Talk:Galilean transformation

message: The English in this article is terrible - example:
"From the point of view of group theory, Einstein's special theory of relativity the Lorentz transformation group events, it is essentially a particle do uniform motion of the Lorentz transformation group - This is the core of Einstein's special theory of relativity all."
I'm not an expert in this field so don't feel comfortable editing it, but that sentence is embarrassing.
:What is worse: the article contains absolute nonsense. JocK (talk) 21:31, 4 January 2008 (UTC)
replies: text: Have made a start with a thorough clean-up. JocK (talk) 21:57, 4 January 2008 (UTC)
thread_title:  This article is terribly written 

message: My problem when reading this article was the lack of introduction of the "operators", E, C etc. Which transformations are they associated with? Why is there a hbar in this. I believe Galilei was unaware of quantum mechanics. It would be much better to use operators without hbars. Anyone ready to contemplate the Lie-algebra aspect of GT, will not be particularly disturbed by this deviation from the standard qm-textbook variants.  —Preceding unsigned comment added by 212.37.14.186 (talk) 14:06, 28 April 2009 (UTC)
thread_title:  Please, explain the "operators" 

message: Surely that video of spacetime distorting with velocity changes in accordance with Einstein's relativity shouldn't be on a page about Galilean relativity? 165.124.205.18 (talk) 23:27, 8 June 2010 (UTC)
replies: text: Huh? That video uses the Galilean transformation, not the Lorentz transformation. mike4ty4 (talk) 10:27, 31 December 2010 (UTC)
thread_title:  Spacetime video? 

message: The last sentence of Tanslation stated {Note that the last equation expresses the assumption of a universal time independent of the relative motion of different observers.} I think that is just one of the explanations for {t'=t}. There are at least two other ways to explain {t'=t}:
1. If the speed of light is infinitely fast, then, the picture of event-happening will be sent to all observers instantly so that all observers will record same event time t'=t.
2. If we assign observers at the location where the event is happening to record event time for their systems, then, since observers are all at the same place with zero distance from the event-location, they should record same event time t'=t.
Actually, the assumption of a universal time is not as clearly defined as above two explanations for the possible relation of t'=t. Because the Galilean Transformation (GT) is dealing with two sets of records for the same event eA, happens at a time tA and a location A. If in the stationary system (t,x,y,z), named S, the recorded time is tA=t and coordinate of A is A(x,y,z) while in the moving system (t',x',y',z'), named S', the recorded time is tA=t' and the coordinate of A is A(x',y',z'), then, GT states (t',x',y',z')=(t,x-vt,y,z). As you can tell, the assumption of a universal time does not care about that {an actual observation} is related to LIGHT, hence, the distance away from event or the speed of light should be handled. That assumption does not care about the distance away from event, nor the speed of light, so that it is not a detailed expalnation for t'=t, I think.
John Huang
Jh17710 (talk) 05:14, 23 October 2010 (UTC)
thread_title: About Translation

message: Hi. I think it wouldn't hurt to have a graph similar to this one:
http://www.phys.vt.edu/~takeuchi/relativity/notes/Lorentz-STD.gif  — Preceding unsigned comment added by 78.179.87.40 (talk) 11:01, 9 September 2011 (UTC)
thread_title:  transformed axis graph at t=0 

message: My 2c worth: The approach that this article currently takes, namely that the Galilean transformation is something only used in Newtonian physics helps perpetuate the confusion that existed in the early 20th century and which still persists today regarding relativity and continues to make relativity so difficult to understand or even accept. The Galilean transformation is a logically - indeed trivially logical - proveable transformation between ordinary Cartesian coordinates and a set of convenient generalized coordinates used in the analysis of a systrem moving at a constant velocity v relative to the observer. Standard Cartesian coordinates are projections of the positions of objects in the system onto the stationary axes of the observers reference frame. The Galilean transformation transforms these standard
coordinates into a set of generalized coordinates consisting of projections of the positions of the objects onto a set of axes which according to the observer are moving with the same velocity as the system being analyzed. This really isn't any different to using any other generalized coordinates to simplify the analysis of a system and it is valid regardless of special reletivity. Saying that the Galilean transformation doesn't hold for relativity is what confuses people and creates misunderstanding and makes relativity sound like hocus pocus. The real issue leading to special relativity and the Lorentz transformation comes in when we introduce a second obsever and wish to convert from the standard Cartesian coordinates of the first observer to those of the second. That is where the Lorentz transformation is needed and where the Galilean transformation is the wrong tool, because that is not what the Galilean transformation is doing. The reason its not doing that is that all observers measure time and space against their own perception of electromnagnetic signals traveling between them and the objects being observed and thus in particular they all measure the speed of light to be same - its like if everyone used their own hand to measure length and then marvelled at the fact that everyone found their own hand to be exactly one hand long :) Because every observer measures with his "own hand", the Galilean transformation is not a conversion from one observers frame to anothers - we need the Lorentz transformation which scales "hand length" so to speak. However the Galilean transformation is still valid as a transformation used by a _single_ observer going from standard to convenient general coordinates. Kuratowski's Ghost (talk) 14:36, 10 December 2012 (UTC)
thread_title:  Perhaps a different approach 

message: I would expect this article to have the following sections:
1. Some discussion of the relation between Galilean Transformation and Newton's First Law. Note that the standard physics version of the Galilean transformation does not include transformations to rotating or accelerating frames, since those are non-inertial frames.
2. Galilean Transformations in Dynamics; Transformation of displacement, velocity(1D, 2D, 3D), momentum, kinetic energy. 
3. Galilean Transformations in systems of particles; Center of Mass Transformtions; Galilean Transformations in Fluids
4. Invariance of Classical Lagrangians under Galilean Transformations
5. Galilean Transformations in non-relativistic Quantum Mechanics; Relation to Unitary Operator, Momentum operator
6. An independent section discussing the limitations/extensions of Galilean transformation to Relativistic Phenomena. It is tiresome when the article mentions special relativity every other paragraph.
7. The stuff on group theory really seems to pertain to the Galilean Group (which is Galilean boost, translation, rotation, time translation) and not specifically to the Galilean transformation. The equations should really be limited to the article on the Galilean Group (which has several other issues of its own). And maybe just a paragraph in this article about how the galilean transformation is one part of a larger class of transformations known as the Galilean Group with a link.
70.124.92.52 (talk) 16:36, 26 October 2013 (UTC)
replies: text: Go ahead and fix it. - DVdm (talk) 20:18, 26 October 2013 (UTC)
thread_title:  This article is missing so much information. 

message: Some of the commutation relations like [C_i,H] = i P_i use a multiplicative i. But isn't the Lie algebra of the Galilean group a real algebra? Isn't there a confusion in the article with Representation_theory_of_the_Galilean_group and Quantum mechanics considerations? 94.245.87.72 (talk) 09:30, 5 November 2013 (UTC)
thread_title:  What is i ?