imatfaal

I know this is a bit off-topic but as the credibility of the paper Metric in Reference System Transformation has been questioned I thought I would check the bona fides of the journal / publisher. This is their registered address: I haven't checked them out in the Predatory Journals schedule - but I reckon I might find them

I did look at the drawing. I think the triangles are not necessarily similar (ie there is a circumstance in which they are similar - but most of the time they are not). Drawings are very misleading if you use them to measure lengths and angles (as you are doing). You should use diagrams to get your thoughts straight but use geometrical rules to determine things like congruency. I can draw an equilateral triangle - with enough precision to be confident in it to the full extent of a rough diagram - in about twenty seconds. Take a picture with a smartphone. Upload it. You are making more assumptions than I did - there is an autocad viewer in the windows 10 appstore. I viewed your diagram And there is a wrong. For example; one of yours - if a+b<c then a,b, and c CANNOT form a triangle and it is wrong to posit the triangle ABC. We know a huge amount about triangles, constructive and deductive geometry, and, to move on in complexity, trigonometry. The main problem is that you don't seem to have a good grounding in this. But as a geometry puzzle it lacks precision - everyone reading it should be able to reproduce the construction easily but this is not possible because you chance the rules when some part is proven to be wrong

! Moderator Note Frank Jacobs hijack split off to its own thread. Keep to the OP please.

Только несколько слов. I have no fluency in any other languages and it does shame me. I work in an international business in which I speak only English to colleagues of multiple nationalities most of whom have English as a second language, some have it is a third... but in any foreign language I have to spend a several minutes checking just a few words.

! Moderator Note Ok - so moved again, this time to Philosophy. This is not permission to forget about rigor

! Moderator Note moved to speculations. If you would prefer philosophy then let me know.

! Moderator Note You need to make sense. You also need to stop putting the bulk of your argument in a linked document which many of the members will be hesitant to open.

The sender Alice locks the box with her padlock Alpha and sends it to Bob. Bob locks the box with his padlock Beta as well as leaving padlock Alpha in place (he has no key to Alpha) and returns box to Alice. Alice undoes her padlock Alpha and leaves Bob's padlock Beta (which she has no key to) on the box - she returns that to Bob. Bob unlocks his padlock Beta and gets contents of box. Commutative algorithms allow Alice to do the unlocking of her encryption whilst Bobs is still viable and without disrupting it.

! Moderator Note Link in your removed per the rules. Please post basis of discussion here - the rules are explicit that members should not be forced offsite in order to participate in debate.

Consensus is that theory says zero mass and experimental evidence does not contradict zero mass.

The way I understand it (and this is really beyond my comfort zone) is that some parts of physics might work with an absolutely tiny mass (ie within the bounds I posted above) but others just would not. Quantum electrodynamics is incredibly accurate, underlies much of our present ideas, and just does not work if mass is non-zero. The presence of zero mass allows certain things to be also set to zero - but any non-zero amount for the mass of the photon means that these parts of the calculation boom up to infinities. So it is not that some theories loses a tiny bit of accuracy - it is that one of our most accurate and predictive theories cannot work if mass is non-zero . I think the same is true for quantum chromodynamics (as the gluon must also be massless), and clearly any of the unifications between the strong, the electromagnetic and the weak. No physicist would be categorical that there is no possibility of a non-zero value because empirical data rules everything and you cannot prove a zero in these terms. But claiming a non-zero mass is a positive statement - and it is a huge claim - thus some evidence other than a a feeling of unease at the idea of masslessness and a misunderstanding of high school equations must be given to back that claim up

It is next to impossible to prove experimentally that anything is zero. We have shown in a lab that the mass is less that 10^-13eV/c^2 and via observations of galatic magnetic fields that the mass should be less than 10-27 eV/c^2. But you cannot prove a zero - because there are always experimental imprecisions and errors; this will lead to error bars and your figure could lurk in the error bars. Theoretically big portions of modern physics would fail - quantum chromo/electro-dynamics would fall over and no longer be re-normalisable and thus no longer give the astonishingly accurate results that it does.

Because we know and understand the physics.

If EDC is right triangle with Angle EDC (per your autocad) as 90degs then triangle ABE can never be similar. Angle ABE is 60 degrees, Angle BAE is less than 60, and Angle AEB is the same as Angle CED (and cannot be 90 degrees) . To summarise EDC is a right triangle and ABE cannot have right angle. Therefore not similar It is not. Angle AEC is same as Angle BED. Angles EAC and DBE are less than 60 degrees. Angle ACE is 60 degrees thus for triangles to be similar then EDB must be 60 degrees and it is clearly not. Think not. Cannot be bothered to prove

Any calculation with a massive particle (ie proton or electron in this question - or neutron in the first) which has a speed of c is based on a false premise and can have no sound conclusion. One of your initial propositions is false - ie the massive particle travelling through space at light speed - anything that follows is unsound and of no worth. You are correct in saying an anti-neutrino is produced in beta-decay - but what you have is also not what exactly we call an anti-neutrino it would be far too massive. An anti-neutrino is almost exactly the same as a neutrino (there is obviously no change in charge) except for a flip of lepton number and the fact that anti-neutrinos have a right-handed helicity and neutrinos have a left-handed. In a Majorana analysis the neutrino and anti-neutrino are the same particle but just have different chirality. The mass of either particle / both chiralities is miniscule compared to electron or proton/neutron - much less than one eV/c^2

! Moderator Note I have locked this thread because it has been pinned by one of our experts - the explanation by Matt Strassler is good but the video lecture by Sean Carroll seems to be rated as excellent. These notes will serve as a mini repository for future questions - and may be expanded. However, I do not want a pinned thread to be open for discussion - this would allow the potential addition of many less desirable pieces of mis-information from the slightly misconstrued to the full-blown deepak-chopra. The discussion so far has been first rate and any of the discussants should feel free to re-open a new thread to continue. Any future resources that are of a similar quality can be appended by a member of staff. thanks

I think the major change in the orbit is basically what we would expect from a GR calc/model rather than a Newtonian. I know they run those calcs for binaries - I think you need to be able to work out the masses involved both via observation and by orbit (to compare gravitational mass and inertial). But then the fiendish ways experimentalist get around problems occuring light years away regularly baffles me

! Moderator Note one thread per question please. thread locked

5% of interstellar dust is in the higher mass region of >10e-11 grams. But even these dust grains at the larger end at .1c have little energy (about a joule). However when they impact they will give off radiation - which could be very hi-energy gamma rays. You can see how much mass will be cleared by a spaceship in my calc in above post - multiply by 86000 to give 10 light years worth of interstellar dust. Still not much However going through a dust cloud raises the density of the particulate matter by over ten thousand fold. I cannot see a breakdown by size of particles in a dust cloud but I assume that the number of high mass particles will be greater (they aggregate). A grain of about a microgram has the same kinetic energy as a family hatchback at the motorway speed limit. This is the danger. You only need one - in your journey of a hundred years...

There are lots of ways to explain quantum mechanics - all equally unsatisfying; they are called interpretations. All the interpretations have the same amount of evidence - ie none! As soon as someone figures out an experiment which would evidence one interpretation or disprove the others then qm will change.

Belief is the acceptance of an argument without evidence - there really is no place for that in science. We don't "believe" in quantum mechanical phenomena - we measure, we experiment, and we model; quantum mechanics is the best model we have which explains all the measurements, has not yet been shown to be invalid by experiment, and fits in with other parts of our theory of nature. There are an almost endless supply of theories - but there is an endless and ever-varying supply of fact. And the facts will all fit together with the correct model - but there is no guarantee than the theories will. You are correct this is a forum and not a seminar - but incorrect in thinking that this fact gives us licence to be sloppy. We strive to adopt a scientific approach and eschew pop-science and pseudoscience; we know that we will not reach the rigor of a university seminar but that is no reason not to try. I have quoted from here in academic papers. Take ourselves less seriously - right. I should change my views, Phi should alter his perspective , and all the other members with hundreds of thousands of posts between them should reconsider because a member with 8 posts says so - right. We like science, we post here because of that shared interest; if we wanted to just chew the fat we would post elsewhere (and many of us do)

1. dust in the intersteller medium (just over 1% of mass) --> rho = 2e-26 g/cm^3 2. an hour at .5c is 5.4e11m S = 5.4e13cm 3. estimated frontal area of space craft --> 10m x 10m --> 1000cm x 1000 cm --> A =10e6 cm^2 4. volume cleared of intersteller space by ship cruising at .5c for an hour --> V = A x S = 5e19 cm^3 5. mass of dust impacting space ship per hour --> V x rho = 10e-6 g/h = 1 microgram per hour

friendlytoast57 requested to have her/his account deactivated - we obliged

! Moderator Note Thread locked. friendlytoast57 We don't do homework for you - especially not for whinging and ungrateful people who hate science (did the name of the forum not give you any hints that the membership here probably do not hate science?) And per your request I have suspended your access to the forum

This is initial problem - take any two numbers greater than two and multiply them together and the product will ALWAYS be greater than the sum. BUT for a triangle the length of two shorter sides must SUM to greater than the third. This is an internal and irresolvable contradiction. The long side is the product of the two shorter and thus will be greater than the sum of the two shorter sides BUT AT THE SAME TIME for it to be a properly formed triangle it must also be less than the sum of the two shorter sides. If you get a contradiction like this you know you must restart with new propositions. The problem with introducing pi like this is that pi is an irrational number (it is actually transcendental). An integer multiplied or divided by an irrational will lead to another irrational. I think - but have not checked - that your construction will have sides all of which will be irrational lengths. All primes are integers - no primes are irrational Triangle ECD would be similar to EBA for only one version (ie one possible prime if the idea worked) and that would be when angle ABE equalled angle EDC with both being 60 degrees or 2pi/6. Angles AEB and CED are equal. But that is the limit of similarity in the general case First things first. Explain how you will construct triangle - you have three sides explain the relationship between them and your primes. And let's check you can actually construct a triangle within those parameters. Remember if the angles are all 60 degrees then you must have equal side lengths - non-negotiable; and vice versa. Also remember three side lengths uniquely determine a triangle - so that is a good starting point.