Dicart
Registered Senior Member
Your kidding ?
Are you stuck to the (objective...) universal time of the Universe ?
100 years ago, this myth disappeared.
Does time exist?
- Thread starter Saint
- Start date
Your kidding ?
Are you stuck to the (objective...) universal time of the Universe ?
100 years ago, this myth disappeared.
Dicart
Registered Senior Member
Same for me, but i am not specialist.
Write4U
Valued Senior Member
What myth? That the BB was the beginning of duration of this Universe?
13.8 billion years
You are misinterpreting my posts.
My posit is that time is an emergent result of change, to which humans have symbolically assigned values as units of duration. Duration of change is universal. Assignment of symbolic time values to duration is man made.
Last edited:
Dicart
Registered Senior Member
Write4U
Valued Senior Member
So that we can communicate with each other. The universe is a dynamical mathematical pattern which exhibits an infinite number of durations of change, which we have dubbed time frames and given arbitrary value units, so that we don't arrive late at work..
p.s.
https://www.sleepfoundation.org/circadian-rhythm
Last edited:
Dicart
Registered Senior Member
So that we can communicate with each other. The universe is a dynamical mathematical pattern which exhibits an infinite number of durations of change, which we have dubbed time frames and given arbitrary value units, so that we don't arrive late at work..
Why not.
But you are aware that there are many "times" ?
Furthermore, you argue that the Univers is 13.8 billion "years old", this is what many people say, but if you start to understand what time is... this is nonsense.
Saying this, you say :
1. That time is a global property of the Universe.
2. That Universe is a physical object.
Two nonsense.
Saying that, you forget that there are "world lines" (it is not me who invented that, but Hermann Minkowsky) and every "line" do his own evolution.
Therefore, there are world lines much more older that others, and some of them are even so far from us that we can suppose them "at infinity".
Saying the Univers is 13.8 billion years old when we are talking about the fundamental of time, is nonsense.
It is not true, but it is not even false...
https://en.wikipedia.org/wiki/World_line
Hello , I am a professor !
We use clocks to make a record of time , time being a present measure of the past in this reference of use !
There is also other references of time use , time is not one specific entity .
Space-time is a functional coordinate system that can predict events .
The most fascinating reference use of time is the ageing process . In this reference use , time can speed up or slow down .
exchemist
Valued Senior Member
The hell you are.
Mike_Fontenot
Registered Senior Member
I was very glad to see that Brian Greene's great alien example is available on YouTube again. The NOVA version of his same example was taken off of YouTube as a copyright violation a year or so ago.
The most important question to me is whether the "current age of a distant person, right now", according to an observer who has accelerated recently, has a single, real value. I'm certain the answer is "yes", but that certainty is based on philosophical considerations, not on considerations of physics. Physics seems to allow at least four different answers, two of which obey the principle of causality. Unless and until the physics provides a single answer, the physics must be considered to be incomplete.
BdS
Registered Senior Member
The speed of light is constant for ALL observers, you can get a real value based on c for all observers. The devices we use to measure time are not flawless since they rely on distance to measure a duration and the distance changes at different speeds. But the speed of light remains constant.
Mike_Fontenot
Registered Senior Member
The speed of a light pulse, that any observer measures as it passes him, is indeed equal to "c". But if that observer is accelerating, a distant light pulse will NOT be traveling at speed "c", according to him. In some cases, he will even conclude that that pulse is moving in the opposite direction from what some other observers conclude. And he will sometimes conclude that the distant pulse is traveling at a speed much greater than "c".
BdS
Registered Senior Member
I'm adding the bold text.
The speed of light is constant for ALL observers in their own frame of reference, you can get a real value based on c for all observers. The devices we use to measure time are not flawless since they rely on distance to measure a duration and the distance changes at different speeds. But the speed of light remains constant.
What you gain in time you lose in space and what you gain in space you lose in time.
When we measured the speed of light we measured it in Earths frame of reference I think? and the speed of the Earth already contains an altered path for the light duration to travel. To get the true duration of speed of light we'd need to be stationary relative to space so there is no longer path for the light to travel. The problem is if you try measure the speed of light its relative to your frame of reference how long the duration will be. Makes me wonder if the current c speed 299792458 m is too close to 300000000 m to be a coincidence.
The speed of light is constant for ALL observers in their own frame of reference, you can get a real value based on c for all observers. The devices we use to measure time are not flawless since they rely on distance to measure a duration and the distance changes at different speeds. But the speed of light remains constant.
What you gain in time you lose in space and what you gain in space you lose in time.
When we measured the speed of light we measured it in Earths frame of reference I think? and the speed of the Earth already contains an altered path for the light duration to travel. To get the true duration of speed of light we'd need to be stationary relative to space so there is no longer path for the light to travel. The problem is if you try measure the speed of light its relative to your frame of reference how long the duration will be. Makes me wonder if the current c speed 299792458 m is too close to 300000000 m to be a coincidence.
Last edited:
Dicart
Registered Senior Member
No, the Earth could travel at every speed whatsoever, when we mesure on Earth the duration of the travel of light for some distance, this duration is always the same.
Earth could travel at almost the speed of light, this duration would be the same too.
Speed of light do not add to the speed of what emmit the light.
Other experiment :
You are in a spaceship traveling at 0.8C.
You position yourself in the middle of the spaceship with two other scientists, everyone has a clock (so 3 clocks, 3 people).
The two other scientists position theirselfs, one in the front of the ship, one in the back of the ship.
At 8 and 1 minute o'clock precisely, you shoot a beam of light toward the front.
At 8 and 2 minute o'clock precisley, you shoot a beam of light toward the back.
The two other scientits note the time of arrival of the beam.
You can deduce the duration of travel for the light for the two beams.
What do you think ?
1 : The 2 durations are equal.
2 : The 2 durations are not equal.
2.a : Duration toward the front is longuer.
2.b : Duration toward the back is longuer.
Last edited:
Write4U
Valued Senior Member
A simpler example is standing or running up an escalator moving at the speed of light. You get to the top at the same time (duration) either way.
IMO, all increments of time are artificial. Time does not exist independent of duration of something else. Therefore time has no inherent properties of any kind. It does not exist as an independent quality or quantity.
IMO, all increments of time are artificial. Time does not exist independent of duration of something else. Therefore time has no inherent properties of any kind. It does not exist as an independent quality or quantity.
Last edited:
BdS
Registered Senior Member
I think 1, because the speed of the spaceship remains constant and that means its frame of reference is constant.
Now conduct the experiment with 2 complete scenarios, 1 spaceship at 0.8c and 1 spaceship at 0.6c. The 2 ships dont agree on the duration because of the different path lengths for light to travel because of their different speeds. We use "time dilation" to explain the difference.
Dicart
Registered Senior Member
I think this has not to do with the fact that the speed of spaceship remain constant.
But yes, all measure and observations lead to the answer 1.
But now... saying this, isnt it confusing ?
How can we now explain that the front of the ship is attained by the light beam with the same duration as the back of the ship ... if velocity of light doesent add to velocity of ship ?
If the velocity of ship doesent add to C, why do the light beam attein the front of the ship as if there were no motion, altought the front of the ship advance while the light beam advance ?
Same question with the back : If the velocity of ship doesent add to C (so here C would be decreased by the speed of the ship), why do the light beam attein the back of the ship as if there were no motion, altought the back of the ship is rushing toward the beam ?
Here, without too much tinking, we should conclude that, a contrario, the speed of light add to the speed of the ship (like if we would trow some tennis balls).
How can we explain this contradiction ?
Write4U : This is why i prefer this kind of gedanken experiment that lead to questionning, before the one with the escalator (there is not much to say in this case)
time = distance/speed.
Time is the process of waiting for an object to pass a distance at a certain speed.
Do you understand it?
Write4U
Valued Senior Member
Here is a gedanken experiment. When two objects approach each @ C from opposite directions do they approach each other @ 2 x C ?
If so, how can that be? If not, why not?
Dicart
Registered Senior Member
Ohhhh, very nice !
It is my favorite.
I think i know why (the physical explaination i mean).
But you first : Do you know why (why not of course...) ? (i never heard anyone answer the question).
Last edited: