constructing QCD terms works) and glued it somehow to relativity, this will change. We know quite a bit about the nonperturbative regimes of QCD as well, by the way, and it is fully consistent with special relativity. Compatibility with general relativity, once again, is irrelevant: at very large scales, QCD is unimportant, and at very small scales, gravity is unimportant, unless you get all the way down to the Planck scale.

      nfortunately, he only partially address my key concern. Namely, tthat we're too confident (at the moment and IMHO) in our understanding of the universe. This is not a concern that you've really justified. Some things we can be confident in, some things we can't, and you've done a poor job of delineating which is which.

      For example, we don't need to be in a "giant but unknown" gravity well. We already know we're in a giant gravity well (the Virgo Supercluster, right?). The problem is that we may be wrong about how far down we are inside that well. You're being ridiculous. We don't even need to take the existence of the Virgo supercluster into account. Any significant redshift due to that would require very obvious zeroth-order modifications to gravity which would show up, basically, everywhere we look. That, or completely ridiculous modifications to the masses of galaxies which would, again, change all the orbital dynamics we see.

      If you want to propose that we don't know everything about the universe around us, you need to come up with much less absurd proposals.

      And the concept of "dark energy" is subsumed into the cosmological constant. So what? The cosmological constant is one of many proposals for dark energy; we cannot yet constrain them to one alternative.

      Let me go way back to a quote from your original post. I never wrote that. You're quoting someone else.

      We are almost certain that gravity has to propagate at the speed of light because that is an implication of general relativity which fits quite well at the macroscopic scale. Yet 90 or so years after the creation of the general relativity theory, you don't see similar claims of certainty despite 90 years of no proof to the contrary and plenty of confirmation in the theory of general relativity and no genuine violation of the speed of light (ie, as of yet no information propagates faster than the speed of light). You do too see similar claims of certainty that gravity propagates at the speed of light, and you see those claims because of (not "despite") the confirmation of GR and lack of violation of the speed of light. In fact, the speed of gravity has been experimentally tested and agrees to the speed of light within a few percent (see the 1993 Nobel prize). I've worked in the gravity community, and I can assure you, there is no doubt there about the speed of gravity. This is a false analogy.

      In comparison, we are claiming after a decade or two of observation, that we are confident that the universe has positive cosmological constant or that the neutrino has nonzero mass. Yes, we are confident. Not as confident as we are about GR, but still confident. So?

      It's also easy to point to any number of new theories which were well-accepted within less than a decade of observation or experimentation, and remain accepted today.
    7. Re:I disagree by khallow · · Score: 1

      You're being ridiculous. We don't even need to take the existence of the Virgo supercluster into account. Any significant redshift due to that would require very obvious zeroth-order modifications to gravity which would show up, basically, everywhere we look. That, or completely ridiculous modifications to the masses of galaxies which would, again, change all the orbital dynamics we see.

      Eh, glancing around, it appears to me that the necessary adjustment would have to be one or two orders of magnitude greater in scale than the Virgo Supercluster. I suppose it could happen, but where is the first-order modification (dipole moment) in the cosmic microwave background? That would be observable.

      I never wrote that. You're quoting someone else.

      My apologies. Obviously, I thought you had. That sparked my side of this debate.

      It's also easy to point to any number of new theories which were well-accepted within less than a decade of observation or experimentation, and remain accepted today.

      Eh, new theories are on probation and should be that way. Having said that most of the stuff that's been bouncing around in this threat isn't really new. The data is new, but the theories have been around for a while.

  43. Both Sun and galaxies centers are accelerating by Alex+Belits · · Score: 4, Insightful

    This article (and the whole MOND thing) would make some sense if the systems described in them were not accelerating because of gravity. Sun is subjected to the gravity forces toward the center of our galaxy, so its path relative to the center of the galaxy is not a straight line but a circle -- though a very large one. I find it to be an extremely weird oversight considering that the whole hypothesis exists to describe parameters of the very same motion of stars in galaxies. So even when a point on the Earth surface is not accelerating in the Sun's coordinate system, it still does in the galaxy's coordinate system.

    Worse yet, MOND does not explain anything about galaxies because galaxies themselves accelerate. They are not distributed evenly and uniformly in space but form clusters. Each cluster just like a galaxy itself, is pulled together by gravity, so galaxies experience some acceleration in the cluster's coordinate system because of the gravity of other galaxies.

    Obviously this acceleration is not detectable locally because it is caused by gravity -- for the same reason objects in orbit are "weightless". To find out that you are in freefall (or in orbit, what is the same thing) without looking at other celestial objects you have to throw something and observe its movement -- since gravity is not parallel and uniform everywhere, after the object will get far enough from you, it will be noticeable that its trajectory is not a straight line relative to you, as it would be if you weren't accelerating at all. However locally gravity and acceleration are indistinguishable, and at the scale of Solar system or galaxy the size of such "local" area is huge.

    MOND is talking about absolute acceleration that should be clearly distinguishable from gravity. However if we will try to find something in the universe that is really "unaccelerated" by this definition, there will be very few objects in this category, if any. Certainly it would not be massive centers of galaxies, Sun or two spots on the Earth surface the author of the article proposes as locations for his experiments.

    This is the theoretical part of the problem. Now, the practical one. In two proposed spots the conditions that article author expects to happen last for a very short time and happen once a year. The extent of effect is similar to the influence of gravity from many existing celestial bodies. Tidal waves caused by Moon and affected by the shape of oceans, condition in the atmosphere, movement of Earth crust, etc. are likely to produce more noticeable influence on any test body that may be used in the experiment. Though I didn't do any calculations, it's hard to believe that variations of tidal waves caused by changes in weather will be less than supposed effect of "modified" 2nd Newton's Law even if it worked the way that the article author's proposed. And since conditions are supposed to be so rare, there is no way to collect enough samples for any statistical analysis.

    In the end, I can add that if your experiment is to look for a black cat in a dark room, it shouldn't be a surprise if the result is negative regardless of the actual presence of a cat. However this makes no excuse for proposing that the cat is in the room when there is no reason for it to be there in the first place. Both theory and proposed experiment look extremely stupid, and if MOND can be modified to explain why it should include movement of stars within galaxies but not movement of galaxies in clusters, maybe it would be worth a second look. For now it's just that -- stupid idea with no foundation and no viable method of verification.

    --
    Contrary to the popular belief, there indeed is no God.
    1. Re:Both Sun and galaxies centers are accelerating by julesh · · Score: 1

      So even when a point on the Earth surface is not accelerating in the Sun's coordinate system, it still does in the galaxy's coordinate system.

      While movement on a galactic scale is quite rapid (in the galaxy's frame of reference), I believe the acceleration of any individual body is rather small, and can probably be ignored for any short timescale purpose.

    2. Re:Both Sun and galaxies centers are accelerating by ThosLives · · Score: 3, Interesting

      I don't think it has to do with acceleration of galactic centers. I think it has to do more with the effective radius used in the calculations.

      For instance, in a traditional central-body problem, you have a very basic set of equations that says the path of any body around another body will be a conic section, with modifications due to more than two bodies in a system.

      What I've never seen in literature, and I've seen the plot of angular velocity versus radius that "flattens out" for galaxies, is just what that angular velocity is? Is it angular velocities for individual stars, or an average?

      If it is just an average, then I wonder is it an effect due to observation. What I mean is this: when looking at a gas here on earth, the average temperature is a good measure for its properties. However, only a small portion of the individual molecules in the gas actually have that exact temperature. The same for a stream of exhaust from a jet - the jet has a general average velocity, but each individual particle has some other velocity that contributes to the bulk average velocity.

      I am wondering if the aggregate motion of a galaxy is like gas temperature or velocity; that is, it may be a superposition of the individual accelerations of the individual starts and nebulae in the galaxy. That is, is it possible to generate a system only with particles that obey classical (relativistic) gravity but can appear, in aggregate, to disobey the mass proportionality of Newton's Second Law? I suspect that 'galactic' measurements are like measuring bulk properties of a gas rather than looking at the kinetic model. Something perhaps like the recent storm on Saturn / water in a spinning bucket articles where simple motion of individual particles gives rise to more complex aggregate behavior.

      --
      "There are a dozen opinions on a matter until you know the truth. Then there is only one." - CS Lewis (paraprhase)
    3. Re:Both Sun and galaxies centers are accelerating by grikdog · · Score: 1

      It's the old elastic zipper problem, isn't it? One measurement doesn't distinguish between the relative motions of subject and object. The glory bit about quantum dynamics is, the experiements are so obvious and so counterintuitive it makes your brain ache. But the difference between MOND and Dark Matter is like the difference between Epicylic Motion and Phlogiston. First, catch your zebra. THEN measure its antlers!

      --
      ``Tension, apprehension & dissension have begun!'' - Duffy Wyg&, in Alfred Bester's _The Demolished Man_
    4. Re:Both Sun and galaxies centers are accelerating by Alex+Belits · · Score: 1

      Then just compare movement of stars in galaxies with different acceleration measured against other galaxies. Dense clusters, or small galaxies orbiting larger galaxies would provide examples of higher acceleration, so if the hypothesis is true, movement of stars in them would be different from movement of stars in galaxies that are supposed to be accelerating less.

      One thing that is good about the Universe is that it has plenty of very large, weirdly shaped objects in it.

      --
      Contrary to the popular belief, there indeed is no God.
    5. Re:Both Sun and galaxies centers are accelerating by julesh · · Score: 1

      As I understand it, this observation has already been made, such an effect has been noted, and is what provoked the development of the theory that this new experiment is designed to test.

    6. Re:Both Sun and galaxies centers are accelerating by Alex+Belits · · Score: 1

      Any references to anything published about that?

      --
      Contrary to the popular belief, there indeed is no God.
    7. Re:Both Sun and galaxies centers are accelerating by Anonymous Coward · · Score: 0

      >This article (and the whole MOND thing) would make some sense if the systems described in them were not accelerating because of gravity. Sun is subjected to the gravity forces toward the center of our galaxy, so its path relative to the center of the galaxy is not a straight line but a circle -- though a very large one. I find it to be an extremely weird oversight considering that the whole hypothesis exists to describe parameters of the very same motion of stars in galaxies. So even when a point on the Earth surface is not accelerating in the Sun's coordinate system, it still does in the galaxy's coordinate system.

      Mod parent back down. There was no "oversight". Yes, the sun is accelerating around the galactic core, but according to the very hypothesis the article proposes to test, that acceleration is sufficiently low to require a modification to Newton's law of acceleration. The proposed test attempts to negate the effects of earth rotation and earth orbit around the sun, which, if successful, would be sufficient to test the hypothesis.

    8. Re:Both Sun and galaxies centers are accelerating by Alex+Belits · · Score: 1

      The Sun is at more or less average distance from the center of the galaxy, so even if modified 2nd Newton's law makes the galaxy rotate in a different way, Sun's acceleration would be in the "modified" part of the curve but not negligible at the extent that it can be assumed to be an inertial reference system. We constantly ignore acceleration caused by gravity and treat reference systems as inertial because at the scale of experiments they act as if they are inertial until we move far enough to notice the change in the direction of gravity. Not so for this hypothesis -- for its purpose gravity and acceleration don't make each other invisible.

      So yes, if we stop moving relatively to the Sun our acceleration will likely be in the range when the behavior is "modified", but we still have to take into account that we are accelerating if we add any further acceleration. To verify the hypothesis he would need the sum of Sun's acceleration and acceleration of the lab due to imprecise choice of position, plus acceleration due to unaccounted external influence (such as fluctuation in tides) to remain within the "modified" range. Otherwise we are back to the conditions where the hypothesis would produce the behavior of regular Newtonian mechanics even if the hypothesis is true.

      --
      Contrary to the popular belief, there indeed is no God.
    9. Re:Both Sun and galaxies centers are accelerating by julesh · · Score: 1

      For an overview, see the Wikipedia article. That has references to some more detailed papers on the subject.

  44. testing a "zero" by khallow · · Score: 1

    I think the point here isn't that there's some weird hiccup that only occurs during this brief time, but rather that standard theory predicts that a certain observation over this brief period should be zero while MOND predicts a nonzero value. Testing whether something is zero or not is one of the more sensitive types of tests out there. As an example, it's a lot easier to figure out whether there is a person or not in a room than to figure out whether there are 1,000 or 1,001 people in a room. By measuring during this brief time, certain normal effects, which would drown out the data that this guy is looking for, are absent. It eliminates a source of error in the experiment assuming his calculations are correct.

  45. he published a paper? by drolli · · Score: 1

    now, please everybody repeat after me: A link to thre preprint archive is not a link to a published paper, because a preprint is a preprint and a paper is a paper (even if it is pdf nowadays....).

    1. Re:he published a paper? by alienmole · · Score: 1

      He made the "paper" available on the internet, which qualifies as publishing even if not in a peer-reviewed sense. Our terminology haven't really caught up to the internet yet. For example, calling a paper a "preprint" doesn't necessarily make sense if it isn't going to ever be published in a traditional form.

    2. Re:he published a paper? by drolli · · Score: 1

      Excuse me, it is somethin ehich is called commonly a "preprint server". That defines it to be a preprint. If the Author wants to publish it, he can use his own website. This is called self-publishing and also works if you want yourself to be the editor of a book you wrote.

    3. Re:he published a paper? by alienmole · · Score: 1

      Excuse me, it is somethin ehich is called commonly a "preprint server". That defines it to be a preprint.
      "Commonly", huh? ArXiv calls itself an "e-print service", and many of the papers on it have been published elsewhere, as well as being published on arXiv. See how I used the word just then? Check the definition, it's a valid use, and that's my point.

      In any case, the paper in question was also published in Physical Review Letters, Mar 9. So even by your definition, it's published.
    4. Re:he published a paper? by drolli · · Score: 1

      > In any case, the paper in question was also published in Physical Review Letters [aip.org], Mar 9. So even by your definition... Ok I'll consider reading it now, when i have time.

    5. Re:he published a paper? by fatphil · · Score: 1

      Wrong.
      It's a paper, even if it's a preprint.
      It's been published, even if it's been published somewhere where anyone can publish stuff.

      The concept you're missing is that of _review_ (and acceptance).

      --
      Also FatPhil on SoylentNews, id 863
  46. Like religion? by FatSean · · Score: 1

    People teach their religion as fact. Sometimes even to young children who don't know any better.

    --
    Blar.
    1. Re:Like religion? by Anonymous Coward · · Score: 0

      I suppose you support that children should be taught the outdated (arguably wrong) newtonian mechanics? I agree with you about all religions in the world except for one, though. That one teaches facts, empirical evidence, that anyone can reproduce if he follows some (at first sight simple) rules and changes his attitude towards life and other humans. If you search for it hard enough, you'll find it. Good luck.

    2. Re:Like religion? by Anonymous Coward · · Score: 0

      I should've just said: it still is known also by "Theory of Evolution". If it has "Theory" in the label, it should stay there. For the anti-faith people, same goes for "Intelligent Design" (is there a "Theory" label?). In the end, the label doesn't matter, it is what it is. Your choice to take it. Denying "Theory of Evolution" doesn't change whether it happened, same with ID. Whichever is stronger will survive. Teach what science you want to teach in the classroom.

      For the one-line post above, young children can be taught anything, regardless of what it is. If history can support a particular faith/religion as true, it will. But it's still your choice.

      Everyone is all about "here and now, what we see and know", nothing wrong there. That doesn't mean that's it.

      Oh yeah, someone made a post about some people canvassing door-to-door, and it made the poster conclude that the canvassers were insecure and needed someone to believe with them. I suppose, to be fair, you would apply that to everything else and see where that goes?

  47. You almost got it by Anonymous Coward · · Score: 0

    "No. Coriolis force exists."

    More accurately: No coriolis force exists

    The coriolis force is a fiction which describes the deflection of objects relative to the surface of the earth. In that regard, it's much like centrifical force.

    http://www.worldwidewords.org/qa/qa-cen1.htm

    In any event, I'm reasonably certain that you haven't flown north of the tree line with a pilot sufficiently experienced to point out the bump. When it is pointed out to them, most people do notice it. The next thing will be that you try to tell us that you can't hear the aurora borealis.

    http://serendip.brynmawr.edu/biology/b103/f00/web3 /gallagher3.html

    Anyway, the grandfather post is just as accurate as the article to which it was posted.

    1. Re:You almost got it by Alex+Belits · · Score: 1

      More accurately: No coriolis force exists

      The coriolis force is a fiction which describes the deflection of objects relative to the surface of the earth. In that regard, it's much like centrifical force.


      This is an old and tired argument about definitions, and one that many stupid people repeat when they are pretending to be smart. "Force" does not always mean "result of interaction of an object with some field" (the only thing that can really "move objects"), for many practical purposes it can be defined as "cause for any acceleration of an object in any reference system", so even inertia can be seen as a force if your reference system is not inertial. And, of course, in General Relativity gravity is "not a force" if such a narrow definition was accepted.

      In any event, I'm reasonably certain that you haven't flown north of the tree line with a pilot sufficiently experienced to point out the bump. When it is pointed out to them, most people do notice it.

      Who cares what people "experience" when they are told that they have to expect it? What kind of research is that? There are accelerometers for that purpose. Coriolis force doesn't do anything magical at any particular latitude except zero where it does not exist at all. At best it causes large-scale patterns of winds in the atmosphere that have latitude-specific details. None of those things cause any "bumps" unless plane's own navigation system somehow changes its way of compensating for something when passing some "magical" latitude. If there was such a "bump" it would be outlined in a giant thin wall of clouds along 63 degree north latitude because any water vapor, drops of water or ice passing through it with a wind blowing north or south would be "bumped" as well, and some of it would change its phase forming a wall.

      And, of course, rotation of water in drains is unrelated to Coriolis force and is caused by the fact that nothing is absolutely symmetrical, and any rotation amplifies itself when water flows toward the center. It's not uncommon to have two drained reservoirs side by side with water rotating in the opposite directions, and of course, water spins when drained even if you are directly on the equator.

      --
      Contrary to the popular belief, there indeed is no God.
  48. Let's get physical. by Anonymous Coward · · Score: 0

    First of all, Newton's laws of motion are not Universal, we know it. More than one hundred years ago, Einstein proposed his "extended version": relativistic dynamics, which works fine in the case of high speeds, twenty years later Schrödinger and Heisemberg along with other geniouses formulated Quantum Mechanics(our most powerful theory). Years later, more theories have appeared, very beautiful and fine theories which describe physical phenomena correctly where you "can" apply them, I mean, a physical theory, as Newton's laws of motion, are just a mathematical model(cool differential equations, or more abstract stuff) and which describes nature whitin it's limits... every model has a domain of application and whenever you apply it out of it you can get weird things(the problem is that actually the limits of this domain are not well defined).

    Newton's laws of motion and all which can be derived from them work extremely fine in our macroscopic dayly world... But whenever you look to something very little(one atom), you need to apply Quantum Mechanics, and whenever it moves fast(near the speed of light) you need relativity, or if both happens Relativistic Quantum Mechanics... and so on, you just say:"ok, here I will found a couple of non-classical effects, so I need a non-classical theory, let's forget about Newton and use another theory", but Newton's law of motion are still valid!, they've been used for describing the macroscopic world extremely well since they were formulated more than two hundred years ago, and today, we have no experimental evidence of a change in the way nature works and so we can be confident about the usefulness of Newton's law of motion... for every-day life(if you work in a particle accelerator forget about the last :) ).

    This russian guy may have just devised a method for measuring some weird effects... :). But we can still go to Antartida and use Newton's law and they will be fine :).

  49. Well actually ... by Anonymous Coward · · Score: 0

    My post was just as accurate as the story.

    The confluence of circumstances (velocity, acceleration), that occur at 80 deg. N twice a year for 1/1000 of a second, could be reproduced anywhere on the surface of the earth.

  50. I'm testing the SCHLEP theory... by jpellino · · Score: 1

    Which postulates that the amount of time for a research assistant to get back from Quiznos is directly proportional to the gastric sounds of everyone else in the lab, and inversely proportional (to the second power) of the immediacy of the stuff left to do in the afternoon.

    --
    "Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
  51. Funny you should be joking by roman_mir · · Score: 1

    For a thousand years an entire religion has been based on this exact premise. (So how has it been working out for them?)

  52. Re:Hammer, Feather, Freefall on the Moon: Revisite by JohnFluxx · · Score: 3, Insightful

    That assumes that the difference in position and momentum is greater than the uncertainty principle allows, which isn't immediately obvious. If you do the calculations, you may just find that the difference is smaller than QM allows, and thus there is no difference.

  53. Related topics by Sockatume · · Score: 1

    I read about a fascinating experiment recently which attempts to test whether the laws of physics are invariant with your frame of reference, by comparing the enthalpy of crystallisation of the two enantiomers (mirror images) of a chiral compound. If the laws of physics vary with space (i.e. there's a slight energetic preference to certain orientations in a universal "ether"), then the enthalpies of crystallisation will be different for each enantiomer as your orientation in space changes (achieved by performing the experiment at different times of day, so your orientation changes as the Earth rotates).

    It's one of these experiments which can't absolutely disprove the effect it's looking for (in this case, the idea of a universal reference frame) and instead aims to set an increasingly minute upper bound on the magnitude of that effect. My hat goes off to the people who keep performing such demanding, yet thankless, work.

    --
    No kidding!!! What do you say at this point?
  54. Re:Hammer, Feather, Freefall on the Moon: Revisite by Anonymous Coward · · Score: 0

    You == pedantic to a fault.

    If I were your science teacher, I'd be a bit disappointed in your attempt at adroitness. You see, the moon, being much larger than the feather and the hammer is affected by acceleration toward the earth, the sun, other planets, etc, as well and to such a larger degree that it bears much stronger consideration than your hammer and feather. You have not established the positions of these objects relative to your Moon/feather/hammer arrangement and therefore have not satisfactorily established your conclusion of the hammer landing first. Furthermore, since you've not established the position of the feather and hammer relative to the Moon's tidally-locked orbit around the earth. Since the acceleration the Moon experiences from the hammer must be considered by your pedantry, surely you considered the other vector-summable accelerations in this system!

  55. I'll help... by Follier · · Score: 1

    "But how feasible is this? .... "Gravitational wave detectors are great starting points,""

    Hey I have one of those... it's called a bathroom scale. So I'll keep my eye on it during that 1/1000th of a second and publish my results :)

  56. Re:Hammer, Feather, Freefall on the Moon: Revisite by rock_climbing_guy · · Score: 2, Funny
    It sounds like maybe you're too stupid to understand

    The TIMECUBE.

    --
    Wh47 d1d j00 541, 31337 15n't t3h r0xor5 ne m0r3???
  57. Just a question by BlurredOne · · Score: 0

    Now I may be totally off on this, seeing as how I am not a physicist (and probably cant spell it either), but by him testing this theory, isn't he in a way proving and disproving it?

    I thought that the laws of quantum physics/mechanics stated that just bt observing, one changes the outcome, so by him running these experiments, he is neither proving or disproving his theory, he is just seeing the results of his interaction with the particle?

  58. Yet another silly article by Ancient_Hacker · · Score: 1
    Just on general principles, the idea sounds ridiculous:
    • Astrophysical theories and estimates of dark matter, miniature black holes, "wimps", "gimps", renegade neutrino varieties, and more-- the estimated magnitude of these effects can only be guessed at, and the best guesses vary by factors of two to ten.
    • Newton's law, F = MA has been tested hundreds of times, in all kinds of places, on earth, in deep mines, in the air, in space, and as far as Vger 10 has wandered. IIRC it's always passed within the precision of the measuring devices.
    • So it's basically LUDICROUS to look for TINY variations, we're talking parts per million, to "explain" wild guesses with tolerances of plus or minus 1,000%.
    • And to think that one time and place on Earth are somehow "special" for 1/1000 of a second, well, that's more in the realm of religion than science or logic.
  59. Re:Hammer, Feather, Freefall on the Moon: Revisite by marcosdumay · · Score: 1

    Somebody, please mod the AC up.

  60. Re:Hammer, Feather, Freefall on the Moon: Revisite by hitchhacker · · Score: 1

    Avoiding any air-resistance, you don't need some gravity-from-the-moon argument to show that the hammer will hit first. It's quite clear from the equation that the hammer will hit before the feather. The extreme mass of the Earth relative to both hammer and feather makes the difference in acceleration practically irrelevant. Nevertheless, the hammer does hit first.

    Stare at: F=G*((m1*m2)/r^2) for a while.

    -metric

  61. Re:Hammer, Feather, Freefall on the Moon: Revisite by Anonymous Coward · · Score: 0
    That's the equation for the force, not the acceleration. The acceleration of the hammer is given by


    F=(m1)a


    (assuming the hammer has mass m1 and the Earth has mass m2). So, substituting:


    a = (G*((m1*m2)/r^2)/(m1) = G*m2/r^2


    i.e., independent of the mass of the hammer.

  62. Changed by Anonymous Coward · · Score: 0

    HA!

    He changed the outcome by observing it.

  63. Some people need to re-read Einstein by Teancum · · Score: 1
    All of this talk about reference frames and trying to decide what the "absolute" accelerations and velocity of everything is just makes my head spin and wonder where these physicists come from that they havn't read about about this nearly Century-old theory proposed by the crazy Swiss patent examiner named A. Einstein.

    Essentially speaking, it really doesn't matter what frame of reference you are using. From a certain point of view, everything in the Universe is gravitationally attracted to you, not the other way around. Or that the Earth, while you are falling above it, is accelerating toward you at 9.8 m/s. All physical effects are one body relative to another, and there is no independent frame of reference.

    Of course this guy could be claiming that there is in fact a universal frame of reference that is independent of all other objects in the universe, and can try to define all sorts of motion based on this universal reference. That, however, is a bold theory and requires some extraordinary proof, not just some minor discrepencies as is being demonstrated here.

    Of course Relativity is based in part on the fact that no matter which way you measure light traveling toward you, it is always going at the same speed. This of course is one of the reasons why it is called Relativity... as this is also a demonstratable way to prove that there is no universal frame reference that would influence the speed of light. This is something that would have to be explained in a universal reference frame theory.

    This isn't to say that gravitational effects don't show up, because they do, but those effects don't need to be defined in any particular frame of reference, other than to simplify the mathematics of trying to figure out what the acceleration would be for any set of objects.

    While not explictly stated in the article or paper, I think this particular person with the MOND theory is also implying a universal frame reference, or else the issue with having specific lattitudes and precisely timed periods of time that only happen a couple of times per year makes no other sense.

    And we know for a fact that Newton's laws are not perfect, and need further refinement due to Einstein's theories. The motion of Mercury needs to be accounted for the fact that it is moving very close to a massive body, where being deep in the gravity well of the Sun time actually slows down.

    If you are talking about orbital vectors and trying to derive the data from the GPS constellation, you need to account for relativistic effects both due to the fact that the GPS satellites are further out of the Earth's gravity well, and the fact they are also traveling at large enough velocities that measurements of the atomic clock signals that are broadcast from the satellites have relativistic time dilation effects.

    Basically, Einstein both proved this guy correct (Newton's 2nd law does need to be adjusted on some fine points) and flat out wrong (that you need to use a universal frame reference to detect this adjustment).

    For me, if you want to make some very genuine physical science research, I would recommend two huge areas of study:
    • Measurement of "G" - the universal gravitational constant - Just as refinement of the measurement of "C" (the speed of light) brought about some interesting ideas that changed the study of physics (like Relativity), the study of "G" may produce some interesting science... especially if "G" is not a constant but changes from one place in the universe to another. Or other crazy knowledge may come from knowing this constant to a higher degree of precision.
    • Mesaurement of frictional coefficients - While there are some good theories about what causes friction of any kind, detailed knowledge of how materials interact with each other is more of a "cookbook" than a serious study of why friction occurs and how to come up with the actual coefficient without empirical examples.

    Neither area of study has may physicists who

  64. Well it was intended to be funny by Anonymous Coward · · Score: 0

    The post was a satire (slightly lame I admit) of the original story. The original story is an April Fools joke as was pointed out by the first poster.

    The bump story was devised by an old bush pilot. His greatest joy in life was to see how many newbs he could sucker as he flew them north. There was indeed a bump but it was caused by the pilot.

    The one part of the original story that was accurate was the description of 80 deg. north as being unhospitable. In the Canadian arctic, the only people living there are 'imported'. I camped for several months (including the spring equinox) on John Richardson Fjord just across from Greenland at 80 deg. N. That's when I learned the 30 30 30 rule: At 30 below (F) with a 30 mph wind, exposed skin freezes in 30 seconds. On the other hand, if you think vegitation (like trees for instance) gets in the way of the scenery, you'll love it. The mountains are completely unsullied by ugly green living things. ;-)

  65. Where is Ptolemy When You Need Him by jman.org · · Score: 1

    Even if this *isn't* an April Fool's joke, Mr. Ignatiev is forgetting that the sun is not the only mass which exerts force on the earth.

    Am by no means a physicist, but most likely this phenomena is simply explained by "upstream" forces such as the Milky Way itself, the universe beyond that, etc. My simplistic image is that of an underwater stream, causing ripples on the surface, whose effect you could override by swirling a stick. As soon as you stop swirling, the stream's inertia is again able to affect the water around it.

  66. Theory of Gravity? by FatSean · · Score: 1

    If it works, use it.

    Evolution theory works better than 'God made it'.

    Sorry.

    --
    Blar.