## Relativity?

How does science work? And what's all this about quantum mechanics?

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ken
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### Re: Relativity?

surreptitious57 wrote: Thu Oct 12, 2017 2:21 pm
ken wrote:
surreptitious57 wrote:
The clock would stop because any thing travelling at the speed of light cannot experience time which is why
photons or any massless particles are timeless otherwise they would not be able to travel as fast as they can
So how long does it take a photon or a clock or a human being or a ufo to travel the distance of 3 light years
A photon will take no time at all for it does not experience time while the others can only travel
below the speed of light but I cannot be more specific than that as their speeds will be arbitrary
How long does it take a photon to travel from the sun to earth?

Is that no time at all also?
ken
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### Re: Relativity?

uwot wrote: Thu Oct 12, 2017 5:38 pm
davidm wrote: Thu Oct 12, 2017 4:59 pmSee here.
Or here: http://willijbouwman.blogspot.co.uk
I think I have it covered.
As long as you only think that, you are correct.
surreptitious57
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Joined: Fri Oct 25, 2013 6:09 am

### Re: Relativity?

ken wrote:
surreptitious57 wrote:
So a human being travelling at the speed of light between two planets would literally arrive in no time at all
But if it takes 3 years to travel a distance of 3 light years away then how could a human being travelling at the speed
of light between two planets 3 light years in distance away from each other for example literally arrive in no time at all
Because nothing travelling at the speed of light can experience time. The measurement of time with regard to light years is from an
external frame of reference only. However from the internal frame of reference of a human being travelling at the speed of light no
time can ever pass just as it does not pass for a photon. For a photon can travel the entire distance of the Universe in no time at all
ken
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### Re: Relativity?

davidm wrote: Thu Oct 12, 2017 6:16 pm
ken wrote: Thu Oct 12, 2017 10:30 am
thedoc wrote: Thu Oct 12, 2017 5:22 am

Too late.
Why does it appear to late, to you?
Maybe because of your post time stamped Thu Oct 12, 2017 5:22 am
Maybe or maybe not.

By the way where is My post with that time stamp?
ken
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Joined: Mon May 09, 2016 4:14 am

### Re: Relativity?

davidm wrote: Thu Oct 12, 2017 4:59 pm
uwot wrote: Thu Oct 12, 2017 10:48 am
ken wrote: Thu Oct 12, 2017 10:22 amClocks do NOT experience time so that is NOT why a clock would stop at the speed of light.
A clock would NOT stop, travelling at the speed of light, just like a human being would NOT stop ageing travelling at the speed of light.
What you have to realise, is the role that photons play in making things happen. At the atomic level, the most important thing that happens is that a photon passes from one atom to another. In simple terms, imagine two atoms next to each other. If they are 'stationary', then a photon can take the shortest path between them and the 'event' happens in the quickest possible 'time'. If, however, the two atoms are moving together in a parallel course, then in order for a photon to pass from one atom to another, it has to take a longer path to where the atom will be when the photon arrives. So the event takes longer to happen. If, for the sake of argument, the two atoms could travel at the speed of light, then the event will never happen, because the photon is going flat out, just keeping up. While all that's going on, the Earth will still be spinning and going round the Sun, and in that sense, time will still be passing, but for the atoms, nothing happens. That is true whether it's two atoms, or two gazillion. So if you could travel at the speed of light, while days and years would still be passing on Earth, nothing at all would happen to you, and as far as you would be concerned, no time would pass.
The above is absolutely correct, of course, but it’s worth stressing why, exactly, this is so. One might be tempted to suppose that the photon adds the velocity of the atoms to its own speed, and if it did, this light clock would still be ticking in synchrony with a “stationary” light clock.

But it doesn’t! Light speed is invariant and will not adhere to the law of addition of velocities. So in the case of the moving atoms, it will take longer (as judged from the perspective of a “stationary” observer) for the moving photon to oscillate between the moving atoms, than it does for the stationary observer’s own light clock to tick off a given unit of time. This is time dilation — the literal slowing down of time.

See here.

One sees that for the rider in motion relative to the “stationary” observer, the photon makes one round trip (as judged from the ground frame) for every three round trips in the ground frame. If a round trip in this case is defined as one second, it follows that three seconds have passed in the ground frame for every one second in the moving frame.
If you are going to look at what I am saying and asking not from what I am actually talking about and instead only look at this from the reference of a light clock point of view, then you will never understand what it is that I am actually asking and saying.
surreptitious57
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Joined: Fri Oct 25, 2013 6:09 am

### Re: Relativity?

ken wrote:
surreptitious57 wrote:
ken wrote:
So how long does it take a photon or a clock or a human being or a ufo to travel the distance of 3 light years
A photon will take no time at all for it does not experience time while the others can only travel
below the speed of light but I cannot be more specific than that as their speeds will be arbitrary
How long does it take a photon to travel from the sun to earth
A photon takes no time at all to travel from the Sun to Earth

A photon takes no time at all to travel anywhere in vacuum regardless of the distance and
so if the Universe was spatially infinite then it would travel right across it in no time at all
ken
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Joined: Mon May 09, 2016 4:14 am

### Re: Relativity?

Walker wrote: Fri Oct 13, 2017 4:56 am
ken wrote: Fri Oct 13, 2017 4:17 am I agree wholeheartedly that WHILE a human body was travelling at the speed of light, if they could, then for that person there MIGHT a perception outside of the body that no time was passing. But, to Me, from when that human body was last at rest, before travelling at the speed of light, if it could, up to when it was at rest again, after travelling at the speed of light, if it did, then the days or years that that body took to travel the distance that it did, at the speed of light, then that is how much that body would have aged by. And, if for example that body was in front of a mirror when they were travelling, then for that person they would see a normal rate of change. If this is not correct, then why not?
Ken, keep on the track:
Keep on what track?

Is that the same track that people have been on for years now and which is not really leading people closer to any actual new discoveries as of late? It is also the same track that is still being disputed and disagreed with?

Why not leave that well-trodden, ambiguous, maze of a track and just move onto a track that actually leads us into discovering new and further knowledge instead?

I have heard of experiments that were done, and when those experiments are fully looked at and the biases that played a part before and during the experiments were done are fully looked into also, then further knowledge will be discovered. But for now, if you want to stay on this boring track and look at this once again, we can.
Walker wrote: Fri Oct 13, 2017 4:56 amIf the twin in the fast spaceship could see his earthwalking brother, the brother would be moving very quickly. Super speed.
Allegedly.

Also, in what direction is the "fast" spaceship supposedly travelling?
Walker wrote: Fri Oct 13, 2017 4:56 amIf the earth walker could see his flying brother, he would appear motionless.
Or, that brother would appear to be in fast motion, especially considering that brother is in a "fast" spaceship.
Walker wrote: Fri Oct 13, 2017 4:56 amFor the flyer, everything on the spaceship appears normal.
If you say so.
Walker wrote: Fri Oct 13, 2017 4:56 amFor the walker, everything on earth appears normal.
Again, if you say so.
Walker wrote: Fri Oct 13, 2017 4:56 amWhen the flyer returns, he looks as he did when he left.
Walker wrote: Fri Oct 13, 2017 4:56 amHowever, the earth walker is old and gray, on his last legs.
The earth walker could have been relatively "old", ('old' has no actual meaning if it is not in relation to some thing else) grey, and on their "last" legs before brother flyer went flying.

I forget the name of story, but here’s a great plot. A starship pilot lands on earth for some downtime. He goes to a public place and gives a child a rare space gem. It’s red, and he tells her where it’s from. He then leaves for his next flight to the stars. I think he’s flying goods. It’s the usual short flight. He picks up another gem and returns to earth for his time off. He goes to the park. He does the same thing with another kid. He gives the gem to a kid. Then, he does something else that he didn’t do the first time. He somehow finds the first kid. She is now a woman, and she has thought of him all of her life. For awhile he has a very good friend, until his next trip to the stars.
Walker wrote: Fri Oct 13, 2017 4:56 amMany of the details escape me because I read it when I was a kid. But that’s the gist. It was a kid’s story, so don’t get weird.
What do you mean by "don't get weird"?

And, quite a few people in this forum might tell you that I can not get weird as I was already weird before.
Walker wrote: Fri Oct 13, 2017 4:56 amSo, what do you think, Ken?
The thinking in this head right now is, 'I have absolutely no idea what you are trying to say by that "great" plot.
ken
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### Re: Relativity?

surreptitious57 wrote: Fri Oct 13, 2017 5:56 am
ken wrote:
What is time
Time is defined as the passing of a thought or the passing of an event or
the distance between events where an event is a location in space time
When you say "time is defined" what do you mean by 'is'? Are you saying that is the one and only definition of "time" or that is how 'you', surreptituous57 defines "time"?

Are you aware that using the same word in the definition, of the word being defined, is not really helpful in defining nor clarifying what the word actually means?

But if that is the definition you want to give to "time" let us see how long it takes before you contradict your own definition.
ken
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### Re: Relativity?

surreptitious57 wrote: Fri Oct 13, 2017 6:20 am
ken wrote:
surreptitious57 wrote:
So a human being travelling at the speed of light between two planets would literally arrive in no time at all
But if it takes 3 years to travel a distance of 3 light years away then how could a human being travelling at the speed
of light between two planets 3 light years in distance away from each other for example literally arrive in no time at all
Because nothing travelling at the speed of light can experience time.
HOW do you KNOW this?

Do you know a human being who has traveled at this speed and asked them to clarify for you?
surreptitious57 wrote: Fri Oct 13, 2017 6:20 amThe measurement of time with regard to light years is from an
external frame of reference only.

Also, how do you "measure time"
surreptitious57 wrote: Fri Oct 13, 2017 6:20 amHowever from the internal frame of reference of a human being travelling at the speed of light no
time can ever pass just as it does not pass for a photon.
So, if it takes a human being or a photon, let us say, 8 and half minutes to travel from the sun to the earth at the speed of light, to you, it took no time at all, but to most other human beings they would say it took 8 and half minutes, is this correct?

Also, to travel a certain distance, even at the speed of light, takes some, what is called, "time". So, what happens to the human being travelling at the speed of light, if we were to imagine that the atoms of the body would stay intact? Do they;
age at a normal rate as they did before leaving earth?
stop ageing but keep living?
die? Or,
some thing else?

surreptitious57 wrote: Fri Oct 13, 2017 6:20 amFor a photon can travel the entire distance of the Universe in no time at all
Okay, I now understand what you observe. This is just different from what I observe.
ken
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Joined: Mon May 09, 2016 4:14 am

### Re: Relativity?

surreptitious57 wrote: Fri Oct 13, 2017 6:30 am
ken wrote:
surreptitious57 wrote:

A photon will take no time at all for it does not experience time while the others can only travel
below the speed of light but I cannot be more specific than that as their speeds will be arbitrary
How long does it take a photon to travel from the sun to earth
A photon takes no time at all to travel from the Sun to Earth
How long does it take light to travel from the sun to the earth?

Maybe we are just using the word 'photon' differently?

How do you define 'photon'?
surreptitious57 wrote: Fri Oct 13, 2017 6:30 amA photon takes no time at all to travel anywhere in vacuum regardless of the distance and
so if the Universe was spatially infinite then it would travel right across it in no time at all
Fair enough. If that is what you observe, that is okay with Me.
uwot
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### Re: Relativity?

ken wrote: Fri Oct 13, 2017 4:17 amWhat role does photon play in making things happen.
This from wikipedia: "It turns out that all interactions which affect matter particles are due to an exchange of force carrier particles..." https://en.wikipedia.org/wiki/Exchange_force
Photon exchange is the basis for all chemical reactions. They in turn are responsible for every metabolic event that happens to you, and it is those events that determine the ageing process. At the speed of light, there can be no photon exchange, because it would require photons to exceed the speed of light. So: No photon exchange. No metabolic events. No ageing. The same is true for brain states; if you accept that the brain has at least some role in consciousness, then your consciousness is also affected, and very possibly stops altogether; which would be my guess.
ken wrote: Fri Oct 13, 2017 4:17 amWhat do you mean for the atoms nothing happens?

The atoms are still travelling between objects at the speed of light, so that is what is happening, is this wrong?
Fair enough. The atoms get from one place to another, but the types of interactions, the exchange of photons, for example, that take place between atoms at sub-light speed, simply cannot happen; if light speed really is the limit.
ken wrote: Fri Oct 13, 2017 4:17 amI agree wholeheartedly that WHILE a human body was travelling at the speed of light, if they could, then for that person there MIGHT a perception outside of the body that no time was passing. But, to Me, from when that human body was last at rest, before travelling at the speed of light, if it could, up to when it was at rest again, after travelling at the speed of light, if it did, then the days or years that that body took to travel the distance that it did, at the speed of light, then that is how much that body would have aged by.
What experiments like Hafele-Keating, and relativistic muon decay (more wiki for you: https://en.wikipedia.org/wiki/Time_dila ... _particles ) is that speed does affect the rate at which things happen. So, weird as it is, the ageing of your body is determined by what happens to it, rather that the number of times the Earth goes round the Sun.
ken wrote: Fri Oct 13, 2017 4:17 amAnd, if for example that body was in front of a mirror when they were travelling, then for that person they would see a normal rate of change. If this is not correct, then why not?
Assuming that consciousness is a function of brain processes, they wouldn't see anything, because their brain would have stopped functioning.
surreptitious57
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Joined: Fri Oct 25, 2013 6:09 am

### Re: Relativity?

ken wrote:
surreptitious57 wrote:
ken wrote:

But if it takes 3 years to travel a distance of 3 light years away then how could a human being travelling at the speed
of light between two planets 3 light years in distance away from each other for example literally arrive in no time at all
Because nothing travelling at the speed of light can experience time
Do you know a human being who has travelled at this speed and asked them to clarify for you
No but then why would I need a human being to tell me that time cannot be experienced when travelling at that speed
Are there not other ways knowledge can be acquired rather than from personal experience which is not always reliable
surreptitious57
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Joined: Fri Oct 25, 2013 6:09 am

### Re: Relativity?

ken wrote:
if it takes a human being or a photon let us say 8 and half minutes to travel from the sun to the earth at the speed
of light to you it took no time at all but to most other human beings they would say it took 8 and half minutes
Were I travelling at the speed of light then it would take no time at all
And were I a stationary observer it would take eight and a half minutes
surreptitious57
Posts: 4217
Joined: Fri Oct 25, 2013 6:09 am

### Re: Relativity?

ken wrote:
How do you define photon
A particle or quanta of light or electromagnetic radiation that is massless and
timeless and infinite and travels at 299 792 458 metres per second in vacuum
surreptitious57
Posts: 4217
Joined: Fri Oct 25, 2013 6:09 am

### Re: Relativity?

ken wrote:
surreptitious57 wrote:
ken wrote:
What is time
Time is defined as the passing of a thought or the passing of an event or
the distance between events where an event is a location in space time
Are you aware that using the same word in the definition of the word being defined
is not really helpful in defining nor clarifying what the word actually means
Yes I am so I will remove spacetime from the definition of time so it is re defined as
the passing of a thought or the passing of an event or the distance between events