Hearts Posted March 3, 2011 Share Posted March 3, 2011 Why isn't time considered another dimension of space? Link to comment Share on other sites More sharing options...
Schrödinger's hat Posted March 3, 2011 Share Posted March 3, 2011 Umm, by relativists, it is. Except space-time is not Euclidian (time isn't quite the same as the other directions) Link to comment Share on other sites More sharing options...
Hearts Posted March 3, 2011 Author Share Posted March 3, 2011 (edited) ah I see.. is there any formal definition of space? I know not everyone agreed on one for time yet... any useful (beginner-friendly) links on this for me? my physics is kinda rusty. Much appreciated and thanks Edited March 3, 2011 by Hearts Link to comment Share on other sites More sharing options...
Mr Skeptic Posted March 3, 2011 Share Posted March 3, 2011 Our formal definition for distance is the length traveled by light in a given time: The metre is the length of the path travelled by light in vacuum during a time interval of 1⁄299 792 458 of a second. This gives us an exact speed of light. As for time, I think it is basically "the stuff measured by clocks". Link to comment Share on other sites More sharing options...
Hearts Posted March 3, 2011 Author Share Posted March 3, 2011 Hmm, @mr skeptic: I can't help but feel that your definition of space is akin to defining time as.... the second has been defined to bethe duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.~ wikipedia I probably misunderstood~ Link to comment Share on other sites More sharing options...
Iggy Posted March 3, 2011 Share Posted March 3, 2011 As for time, I think it is basically "the stuff measured by clocks".[/url] I think so too, and I think "the stuff measured by rods" would be a good definition of space. Just as in Euclidean geometry the space-concept refers to the position-possibilities of rigid bodies, so in the general theory of relativity the space-time-concept refers to the behavior of rigid bodies and clocks. -Space-Time by Albert Einstein any useful (beginner-friendly) links on this for me? my physics is kinda rusty. The link I just quoted from is the 1926 Encyclopædia Britannica entry on space-time written by Einstein. From what I just read, it looks like a good treatment of the subject. 1 Link to comment Share on other sites More sharing options...
Hearts Posted March 3, 2011 Author Share Posted March 3, 2011 Hmm, now I think that most, if not all of our definitions (of anything) are just expressions of it in other terms. And since concepts like time, space, matter and energy are so fundamental in nature that expressing them in other terms (defining it) is impossible. But if there are no proper way of telling what they really are, how come there are so much physics revolving these concepts? Link to comment Share on other sites More sharing options...
Schrödinger's hat Posted March 3, 2011 Share Posted March 3, 2011 Yes, scientists usually use a pragmatic definition for these things. When someone asks 'what is ____' about something we can't conceptually break down any further, we point to one. You're either getting into the realm of symmetry/standard model where things get real strange and the 'shut up and calculate' mindset is common (I think following that road won't give you the type of answer you're looking for, either), or into the realm of philosophy. There's a topic on this already, join in http://www.scienceforums.net/topic/55326-what-do-we-men-by-space/page__p__593259__fromsearch__1#entry593259 1 Link to comment Share on other sites More sharing options...
Mr Skeptic Posted March 3, 2011 Share Posted March 3, 2011 Hmm, now I think that most, if not all of our definitions (of anything) are just expressions of it in other terms. And since concepts like time, space, matter and energy are so fundamental in nature that expressing them in other terms (defining it) is impossible. But if there are no proper way of telling what they really are, how come there are so much physics revolving these concepts? Is that any different than how in most systems of geometry points are never defined and yet they are used throughout? (not only are points not defined but they explicitly say they won't bother to define them) Hmm, @mr skeptic: I can't help but feel that your definition of space is akin to defining time as.... the second has been defined to be the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.~ wikipedia I probably misunderstood~ No, I defined distance in terms of time. This definition is essentially defining time as the stuff measured by using the cesium 133 atom as a clock. On the other hand, Einstein I believe defined time as distance/c by using light-clocks for his time measures. I've previously made a list of things that you will be able to understand if you know what distance is: http://www.scienceforums.net/topic/26568-stuff-explained/ Link to comment Share on other sites More sharing options...
Hearts Posted March 3, 2011 Author Share Posted March 3, 2011 hmm... got some digesting to do~ Link to comment Share on other sites More sharing options...
physics confusion Posted June 10, 2011 Share Posted June 10, 2011 just going to shake things up a bit. where i come from, time is already considered to be a dimension. The fourth dimension is time. Some theoretical fourth dimensional objects have already being thought up (i think ones called a concavagram). these objects are only visible when time is factored in. Link to comment Share on other sites More sharing options...
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