“Already in my original paper I stressed the circumstance that I was unable to give a logical reason for the exclusion principle or to deduce it from more general assumptions. I had always the feeling, and I still have it today, that this is a deficiency.” -Wolfgang Pauli
There's never a shortage of scientific topics to explore and take interest in here at Starts With A Bang! While we have our usual slew of articles, controversies, opinions and more this week, I'm also so pleased to share a new podcast with you! This month, thanks to our Patreon supporters, we took on a very bold topic, the one of our very existence. Believe it or not, there's one quantum rule that makes it all possible, and that's the Pauli exclusion principle!
- Can the Universe ever expand faster than the speed of light? (for Ask Ethan),
- Three spectacular nebulae caught together, revealing stunning details about star birth (for Mostly Mute Monday),
- From wartime devastation to academic discrimination, Cecile DeWitt-Morette overcame it all (a retrospective by Paul Halpern),
- Goodbye, Planet Nine! New and better data disfavors a giant world beyond Neptune,
- LIGO's successor approved; will discover incredible new sources of gravitational waves, and
- Are mass exinctions periodic, and are we due for one?
With everything we've covered, you've had plenty to say, and I want to address as much of it as possible! Come join us for this edition of our comments of the week!
Although we've seen black holes directly merging three separate times in the Universe, we know many more exist. Here's where they must be. Image credit: LIGO/Caltech/MIT/Sonoma State (Aurore Simonnet).
From Paul Dekous on criticism of LIGO: "To my knowledge it is the first ‘official’ criticism so it’s not like they have to use their time to fight of any other criticism, at least they could have said; “sure, now is a bad time, but you’ll get a response in a month or two”."
There are a lot of reasons to be skeptical of what someone is doing, but it's vital to not be overly skeptical. This is not the same situation as faster-than-light neutrinos, as the BICEP2 results, or even as WMAP claiming insanely early reionization. If the Danish group is right, it means that the LIGO detections are still there, and still robust, but at a lower significance. It also means that there is a component to the LIGO noise that they haven't correctly accounted for, and that might be problematic.
That's best-case-scenario for the Danish group. The other major (and favored) scenario is that it is the Danes that are wrong. This has courted enough controversy that this time I will likely write a piece myself this week on LIGO, its criticism, and what it all means.
A Higgs boson event as seen in the Compact Muon Solenoid detector at the Large Hadron Collider. This one high-energy collision illustrates the power of energy conversion, which always exists in the form of particles. Image credit: CERN / CMS Collaboration.
From Elle H.C. on a strange phenomenon from CERN: "Well I was always curious if collisions at the LHC could cause tiny vibrations in SpaceTime and shake up surrounding matter with the risk of disrupting protons, like how you can shake and break a glass from a distance, with a speaker with a strong enough amplitude."
I have never heard of this theory. How would it work within the Standard Model and/or General Relativity? I, myself, am not aware of any physically consistent scenario that has this sort of consequence arising from the LHC. I brought up Hitchens' razor this week -- what can be asserted without evidence can be dismissed without evidence -- and I am curious whether that applies here?
A single dish that's currently part of the MeerKAT array will be incorporated into the Square Kilometer Array, along with around 4,000 other equivalent dishes. Image credit: SKA Africa Technical Newsletter, 1 (2016).
From Frank on how telescopes create images: "I never understood how radio telescopes create images."
How is a radio telescope different from any other telescope? When a signal arrives, you only need to deduce just a few pieces of information about that signal:
- How much energy was in the signal,
- What the measured frequency of that signal was,
- And where on the sky that signal was located.
That's it. The first one can tell you the "apparent brightness," the second tells you a combination of the rest-frame frequency and the cosmic redshift, and the third one tells you angular position. So point your telescopes, they reflect and focus the waves to a point, and we assign a color/magnitude to that particular position dependent on how we choose to visualize/represent the radio signals.
It's really no different than how we "color the Universe" in any other light. I strongly recommend, in that vein, if you want to learn more in general, that you read the book Coloring The Universe by Arcand, Watzke and Rector, which I reviewed in a bit of depth around a year ago here.
From eric on the nuclear physics phenomenon of the island of stability: "A word of caution for the layfolk: “stability” is a relative term. It’s entirely possible that the nuclear shell effects Ethan talks about increases the stability of the isotopes in the ‘island of stability’ by a factor of 1,000 or even 1,000,000. But that may mean increasing their expected half-lives from nanoseconds to milliseconds. AFAIK nobody int the business expects these elements to be truly stable or even stable enough to allow us to build up macroscopic supplies of them as we do the actinides. But hey, we won’t know for sure unless/until we produce them."
This is a really good point. When we talk about nuclear physics, we're dealing with tremendously complicated systems where the strong nuclear force and electromagnetic force -- and even the weak force -- are all at play in extremely large composite systems. A single proton has three valence quarks; these nuclei in question have over 250 nucleons each, with around 800 valence quarks alone, all in a single quantum system. We can predict that these various isotopes of particular nuclei will be more stable than the ones surrounding them on the periodic table, but exactly how much needs to be determined experimentally.
And that is still, apparently, quite a ways away.
From Frank Bennett on whether the Universe can expand faster than light: "I think you need to show, as you have in other articles, that the effect is a purely geometric consequence of the expansion."
It's quite difficult to show that for a single object. When you measure the light from, say, a distant galaxy, you can measure the same things I talked about when the other Frank asked about how radio telescopes create images, including the wavelength and distribution of light from that object. Some of that redshift will be due to the stretching of spacetime; some of that redshift will be due to "peculiar velocity," or the motion of the object itself relative to its local frame-of-reference.
The only way to know how much is one type versus the other is to measure a large variety of objects at a variety of distances; you'll wind up with a picture of the overall expansion of the Universe and another picture, superimposed atop it, of the local effects of gravity pushing and pushing individual galaxies at speeds of tens, hundreds or even thousands of km/s relative to the overall Hubble flow. But on large scales, that geometric effect is easily seen, and extraordinarily prominent.
In this illustration, one photon (purple) carries a million times the energy of another (yellow). Fermi data on two photons from a gamma-ray burst fail to show any travel delay, showing the speed of light's constancy across energy. Image credit: NASA/Sonoma State University/Aurore Simonnet.
From Pentacho Valev on what the constancy of the speed of light means: "Any correct interpretation of the Doppler effect implies that the speed of light varies with the speed of the observer."
Not quite, and I have read many of your comments to attempt to see where I think you're making a mistake. You're saying, basically, that:
- You measure a frequency for your light.
- Frequency is the speed at which the pulses move divided by the distance between the pulses.
- A moving observer sees a different frequency than a stationary observer.
And therefore, you conclude, that the speed at which the pulses move must be different for different observers, and hence the speed of light is constant. That's what I think your reasoning is.
But what Einstein's theory says is that the speed at which the pulses move is always the speed of light in a vacuum for any type of light or any observer. So what's changing, for different observers, is twofold: the distance between the pulses, which you have right, by the fact of length contraction, but also the way that each observer measures time, due to the effect of time dilation, which is not encoded anywhere in your plain-English descriptions but which matters nonetheless. That is how the speed of light remains constant for all observers.
Read this a few times and think about it for a while, and see if you don't rethink how you've conceived of this problem.
Cecile DeWitt-Morette at her desk in her office in R.L. Moore Hall. Image credit: University of Texas at Austin, News and Information Service / L. Murphy.
A classic Ethan vs. Denier moment as related by Denier this past week on the topic of Cecile DeWitt-Morette: "Ethan: When you have rules that treat men and women equally in theory, but the practical application of the rules leads to unequal results, that’s a classic example of a rule that doesn’t work.
Denier: No Ethan. Bad!
When the practical application of rules leads to unequal opportunity, that’s a classic example of a rule that doesn’t work. The insistence of equality of outcome is a nightmarishly illiberal idea."
So there's a lot more to Denier's comment(s) that you're welcome to read, but the crux of this is very difficult, because I don't inherently disagree with the premise here. Unequal opportunity is bad; if everyone has equal opportunity and we see unequal results, that's not inherently bad. In fact, that would be, ideally, what a true meritocracy would look like.
The problem arises when we get into the practical applications. How do you measure whether the opportunity is equal or unequal? Is that something that's even possible? The original rules of UNC appeared to be equal, right? That if one spouse was faculty, then anti-nepotism rules just prohibited the other one from becoming faculty. But practically, most qualified male/female couples had the male member be older and more career-advanced when hired, which effectively barred the female member from access to a full professorship. You will notice that UNC's rules and goals are very, very different now.
The best argument I ever read about this issue was written by David Souter, when he spoke at Harvard in 2010 on the topic of Plessy vs. Ferguson. It's incredibly nuanced, talking about the different questions one was asking about the topics of what equal/unequal opportunity means: does it mean equal facilities, equal access, equal results, etc.? And while the answer to the question of race and segregation and barring access is a no-brainer today, he does a good job of getting into the heads of judges circa the late 19th century. So you can argue about opportunity vs. results, but when you see unequal results, boy, does it strongly suggest the presence of unequal opportunity.
Cécile DeWitt-Morette (on ladder) and colleagues, circa 1973, give a temporary observatory that will be used in Mauritania a dry run in a UT campus parking lot. Image credit: University of Texas at Austin.
From Elle H.C. on what Cecile DeWitt-Morette actually faced: "Some comments here are distasteful, and all this because she dared to speak up about some inequality along the way.
What do you want, that she just had kept it quiet and only talked about how good life has been to her?"
You can read an entire history of the event in an interview that the American Institute of Physics did with Bryce and Cecile when both were still alive. You are, of course, free to think whatever you like about it, but this is what they have to say in their own words. Here are some relevant parts:
Bryce: "But in the meantime, the people at Chapel Hill has persuaded me to consider putting this thing in Chapel Hill. And I was assured by the department there that it would be bona fide and it wouldn't be run by Bahnson. Chapel Hill is a beautiful place, and I was wanting to get out of Livermore for an academic position, so we went there, both of us, as visiting research professors. After a few years I was given a regular professorship and Cecile was demoted to a lecturer."
Cecile: "Without being told it was a demotion. "Oh, it will be so much better for you." And that's the part I didn't like, the hypocrisy of letting me believe that it was better. And in the French context, it could have been better, so I took it for granted."
Cecile was, no doubt, an opportunist, like a great many other people. And she demanded good things for herself, like many others. Should she just have settled for whatever was offered to her? I would again point to the changes in how spousal hiring is done at UNC and across academia as evidence that her decisions helped affect some tremendous positive change.
In theory, Planet Nine would likely be similar to the exoplanet 55 Cancri e, which is approximately twice the Earth's radius, but eight times the Earth's mass. This new study, however, disfavors the existence of such a world in our outer Solar System entirely. Image credit: NASA/JPL-Caltech/R. Hurt (SSC).
From John on the demise of the evidence for Planet Nine: "The falsifiability of the Planet Nine theory made it Science. The observations made it unlikely. Sic transit gloria mundi novem."
I liked Planet Nine as an idea, even though I was skeptical. There are other, indirect pieces of evidence that have come out against Planet Nine, largely based on the observations of TNOs in the outer solar system, but I thought it was most important to highlight the fact that Batygin and Brown's original dataset that motivated it in the first place is now looking... shall we say, woefully insufficient.
Also, I can never see "sic transit gloria" without thinking about Max Fischer anymore.
An artist's impression of the three LISA spacecraft shows that the ripples in space generated by longer-period gravitational wave sources should provide an interesting new window on the Universe. Image credit: EADS Astrium.
From Steve Blackband on LIGO, LISA and noise: "How is this affected, if at all, by your recent post that casts doubts on the LIGO observations and suggests that all they saw was noise?"
First off, no one (serious) is suggesting that "all LIGO saw was noise" at all. People are suggesting that LIGO is seeing correlations in noise that shouldn't be there, and that may pose an issue for the robustness and reliability of the signals, which still show up even with that correlated noise.
But what's awesome about LISA is that the overwhelming majority of sources-of-noise that LIGO must contend with disappear for LISA. LISA will have the vacuum of space to contend with, rather than the best vacuum we can make inside a long chamber here on Earth. LISA will be in orbit around Earth, and will lose all the sources of noise from the Earth's ground. Thermal noise will be at a minimum due to active and/or passive cooling on the spacecraft. (I'm not sure that's been finalized.)
One of the best parts of LISA, that I tried hard to emphasize, is how non-noisy it will be compared to LIGO. And if there is this mysterious noise correlation, that will be incredibly interesting, and perhaps will lead to -- if not new physics -- at least new advances in understanding the sources of a new type of interferometer noise.
Special relativity (dotted) and general relativity (solid) predictions for distances in the expanding Universe. Definitively, only GR’s predictions match what we observe. Image credit: Wikimedia Commons user Redshiftimprove.
From Sinisa Lazarek on dealing with relativity/Einstein deniers: "And then at the end of the day, when scientists call you cranks, you feel in your arrogance/ignorance that there is some conspiracy that no one is allowed to question GR/SR, when it’s not the case. There are hundreds of valid scientific papers out there with valid arguments on how to build/change something beyond GR. Questioning GR doesn’t make you cranks… HOW YOU question GR makes you cranks."
What do you do when you're presented with something that doesn't make sense to you? You think about it, you listen to it, and yet it just defies common sense. You know, in your gut, that it can't be right. What do you do?
We all get that knee-jerk reaction, the one that says, "that's gotta be wrong!" I had it yesterday; a friend of mine was telling me about kissing bugs, and that they bite your lips and put something into your blood that just lays there, dormant, for a decade or more, and then you develop symptoms and die. And I had that reaction, and said that it sounded like those made-up animals that Australians tell tourists about to trick them, like 'drop bears' and 'circle snakes.' (And yes, I know 'rock melons' are real; thanks Australia.) But what did I do? Did I just talk about how that can't be right, and tell what I knew to argue the point? Or did I look it up, and learn that kissing bugs are a common name for the insect that transmits the protist that causes Chagas' Disease?
My point is that it's easy to rely on common-sense and decry something that runs counter to that as an obvious falsehood. But life isn't obvious, and in particular, science isn't obvious. In fact, the fact that science isn't obvious is why it's so hard, why it takes so much training, and why the knowledge it takes to engage in it is so specialized. If it were obvious, we wouldn't need to be scientists to make the advances we've made. Think about this the next time someone advocates "common sense" solutions to our problems. Do you want common sense? Or do you want hard work, science, and evidence? Think about it, because if you're willing to put in the hard work, you can learn it all for yourself.
A large, rapidly moving mass that strikes the Earth would be certainly capable of causing a mass extinction event. However, such a theory would require strong evidence of periodic impacts, which Earth doesn't seem to have. Image credit: Don Davis / NASA.
From Denier on my opinion about our ability to introspect: "Were the last few words just a throw-away bit with truthiness feel used only to provide punctuation to the end of your piece? Or is there an epistemological school you are drawing from for that statement? Do you think that as a species we don’t do collective introspection well?"
What I said, in particular that led to this question was: For the foreseeable future, the Earth isn’t at increased risk of a natural disaster coming from the Universe. Instead, it looks like our greatest danger is posed by the one place we all dread to look: at ourselves.
It isn't about introspection that I was getting at, but rather the well-documented fact that humans are quite bad at evaluating risks. In particular, we're very bad at evaluating low-probability high-consequence risks, and almost always overstate those in our minds, compared to higher-probability risks. The idea of a catastrophic impact -- the focus of my entire piece -- is one such example of a low-probability high-consequence event, and it's one that humanity really frets about. The idea that the LHC would create a black hole and then that the black hole would destroy the Earth was another. And yet, actual problems like the deadliness of mosquito-borne diseases or simply the flu are just brushed off.
It is our ability to fret about phantom problems and exceedingly unlikely scenarios while failing to mitigate actual, ongoing, tangible dilemmas that frustrate me.
And finally, from Jose Pacheco on brown dwarfs: "One thing’s for sure, Brown Dwarf. You’ll never be bright enough to make Dad Star proud."
But this isn't because of a failing on either the brown dwarf's part or of another star that ever existed in the Universe; it's because all the other stars -- parent stars, sibling stars, etc. -- likely will no longer exist by time the brown dwarf merges with another to become a true star. The rate of decay is slow; gravitational radiation carries away mere Watts of energy for this brown dwarf system. But give it enough time, like all the time the Universe has left, and eventually this orbital decay will make a star. No matter how long-gone your progenitors are, you still shine bright, all the same.
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"How would it work within the Standard Model and/or General Relativity?"
Maybe a question for Stephen Hawking, and the vaporizations of Black Holes.
At the LHC the argument was made that Micro-BHs could form, and it wasn't excluded. But the risk was dismissed because they would vaporize immediately, and there is the argument that Earth and other planets are struck Cosmic Ray-wise with zillions of these 'possible' MBHs and nothing happens. All faire and square.
But as with the breaking of a glass they can record one *tick* on the glass to record its tone and than play it 'artificially' on repeat so the glass start to wobble excessively until bindings are cut off and the glass bursts, and the tension of the excitement is released.
We can make a comparison to Cosmic Ray collisions in nature as irregular *thicks* on the glass here and there, so sure everything will wobble a bit but the amplitude is not dense enough and it doesn't last long in one place. In contrary at the LHC the density and frequency rate at one specific place is a billion times higher than in CRs in nature, so here you have the man made loudspeaker-effect that is unseen in nature.
Now let's say we hit a point where the LHC starts to produce an excessive amount of MBHs that vaporize at a certain frequency then isn't that 'vapor' the same as the vibrations the loudspeaker produces, now if we look at Hawking Radiation:
"Physical insight into the process may be gained by imagining that particle–antiparticle radiation is emitted from just beyond the event horizon. This radiation does not come directly from the black hole itself, but rather is a result of virtual particles being "boosted" by the black hole's gravitation into becoming real particles. As the particle–antiparticle pair was produced by the black hole's gravitational energy, the escape of one of the particles lowers the mass of the black hole."
So what we have around the collision spot at the LHC are a lot of Virtual particles and we know that these are more like 'side' vibrations, that we can't observe, only when they turn into real particle pairs when the show up.
So there's a catch 22 the moment this effect shows up it means that the load speakers are shaking everything up as well at a high pitch.
If you have see the biopic on Stephen Hawking with Eddie Redmayne than you'll remember the scene where he got the idea for his radiation from watching scintillae escaping the fireplace. Well at the LHC there might come a flashpoint where there is suddenly a lot of this previously 'unseen' heat escaping, shaking up the Atoms in the area around the collisions spot until the point of 'combustion' and a chain reaction might be ignited.
"Hitchens’ razor: what can be asserted without evidence can be dismissed without evidence"
The evidence here is that you are: A. We are doing collisions at an unseen hight rate in one specific spot; B. Atoms can be broken apart; C. Waves can travel in between Atoms; D. There are virtual particles; E. Black Holes should vaporize; F. Micro Black Holes might form; G. Science as been confronted since ever with 'side effects' and chain reactions of all sorts, from fires to epidemics.
Anyway perhaps you are alluding on a 'smoking gun' which I don't have, but the moment there is one it can be too late. How can one stop a chain-reaction on a subatomic level?
“However, one significant problem remains with the nebula: the masses don’t add up. By looking in all these different wavelengths, we can calculate/estimate the mass of the Crab Nebula, and arrive at a figure of about two-to-five solar masses. The neutron star at the core is likely no more than two solar masses, and yet it should be impossible to have a supernova unless your progenitor star is at least eight times the mass of the Sun. So where did that extra mass go? There’s no shell around the nebula, and we’ve looked at length for one. Instead, our models of something — the nebula, the neutron star, or the supernova itself — must have a flaw in it somewhere. The data is better than it’s ever been; now it’s time for scientists to put those final pieces of this great cosmic puzzle together!”
Perhaps no flaw, maybe there was an extra (terrestrial) something, a local man made machine that caused a chain-reaction which induced the supernova explosion, and this nebula is the smoking gun of their involuntary suicide.
It can also explain the Fermi paradox, whereby a highly civilized species that looks for intelligent ways to explore the galaxies will blow itself to pieces to find a fuel, or think of Marie Curie's death:
"The damaging effects of ionising radiation were not known at the time of her work, which had been carried out without the safety measures later developed. She had carried test tubes containing radioactive isotopes in her pocket, and she stored them in her desk drawer, remarking on the faint light that the substances gave off in the dark. Curie was also exposed to X-rays from unshielded equipment while serving as a radiologist in field hospitals during the war. Although her many decades of exposure to radiation caused chronic illnesses (including near-blindness due to cataracts) and ultimately her death, she never really acknowledged the health risks of radiation exposure"
I rest my case.
Ethan Siegel wrote: "From Pentacho [sic] Valev on what the constancy of the speed of light means: “Any correct interpretation of the Doppler effect implies that the speed of light varies with the speed of the observer.”
Not quite, and I have read many of your comments to attempt to see where I think you’re making a mistake. You’re saying, basically, that:
You measure a frequency for your light.
Frequency is the speed at which the pulses move divided by the distance between the pulses.
A moving observer sees a different frequency than a stationary observer.
And therefore, you conclude, that the speed at which the pulses move must be different for different observers, and hence the speed of light is constant [typo perhaps - should be "is NOT constant"]. That’s what I think your reasoning is.
But what Einstein’s theory says is that the speed at which the pulses move is always the speed of light in a vacuum for any type of light or any observer. So what’s changing, for different observers, is twofold: the distance between the pulses, which you have right, by the fact of length contraction, but also the way that each observer measures time, due to the effect of time dilation, which is not encoded anywhere in your plain-English descriptions but which matters nonetheless. That is how the speed of light remains constant for all observers." [END OF QUOTATION]
Your counterargument is based on a wrong premise:
"what’s changing, for different observers, is [...] the distance between the pulses, which you have right, by the fact of length contraction"
Length contraction is irrelevant here - it can only be defined and calculated for objects moving at a speed smaller than c, and the pulses are not such objects. So the idea that the motion of the observer somehow changes the distance between the pulses (or the wavelength of the incoming light) is absurd, and the Albert Einstein Institute explicitly rejects it:
Albert Einstein Institute: "The frequency of a wave-like signal - such as sound or light - depends on the movement of the sender and of the receiver. This is known as the Doppler effect. (...) Here is an animation of the receiver moving towards the source:
By observing the two indicator lights, you can see for yourself that, once more, there is a blue-shift - the pulse frequency measured at the receiver is somewhat higher than the frequency with which the pulses are sent out. This time, THE DISTANCES BETWEEN SUBSEQUENT PULSES ARE NOT AFFECTED, but still there is a frequency shift: As the receiver moves towards each pulse, the time until pulse and receiver meet up is shortened. In this particular animation, which has the receiver moving towards the source at one third the speed of the pulses themselves, four pulses are received in the time it takes the source to emit three pulses." http://www.einstein-online.info/spotlights/doppler
Again: Any correct interpretation of the Doppler effect proves variable, not constant, speed of light. This is to be expected because the variation of the speed of light is in fact the cause of the Doppler effect. When the initially stationary observer starts moving towards the light source with speed v, the speed of the light relative to him becomes c'=c+v (in violation of Einstein's relativity) and accordingly the frequency he measures shifts from f=c/λ to f'=c'/λ=(c+v)/λ:
"Let's say you, the observer, now move toward the source with velocity vO. You encounter more waves per unit time than you did before. Relative to you, the waves travel at a higher speed: v'=v+vO. The frequency of the waves you detect is higher, and is given by: f'=v'/λ=(v+vO)/λ." http://physics.bu.edu/~redner/211-sp06/class19/class19_doppler.html
"vO is the velocity of an observer moving towards the source. This velocity is independent of the motion of the source. Hence, the velocity of waves relative to the observer is c + vO. [...] The motion of an observer does not alter the wavelength. The increase in frequency is a result of the observer encountering more wavelengths in a given time." http://a-levelphysicstutor.com/wav-doppler.php
A. Yes, there are many collisions, but no two EVER occur at the same point in space. The earth is rotating. It's also revolving around the sun. The solar system is revolving about the galactic center. The galaxy as a whole is moving relative to other galaxies in the local cluster. The local cluster is moving relative to other clusters. We NEVER see two collisions occur at the same spatial location.
B. Yes, atoms can be broken apart. What relevance does this have for anything? Such fission events do create energy, and can cause great devastation if allowed to do so in a way that sustains a nuclear explosion, but that's not particularly relevant in a particle accelerator, is it?
C. Yes, waves can travel between atoms. They're called electromagnetic radiation or gravitational radiation. There's no evidence that there's any danger from these. There's also no evidence for any other wave phenomena travelling through the vacuum. What evidence is there that electromagnetic waves or gravitational waves can have any devastating consequences?
D. Yes, there are virtual particles. There are virtual particles everywhere, though, not just in particle accelerators. These really have no measurable effect, though. If they did, they'd be REAL particles, not virtual ones.
E. Black holes should vaporize. I agree. On a timescale dependent on the size of the black hole, that is true. Why is it relevant?
F. Micro black holes might form. Sure, and they might form when the atmosphere gets hit by cosmic rays of much greater energy than what the accelerator can produce. Why does that not cause a problem?
G. Yes, chain reactions can be hazardous. What evidence do you have that collisions in a particle accelerator will cause any kind of chain reaction, though? Another case for Hitchen's Razor, it would appear.
You postulate some kind of resonance like that of a glass breaking because of a sound wave. That resonance, though, is a result of the frequency of the sound wave matching the natural vibrational frequency of the glass. The incoming waves reinforce each other and build to a large amount of energy, capable of shattering the glass. In the case of the particle accelerator, what exactly is it that's resonating? The particles being collided? The accelerator itself? If there's nothing to resonate, then there's no way for such a resonance to cause a problem.
Remember that any such phenomenon that could be observed in a particle accelerator could equally well be observed in cosmic ray collisions of higher energy. If there's no evidence of such in cosmic ray collisions, why would you expect such phenomena in accelerator collisions?
Just for the heck of it, I checked out one of your links. The derivation was one based on classical mechanics as a simplification and it ignored relativity completely. This is a good approximation in some cases, such as the Doppler shift for sound waves, but it is incorrect for light. Besides, it does not claim (as you said) that the wavelength is unchanged. The derivation yields different results for a moving source and a moving observer (a sure clue that relativity is ignored since relativity tells us that the two are physically equivalent). For a moving source, it gives wavelength equal to the difference of the wave velocity and source velocity divided by the frequency. For the moving observer it's the sum of the wave velocity and observer velocity divided by the frequency. For a resting observer, of course, the wavelength is the wave velocity divided by the frequency.
The main difference in relativity is that the derivation you linked assumes that velocities are additive. That is if a wave is travelling at 500 miles per hour and the source moves toward you at 300 miles per hour, you will observe that the wave travels at 800 (500+300) miles per hour. This is not the correct formula for velocity composition, though, only a good approximation when the speeds are small. When the speeds are large, a more complicated formula applies (you can look it up; it's too complicated to render well here). This formula, though, yields a composed velocity of c when either of the two component velocities are c, hence when working with light, the moving observer does indeed measure c for light speed.
Not at all. Take for example crime statistics on arson. Men are arrested for arson at over 4.5 times the rate women are. The idea the differential suggests the presence of unequal opportunity is laughable. Women can purchase matches just as easy as men can.
In the case of Cecile DeWitt-Morette there very well may have been the presence of unequal opportunity and at any rate it is anecdotal so isn’t proof either way. That said, she should not be wholly exonerated from role her choices played in bringing about the situation. She did choose to stay married to her husband, did choose to support his move to UNC, and chose to work at UNC herself for 15 years rather than apply to be a full professor at Duke University just up the street.
On Cecile DeWitt-Morette I think you and I agree a lot more then we disagree.
@ Sean T
you should check Pentcho's comments on the LIGO post... just for heck of it...
It doesn't matter what we argue, even given plain every day examples that prove his reasoning is wrong.
Basically he doesn't believe in blue-red shift of light. He can't distinguish between classical vs relativistic doppler effects. He can't explain why we keep getting the same constant speed for light even tough he argues that we should see speeds over the speed of light if the source is moving towards us.. etc etc...
He's not here to learn.. he's here just to troll same old (wrong) song over and over.
In reading through your linked piece from Souter I didn’t find anything on the issue of opportunity versus outcome. It has been quite a hot topic lately as that seems to mark the separation between liberals and progressives. Classic Liberals want equality of opportunity. Progressives want equality of outcome and will accept or even demand UNequal opportunity to bring it about.
Souter’s speech seemed more about judicial activism versus constructionalism and his personal justifications for violating the separation of powers by legislating from the bench. Funny enough I thought he shot a hole in his own justification with the Plessy and Brown juxtaposition. Activist Judges in the Plessy case took the temperature of the nation which influenced the outcome. Activist Judges in the Brown case took the temperature of the nation which influenced the outcome, but because the mood of the nation changed the earlier Activist Judges were wrong. Essentially it is that Activist Judges are always wrong, if not today then just give it a few decades and they will be, so Souter feels justified in being an Activist Judge.
Here is my issue with Activist Judges; Democracy is dangerous. It has its benefits for sure but it is dangerous. Democracy is mob rule. The founders of our government very purposely created a Representational Republic precisely because they understood the problems inherent in pure Democracy.
James Madison, Federalist Papers No. 10
With the Judicial Branch they took extra precautions to isolate it from public opinion. They didn’t want that poison anywhere near the judicial system. As put very well by Marvin Simkin:
Then we have former Supreme Court Justice David Souter saying that we should ignore the stated Constitutional Separation of Powers, and ignore the Original Intent, and ignore that the Activist Approach previously led to bad precedent, and go right ahead being an Activist Judge because the will of the people has changed. Eff that. I’m glad Souter is gone. I’d take the Notorious RBG over that guy any day.
Forget Trump for a moment. If you want to know what it would take in the United States for a true Authoritarian to come to power, it is for people like David Souter to be allowed to strip away the protections put in place by the founders that buffers the levers of power from mob rule, then run a demagogue and it is game over. So long as the existing procedural machinery is left it place it can’t happen even under someone like Trump.
Sean T wrote: "Pentcho, Just for the heck of it, I checked out one of your links. The derivation was one based on classical mechanics as a simplification and it ignored relativity completely. This is a good approximation in some cases, such as the Doppler shift for sound waves, but it is incorrect for light. Besides, it does not claim (as you said) that the wavelength is unchanged."
No it does not ignore relativity. When the speed of the observer is small, the relativistic corrections CAN be ignored, and this is textbook wisdom. Many authors teach only this speed-of-observer-is-small case where classical and relativistic analyses coincide, and do not introduce the relativistic corrections at all.
As for your discovery that the author "does not claim that the wavelength is unchanged", it is funny, to say the least. The author says that the speed of the waves is higher for the moving observer, but this obviously means nothing to you:
"Relative to you, the waves travel at a higher speed: v’=v+vO"
Ethan: "... by the fact of length contraction..."
Length contraction is based on how different observers from different frames of reference might theoretically measure length. As applied to physical objects, it is not only absurd but factually wrong to assume that an observation at high speed makes a physical object shrink as compared with a measurement from at rest with the object. Both can not be "the correct" length of the object. There is no physics whatsoever to explain the shrinkage of physical objects, however images of them may *appear* differently, as conveyed by light to a near lightspeed traveler.
"Do you want common sense? Or do you want hard work, science, and evidence? Think about it, because if you're willing to put in the hard work, you can learn it all for yourself."
The "science" of special relativity theory needs to supply the physics of, for instance, Earth's diameter shrinking, more the faster an observer approaches until it is flat as a pancake. Or is that an "equally valid" description of Earth just because SR says that length varies with the observer's frame of reference?
Is that too much to ask before calling before calling length contraction a "fact?"
"... due to the effect of time dilation."
The same can be said for "time dilation." Not a "fact." Clocks don't "measure" an entity, "time." They just tick at various rates depending on the history of forces (acceleration and gravity) to which they have been subjected.
@Sean T #4,
A. Collision spot (speaker) and nozzles (glass) move together trough space, vibrations continuously travel towards the protons that make up those nozzles. It's like throwing a ball back and forth between two cars driving next to each other. I'm sure your arms will get tired and your muscles start to burn even if you're never throwing it from the 'same spatial location'.
B. The fact that Protons can be shaken apart proofs that they are fragile.
C. That's like sticking your hand into a fire for a fraction of a second and saying 'look it's safe. I am not proving that a low frequency and density is dangerous, I am trying to proving that the higher the energy the bigger the danger becomes. This part should be the easiest to understand.
D. Again the same case as C. It is about turning up the heat.
Leave your kid during a normal day in the sun or during a heatwave. Are you going to believe someone that brings up the former and says 'these really have no measurable effect' … and let your kid get sunburned?
E. Because this 'vapor' is energy converted into gravitational vibrations that are boosted onto the protons of the nozzles. You remember the glass being exited by the sound waves.
F. Really? I explained this over and over again in my comment, why are you not reading what I write?
I'll repeat, density and frequency at one specific spot. Remember the speaker, you can play for a fraction the pitch of the glass really loud, but the glass won't break those are the HECR collisions you refer to, while I am pointing out repeatedly that it's the ongoing high frequency that causes the effect of breaking the glass. It's the same as robbing wood for a longer period to start a fire vs. smacking it hard for just a fraction. It is about building up energy, wearing matter out, got it?!
G. It is only to show that when dealing with physics we can get chain reactions in all shapes and forms, and at all levels; from an avalanche, to a forest fire, to an A-bomb, it would be unique if there wouldn't be one at a subatomic level. It looks like a law, sort of like Moorse's law for transistors, you draw a line from point to point …
"Remember that any such phenomenon that could be observed in a particle accelerator could equally well be observed in cosmic ray collisions of higher energy."
You are simply refusing to read what I write. Read up instead of making such a futile remark. I mentioned enough times the difference in density and frequency. Actually the largest part of your comment here was completely besides the point and full of ignorance.
Robbing > Rubbing
"Take for example crime statistics on arson. Men are arrested for arson at over 4.5 times the rate women are. The idea the differential suggests the presence of unequal opportunity is laughable."
This is an interesting example, it proofs that man are more testosterone driven, and commit easier violent crimes, probable also push and exclude woman towards the back and rape them. It is a good reason to be weary why woman are less represented in certain fields even when they have equal rights.
BTW your arson example also fits also perfectly with my LHC argument that 'mankind' will set the world on fire, and burn it to the ground. In is a gene.
I certainly do not speak for progressives write large, but IMO you have sadly and ridiculously misread your opponents, strawmanning them quite badly. Few to no progressives want a Harrison Bergeron type world of mandated equality of outcomes. Maybe some on the extreme left does, but IMO it's not the goal of the movement.
Where progressives differ from conservatives is that progressives recognize that luck plays a big role in many people's lives and that bad luck is in many ways the antithesis of 'equal opportunity.' Where a conservative would say "you got cancer? Well, everyone had that chance. Tough luck, pay for it yourself, society should do nothing to help you," the progressive says "getting randomly struck by a disease prevents the equal opportunity for a prosperous life that the state promised you. Thus it makes sense that we all contribute to a fund that will mitigate the effect of that bad luck and restore back to you the equal opportunity to have that life." Likewise with unemployment and welfare - a conservative says "if you got fired, you probably deserved it. The state will not help you. Depend on your friends/family, or work, or starve." The progressive says: "many layoffs and firings are due to circumstances beyond the control of the person, and unemployment can strike even good workers. Thus providing the unemployed some bridging resources while they get back on their feet creates the opportunity for people to plan their lives and make good strategic decisions in spite of the short-term vicissitudes that would steal their opportunity for a good life."
Or to put it more simply, conservativism is a 'just world' system - it works to the extent that nature (and circumstance) is just. It fails when nature and circumstances get further away from just. Progressivism seeks to modify that system in recognition that neither nature nor circumstance is, in fact, close to just.
You can find this physics in any quantitative discussion of SR, from wikipedia and many other sources. The equation for length contraction is deductively derived from Einstein's two postulates (physical laws invariant for different inertial reference frames; speed of light is c in all frames). Thus if you accept them, there is pretty much no way to logically or deductively reject length contraction. But Sinisa told you this months ago, and you never tell us which postulate you reject (probably a psychologically safe move, since both are observationally easy to test) so I have no doubt you'll continue to reject it for nonrational reasons.
The most fundamental thing(s) required for any understanding of relativity happens to be the very thing(s) that are being rejected as the very source of it's fundamentally falseness. Every iteration of the conversation is a new ride on the very same carousel, playing exactly the same music. Simultaneously entertaining and hopelessly futile.
Conservatives are a whole different kettle of fish. I'm leaving Conservatives completely out of this discussion and only referring to leftist Classical Lockean Liberals versus leftist Progressives. Many believe 'Liberal' and 'Progressive' to be synonyms. They are not, and much has been made of the differences lately by those on the left dismayed at the state of affairs on their own side.
One of the more outspoken voices on this subject is Dave Rubin, a gay married atheist of Jewish ancestry, pro-pot legalization, pro-choice, life-long lefty voter who got his online start on The Young Turks.
In the following video Rubin spends the first 5 minutes monologuing on the difference between Liberals and Progressives and Libertarians, and why he feels somewhat abandoned by the left. He's interesting and not at all abrasive if you've got 5 minutes.
There is nothing wrong with being extremely skeptical. It is not like I hate this project and want to stop it, they can build a few more detectors and I support LISA. Show me what you got.
Looking forward to your article.
Okay then enlighten me. What exactly is it that is vibrating that will cause the disaster? Is it the protons being collided? Is it the detector? Is it air inside the system? You are throwing out ideas, but have no physical mechanism by which those ideas could be true. Argument by analogy is faulty if the analogy doesn't apply. Like I said above, the glass shatters because of vibrations in the glass that match its natural vibration frequency. What in the accelerator is vibrating?
As for your argument about repeated collisions, that too is specious. Each collision involves two protons; two DIFFERENT protons. The same protons are not colliding over and over again. The decay particles will interact with particles in the detector, but you do realize that two successive collisions will have a miniscule probability of reacting with the SAME particles in the detector. Each proton-proton collision produces a handful of decay particles. Let's be generous and say 10 particles are produced in each collision. The detector is a macroscopic object, meaning it's made of on the order of 10^20 or more particles. What is the probability that two successive collisions will produce decay products that react with the SAME particle in the detector? It's on the order of 10^-19 or less. That means that the proton-proton collisions in the LHC are not really any different than the high-energy cosmic ray collisions in the atmosphere. The energy from each collision is dissipated via independent interactions with different particles in the detector system. Further, if there were multiple interactions with the same detector particle, they would have to be closely spaced in time. The detector particles will be in an excited state as a result of a collision with a decay particle. This excited state last only for a very brief time (on the order of 10^-15 seconds or so, depending on the state and the nature of the interaction). Two particle collisions interacting with the same detector particle spaced even 1 second apart would be equivalent to independent interactions.
Finally, while the energies involved SOUND very high, they in fact are not in macroscopic terms. Suppose that the LHC is running at 13 TeV at a rate of 10^12 collisions per second. The energy for each collision is approximately 2 microjoules. The power produced in these collisions is therefore about 2 megawatts. This is substantially lower power output than a good sized power plant.
You have basically put forth ideas without evidence for their validity. It would be valid then to dismiss those ideas without evidence. Of course, we DO have evidence for the invalidity of your ideas. The LHC has been running for some time now. Have there been any reports of catastrophic disasters resulting from its operation? Are we not still all alive? Is the earth not intact? A good scientist recognizes when his or her ideas have been falsified by the data and gives up on them.
Just an aside: from a point of view of actual physics, if there WERE an energy that in and of itself would create situations that might cause issues, that energy would naturally be expected to be on the order of the Planck energy. If you are not aware of it, the fundamental constants (G, h, c) can be arranged in such a way as to produce quantities that have units of mass, length and time. This gives a unit system that in some sense is the natural unit system of the universe. The quantities seem to represent inherent limits of the universe. For example, it is theoretically impossible to measure a length smaller than the Planck length or a time shorter than the Planck time. Given a standard unit of mass, time and length, it is then possible to produce derived units for most other physical quantities. The Planck energy is one such quantity. It would be equal to c^2 times the Planck mass. The Planck energy turns out to be larger than the collision energy at the LHC by a factor of roughly 10^14. We have quite a way to go before we would have to worry about hitting such a limit.
eric @ 16: "). Thus if you accept them, (My note: the postulates of SR) there is pretty much no way to logically or deductively reject length contraction."
Math and theoretical postulates do not make physical objects shrink. As I said, there is no physics of a shrinking objects ( Earth for instance) depending on differences in observation. That would be the optical physics of images conveyed by light to near lightspeed observers.
It the real physical world (beyond observational differences) planets (and stars) are NOT FLAT. SR must eventually get over insisting on physical shrinkage as a result of observational differences.
edit: In the real world...
Regarding ‘different’ protons … you could look at the LHC as a combustion engine, each time gas is injected into the same cilinder, there’s a spark and BAM! you have a combustion, the piston is pushed upwards and fuel is converted in kinetic energy. When it’s the cilinder of a Harley Davidson motor, you’ll hear the loud explosions: BAM-BAM-…-BAM
In short we put fuel into the motor, we have a chemical explosion and we get kinetic energy, heat, combustion gases and sound waves.
So each time we inject a new portion of fuel, but the place where the combustion happens stays the same, it is in the cilinder. The same goes for the LHC each time new collisions happen with new protons, but it’s always at the same spot surrounded by the same nozzles.
Now when we collide Protons at the LHC we get all kinds of decays, you could compare these to the kinetic energy, the light flash and the combustion gases of the motor, and we can detect these.
My argument is that p+p+ collisions generate also undetectable vibration within SpaceTime, The Vacuum and/or the HiggsField. Just like the gravity waves (presumably) detected by LIGO.
I like to compare those vibration to the sound-waves. If you only have visual tools to look at a motor you will only see the flash, the piston being pushed upwards and the fumes escape. What you will fail to notice are the sound waves. The LIGO experiment has shown how difficult it is to record vibrations in SpaceTime, there is too much noise to detect everything and LIGO is done in complete silence. The LHC is the opposite with noting but noise so detecting more ‘gentle’ waves is a no-no. Think again of the Harley, the LHC can’t hearing the BAM-BAM’s, they go under the radar.
BTW if you are familiar with Harley’s then you know that nuts and bolts will start to rattle lose from vibrations of the one- or two-cylinder power-plants. This is the same as the Glass that starts breaks, and it can be pretty dangerous cause the bike might fall apart causing a crash.
Now your objection is:
“The decay particles will interact with particles in the detector, but you do realize that two successive collisions will have a miniscule probability of reacting with the SAME particles in the detector.”
This is true for the elements we can see (kinetic/flash/fumes) but the gravity waves detected by LIGO travel spherical like a wave through a medium, actually even light is a wave (and a particle).
So each time a p+p+ collision happens all the particles surrounding the collision spot can feel these waves. Of course the further matter is from the collision the less intense these waves are.
This contradicts your second objection:
”That means that the proton-proton collisions in the LHC are not really any different than the high-energy cosmic ray collisions in the atmosphere.”
In nature there are about a thousand Cosmic-ray collisions of a few GeV’s (1 GeV= 10^9 electron Volt) per second per m^2. In LHC it are about one 1 billion per second per cm^2. That’s 1.000.000 times more for an area which is 10.000 smaller, it is a density & frequency difference of 10 billion and unique in the Universe.
BTW during the last run at the LHC in 2015 we had collisions that were even 10.000 times more intense, with energies of 13 TeV (1 TeV= 10^12 eV). These collisions are in nature of course less frequent per m^2 while the density & frequency at the LHC of 10 billion per cm^2 was maintained. Look at this graph to get an idea: https://upload.wikimedia.org/wikipedia/commons/8/87/Cosmic-ray_spectrum…
You could compare this to having one Harley Davidson driving around your house BAM-BAM or 10 Billion of them, have you ever heard the story of the walls of Jericho that fell after Joshua's Israelite army marched around the city blowing their trumpets. :)
And regarding your last objection:
“Finally, while the energies involved SOUND very high, they in fact are not in macroscopic terms.”
Yes that is true, but the density and frequency rate of the collisions is extremely high, you can compare cosmic rays to rain drops, water being soft an gentle or even hail hitting hard; but at the LHC with its extreme high frequency and density you get something like those intense waterjets that can cut marble. The same for breaking glass with sound, continuous high frequency receptive vibrations.
Next you have also the fact that to start of a chain-reaction very little input can be enough to start it, a small spark on some dried out (strained) grass etc.
Anyway, a Proton has an inner mechanism with it’s tree quarks, gluons and seaquarks; if something starts to disrupt that mechanism a Proton could loose it’s function of being ‘positive’ and implode, what happens than to for example an iron Atom if it’s nucleus is disrupted, will it split?
If the vibration carries away energy, it will be detectable because all the other energy output in the product will not equal the input energy of the reactants.
That would make it really easy to detect. The only way your effect could be real but "undetectable" is if all the particles surrounding the collision spot didn't feel those waves.
A part of my argument is that there is a flash point, like the glass that bursts after a longer period of excitement. We increase energy and luminosity at the LHC and are shaking up surrounded Protons harder and harder but we can't detect that they we are straining them and that they are wobbling much harder because they are keeping their relative structure.
It is only past a certain tipping point that the glas breaks. The same goes for those protons surrounding the collision spot, were we reach a frequency and intensity of collisions at the LHC that causes them to break. At that point it all surfaces what was going on, and becomes 'detectable'.
The problem here is that it could be too late and that we, by accident, have started a chain reaction. Think of having a bucket of gasoline and you trow a rock in it, nothing will happen except for a big splash! But if you heat up each time that rock a little more until it sees red than, then we will get once we reach the flash point an ignition and an rapid explosion and you could set your home on fire.
you've been down this road before... years ago... so much so that you even got banned on this blog, because your "scare-theory" was so non-scientific that it became painful.
It's still non-scientific, and it's still painfully whack. Nothing is happening at LHC to cause the world to blow up. There are no spooky vibrations, no black holes etc etc..
Please stop posting this non-sense again. In last couple of months you actually had nice comments and productive discussions. Why this change in tone and mindset all over again?
"There are no spooky vibrations, no black holes etc."
LIGO detected vibrations of BH, that's new.
BTW I am not saying that it will happen, it is just something that needs to be taken in consideration. Sure you can be like Denier and be ignorant.
"LIGO detected vibrations of BH, that’s new."
I'm talking about your rants about LHC making micro-black holes and cascading vibrations and whatnot that you are afraid off! Don't twist my words.
I am not 'ranting' here, I am answering Ethan's questions:
"How would it work within the Standard Model and/or General Relativity?"
"I brought up Hitchens’ razor this week — what can be asserted without evidence can be dismissed without evidence — and I am curious whether that applies here?"
But okay, so are you now saying that there can be no micro-black holes produced by the LHC, and if there were that they wouldn't boost out virtual particles? You do know what virtual particles are, don't you; and you do know that you are contradicting here serious theoretical research.
BTW may I remind you what Ethan has told you about things YOU don't 'believe in:
"What do you do when you’re presented with something that doesn’t make sense to you? You think about it, you listen to it, and yet it just defies common sense. You know, in your gut, that it can’t be right. What do you do?
We all get that knee-jerk reaction, the one that says, “that’s gotta be wrong!”
But what did I do? Did I just talk about how that can’t be right, and tell what I knew to argue the point? Or did I look it up, and learn that kissing bugs are a common name for the insect that transmits the protist that causes Chagas’ Disease?"
So please do reflect a little before saying that is not possible.
Yes, chelle... instead of comparing LHC to combustion engine, and some weird vibrations that only you understand shaking spacetime from protons... look it up first, inform yourself.
p.s. your dead giveaway is that you compare what LHC is doing to irrelevant macroscopic things. Glasses shattering from sound, gasoline, fire etc...
Wanna argue something... use real science. Don't compare things which aren't comparable. We are all grown boys and girls here with decent understanding of physics, so either argue exact things that are going on with exact results.. or you're in the same basket with MM, pantcho etc...
I talk about MBHs that vaporize, p+p+ collisions and GWs.
Ethan didn't seem to have a problem when I wrote:
"Well I was always curious if collisions at the LHC could cause tiny vibrations in SpaceTime and shake up surrounding matter with the risk of disrupting protons, like how you can shake and break a glass from a distance, with a speaker with a strong enough amplitude.”
Your argument by analogy is faulty. When the analogy breaks down, so does the argument. If you are talking about multiple collisions producing vibrations in spacetime, remember that no two collisions EVER occur at the same point in spacetime. The LHC is moving quite rapidly through spacetime (technically, at the speed of light if your discussing 4-velocity). In spatial terms alone, it's moving quite rapidly as well, so there are no two collisions occurring at the same spatial point either. We need only deal with SINGLE collisions, not accumulations of energy from them.
Now if you're talking about the collisions somehow interacting with the air inside the lab, the detector itself, or some other matter present, then sure repeated interactions could occur. What mechanism though would direct the p-p decay particles to interact with precisely the same environmental particle multiple times within a short time span (short enough that an excited environmental particle would interact before it returned to a relaxed state). It's highly improbable without such a mechanism that this would happen.
Without multiple microscopic interactions, all you are talking about is dissipation of energy at a macroscopic level. The energy dissipated is quite a bit lower than the energy being dissipated at a typical power plant. Nobody's concerned about a power plant producing catastrophic consequences (discounting the environmental damage and contribution to global warming). Why would the LHC be different? The repeated interaction you are concerned with just is not a factor like you seem to think it is. Arguments by analogy rarely work well on a microscopic level.
Besides, like I said above, the LHC has been operating for more than two years. Where are the micro black holes? Where are the protons being disrupted? Your idea may have been scientific in the sense that it is testable, but the test has now been run, and it's wrong.
Sean T #34:
"remember that no two collisions EVER occur at the same point in spacetime."
Sean T #4:
"there are many collisions, but no two EVER occur at the same point in space."
I responded to this at #11. The same goes for your other remarks, what's the use to answer to your questions if you ignored what I write?
One remark though, you say: "the test has now been run", so why keep upgrading the machine?
Why keep upgrading the machine? Well, despite your opinion to the contrary, running collisions at greater energies and greater luminosities will, in the opinion of real physicists, generate better data that may lead to scientific breakthroughs.
In case you did not comprehend my point. The test I was referring to was the test of your hypothesis that the LHC would somehow cause a disaster. It has not. I did not mean to imply that the real physics being done using the LHC was finished.
Sinisa Lazarak @32: "... or you’re in the same basket with MM...'
Rather than continuing to "put me in a basket" with "cranks" (all critics of relativity) address my statement:
"As I said, there is no physics of shrinking objects ( Earth for instance) depending on differences in observation."
Anyone who accepts SR's absurdity that a pancake shaped Earth ... or having various diameters depending on the speed and direction of approach of all possible observers... is valid science is seriously deluded by the belief that the length of things "depends on whom you ask," as Ethan promotes here... and of course acceptance of the "postulate" that length must be variable if lightspeed is constant.
How would length contraction actually work, physically speaking? Compression requires force... a lot of it to flatten Earth!
But y'all continue to ignore that little fact and chant along with SR doctrine that it all depends on the observer. That is philosophical idealism, NOT OBJECTIVE SCIENCE.
maybe you missed my comment about why you are cranks.. the link to it is up there in the middle of the article. No, not all critics of relativity.. just one particular bunch.
"The test I was referring to was the test of your hypothesis that the LHC would somehow cause a disaster. It has not."
You don't say.
I wrote plenty of times that one day we might reach a flash point if we keep on increasing the energy and luminosity of the collisions. But Mr. T here already knows that the 'test' is done and that it has invalidated my argument, but oh 'real physics being done using the LHC isn't finished'.
I find you to be a dishonest debater.
Don't worry, you're not a crank, you're just dumb.
I don't mind being called a crank, because my hypothesis is crazy. We are sort of on the opposite sides of the spectrum, you lack imagination, while I have too much. ?
I think, like a lot of cranks, you confuse "my idea was considered and nobody found it convincing" with "my idea was not fairly considered." In my opinion the former happened (and continues to happen, with each new objection), not the latter
If protons are like ringing glasses, then CERN risks the destruction of the world. But if protons are like power rangers, then banging them together will create a cool giant robot! And right now, both of those metaphors have equal evidence and theory behind them. So I consider them. Here is me, considering them. Rolling them over in my mind. Okay, they are considered. Since the evidence of these metaphors being accurate descriptions of reality is zero in both cases, after due consideration I decide they are not worth changing my experiment over and I move on..
But have no fear! All you need do is go out and get some evidence that protons are like ringing glasses and that your hypothetical waves do exist, and scientists will reconsider your idea.
you confuse “my idea was considered and nobody found it convincing” with “my idea was not fairly considered.”
Whatever, semantics, the general idea is that MBs wouldn't produce notable gravitational waves. They are something like 50 to 100 orders of magnitude too weak to be detected, and also 20 to 50 orders of magnitude too weak to play a role in the collision.
The key issue stays that the high frequency isn't considered even though we have plenty of examples in physics where frequency plays a crucial role.
Look at the fire of the tower in London, they didn't consider the flammability of the panels, well surprise, surprise.
History repeats itself over and over again, even with your joke:
"if protons are like power rangers"
They also used to laugh with Kekulé's structural formula of benzene as being monkeys, I guess now idiots like power rangers, what's new:
"All you need do is go out and get some evidence that protons are like ringing glasses and that your hypothetical waves do exist, and scientists will reconsider your idea."
That's something I have already realized some time ago, and I am working on that, no worries I am getting closer.
If you like to sponsor my research feel free to do so ?
So... still avoiding the substance of the criticism that there is no physics of shrinking physical objects (as per SR).
It's all based on the "subjective experience" of Observer A vs Observer B (human or muon or whatever) such that the " flat Earth" (as seen from the fast approaching traveler) becomes "equally valid" with the actual physical ( factual, not fantasy theoretical) nearly spherical Earth with all epistemology supporting it.
Rather it's still just "attack the critic" who dares to declare that "the emperor (of SR) has no clothes"
craving attention, are we? ROFL! Read a book or two instead...
Ok, I thought a few years back you said that the LHC run in its current configuration would cause a disaster. Since it did not, you were incorrect. Now, if you want to move the goalposts and posit a different higher energy and frequency, fine, go ahead. The upgrades are going to continue to go forth, and your hypothesis will be tested in due course. Please, though, tell me the VALUES for energy and frequency that will cause disaster. Until you can quantify it, you absolutely will not be taken seriously.
Even after quantifying your idea will probably be dismissed as lacking in physical mechanism, but by not quantifying you can always keep saying that we just haven't reached high enough energies and/or frequencies yet and your idea then becomes unfalsifiable. There are always bigger numbers that haven't been tried yet, so if you are allowed to just keep moving the goalposts, your idea cannot be proven wrong.
The fact that you are attacked for being critical of relativity does not imply that you are correct in your criticism. If you declare that the emperor has no clothes, when in fact the emperor is dressed in full imperial regalia, then you will be rightly attacked as being delusional.
@Sean T #47,
"I thought a few years back you said that the LHC run in its current configuration would cause a disaster. Since it did not, you were incorrect."
Again you are dishonest debater. I did not say that LHC would cause disaster.
How could/can I know what the flash point will be, that's like asking the first person who lit a fire how much heat it will take before igniting it? That's also what I said before, 'there’s a catch 22'. You need a reference, but the reference could be disastrous from the get go.
And you are equally dishonest. Why did you oppose the LHC, then, if you didn't think it would be disastrous? Why do you continue to oppose it?
Let me try this by analogy since argument by actual physics seems to not work, and you seem to like arguments by analogy. The LHC experiments are analogous to a child throwing a tennis ball at a brick wall. If he throws it hard enough, it could break a hole in the wall. However, he's simply not capable of throwing the ball that hard, so there really is no danger. The frequency is really irrelevant. You can throw that tennis ball against the wall thousands of times a second and the wall isn't going to break. You need more energy to break the wall. The energy from the previous throw is dissipated by the time the ball hits the wall again.
Now, as I have said above, physics can give us an idea of the amount of energy needed to cause things like you are afraid of with colliders. That would be energies for interactions on the order of the Planck energy. The energies of the LHC interactions are 14 orders of magnitude smaller than this, so there is little danger.
That's the physics of the situation. If you want to be taken seriously, provide some physics of your own. What is the mechanism by which a resonance can cause damage? What is doing the vibrating? What is the resonant frequency or frequencies that could be dangerous? How is energy from a given collision stored and added to the energy from subsequent collisions?
Such and such MIGHT happen is not an argument. I MIGHT win the Powerball. If you're going to question accepted and well-established science, then anything MIGHT happen. The LHC MIGHT turn into a giant bird that will eat the entire human race. A wormhole MIGHT open and a hostile race of aliens MIGHT come through and destroy the earth. Obviously, I have no justification for thinking any of those things WILL happen, but neither do you for what you say might happen.
* "Why did you oppose the LHC, then, if you didn’t think it would be disastrous?"
There is a difference between 'will be' and 'can be'.
* "You can throw that tennis ball against the wall thousands of times a second and the wall isn’t going to break. You need more energy to break the wall. The energy from the previous throw is dissipated by the time the ball hits the wall again."
We are not talking about 1000 times but a difference of 1.000.000.000 times. I am almost sure that at that frequency you will pulverize the bricks and blow a hole right through it.
Keep in mind that the collisions at the LHC are 100.000 times hotter than the center of the Sun, the force with which you are throwing the ball is quite energetic.
* "If you want to be taken seriously, provide some physics of your own. What is the mechanism by which a resonance can cause damage? What is doing the vibrating? What is the resonant frequency or frequencies that could be dangerous? How is energy from a given collision stored and added to the energy from subsequent collisions?"
Those are good questions. Vibrations can be virtual particles; as mentioned above 'They are 50 to 100 orders of magnitude too weak to be detected, and also 20 to 50 orders of magnitude too weak to play a role in the collision.' So indeed if there are waves shaking up a Proton than the question is how much strain a Proton can take and how much time there is between an excited state and a 'relax' state.
* "Such and such MIGHT happen is not an argument."
If you look at the history of physics than my argument is quite down to Earth. There are plenty of examples of dangerous previously unknown side effects that showed up. I already mentioned Marie Curie’s death: "The damaging effects of ionising radiation were not known at the time of her work …"
Anyway, we are continuously treading into unknown territory with this record breaking luminosity, this is no child's play. I don't believe that your ridicule such as 'a giant bird that will eat the entire human race' is here in place.
If protons are like ringing glasses, then CERN risks the destruction of the world.
Conversely, if protons are like ringing glasses, and CERN risks the destruction of the world, then ringing glasses also risks the destruction of the world.
@Naked Bunny with a Whip,
"…then ringing glasses also risks the destruction of the world."
Then how would you fit In the high frequency and density of p+p+ or heavy iron collisions into this analogy:
"The Higgs field is responsible for giving mass to certain elementary particles. The Higgs boson is a particle associated with that field. Physicist David Miller of University College London earned Waldegrave’s bottle of bubbly by explaining both. To do so, he described a busy cocktail party.
An average person could wander through the crowd with ease. But a more popular figure would be mobbed as soon as he or she entered the room, making passage more difficult. In this example, the party-goers represent the Higgs field, and the people walking through the crowd represent particles to which the field gives mass. A person who is significantly impeded by interested guests is like a particle given a large mass by the Higgs field.
An excitation of the Higgs field is a Higgs boson. You can picture this as a bump that travels down a rope when you twitch one end of it, as the TED-Ed animation suggests.
In a cocktail party, this kind of excitation might move through the crowd if a rumor spread from one end to the other (illustrated above). People nearest the rumor-originator would lean in to hear it. They would then pass it along to their neighbors, drawing together a new clump of people, and then return to their original positions to discuss it. The compression of the crowd would move from one end of the room to the other, like a Higgs boson in a Higgs field.
Miller’s analogy isn’t perfect, but so far it has survived the test of time. When scientists on experiments at the Large Hadron Collider at CERN announced the discovery of the Higgs boson in 2012, many of them described what they’d found by saying, “Imagine a cocktail party…”
Is there an honest scientist (amateur or pro) in this forum (regular contributor or reader) who will answer my challenge in #45?
(I didn't expect an answer from SL.. see #46.)
Ethan and the mainstream choir here totally avoid the absurdity of a shrunken Earth diameter with no physics of physical contraction. It "absolutely" contracts, and how much and in what direction "depends on whom you ask," says Ethan.
This passes for "science" among those totally indoctrinated by special relativity theory, and Ethan goes along with the mainstream.
Ps; Sean T, #48: "... then you will be rightly attacked as being delusional."
A question for the hypothetical honest scientist to whom #45 is addressed: Which is delusional, the one claiming that Earth is flat (as he approaches at near lightspeed) or the one in orbit observing our nearly spherical home? It can't be both. Which is true and which is based on a delusional belief (SR.)?
edit: ... to whom #54 is addressed. (I'm dyslexic at times.)
Ever wondered if this is what made it difficult to understand what other people write, and got you stuck in this conflict situation?
Your arguments, as in this thread, have been exposed as nonsense.
My argument... that a "flat Earth" as "equally valid" (because "length is not invariant") is total nonsense... has never been addressed. All y'all have on that is more personal attacks.
Dyslexia does not make one stupid. It requires serious stupidity to believe in shrinking physical objects, depending on how they are observed!
It's not an attack, I am trying to help you solve your issue. People have tried to explain you the situation plenty of times, but can't seem to make the connection, honestly you look dumb. I already told you that, and I am almost sure that everyone with a bit of a brain thinks the same of you. Has it ever occurred to you that it's not them but you, yourself, who's the one that is wrong?
"Dyslexia does not make one stupid."
But it makes it difficult for someone to read what people write.
This goes back to the suggestion I made some time ago to talk with a local physicist. If you don't have to read it, and this way you can avoid that hurdle. Have you ever considered taking that advice, or are to stubborn?
Regarding my own argument on small vibrations shaking up matter, it hasn't been exposed, Ethan has discussed this and it comes down to multiple unknowns such a the Vacuum that damps, or how many possible (?) vibrations a proton can take.
At this point it is a hypothesis not even a theory, something we can be openly discuss. The physical phenomenon is an sich also no different than cooking a potato. If you could read more easily you could have grasped that as well.
Unfortunately I am not even sure if you're able to grasp what I'm writing here. So again also this comment could be in vain.
I find your comments @# 59 extremely offensive on many levels.
You equate occasional reversal of numbers and letters with stupidity and inability to comprehend what is written. Not too surprising considering (as a psychologist) your level of comprehension of science, as in this thread.
You don't have the intellectual honesty or personal integrity to address the obvious argument that things don't shrink as a result of differences in observational perspectives. Of course you are not alone in that lack of integrity. SR is based on it.
This will be my last reply to you. You seem too stupid to be worth my time.
How about that flat Earth, anyway?
I will say the same thing to you as I said to Elle: you are getting ""we addressed your idea and rejected it" but confusing it with "we didn't address your idea."
We've addressed it tens of threads, tens if not hundreds of posts already. You just don't like the answer we give you. It's not nonsense, it's deductively derived from Einstein's two principles, which have themselves been empirically tested and to our best understading are true. Thus any implication deductively derived from them must, logically, also be true. The contraction itself has also been empirically tested, by observing things like muon half-life.
I get that you reject this data as erroneous. I get that you reject some of the deductive implications of Einstein's principles. What I don't get is how you confuse all this comprehensive addressing of your point with the notion that we've never addressed it.
Do you think it only counts as addressing your point if we change your mind?
"You equate occasional reversal of numbers and letters with stupidity and inability to comprehend what is written."
Exactly, I know it's not flattering but that's what it is, some people can others can't. But that doesn't mean that you dyslectics are overal stupid, there are multiple methods to digest information therefore I encourage you to go talk with a physicist.
There are plenty of dyslexics who enjoy listening to an audio book over reading a book.
You always feel your under attack and you start attacking people, it's time that you stop attacking and listen to people. But I have the impression that you are addicted to generating conflict and the attention you get out of it.
Anyway I am happy that you are going to stop replying to my remark, perhaps you should also stop commenting on the blog here in general because Ethan himself made it clear that you are just to ignorant.
Blatantly lying Einsteinians: Einstein was able to predict, WITHOUT ANY ADJUSTMENTS WHATSOEVER, that the orbit of Mercury should precess by an extra 43 seconds of arc per century:
Jose Wudka, UC Riverside: "This discrepancy cannot be accounted for using Newton's formalism. Many ad-hoc fixes were devised (such as assuming there was a certain amount of dust between the Sun and Mercury) but none were consistent with other observations (for example, no evidence of dust was found when the region between Mercury and the Sun was carefully scrutinized). In contrast, Einstein was able to predict, WITHOUT ANY ADJUSTMENTS WHATSOEVER, that the orbit of Mercury should precess by an extra 43 seconds of arc per century should the General Theory of Relativity be correct."
However Michel Janssen (honest in this case) describes endless empirical adjustment (groping, fudging, fitting) until "excellent agreement with observation" was reached:
Michel Janssen: "But - as we know from a letter to his friend Conrad Habicht of December 24, 1907 - one of the goals that Einstein set himself early on, was to use his new theory of gravity, whatever it might turn out to be, to explain the discrepancy between the observed motion of the perihelion of the planet Mercury and the motion predicted on the basis of Newtonian gravitational theory. [...] The Einstein-Grossmann theory - also known as the "Entwurf" ("outline") theory after the title of Einstein and Grossmann's paper - is, in fact, already very close to the version of general relativity published in November 1915 and constitutes an enormous advance over Einstein's first attempt at a generalized theory of relativity and theory of gravitation published in 1912. The crucial breakthrough had been that Einstein had recognized that the gravitational field - or, as we would now say, the inertio-gravitational field - should not be described by a variable speed of light as he had attempted in 1912, but by the so-called metric tensor field. The metric tensor is a mathematical object of 16 components, 10 of which independent, that characterizes the geometry of space and time. In this way, gravity is no longer a force in space and time, but part of the fabric of space and time itself: gravity is part of the inertio-gravitational field. Einstein had turned to Grossmann for help with the difficult and unfamiliar mathematics needed to formulate a theory along these lines. [...] Einstein did not give up the Einstein-Grossmann theory once he had established that it could not fully explain the Mercury anomaly. He continued to work on the theory and never even mentioned the disappointing result of his work with Besso in print. So Einstein did not do what the influential philosopher Sir Karl Popper claimed all good scientists do: once they have found an empirical refutation of their theory, they abandon that theory and go back to the drawing board. [...] On November 4, 1915, he presented a paper to the Berlin Academy officially retracting the Einstein-Grossmann equations and replacing them with new ones. On November 11, a short addendum to this paper followed, once again changing his field equations. A week later, on November 18, Einstein presented the paper containing his celebrated explanation of the perihelion motion of Mercury on the basis of this new theory. Another week later he changed the field equations once more. These are the equations still used today. This last change did not affect the result for the perihelion of Mercury. Besso is not acknowledged in Einstein's paper on the perihelion problem. Apparently, Besso's help with this technical problem had not been as valuable to Einstein as his role as sounding board that had earned Besso the famous acknowledgment in the special relativity paper of 1905. Still, an acknowledgment would have been appropriate. After all, what Einstein had done that week in November, was simply to redo the calculation he had done with Besso in June 1913, using his new field equations instead of the Einstein-Grossmann equations. It is not hard to imagine Einstein's excitement when he inserted the numbers for Mercury into the new expression he found and the result was 43", in excellent agreement with observation."
Sorry, the above comment was for another thread.
eric @61: "We’ve addressed it tens of threads, tens if not hundreds of posts already."
Not true. No one here has ever addressed the physics of supposedly shrinking physical objects... only the theory that observers at very high speed will see objects differently than one at rest with an object.
How does that train-in-a-tunnel or pole-in-a-barn... or Earth's diameter actually, physically shrink? That is the unanswered challenge, and the reason it remains unanswered is that they don't physically shrink, as SR claims. They only (theoretically) *appear to shrink* as an image carried by light would probably be distorted as an observer approaches at near lightspeed. Can you see the difference? SR does not make that distinction but rather insist that length depends on the observer's frame of reference.
Can you honestly believe and insist that a "pancaked" Earth is a valid scientific description of this (or any other) planet? Please set your indoctrination aside for a moment and answer honestly.
I have addressed that, but you simply did not accept or did not comprehend the answer. Let me try again:
In school, you undoubtedly encountered a course in Euclidean geometry. Likely, it was simply called geometry, without the descriptor. In either case, this subject received its full development by the Greek mathematician, Euclid. Euclid started by coming up with several axioms that were (at least so he thought), self-evident. For the most part, this seems reasonable, for example, he stated that given two points, you can draw a straight line through them. One of his axioms that also seems quite reasonable is that given a line, then through a point not on the line, you can draw a single line parallel to the given one. If you draw the situation on a piece of paper, you can hardly see any way that this could be untrue.
However, by the 18th century, mathematicians HAD developed geometries in which this last "parallel postulate" was indeed untrue. There were geometries in which no parallel lines could be drawn through the external point. There were ones in which an infinite number of parallels could be drawn. While these seemed to be "false", the main factor that concerns mathematicians was met by these systems, namely that the axioms were self-consistent. That is the axioms did not contain any contradictions. The were known as non-Euclidean geometries. Did they correspond to the physical universe? Well, seemingly no, but mathematicians did not care. They were studying axiomatic systems regardless of whether or not the axioms comport with reality. The answer cannot be determined by mathematics alone anyway. The question is a scientific one.
As it turns out, this scientific question has indeed been answered. Euclid was wrong. The universe is not described by a Euclidean geometry. One of the implications of Euclidean geometry is that there is a function called the metric (symbolized by the letter s) defined by
ds^2 = dx^2+dy^2+dz^2. This function is recognized as the distance in Euclidean geometry. It tells us how to determine the distance between two points. If we move from point a to point b, we must (generally) move some distance in the x direction, some (generally) different distance in the y direction, and some distance in the z direction. If we know those distances (which we call coordinates), we can determine the distance between two points. In Euclidean geometry this is a useful quantity because it is invariant. In other words, I can assign an origin and some coordinate axes and determine the distance between two points. You can choose a different origin and different axes and determine the distance. The answer we get will be exactly the same, though, even if we don't choose the same origin and axes.
As I said above, though, this is not strictly correct. We recognize the correctness of the above description intuitively because it is approximately correct. It is correct precisely when the observers who are picking their origins and axes are not moving rapidly with respect to the interval being measured. When they ARE moving rapidly, the approximation breaks down, and the value for ds calculated using the formula from the above paragraph no longer is an invariant value. When observers are moving rapidly, the distance measured by one observer CAN disagree with one determined by another observer. This includes the distance from one side of the earth to the other. The moving observer, in the direction of motion, does indeed measure a shorter distance between the near and far surfaces of the earth. It is not a physical shrinking of the earth, but rather a change in the geometry of space that causes the change in distance. The moving observer would measure all kinds of things differently, though, such as a stronger electromagnetic attraction between neighboring molecules (again in the direction of motion), and a stronger gravitational attraction between particles at the surface of the earth and those at its center. The physics all hangs together. The measurements indicate that the expected shape of the earth is not spherical since the forces involved are directionally-dependent. The laws of physics are not broken. It is a completely valid description for the moving observer to state that the earth is flattened in the direction of motion.
The question then arises, "who's right?" Since both observers apply the same laws of physics to the situation, and the same laws of physics are valid for both, there is no way to answer the question in a scientifically valid way other than to state that both observers are right. The situation is completely analogous to the case where you watch a baseball pitcher throw a pitch. If I'm standing next to him and I measure his pitch velocity at 90 mph, and you're in a car driving toward him at 50 mph, you will say that the ball is going 140 mph. If the ball hits your car, you can calculate the kinetic energy of the collision and assess the damage it did to your car and the result will be perfectly consistent with the ball travelling 140 mph. The fact that I saw the ball travel 90 mph is irrelevant. We were both right in our measurements.
The laws of physics do NOT require all observers to measure the same values, only that the measured values be related in certain ways as governed by the laws. You likely have no problem with the argument I gave above that velocity is not invariant from observer to observer. The simple reality is that distance likewise is not an invariant quantity. That is less "common sense" simply because our brains evolved in an environment where we never had the chance to experience the fact that distance is not an invariant. Time, likewise, turns out to not be invariant, contrary to normal experience and Euclidean geometry. Does that mean, as you suggest, that there is no objective reality? Quite the contrary. It simply means that the quantities we take to be invariant are truly not.
The invariant quantity still turns out to be the metric, but a different metric than the Euclidean one. The true points that make up the universe are not the spatial points we usually think of, but rather events. That is things that occur at a specific point in space at a specified time. We can measure the "distance" between two events using the metric of the real spacetime (which is called Lorentzian as opposed to Euclidean). This metric is ds^2= -dt^2+dx^2+dy^2+dz^2. (Depending on the source, you may see this written with the + and - signs interchanged; physically it makes no difference; also, this form of the metric assumes we are using units where c=1. If we don't then a factor of c^2 must appear in the "dt" term). This is the quantity that is invariant and is what replaces both "objective time" and "objective distance" in relativity. the metric invariant (hence length contraction). The invariance of the Lorentzian metric accounts for all of the observations of relativity. The inability to comprehend what happens for moving observers is rooted solely in the insistence on treating the universe as though it were governed by Euclidean geometry. Give up Euclid and it all makes sense.
"So stop complaining about how we need to explain some magical shrinking of distance. We don’t, because that’s not what SR claims happens.
... the object itself never changes..."
You misrepresent SR to suit yourself. It insist that a 20 ft pole can physically fit into a 10 ft barn... if... (several caveats and at least two observers in all examples), and a long train can fit into a short tunnel (invent your own numbers)... "if"... etc.
Study mainstream length contraction before you lecture me on your own version of it again.
"It insist that a 20 ft pole can physically fit into a 10 ft barn"
From my perspective it 'looks' like can fit the Moon in my pocket, go figure. Actually I can fit it in between my thumb and forefinger. Check out these images for proof: http://www.crystalinks.com/holdthemoon.html
You are still thinking in Euclidean terms with regards to the barn/pole example. How do we know that the pole fits into the barn? We close both doors of the barn simultaneously while the pole is inside. The notion of "simultaneous", though turns out to be entirely based on Euclidean geometry. What is simultaneous for a given observer will in general NOT be simultaneous for any other observer.
It is only the observer at rest with respect to the barn that sees the doors closing simultaneously. This is as it should be. The pole is moving very rapidly with respect to this observer, so its length is contracted in perfect accord with the true, non-Euclidean geometry of the universe. It therefore fits momentarily inside the barn. Since it's rapidly moving toward the front door, the doors must remain closed for only a brief time in order to avoid a collision between pole and door.
Now consider the very same situation from the point of view of an observer moving with the pole. This observer will see the front door close then reopen while the front of the pole is inside the barn and the rear of the pole is sticking out of the still open back door. Only after the back of the pole enters does the back door close. The front door reopens and the front of the pole exits the barn. The back of the pole then exits.
Both observers agree, as they must, that the pole never collides with either door. Relativity implies causality. if an event A causes and event B (such as a collision between a pole and a door causing a loud noise and damage to both objects), then for ALL observers event A must cause event B, and therefore for all observers event A must occur before event B. That is not relative. It is only by denying relativity that causality can be violated. Only by allowing motion faster than c can causality be violated. If you really think about it, it is classical physics, which allows instantaneous interactions across a distance, that makes no sense.f
Like I stated above, preservation of causality requires that causes must precede effects for ALL observers. Consider as an example if relativity were false and the gravitational interaction really were instantaneous. Consider what would happen if the sun were to just disappear. Obviously, the disappearance of the sun would eliminate its gravity and the earth would go careening off in a direction tangential to its orbit. The cause is the sun's disappearance. The effect is the change in the earth's motion. Now, consider how this would appear to an observer near the earth. Since the gravitational interaction is instantaneous, the earth would change its motion immediately. However, our observer would not see the sun disappear for eight minutes. The effect precedes the cause, and causality is violated. Since we know this is false, our earlier assumption that gravity is instantaneous must likewise be false. It's easy to come up with similar examples of violation of causality for the other fundamental interactions, so we are left with the conclusion that interactions cannot occur at speed greater than c. Once that conclusion is reached, relativity follows deductively.
How do we "know" that a 20ft pole can fit into a 10ft barn?
Because Einstein made physics all about two observers seeing the same thing differently. That is when objective "natural" science was abandoned for relativity's version of philosophical idealism. What's true about the physical world? "It depends on whom you ask." What utter bullshit!
You're wrong conceptually two different ways. Both coming and going. :) First way you're wrong: in SR the spacetime interval does not depend on who you ask.
Second way you're wrong: clearly there exist real properties that 'depend on who you ask.' Your claim that this is bullflop is, itself, easily disproven. What is the single unchanging and objective value of my momentum, MM? If you're right, you'll be able to empirically demonstrate an answer that question. If you're wrong, you won't. And obviously, you can't, because there is no meaningful answer to the question of what my "single unchanging and objective value of" my momentum. My momentum is relative to the movement of other objects around me.
Relativity preserves causality. Non-relativistic physics does not. Are you not going to call a system of physics where an effect can precede its cause bullflop?
eric and Sean T,
You will find a summary of my criticisms of GR and SR in the latest comments from week 168.
Momentum is cumulative, like in a head on crash. Velocity is relative to whatever... on all scales. Neither. have anything to do with my criticism of relativity.
I have never claimed that an effect can precede its cause. Obvious bullshit, just like different observations causing Earth to change shapes or the "thought experiment" in which a 20' pole fits in a 10' barn.