Dagl1

Sorry , I have not forgotten about the thread, but am a little busy with some reallife things, will respond as soon as time allows me to sit down and think about the topic once more!

I see, that's a good point; didn't think of that, thanks!

Hmmm, I realise my words are pretty fuzzy when I describe it, but here it goes: A frame is a particular set of I suppose coordinates that are based upon a specific observer. I would say that a grid centered around a specific observer is a frame of reference. Inertial would then imply that it isn't accelerating (but that part I still don't really get, as you can always set yourself to be non-moving and non-accelerating by just thinking of your surrounding as decelerating). That is a pretty ambigious definition; I never really thought of the definition as described in words; If I am on Earth, then since the Earth is moving with me (ignoring its rotation and stuff, because I suppose that might give some additional problems) the Earth and I are in the same frame of reference. A rocket flying away from me, or a person on a train (very fast moving) is in a different frame of reference. Is this correct, or am I missing it;/ Regarding the proper distance, so far I can understand (I think); with no movement relative to two points, we find the proper distance, which is also the largest (with all movement reducing the distance?). If I moving with the speed of light, that then also means there is no distance right? Constant * sqrt(1-(1/1)) = Constant *sqrt(0) = 0 right? And any speed in between 0 and c will be between the proper distance and 0, relatively? I see now that this also answers my question regarding how we know this distance is the actual distance, as this function doesn't really allow for anything bigger than Constant*1, and therefore that is the proper distance (hope I am correct here). Still very interested in what you can then tell me about the proper length! also thank you for the continued responses!

The problem wasn't the sketch, I see now that the difference between speed/velocity was something I wasn't really taking into account. Yes we got it straight;p

As long as we understand each other now;p I feel my sentence meant that, but I see it can mean multiple things, sorry for being vague. The semantics discussion are not as important for this thread. Edit: changed sentence

Is that not what this means? If I am not moving, and I see you not moving, then we are both in the same frame? How could it otherwise be? If A sees B not moving, and B sees A not moving, assuming both take themselves to be at rest, is there a possibility for them to not be at rest? This is what 'two observes that are in their frame both at rest' means or can it be taken differently? Am I still missing something or is this just more semantics? Sorry Studiot! I come and go, didn't notice your message earlier; I can definitely go with your explanation of East and West and using negative there, maybe it was a bit pedantic of me, but approaching has no directionality (as far as I understand the term). Anyway, for S who is in the East, S will see T is moving East, or S is the one moving Westwards to a stationary T?

Thanks, I understand that it is a classical (non QM) thing, but my questions about the synchroton are more regarding relativity and the length contraction, I suppose I might think about it a bit longer and then maybe ask it as a seperate question. Either way thanks for everyones explanations

I was not very careful in that last response; Two observers that are (in their frame) both at rest, are in the same frame. If from the perspective of one of them, the other is moving, then they are not in the same frames. This is at least how I understood it, but I see now that my response is not saying that. What I meant with "If the T and S are not moving at the same speed relative to each other, they by definiton can't be in the same frame right?" is that if they aren't at rest (both moving along line A-B at the same speed so that the distance between them does not change), they must be not in the same frame. But I see now that what I said was pretty vague/incorrect, my bad. Okay just to reiterate what you said (to make sure that I am following you). Each observer has its own frame, and one observes movement relative to their frame. I thought I understood inertial frames, but even if you are accelerating, you can just take your own frame as inertial right, and thus say that whatever you are comparing your frame too is decelerating (or vice versa)? If I am in my own frame, and I observe someone moving accelerating towards me, am I not still in my own inertial frame though? This I cannot understand, how can one approach at a minus velocity, they both see each other approaching at 0.8c? Maybe this is the big hiccup but... if I run towards you at 5 km per hour, then you are approaching me at 5km per hour, from your perspective you, I would be approaching you at 5km per hour. Ignoring that in this example I am obviously the one running, but let's say we are in space and neither of us is doing anything, we are just in motion. Why would one of us think the other person is going backwards (this is what negative velocity implies, or at least how I interpret it, but that is probably wrong then). You call it the relative velocity, but that relative velocity must remain a positive number right, otherwise one would think someone is receding while the other thinks they are approaching? I suppose as you said, I should first understand the previous points, but this makes sense a little. If I move towards a star at 80% the speed of light, and I measure the distance to be 6LY, then if I moved very slowly towards it it would have been 10LY? And measured from the star, I too am 6 LY away when moving at at 0.8c, right? Okay! That is pretty understandable. How does gravity (acceleration) then come into play with distances (although maybe that is a question I can ask in another thread afterwards, after making sure the last points were understood). Thanks everyone for their answers and continued responses!

Yes this seems to be clear, as each has its own relative motion, they are in differnt frames. If the T and S are not moving at the same speed relative to each other, they by definiton can't be in the same frame right?

I generally understand your responses to my initial question, but now I wonder how we can even have any 'proper length', of course in 1 frame of reference we can agree on a specific length. But within the universe is there then anyway to say what 'proper length' is, if the distances are all different from different points of view. Is there ever a way to get down to a 'universal length', as this is what 'proper length' implies for me. But I thought that was one of the things that relavivity brought us, that there is no one main frame of reference, and thus also no one main of distance between points? Studiot seems to be providing me at least in part with an answer: Although I still don't entirely get how this is a 'proper distance', does the proper distance represent the amount of protons I could put in a row to reach such a point? But even those can get length contracted? How do we know that the proper distance is not actually still measured from a moving frame, or that there is even a 'stiller frame'? No criticims perceived , I love the detailed responses and am happy you guys are sticking by me even as I am floundering through incomplete comprehension! I then also have another question as to how the expansion of the universe comes into play with this, how does length contraction work for galaxies far away and which are accelerating away from us, already at speeds faster than the speed of light. When we say nothing can go faster than the speed of light, I am aware that due to how this is calculated the 'actual speed' of two things at relative speeds is never faster than the speed of light (I hope I am correct in my understanding here?), so I suppose we use that calculation for length contraction? What I am getting at is that in my mind, given that galaxy A and galaxy B are already at such distances that the expansion of the universe leads to faster movement away from each other than light will be able to travel (so the galaxies that are on the edge of the observable universe and will then 'move out' of that bubble). How does lenght contraction not lead us to say that these are actually very close (because relatively we are moving at enormous speeds)? I really seem to have some trouble with this whole concept;p

@swansont Your explanation made it quite clear what the problem with this idea about speed of electrons is. I then do wonder why this wouldnt apply to synchrotons? Or I should clarify, when you said that synchrotons are classical and we can speak of the speed of electrons, does that mean that the book didn't water down that explanation (so a higher frequency of radiation is observed because the electrons are moving at relativistic speed and as such the frequency is higher than just the regular amount of times of orbiting per second?) That to me still seems a little illogical (and thus I probably misunderstand it), as even if space is warped, the amount of times it should go around 360 degrees should not change even if it goes at very fast speeds? I feel either this is another piece that I have to get my head around, or my assumptions might be wrong. So to reiterate; if a electron moves 30000 times per second around an synchroton, and it is moving at relativistic speed (99% the speed of light for example) (ignoring that for such amount of orbits per second the synchroton might be necessary to be super large), does that we observe a higher frequency than 30000, because it has more energy, or because it somehow manages to pass a point (let's say at 0 degrees of the orbit) more than 30000 times because the space is contracted? For me this doesn't make much sense so I hope you or someone else can shed light on this! Thanks everyone already for their responses!

Thanks! I will read and digest the information in detail later today!

Thanks everyone! Later today or tonight when I have more time I will go over your responses and actually stand still to think about them!

Okay thanks, I will try to look more into it! Thus far it is not yet completely understood by me, but maybe I need to read a bit more into this if I want to really understand it.

It seems you and I don't use the same definition of intelligence... Chance, chaos, they don't exist? I really am unsure why or how you get these ideas. I don't think these ideas hold up to scrutiniy, but I also realise that this is the extent to which you answer, so it might not be a very fruitful discussion. Things like 'be absurd' are... well your opinion. You like to state the way things are, but don't provide evidence or even follow sound logic that makes sure there are no other possibilities. It might be a good idea to focus on explaining your concepts in more steps, explain why things are like this and not in other ways. Thus far you did not seem to answer my question, or those of other people. I asked "Why does intelligence have to have always existed, what evidence is there for this. What evidence can you provide that goes agains the claim 'intelligence has not always existed' or 'there was no intelligence on Earth before life'. " One can only find several extra statements from which to understand that your definition of intelligence is different from that of other peoples. It might be good to give a proper definition of the words you use. Are they different from what some dictionaries propose, if so, you should note this down so we can understand.