🎓 Dr. Freemo 🇳🇱 @freemo@social.cleverlibre.org

@3ammo sure.. which means the fact that you think you can measure light one way in the newtonian view, and it turns out you cant (without getting contradictory results) only proves the original assertion, that is, that light can only be measured round-trip and it is fundementally impossible to measure one-way speed of light.

@3ammo your use of words are loaded here.. you are correct that a lorentz transformation assumes the instantaneous speed of light is a constant in all frames.. but it does not derive from that as a **postulate** it derives from that as a **convention**. It is an important difference. If it were a postulate it would assume it makes some meaningful difference, and states something about how the world **is**... the symmetry of C is not of this nature. Because the symmetry of C is a convention, used simply because it gives you the same experimental results but is simpler, and not an assertion of reality, then the lorentz transformation is derived while using the **convention** that c is symmetric.

To put it another way, you could, if you wanted, pick any arbitrary asymmetry for the speed of light that preserves the round-trip speed of light as C, and then re-derrive the lorentz transformation based on that (and get a much more complex result).. you can then apply that modified lorentz transformation to any real world experiment and wind up with the exact same results as the much simpler convention... again distinguishing it as a convention rather than a postulate.

@3ammo By the way even einstein said that the idea that C is symmetric in both directions is **by definition** (convention) and not as a postulate. Here is his own words on the matter in one of his published papers.

First he says:

> "But it is not possible without further assumption to compare, in respect of time, an event at A with an event at B."

In this sentence he points out that we can not experimentally or otherwise theoretically conclude anything about these individual times without making an assumption, which implies it is arbitrary. He goes on to say (he put by definition in italics not me):

> "We have not defined a common 'time' for A and B, for the latter cannot be defined at all unless we establish **by definition** that the 'time' required by light to travel from A to B equals the 'time' it requires from B to A"

In other words the symmetry of light is by definition, and not an assertion as to **what is**, namely, a convention.. he never says "we assume light to be".. he says "establish by definition", which is exactly what a convention is.

@trinsec I dont even think I have favorites, but I do really like the rincewind character. The guy is the hero everywhere he turns but is convinced it is all just coincidence, which in discworld is the best way to invoke luck in the first place and why he gets into the scenarios he is in,a nd out of it.. it is a take on the stereotype of the fool that is just so perfect.. him being the fool and oblivious to his extreme luck is why he is lucky at all and why he doesn't just die :)

@3ammo This isnt true because your missing the fundemental point... one-way light speed is impossible to measure, determine, or see.. so if it exists, if that is reality, it is unknown to use and can in no way effect what we observe and in turn in no way effects our math or models... Sure we can throw it in and assume c is different in a certain direction because its "reality".. but if we do that the results of all the equations (since the real world is always 2-way) remain the same anyway (and thus why its a convention not a postulate)... so all the complexities you mention are also moot.

@3ammo The problem here is if you pretend we are newtonian people (which we are not since the world is relative and not newtonian) any attempt you make to measure the speed of light accurately will give contradicting and failed results, in part because you assume there is no problem synchronizing clocks when in reality there is.

If i just assume a newtonian world, sync up two clocks at rest then transport the receiving clock to a distance location, measure the speed of light, then bring the clock back and compare I will get one measure for speed of light. If i do the same experiment but this time the transmitting clock is the one physically moved I get an entierly different measurement for the speed of light. Since we are pretending the world is newtonian it essentially shows us little more than "it is impossible to measure the speed of light (using newtonian physics), you will get different values when irrelevant aspects of the experiment change!".

In short because relativity is more true than newtonian physics it is only using relativity you can measure speed of light at all (albeit it 2-way speed of light), and newtonian physics makes it impossible to accurately measure the speed of light at all.

@3ammo So here is why its a convention and not a postulate... simply speaking if you pick some other convention that ensures the round-trip is unchanged but it is asymmetrical, all the math we do will give the same final results. Thus its a convention because it doesnt really matter since everything is eventually a round-trip anyway, so we just pick the easiest way to get the answer.

As an example imagine a world at the most extreme asymmetry where light travels at c/2 in one direction and instantaneous in the other. If you use this convention and then apply the new form of lorentz transformations to any thought experiment that could be carried out as a literal experiment, you get the same result as you would get if c was symetrical. What happens is the error is just enough that it cancels out and produces the same results.

Consider communicating with a distant astronaut and how we perform the very simple lorentz transformation there to synchronize time. Lets assume we know the real time (I will abbreviate it RT) and lets assume there is a meassured time, ill call this MT.. here is how it works out assuming C is symetrical.

1. Astronaut flys 1 light hour away, experiment starts, RT 0:00

2. Earth sends light signal to astronaut saying "The time here is 0:00" (RT)

3. Astronaut receives message claiming time is 0:00, he knows he is one light hour away so he now sets his clock to 1:00 (MT), he then replies "message received, I have now set my clock to 1:00" and sends this back home.

4. Home base gets the message saying the astronauts MT is 1:00, knows again it is one light hour away so concludes after lorentz transformation that the MT is now 2:00. Looks up at his clock, the RT, and sees it says 2:00. Concludes the astronaut clock and home clock are set to the same time.

But now lets look at the same scenario where the speed of light is c/2 in one direction and instantanious in the other, but the scientist dont know this so use the **convention** that c is symmetric. Being just a convention it should all work out (if it were a postulate then it would be meaningful and thus effect results and things would break here).

1. Astronaut flys 1 light hour away, experiment starts RT 0:00

2. Earth sends light signal "The time here is 0:00" (RT)

3. Astronaut receives signal, assumes c is symetric, therefore performs the same lorentz transformation as before and determines that the time must be 1:00 (MT), in reality because c/2 the RT is 2:00, so the astronauts clock is technically off by an hour. Astronaut replies "I have now set my clock to 1:00".

4. Home base again gets the message of the astronaut claiming the time being 1:00, home base again assumes time is symmetric so gets the same result he did in the earlier experiment assuming that the astronauts clock must be 2:00 by the time they hear the return message (which took an hour to get to them).. sure enough they look up at the wall and it matches RT of 2:00... but in reality the signal was not symmetric and the return time for the light signal was instantaneous instead. That means by the time homebase heard "my clock is set to 1:00" and they assumed it was RT 2:00 by the time they heard it this was wrong, the reply was instantaneous and in reality the astronauts clock was 1:00 by the time they got their response and their transformation was wrong, and the clock is still slow by 1 hour. However it appears to them everything is correct, the full round trip time was still c, they got all the same answers at all the same times they would have if it was symmetrical. So even though it is technically wrong, the results work just as well

In fact you can pick any arbitrary asymetrical convention you want, so long as the round-trip results in a average speed of c, and you will get the exact same results and both sides of the communication would be unable to tell any difference at all.

This is why its a convention, you can pick any asymmetry you want and none of the results will ever change, therefore a convention is picked arbitrarily to be easy. No one needs to say "this is how it is" because nothing changes whether it is that way or not

@josias While that is certainly part of why those in success may discount others without success I dont think its the most important part, the important part is how success is almost always dependent on both success and luck. which means you cant be lazy and do hard work, but if you do you still might fail.. but if you work even harder and continue to do said hard work eventually you will be the odds (roll a dice enough times you eventually will get a 20).

“In fact he was incurably insane and hallucinated more or less continuously, but by a remarkable stroke of lateral thinking his fellow wizards had reasoned that, in that case, the whole business could be sorted out if only they could find a formula that caused him to hallucinate that he was completely sane.*

*This is a very common hallucination, shared by most people.”

― Terry Pratchett, The Truth

If you think alot about why inequality happens, or how much of inequality is laziness vs circumstance, this is an excellent video that explains that but without the guilt or virtue signaling. Great math and statistical explanation of the dynamic.

Really everyone should watch this:

https://youtu.be/3LopI4YeC4I

@josias Not in any way that you could notice or measure anyway.

Just added the #hamradio emoji a few people asked me for.

#radio #ee #rf #amateurradio

@trinsec Man... now i need to reread some discworld stuff! It really is one of my favorites series and writer.

@trinsec brownie points for discworld reference :)

@MutoShack neovim isnt bad either...

I'd start with spacemacs at it is the most popular so it tends to be the most refined/complete.

@trinsec The way it works is simple really.. 1) Our current best estimates state that Betelgeuse will go supernova at some point in the next 100,000 years (other than that we can pin down when it will start and when it does start it will all happen rather fast)... Next we know on average our galaxy experiences 2 supernova a year. So if you have a life span of ~ 100 years that works out to ~1 in 500.

@miamiautumn Up until this point I've been tolerant of your account on the grounds that you saw pedophilia as attraction to minors but not necceseraly acting on it, and thus providing therapy or other help to these individuals without judgement. I have no issue with a pedophile who recognizes their feelings are unhealthy, seeks help, and recognizing touching or sexually engaging with children is wrong.

However this post and a few like it seem to suggest that you are tolerant of pedophiles who actually touch little children sexually (contact ideology)... this is the line right here and personally I am ok supporting the ban of this account for now having crossed this line.

I have linked the other moderators and want to give you a chance to speak if you have anything you'd like to say. For the moment my vote is going to be to support a ban.

@arteteco @Sphinx @khird