Things moving away are also shorter.
That’s because of what is happening when you do the measurement.
You look at the one end of the metre stick at certain point in time and space t0,p0. You then look at the other end at another point in time and space t1,p1. In the amount of time between t0 and t1, that end has moved towards the first position that you looked at (p0). When you make the measurement p1-p0 is not equal to 1 metre for you.
That is the Doppler effect concerning the light coming at you - that doesn’t count - a separate issue. The theory isn’t supposed to be dependent on how a measurement is being made.
…and once again, the length of the meter stick does not depend on who is looking at it, and what velocity they are traveling, just like a rotation of the Earth around the Sun does not depend on who is looking at it and what speed and direction of travel they are traveling.
Likewise, 1 complete rotation of a crankshaft does not depend on if you look at it and from how far away, or what speed direction you look at it. One complete rotation of the crankshaft is ABSOLUTE! It does not depend on who you ask, and a meter stick’s length does not depend on who you ask!
And by the way, if your tachometer is accurate and claims the crankshaft is rotating at the rate of 3,000 RPM, then if the crankshaft completes 3,000 revolutions, that TIME is exactly 1 MINUTE, regardless of who you ask or how fast they are traveling! 3,000 RPM IS EXACTLY 3,000 complete revolutions in EXACTLY 1 minute!
MD - if you somehow instantly changed all motion throughout the entire universe - making it slower to half speed - would time still be the same?
Nah - that is the second video I have seen from that bloke where he makes an invalid argument.
There is no requirement to make the measurements of position from end to end of the stick at different times - there is such a thing as parallel processing - both operations happening at the same time.
There has to be a better explanation. And his synchronicity issue is invalid also (separate issue).
He is just pulling a Biden.
Yes, the time (duration) would still be the same. Earth would only travel 1/2 the distance in the same duration of time. So it would take twice as much time to complete 1 lap around the Sun.
Since a “year” is 1 lap around the Sun, a “year” would be a different duration of time. A year would be twice the duration of time that it currently is. It is a clock running slow, according to the current standard of time that we call a “year.”
There’s an explanation showing the same result with space-time graphs.
But if you think his argument is invalid, then I doubt that the graphs will convince you.
Here it is if anyone is interested:
[youtube]https://www.youtube.com/watch?v=TxW6_E3uLuo[/youtube]
He throws me off when he distorts the graph and says that “rocket-clone” measures things differently. I can’t verify his distorted graph. I’m not saying it is wrong - I just don’t see where that came from.
He doesn’t appear to be making the same argument as the first bloke.
Wiki just declares that it is all true - no explanation as to why - and not enough detail concerning directions of travel and any other confusing issues.
So how do you know that it hasn’t happened already? And if it has - are you going to accept that all of your time measurements are wrong? What if it changes again? How are you going to know when to correct for universal time shift?
I strongly differ. Wiki does explain it, with all the relevant maths to back it up.
I think that it is too advanced for the audience here.
I would then say that the Scientific American article I linked earlier explains it all very clearly, with a minimum of math. And it shows that accelerated frames are not necessary to explain the elapsed time differential between the two twins.
Because my tachometer is accurate. I can count the revolutions of my crankshaft when the tach reads 3,000 RPM. When 3,000 revolutions have occurred my stopwatch measures exactly 1 minute. If I slow the engine to 1,500 RPM and count the revolutions the crank makes, the stop watch says it takes 1 minute, in the time it takes for the crank to make 1,500 revolutions.
My stopwatch also measures exactly 1 revolution of the Earth around the Sun as the same amount of time for the crank to make 60 x 24 x 365.25 x 3,000 revolutions when the Tach is reading 3,000 RPM.
I can verify the two different systems match exactly at two different RPM. The Earth makes 1 revolution in 1 year and the crank makes 60 x 24 x 365.25 x 3,000 revolutions when the tach reads 3,000 RPM, in the same duration of time, as noted by 1 stopwatch!
I can change the speed of my engine, measure the rate with the tach, and the time agrees with the Earth time, as far as how many times the crank revolves per same unit of time the Earth revolves around the Sun.
Is there something wrong with you?
How many other banal examples do you want to unremittingly spew?
Odd this.
Surely any tape measure that is used to measure the length would also be affected by the phenomenon, so that a metre would still appear to be a metre at .999 speed of light.
And since the length returns to normal when you return to earth it would be as if nothing had happened.
Not so time dilation since everyone on earth would have died of old age, waiting for the penny to drop in Motor Baby’s brain and this fucking thread digression could end.
Yes, we’re not talking about things. But also, we’re not talking about measures. We’re actually talking about length.
Length is either the object of measurement or it is the result of measurement. You think it’s the latter, I think it’s the former.
I merely claimed that length belongs to the object. We say that objects have length, that objects are long, that some objects are longer than other objects, etc. We also measure length. We don’t measure something (whatever that something is) and then call the result of that measurement “length”. The symbol that is “1 foot” is not length itself. It is a description of length. One and the same length can be described in many different ways. “1 foot” and “30.48 cm” are two descriptions of one and the same length. They are not two different lengths. Moreover, the involved ratios (what “1” and “30.48” stand for) aren’t lengths either.
Consider the following. The word “volume” means “the amount of space the object occupies”. It does not mean something like “the amount of space the object occupies divided by the total amount of space”. If that was the case, volume would be something that can be expressed with a single number – no units required. IF the amount of total space is equal to the amount of space occupied by some object, then the volume of that object, according to this definition, would be 1. And if for some reason the total amount of space increased, say by factor of 2, and if the amount of space occupied by the object remained the same, the volume of that object would now be 0.5. In other words, the volume of that object would decrease even though it’s only the space that surrounds that object that increased in size. I don’t think that’s how the standard definition of the word “volume” works.
Right. Descriptions such as “5 inches”, “1 cubic meter”, “30 m/s”, “60 years” and so on do not belong to objects we’re measuring. Rather, they are objects created by subjects. They start as concepts in the subject’s brain and then they are brought into existence by being expressed in words (written or spoken) by those same subjects. That much I can accept.
But “5 inches” spoken or written isn’t length but description of length; “1 cubic meter” spoken or written isn’t volume but description of volume; “30 m/s” spoken or witten isn’t speed but description of speed; and “60 years” spoken or written isn’t time but description of time.
And the same applies not only to written/spoken descriptions but also to various ratios that these decriptions often convey.
The statement “The red ball is 2 times the size of the green ball” is describing a volume, but also, it is describing a ratio. It states that the ratio is 2. That ratio does not belong to the object but it also does not belong to the subject. It lies somewhere in between the two objects – or perhaps we can say it belongs to the two objects as a group. Either way, it does not belong to the subject (the ratio is the same regardless of what any subject thinks) and it does not belong to the objects individually. But that ratio is not volume. If the green ball increases 2 times in size and the red ball remains the same size, the ratio would decrease to 1 even though the size of the red ball is the same.
Does he (or anyone else) have to?
The point is that the word "time’ is conventionally defined in such a way that if we somehow slowed down the entire universe, time would still be the same.
This is a linguistic issue, so whether or not it’s possible to detect that the entire universe has slowed down is irrelevant.
I can understand the need for unconventional ontologies. I understand that they can make it easier for scientists to complete their task. But it’s a bit of a problem when existing ontologies that have their own uses are destroyed in favor of an ontology that is useful within a very limited domain of application.
What’s the problem of simply admitting that they are using words in a different way?
What’s the conventional definition of the word “year”?
Why not simply do a simple Google search?
How many times did the Earth orbit around the Sun for the first twin? How many times did it orbit around the Sun for the second? The same number of times, right? End of story.
It seems to me that people are excessively defensive of their trusted authorities. The slightest hint that the scientific establishment is doing something wrong is met with overreaction.
While I’m flying around, I use the clock that I brought with me, right?
And it doesn’t show me the time on earth. It shows me the local time in the spaceship.