Science a GoGo's Home Page Forums General Discussion General Science Discussion Forum i just duno why you can't observe light speed as half c

no actually your moving in relationship to light. light moves at a constant, which means its something that can be measured at all speed.

Light moves at a constant relative to what? The point of relativity is that light has the same speed c relative to any inertial reference frame. Thus even if another inertial reference frame moves with 0.8c relative to you, a person in that reference frame will still measure light speed as c relative to his reference frame.

An excellent explanation that dehammer still won't understand.

Thanks, you nearly make me feel guilty about what I have just posted about you. I believe that we should still be able to have a true scientific discourse.

Best regards,
Johnny Boy

I do too.

I too try to be objective.

lets see. person a is moving away from person b at .8 speed of light, and light headed in the opposite direction is moving away from him at speed of light so the light is moving away from person a (who has not changed his speed at all) at 1.8 times the speed of light? no. its the perception that is the key. it would appear to person b that the light is moving away from him at light speed, but the light would still be moving away from person a at the same speed. he never altered his movement. light never sped up. the light is moving the same speed for both of them. just they perceive it differently.

The fact that person a is moving at 0.8c from person b and experiences light moving away from him at light speed c, does NOT mean that person b measures a light speed of 1.8c in his reference frame. This is the whole point of special relativity. When measuring light speed in your inertial reference frame (within which you are stationary) you will measure the speed of light as c notwithstanding the speed at which the light source is moving relative to you. Speeds cannot be added linearly when applying special relativity.

then explain how the same photon can be moving at two different speeds at the same time. it cant. person b will see the light speed move at a different speed because his perception of time outside of the ship has been slowed. that is what that means. not that there are two different photons moving at two different speed or that the photon moves at two different speeds.

the only other possibility is that every person is in his or her own universe and everything is duplicated.

please explain in the normal universe how the same thing can move at two different speeds at the same time. it does not matter how special you make it, it cant be two places at the same time. the perception is what you are missing. each person moves at a different rate though time, based on how the time is dilated for them.

ive had a number of armchair scientist try to explain it, but none of them can explain that one point and keep repeating the same thing "its special". a real scientist (and ive read what they say) has no problem with it. nor, if you read the theory without preconcieved ideas, would you. there is only one light speed (though a given medium), and it is not based on anyones perception. your perception of it is based on your speed in relation to it, not vice versa. man is not that important in this universe. we are not masters of it, nor the center of it. it does not base its actions on our desires.

Dear dehammer,

I am not going to quote your arguments but direct the attention of readers to your last posting. In order to measure anything, one must first have a reference frame. To say that anything is stationary one must specify in which reference frame. In pre-Galilean times it had been believed that the earth must be stationary because other objects fall down to it and then become stationary. Galileo pointed out that you can also be stationary when sitting on your deckchair on a moving ship. Thus being stationary is a relative concept; i.e. a will see b as moving while b will be convinced that he is stationary while a is moving. Galileo pointed out that if you are moving with a constant speed, you cannot do any mechanical experiment, within the reference frame within which you are, to determine wether you are moving or not.

After Galileo, up to the time of Einstein, it was, however, still believed that there exists a reference frame that is uniquely stationary. Maxwell's equations led the scientific community to believe that this framework is the ether that fills the whole universe and within which light waves manifest. Experiments were then devised to test what the speed of the earth is relative to the ether. They could not measure any speed and found that they caould (maybe) explain it by postulating an "ether drag" which, in turn, led them to the Lorentz transformations of coordinates and time. Experiments to measure the speed of the earth relative to the ether were, however, doomed from the start. Why? Because Maxwell's equations give the same speed c, notwithstanding which reference frame you use. Einstein was clever enough to bring this in relationship with Galileo's principle of relativity by stating that when you are moving with a constant speed there is no experiment whatsoever, even measuring light speed, that one can use to determine wether one is moving or not.
He then showed that this assumption can be used to derive the Lorentz transformation; which, in turn, can be used to prove that light speed measured relative to inertial reference frames moving with constant speeds relative to each other, will always be equal to c within any of these reference frames. So far this conclusion, no matter how strange to us, has not yet been experimentally found to be wrong. Therefore, until experimentally proved otherwise, this is the way nature is. That is the way science looks at the world; what we in our small human minds consider logical might not be, and therefore "our logic" has to be verified by experiment.

dehammer wrote:
"then explain how the same photon can be moving at two different speeds at the same time."

Tsk tsk tsk. Did you sleep through classes in high school? This question evidences a complete lack of even the most basic understanding of high school physics.

The photon is not moving at two different speeds. Neither is this is not a question of speed. It is a question of space-time: one entity.

in otherwords you are of the believe that each person is the center of his or her own universe and everything else is just there for him. must be very lonely being the only thing in your universe.

dehammer wrote:
"in otherwords you are of the believe that each person is the center of his or her own universe"

Since you refuse to acknowledge your ESL status ... the word is "belief" not "believe."

No. I believe that Einstein's formulation of relativity is the most accurate description of objective reality. I can't recall him ever stating what you did.

So, very simply put, you need to educate yourself because I am not going to try to teach a high-school physics class to you here at SAGG. And neither is anyone else.

ive read the theory, ive also had a teacher that believed like you that each person was in his own universe. he also believe that a vertical axis windmill did not need to move.

you see thats the problem. people who can do, those that cant teach, yet they still expect others to believe that they know everything. I dont have the link right now so i will not expect you to listen to this (after all you believed that the guy that you posted a link to said that the heavier weight of water added to the the ocean when ice melted on the ocean floor would push the lighter weight of land that had loss the ice down while everyone else read that it would push it up). I read where a researcher (one of those that actually worked with the theory) took the time out to answer a bunch of question for a high school science club. HE complained about teachers teaching it wrong.

the best way to understand it, is not to let others tell you what it means but to read it yourself. i have, you should try it. At no point does Einstein say that there would be more than one speed of light. HE said that the speed of light was set. Everything else was related to it. not vice versa.

dehammer wrote:
"ive read the theory, ive also had a teacher that believed like you that each person was in his own universe."

Thank you for demonstrating the value of testing. You continue to misunderstand me. I've no doubt you misunderstood your teacher. And your desire to flaunt your wilfull ignorance in public is disgusting.

then explain how the same thing can move at two different speeds in the same universe.

in relation to the observer it does appear that things are moving at different speeds, but light has only one speed, and that is not in realitive to anything. everything else is moving in relation to that speed. as long as you refuse to examine the theory yourself and go by what others tell you or what you have heard other say, it does not do any good to try to explain it.

in the time ive have dealt with teaching, i have discovered that there are two types of teachers. those that are political and those that know what they are talking about. the second are more than willing to learn new things, and are not the least bit afraid to admit they dont know something. they hate to say that they will not learn something. You have shown that you are a political type teacher and are not the least bit willing to admit you dont know or understand something.

when you are ready to really learn, why not do a search for the theory itself and read it yourself instead of accepting what others have said.

most of the time testing only proves that a student is good at taking test. its when he has to actually apply that knowledge that it shows if he knows it. many of the teachers that teach it, cant show that kind of knowledge, only the book knowledge that testing proves. oh, before you claim i must have failed a lot of test, no, i did ok. cant remember any that i actually failed, none at all in college. of course ive had a stroke since then and have slept quite a few times: i could have forgotten something. what your excuse.

Dear dehammer,

With all due respect, you are really talking utter nonsense. Your arguments remind of those of Mark McCutcheon ("The Final Theory" the so-called book which scientists do not want you to read!) who claims that all physicits have been misled for over four hundred years so that they misunderstand Newton's mechanics. I am not saying that it is imposible that an important point could have been missed even for four hundred years, but then the person who tries and point it out should at least argue from a sound scientific basis. In your case, as well as in Mark's case, you do not understand relativity theory (classical or special). It is clear that both of you have had incompetent physics teachers. It is a pity but it does happen, unfortunately.

i actually got the understanding from reading the theory, and from reading what researchers said, not what teachers said. as for my physics teacher, he was a good math teacher.

there is a big difference between me and the arthor your mentioning: i dont say that researchers have been mislead, only that some of the teachers are not teaching what the researchers are finding. I personally find it more likely when that if a researcher and a teacher have opposite views, the researcher would more likely have a better understanding of it. Ill follow what the researchers say, much more often than arm chair scientist. when i read that more than one researcher say its the perception of the viewer that shows the difference speed, while the reality is that the speed of light is not different at all, AND i have an armchair scientist who gives links to things that prove him wrong claiming they prove him right, saying that the of light is the 186000 miles per second in relation to someone that is moveing .8 light (or .5 or .75) AND at the same time is moving 186000 miles per second in relationship to someone not moving at all. then i'll listen to the researcher, and tell the armchair scientist that he has shown his ignorance once more.

Dear dehammer,

You just do not understand relativity, and you are not willing to try and understand it! Basically you are arguing that light speed in galaxies receding from us at about light speed should be nearly zero. REALLY!! If there is a civilization in such a galaxy, they will se US receding from them at about light speed. If the have a dehammer they will conclude that light speed here in our galaxy (and on earth) will be near zero.

dehammer asks:
"then explain how the same thing can move at two different speeds in the same universe."

I don't have to because no one has ever said that the same thing moves at two different speeds.

And I will not be goaded or cajoled into educating you on basic relativity theory. Get off your bottom and read a book on the subject.

Your repetition of a pathetically ignorant laZyman's perspective is disgusting.

dehammer wrote:
"i actually got the understanding from reading the theory"

No you didn't. You are mentally and technically incapable of reading the theory. But just to see if I owe you an apology explain this:

E^2 - (pc)^2 = m^2*C^4

dehammer wrote:
"and from reading what researchers said"

Nonsense. Absolute and total nonsense. What did you read? Provide title, author, and pubication. Any three will do.

You really do need to put down the shovel.

dehammer, you go wrong because you are making the (hidden) assumption of an absolute time. In nonrelativistic physics if two observers are moving relative to each other you have a transformation rule like:

x' = x - v t

t' = t


Here x is the position of an event that happens at time according to one observer. According to an observer that moves with velocity v in the x direction the x coordinate of the event is x' = x - v t if at time t = 0 he was at x = 0. t' and t are the same.

Accordng to special relativity, however:


x' = gamma (x - v t)

t' = gamma (t - v x/c^2)

where gamma = 1/(1-v^2/c^2)^?

In special relativity you assume constant c, which then necessarily implies the above Lorentz transformation rules implying that time isn't absolute. If you did have an absolute time then the speed of light would be observer dependent.

The two possibilites are not mutually consistent, they lead to different predictions for various experiments.