Can I be taught general and special Relativity on this forum

[P J Strydom]

If I am wasting anyone's time, please advise so I can leave and find another source to assist me in my quest.
I have been thinking about the theory of General and Special Relativity for most of my life. When I was 16 years old, I saw a documentary about Einstein and how he used his thoughts as experiments to test Special Relativity. As I started working, I never had the opportunity to study and to learn Physics, but I read a lot of books about it over the years. today at 57 I would like to get just this one scientific point explained to me.

My problem is that I understand what the Mickelson Morely experiment wanted to prove, what Einstein explain, but I am a fool on the reasons of the mathematical equations of Laurentz and Einstein.
This is what I want to know.
Is it possible that anyone will take the time to patiently explain the Maths to me?
How long will it take on this thread?
What will it cost me?
or if you know about a website where I can learn this science, please advise.
Kind Greetings

 

[phinds]

Can I be taught general and special Relativity on this forum

This is not a tutorial forum so likely not quite what you are looking for. You can pretty easily learn Special Relativity if you remember or can relearn a little very basic high school algebra. General Relativity is a 'whole 'nother beast though and you'll need a few years of graduate level math course to really get the details.

This IS a great forum to get specific questions answered though, so if you hit stumbling blocks in your studies, this is a good place to come.

 

[P J Strydom]

Thank you

 

[jtbell]

Go next door to our "Science and Math Textbooks" forum and use our search feature to search for the word "relativity". That will bring up lots of threads where people ask for advice about relativity textbooks. Ignore the ones about general relativity for now because that's beyond your current level, and focus on the ones about special relativity. Most of those are undergraduate level or above, but there are some references to ones that are more conceptual and use algebra at most. Then you can post for further or more specific recommendations if you want.

You can go quite a ways in basic special relativity with just a bit of algebra, if you're willing to take on faith (for now) the things that require calculus. For general relativity, if you want to go beyond a purely descriptive approach, which doesn't contain much true "understanding", you'll need a solid background in math (calculus at least) and undergraduate-level classical physics (mechanics and electromagnetism). These will also let you appreciate special relativity more deeply.

 

[P J Strydom]

Thank you for your replies.
I do however also see that Einstein not only used mathematics to make his theory explainable, but also used Thought experiments to logically find the answers to Time Dilation, length contraction and mass relation.
Now, in this regard I went and looked at the mathematical equations, and found that the Thought experiments and conclusions made on Time dilation for one, is definitely not correct,
Please explain to me by visual method the following.So far I only found many scientists that don't answer me.
It is a very simple question and I have been struggling with it for a long time.

Please see if you can.
Your answers will definitely sort out all the questions I have, and I will then continue with my studies on mathematics.

If we work on the following thought experiment:

We will move the moon closer to the Earth to one light second (and we will play that this is 300 000 Km/ one light second rounded up)
We will build 3 clocks, special clocks that is visible over 300 000 km, and travel at a slow speed with all 3 to exactly the middle of the distance from the Earth to the Moon where we will meet an awaiting ship and deliver one clock to be placed on the Moon. [This will ensure that if Time dilutes during travelling, all 3 clocks will now be exactly synchronized.]

We will now return to the Earth with the remaining 2 clocks and will place one on the Earth, and one on a very special spaceship that can travel at the speed of light, minus 1 meter per second. (for the benefit that we can not travel at the speed of light, or faster.) [But for this experiment we won't go to calculate the finer details, and will assume that the calculator we use don't have such detail, but will round the one meter up to one light second of speed we can travel]
Now the experiment.
Our spaceship will leave exactly at 12H00 as the seconds hand set us off to the moon.
When we left the Earth, the clock on the Moon (visible from earth) showed one second before 12H00, as the one on Earth was at 12H00 exactly.
Our spaceship travels to the Moon, and upon arrival we check the time on the Moon clock, which will now say what?
12 H 00+1 sec / 12H00 exactly?
What will the clock on the spaceship say?
12H00+1 sec / 12H00 / 12H00-1 sec.
What will the clock on Earth say?

 

[phinds]

Now, in this regard I went and looked at the mathematical equations, and found that the Thought experiments and conclusions made on Time dilation for one, is definitely not correct,

I'll come back to your question later in the day but for now, here's some advice I've given before:

When you come up against something that seems to completely be against established science, it is not a good idea to start off reaching different conclusions and stating them as correct but rather to start off with the assumption that you have made a mistake somewhere and try to find out where it is. If you have NOT made a mistake you will find the flaw in the established science, but that is very unlikely to happen. If you start off thinking that you have overturned established science you are likely to just end up embarrassed.

So rather than saying conclusions made on Time dilation for one, is definitely not correct, it would be better to say something like "I don't see how they can be correct" or better still "I don't understand why they are correct".

 

[P J Strydom]

I'll come back to your question later in the day but for now, here's some advice I've given before:

When you come up against something that seems to completely be against established science, it is not a good idea to start off reaching different conclusions and stating them as correct but rather to start off with the assumption that you have made a mistake somewhere and try to find out where it is. If you have NOT made a mistake you will find the flaw in the established science, but that is very unlikely to happen. If you start off thinking that you have overturned established science you are likely to just end up embarrassed.

True indeed.
I would like to also inform that I have spoken to a lot of PHD's on the subject in the past, and I can definitely make the following statement...
All they do is to come up with statements they don't, or can not explain a simple thought experiment to me.
They are quick to tell me how the mathematics work, and what the results should be, but once I ask follow up questions, they don't answer me.
I watched possibly over 100 hrs on You tube on the topic, and I do not find the answers.

Even Carl Sagan would come up with Time dilation, length contraction and mass variation, but only as statements, and no deeper explanations.
In my mind I say, Come on...it can not be so difficult!
I studied Einsten's book, and i don't get the answer.
Please don't get get me wrong.
I don't say I am super intelligent and Einstein is wrong, and most probably I am simply an idiot when I investigate the topic. But I am not an idiot to be ignored, for if I can not get answers to my questions, I am as a child wondering about the toy he will get for Christmas!

Please note, the above questions is one of 4 and is the most simple one based on the thought experiment of Einstein when he traveled on a train and passed another.
Thank you for your patience.

 

[PeroK]

It is a very simple question and I have been struggling with it for a long time.

Right, so what is the reason for that? Well, one reason is that you have not studied and learned the basic concepts used in physics. Perhaps the most important for learning relativity is the concept of a reference frame.

I doubt you are going to make progress unless you study SR systematically from a reputable textbook.

Also, your thought experiment suggests that you think that the transmission time of signals has something to do with relativity. In fact, it doesn't. For any event, observed by anyone at any distance from it, there is a time delay before the observer sees the event. This is true in all physics and has nothing to do with the theory of relativity.

In all measurements, any time delay has to be taken into account. For everyday situations, however, light is so fast that we generally do not have to take this delay into account. If, however, you were taking a very accurate measurement you would have to take the speed of light into account.

 

[PeroK]

If we work on the following thought experiment:

We will move the moon closer to the Earth to one light second (and we will play that this is 300 000 Km/ one light second rounded up)
We will build 3 clocks, special clocks that is visible over 300 000 km, and travel at a slow speed with all 3 to exactly the middle of the distance from the Earth to the Moon where we will meet an awaiting ship and deliver one clock to be placed on the Moon. [This will ensure that if Time dilutes during travelling, all 3 clocks will now be exactly synchronized.]

We will now return to the Earth with the remaining 2 clocks and will place one on the Earth, and one on a very special spaceship that can travel at the speed of light, minus 1 meter per second. (for the benefit that we can not travel at the speed of light, or faster.) [But for this experiment we won't go to calculate the finer details, and will assume that the calculator we use don't have such detail, but will round the one meter up to one light second of speed we can travel]
Now the experiment.
Our spaceship will leave exactly at 12H00 as the seconds hand set us off to the moon.
When we left the Earth, the clock on the Moon (visible from earth) showed one second before 12H00, as the one on Earth was at 12H00 exactly.
Our spaceship travels to the Moon, and upon arrival we check the time on the Moon clock, which will now say what?
12 H 00+1 sec / 12H00 exactly?
What will the clock on the spaceship say?
12H00+1 sec / 12H00 / 12H00-1 sec.
What will the clock on Earth say?View attachment 219425

Let me give you some of the answer. Let's not worry about the clock on the spaceship for now. To confirm my understanding of the experiment:

We have a clock on Earth and a clock on the moon that are synchronised, in the Earth-Moon reference frame.

A rocket leaves Earth and travels at near the speed of light (as measured from the Earth and/or the moon) and reaches the moon in about $1s$ (as measured from the Earth and/or the moon).

The moon clock reads 12:00:01 when the ship arrives, as does the Earth clock - although it takes a second for the light to reach an observer on the moon, so they see the Earth clock always 1s behind. In this case, showing 12:00:00, when looked at from the moon.

You don't need any relativity here. That answer comes simply from the definition of speed in terms of distance/time. This is nothing to do with the theory of relativity.

That is the part of the answer I wanted to give you.

Now, what is happening in the reference frame of the ship is another matter. For that you definitely need the theory of relativity.

 

[phyzguy]

Let me give you some of the answer. Let's not worry about the clock on the spaceship for now. To confirm my understanding of the experiment:

We have a clock on Earth and a clock on the moon that are synchronised, in the Earth-Moon reference frame.

A rocket leaves Earth and travels at near the speed of light (as measured from the Earth and/or the moon) and reaches the moon in about $1s$ (as measured from the Earth and/or the moon).

The moon clock reads 12:00:01 when the ship arrives, as does the Earth clock - although it takes a second for the light to reach an observer on the moon, so they see the Earth clock always 1s behind. In this case, showing 12:00:00, when looked at from the moon.

You don't need any relativity here. That answer comes simply from the definition of speed in terms of distance/time. This is nothing to do with the theory of relativity.

That is the part of the answer I wanted to give you.

Now, what is happening in the reference frame of the ship is another matter. For that you definitely need the theory of relativity.

What you say here is all true, with one crucial exception. The ship cannot travel at the speed of light. Let's say it travels at 99% of the speed of light. Then, in the Earth-Moon frame, it takes 1.01 seconds to arrive at the moon, so when it arrives the moon clock reads 12:00:01.01, and looking back at the Earth clock, it reads 12:00:00.01 Other than that, I agree with what you said. Where is the problem?

 

[phinds]

What you say here is all true, with one crucial exception. The ship cannot travel at the speed of light. Let's say it travels at 99% of the speed of light. Then, in the Earth-Moon frame, it takes 1.01 seconds to arrive at the moon, so when it arrives the moon clock reads 12:00:01.01, and looking back at the Earth clock, it reads 12:00:00.01 Other than that, I agree with what you said. Where is the problem?

He specifically said "NEAR the speed of light" and I don't think he had 99% in mind. More like 99.99999999999% so his figures are correct.

 

[phyzguy]

He specifically said "NEAR the speed of light" and I don't think he had 99% in mind. More like 99.99999999999% so his figures are correct.

Regardless of how fast he is going, he cannot leave Earth with the clock reading 12:00:00, then arrive at the moon and look back and see the Earth clock reading 12:00:00. I wanted to make sure he understood this point.

 

[phinds]

Look at it this way. He leaves the Earth with the Earth clock reading 12:00:00 He's traveling at essentially the speed of light, so both he AND the light showing the reading on the clock at the time he leaves take the same amount of time to reach the Moon, so yes, it does read 12:00:00 when he gets there even though it has, by then, progressed to 12:00:01 in its own FOR.

 

[phyzguy]

Look at it this way. He leaves the Earth with the Earth clock reading 12:00:00 He's traveling at essentially the speed of light, so both he AND the light showing the reading on the clock at the time he leaves take the same amount of time to reach the Moon, so yes, it does read 12:00:00 when he gets there even though it has, by then, progressed to 12:00:01 in its own FOR.

My point is just that he isn't traveling at the speed of light, so when he looks back at the Earth clock after arriving at the moon, it cannot read 12:00:00. It must read 12:00:00 + "a little bit". We can argue about how small "a little bit" can be, but it cannot be zero. Do you disagree?

 

[PeroK]

My point is just that he isn't traveling at the speed of light, so when he looks back at the Earth clock after arriving at the moon, it cannot read 12:00:00. It must read 12:00:00 + "a little bit". We can argue about how small "a little bit" can be, but it cannot be zero. Do you disagree?

Yes, I disagree. Clocks only have certain accuracy. To any required experimental accuracy a journey of $1c.s$ can take $1.0s$.

In fact, if we assume that the clocks only show the time to the second, then any rocket speed greater than $c/2$ would do! Albeit, such a clock may not be ideal for this experiment.

 

[phinds]

My point is just that he isn't traveling at the speed of light, so when he looks back at the Earth clock after arriving at the moon, it cannot read 12:00:00. It must read 12:00:00 + "a little bit". We can argue about how small "a little bit" can be, but it cannot be zero. Do you disagree?

Ah. I somewhat missed your point, but I do agree w/ PeroK that for all practical purposes is DOES read 12:00:00

 

[phyzguy]

I'm afraid we're hijacking the thread oin an irrelevant side issue. We all agree that clocks have finite accuracy.

@P J Strydom , can we get back to what you are having difficulty understanding. Please state your problem.

 

[newjerseyrunner]

There are several great series on Youtube about it. This one is one I like. Keep in mind two things when on Youtube though: 1) Most people have no idea what they are talking about, and 2) Those who know tend to simplify more than they should. Here is a 5 part series on General Relativity, hosted and written by an actual astrophysicist.

 

[Mark44]

I'm afraid we're hijacking the thread oin an irrelevant side issue. We all agree that clocks have finite accuracy.

Yes to both.

This is what I want to know.
Is it possible that anyone will take the time to patiently explain the Maths to me?

Not knowing what your background in mathematics is, I don't think so. We can answer specific questions, but explaining a pretty large swath of mathematics is not the purpose of this forum.

How long will it take on this thread?

Again, this is not something we do. Not knowing your background in either mathematics or physics, it's impossible to say how long it would take.

What will it cost me?

We don't charge fees.

or if you know about a website where I can learn this science, please advise.

A good place to start would be http://khanacademy.org. They have many videos on lots of different areas of both mathematics and physics.

 

[P J Strydom]

He specifically said "NEAR the speed of light" and I don't think he had 99% in mind. More like 99.99999999999% so his figures are correct.

Gentlemen,
I thank you all on your remarks posted here, and I believe that you are helping me more than what you think.
Please, I will not be very long in my enquiry, so only a few more points of clarification, and I will be fine.
Yes, I do not have a mathematical education as you need, however, I went through the Calculations I found in Einsteins book, even the Laurentz transformation, But I do not understand what the calculations have to do with Time dilation.

Therefore, I need to understand where Time dilation occurs, and all these explanations I find on You tube are skipping something I don't get.
This is why I need to understand the physical explanation on Time Dilation.

according to what I find, the Speed of light never changes in a set medium, this I agree, byt I never find that Time runs slower, all I see is that from one reference frame to the other one will "SEE" a clock running slower, which is an observation, and not reality.
furthermore, I don't agree with the following claim made on Thought experiments.
I will post it soon to explain my observation.
Anyhow, I love your answers and the way you all engage on the topic.
Thank You.

 

[P J Strydom]

Here is picture 2 of 3 I will post on this forum, then I will be done.
Now, The thought Experiment I gave on the 3 clocks shows that it does not matter where one is in any reference frame, say on the Earth, Space Ship, or Moon; time remains constant and it is only the observation that contains a vairable due to the time light takes to travel to the observer.
Now, this is where I am totally confused.
The Thought Experiment with my 3 Clocks, and the Thought experiment i learn from the best PHD's in all the universities that place their experiments on You Tube, uses the Twin paradox to explain time dilation.
This does not have any evidence and the experiment is incredibly non-based on reality, or I am missing out on the one thing I missed out on my whole life.
Where did time run slower for the traveler?
I don't see it.

 

[P J Strydom]

Let me show you what I mean.
Lets assume we will travel to the nearest star to us. (if you want to, Proxima Centauri at 4.22 LY) {say we move PC to 4LY for simplicity}
Again we have this clocks on the Earth, Proxima C, and the Rocket.
We have this special Rocket I spoke off that can travel at almost the speed of light. (lets ignore the fact that it travels at 99.9999999* the speed of light.)
The clocks we use count in exact years.
1. The clock on Earth say it is 1 Jan 2018, and it is synchronized with the clock on the spaceship as well as with the one on ProxC. (remember we delivered the clocks by special delivery a few years ago by traveling with all 3 clocks to the exact middle distance between Earth and ProxC)
2. if we look at the special clock on ProxC, it reads 1 Jan 2014. (it takes the light 4 years to travel back to the earth.)
3. The clock on The spaceship reads the same as what Earth's clock says.
4. My twin brother is on the space ship, and pulls away with this special spaceship at almost the speed of light. at 1 Jan 2018 (Earth Clock and Space ship clock say 1 Jan 2018 / ProxC say 1 Jan 2014)
5. As my brother travels to ProxC, he observes that the ProxC clock runs 2X faster than the Space ship Clock. (due to him traveling into the light of old light in transit to the Earth over 4 Years of travel.)
6. My brother turns back and sees that the Earth Clock is standing still at 1 Jan 2018. (because he is traveling with the light that left with him on departure.)
7. My brother arrives at ProxC on 1 Jan 2022, and finds that the ProxC clock is exactly the same as what the Space ship clock reads. (ProxC was minus 4 years when he left Earth, and as my brother traveled for 4Years, and read all the old light light from 2014 to 2022 from ProxC clock. He gained 4 Years since he traveled from Earth in 2018 and it is now 2022. (ProxC = 1 Jan 2022, Space ship = 1 Jan 2022, but Earth clock =1 Jan 2018)

Checkpoint time dilation observation!
Here we see that even though my Brother traveled from reference frame Earth, to ProxC , in reference frame Space ship, the reference Earth clock stood still for 4 years, the reference frame ProxC advanced by 8 years, and the spaceship reference frame remained constant 4 years of travel.

The quest continue
8 Without missing a beat, My brother returned to earth. (He left in 1 Jan 2022 on spaceship clock and as he departed, he saw ProxC was the same; but Earth was still on 1 Jan 2018)
9 as he traveled, he saw that the Earth clock was now turning 2X as fast, because he is now traveling into old light that left the Earth in 2018 to 2022 and new light from 2022 to 2026.
10. He also notice that ProxC clock is now standing still on 1 Jan 2022, because he is traveling with the light that left when he did.
11. At the halfway mark, My brother looks at his clock, and it say 1 Jan 2024, the Earth's clock is now on 1 Jan 2022, and the proxC clock is still on 1 Jan 2022.
12 My brother arrives on 1 Jan 2026, after traveling return flight of 8 years.
13. The spaceship clock says it is 1 Jan 2026, the Earth clock say it is 1 Jan 2026, and proxC say it is 1 Jan 2022.

Checkpoint Time dilation observation!
Again, my brother traveled from Earth to ProxC and back in 8 years since 2018 to 2026.
The clock on the Space ship shows 2026, and ProxC shows 2022.

Now, on the:
A. Reference frame earth, i saw the clock on ProxC move from 2014 to 2022. Earth clock from 2018 to 2026, and the spaceship clock showed 2018 when it left, and a blackout of light because it was traveling linear to proxC with the light that left and I could not see the spaceship clock for 8 years until 2026 when it arrived here on Earth with the light that came from ProxC when he turned around in 2022.
B. Reference frame Space ship. My brother saw the light of Earth remain at 2018 until he arrived at ProxC. and proxC clock was running 2X faster than his own clock because he was gaining 4 years of old light, and 4 years of light that departed from ProxC since he left. He saw ProxC clock advance 8 years.
C. From reference point proxC the Earth clock was at 2014 and advanced to 2022, itself showed 2018 and advanced to 2026. The spaceship clock light did not show up until it arrived at ProxC with the light that it left with in 2018, and as it left ProxC, the light of the spaceship clock from 2022 to 2026 will not be seen because the spaceship is traveling with the light linear to Earth, and no light reflects in line from proxC to the Space ship to reflect back to ProxC, because the spaceship is just too fast for the light to reach it. However, the light coming from the spaceship from Earth from 2018 to 2022 now arrives from 2022 to 2026 showing the spaceship in reverse. This will be observed up until 2026, and the spaceship will disappear for 4 years where there was no light that reflected back from the spaceship to ProxC.

This is what I see in reality, and I still do not know where the heck Time diluted?
Come on gentlemen, don't tell me to go and study the maths.
Where is my mistake?

 

[PeroK]

Where is my mistake?

As I said before, relativity and time dilation are NOT related to the time delay in an observer receiving a light signal.

Until you accept this, you will continue to go round in circles.

You are probably best to forget everything you think you know about relativity and start afresh.

 

[bhobba]

You are probably best to forget everything you think you know about relativity and start afresh.

Right.

To answer the specific question in your title - its yes - you can. BUT you will find in this and many other areas people ask questions about, science advisers, mentors etc will require you to do quite a bit of work. That is the only real way for true understanding. Not only will us spoon feeding you take an enormous amount of time on our part it simply is not as effective as us guiding you.

So to start with you MUST first understand Calculus. The level required for physics is intuitive so it really isn't that hard - the following will suffice:
https://www.amazon.com/dp/0471827223/?tag=pfamazon01-20

That will allow you to study the Susskind books and videos:
http://theoreticalminimum.com/
https://www.amazon.com/dp/0465075681/?tag=pfamazon01-20
https://www.amazon.com/dp/0465093345/?tag=pfamazon01-20

Then you are prepared for Wheeler and Taylor
http://www.eftaylor.com/download.html

Then you can tackle THE classic on General Relativity - so famous its simply called MTW:
https://www.amazon.com/dp/0691177791/?tag=pfamazon01-20

Note - if I was learning relativity I would not do it via Wheeler and Taylor or MTW. I have a copy (lost it a few years ago but just today got a new copy) because it is so widely used but is not my favorite book - Wald is - however it is very mathematically sophisticated and with a high level of mathematical rigor - MTW is very wordy - having a very low ratio of equations to words. Its surprising how little math is required to study it. In fact as far as advanced textbooks go it such an easy read Scientific American readers were given 25% off because of the feedback they had of, for a graduate level textbook, that even their general readership could get a lot out of it. Wheeler was dead against it - he wrote the book for senior undergraduates and graduate students so only wanted it offered to them. He didn't succeed - personally though I would have been very proud of writing a book like that - but he had a specific goal for the book and it was not meant for the general scientifically literate public that reads Scientific America. Interesting isn't it. I am very mathematically oriented and if that is your bent and background (I have a degree in math and computer science) there are better books/methods IMHO eg:
http://www2.physics.umd.edu/~yakovenk/teaching/Lorentz.pdf

However in your case I have carefully chosen my recommendations so a person, by diligent effort, can understand the physics rather than being exposed to the elegance of much more mathematically sophisticated approaches - you need to build up to it and learn the math as you go.

Thanks
Bill

 

[phyzguy]

Part of your problem is this: "(lets ignore the fact that it travels at 99.9999999* the speed of light.)". As I said in Post #10, you cannot do this. You are basically throwing out the baby with the bath. Try again with the assumption that the spacecraft is going at 50% or 75% or 99% of the speed of light.

 

[P J Strydom]

Thank you so much Sir.
And you are correct.
I need to get the mathematical side under my knee, and not just splashing around in this pool.
And believe me, I am doing it as quick as I can.
However, the references you supplied is welcomed and I am sure it will speed up my process.
Susskind is one heck of a good educator, and I watched a few of his lectures, but now that you recommended him, I will definitely take more time on his education.
I remember there are quite a number on his channel on you tube.

Thank you very much indeed.
Bill, you saw my thought experiment made by some MIT graduate on internet, and I think you might be able to see my predicament.
Look at the Twin Paradox as I placed it and please tell me what I am understanding wrong.

I see that Time remains a constant, but it is only the observation of light from 3 reference frames that seems to influence time.
In other words, all the explanations I saw from well established science descriptions is that they are telling me that because we observe, from the Earth (eg.), that a moving object flying away from us we see the light arriving slower at us because of the time light takes to get to Earth from the rocket.

Do you see where I am getting stuck?
Is the theory of Relativity simply a way to determine where a specific object is in space by measuring the arrival of its light in another time frame?

Because if this is what Relativity actually is, then Time dilation does not exist, and length contraction is simply a calculation on the observation of the same object's light leaving its front and rear and arriving at different times at my time frame. So, why all the fuss?

now you see my problem.
After all what I tried to learn, I still do not know what G&SR is, and no one can tell me?

So, what are all the great scientists doing with G&SR?

 

[PeroK]

I see that Time remains a constant, but it is only the observation of light from 3 reference frames that seems to influence time.
In other words, all the explanations I saw from well established science descriptions is that they are telling me that because we observe, from the Earth (eg.), that a moving object flying away from us we see the light arriving slower at us because of the time light takes to get to Earth from the rocket.

Do you see where I am getting stuck?
Is the theory of Relativity simply a way to determine where a specific object is in space by measuring the arrival of its light in another time frame?

Because if this is what Relativity actually is, then Time dilation does not exist, and length contraction is simply a calculation on the observation of the same object's light leaving its front and rear and arriving at different times at my time frame. So, why all the fuss?

now you see my problem

Yes, your problem is that you have misunderstood the basic idea of SR. And, each time you go to a new source, you interpret the material to fit your false preconception.

It also seems that when someone, e.g me, challenges your error, you simply ignore them. And carry on as before.

The puzzling thing is that you seem to know you are wrong but can't change any of your ideas.

 

[phinds]

So, what are all the great scientists doing with G&SR?

Well, just as one trivial off-the-cuff example, they are making GPS systems. Without taking relativity into account, your GPS would have you driving into buildings and off into wheat fields instead of on the road.

 

[P J Strydom]

Part of your problem is this: "(lets ignore the fact that it travels at 99.9999999* the speed of light.)". As I said in Post #10, you cannot do this. You are basically throwing out the baby with the bath. Try again with the assumption that the spacecraft is going at 50% or 75% or 99% of the speed of light.

OK , so let's us travel at one half of C.

Redy...Steady...
Departing from Earth in time frame Earth we see
Earth Clock = 2018
Space ship Clock= 2018
ProxC Clock= 2014
At time frame Space ship we see
Earth Clock = 2018
Space ship Clock= 2018
ProxC Clock= 2014
At time frame ProxC Clock we see
Earth Clock = 2014
Space ship Clock= 2014
ProxC Clock= 2018

Go!
Arriving at ProxC in time frame Earth we see
Earth Clock =2026
Space ship Clock= 2022
ProxC Clock= 2022
At time frame Space ship we see
Earth Clock = 2022
Space ship Clock= 2026
ProxC Clock= 2026
At time frame ProxC Clock we see
Earth Clock =2022
Space ship Clock=2026
ProxC Clock= 2026

And Hi!
Arriving at Earth back from 8 years return, in time frame Earth we see
Earth Clock =2034
Space ship Clock=2034
ProxC Clock= 2030
At time frame Space ship we see
Earth Clock = 2034
Space ship Clock= 2034
ProxC Clock= 2030
At time frame ProxC Clock we see
Earth Clock =2030
Space ship Clock=2030
ProxC Clock= 2034

Again, here we traveled at half the speed of C, but we know what every clock says and I do not see the Twin gaining on Time?
Gentlemen, what is Relativity, and where do they get this idea that Time runs slower for a traveler?
is there no one that can tell me?
I will go and learn the mathematics, but hell guys, please just explain where Tine started to run slower or faster, because I see that the explanations by Physicists is only a description on how light is observed, and not that time dilates?

 

[bhobba]

Is the theory of Relativity simply a way to determine where a specific object is in space by measuring the arrival of its light in another time frame?

No its a theory believe it or not about symmetry. The link I gave before explains it:
http://www2.physics.umd.edu/~yakovenk/teaching/Lorentz.pdf

But you need math you probably do not have yet to understand it - you need to build up to it.

Because if this is what Relativity actually is, then Time dilation does not exist

Well exist is a very philosophically loaded word in this contest best to not use it.

Here is a better way of looking at it.

Imagine you have a rod wider than your door you want to get through it. How do you do it? You rotate it - then it will fit. Now a watch you carry around with you is like the rod. All velocity does is rotate it so its smaller as seen by the door. In fact mathematically, by what's called hyperbolic rotation, that's just what is going on.

Using this view is time dilation real - that's a philosophical question. The theory doesn't answer that - it just tells you the results - like the rod is smaller in the direction of the width of the door if you rotate it.

How is the twin paradox resolved - well for one twin they are subject to accelerations - and that, at rock bottom is the answer. But you can read the detailed answer here::
http://www1.phys.vt.edu/~jhs/faq/twins.html

What is the rock bottom explanation of GR - simply that when gravity is present space-time is curved. Once you accept that then GR more or less falls out - but the mathematics of why is not trivial. I explained technical detils in a post I did in another thread that I will repeat:

Ok here is the technical rundown why gravity is space-time curvature. Its not at the beginner level level - but it can't really be explained at that level why its pretty much inevitable. You probably will not understand the detail, but hopefully will get a gist.

If we consider flat-space time then let's try to construct a theory of gravity.

We will base it on electromagnetism in special relativity - ie flat space-time - the most elegant form of EM probably being the so called Lorentz gauge formalism. In this formalism ∂u∂uAv = 4π ∂vJv and ∂uAu=0. Au and Ju are first rank 4 tensors - you can look up what they are physically - but its not important to this. Just for the heck of it let's write a similar equation in second rank tensors Φuv instead of first rank ones like Au, so you have ∂u∂uΦjk = -kTjk and ∂uΦuk=0 - k is a constant to be determined. I haven't at this point said anything about Φ or T - we will see what happens if you mathematically analyse it. Define huv = Φuv - 1/2 ηuvΦ.

When you chug through the math you find something very interesting - the equation describing huv is invariant to very small changes of coordinate systems. Well since any coordinate system can be broken into a lot of small changes from another coordinate system this leads to the equations should be invariant to changes in coordinate systems. But that is very intuitive anyway - coordinate systems are man made - nature doesn't decide them - since we choose them, equations should not really change when they do - it's called the principle of invariance. So really you should write the equations in general coordinate systems from the start. We will not only assume that but make no assumption about if space-time is flat or not. In curved space-times an assumption is made - just like if you had some curved sheet in 3 dimensional space - small areas of it can be considered flat - in curved space-time small areas are considered flat space-time. Ok let's do that. When you do you find some interesting things. First the equation of motion of a particle at low speeds and small huv is exactly the same as a gravitational field with a simple relation to huv - in particular Φ = 1/2 k h00 where Φ is the gravitational potential. Hmmm - maybe this has something to do with gravity. Ok let's see what Tuv is - it turns out T00 is the mass density, p. But we know the equations have to be the same in any coordinate system. In small areas in curved space-time, its flat and SR holds - so the equations ∂u∂uΦjk = Tjk and ∂uΦuk=0 must hold. So we start to chug through the math again to find an equation that is the same in any coordinate system but in small areas reduces to the flat space time equations. The equation is Guv = -1/2k^2 Tuv. Guv is called the Einstein Tensor defined by Guv = Ruv - 1/2 guv R (guv is called the metric - and is defined as guv = ηuv + k huv). Ruv, called the Ricci tensor is a measure of the spaces curvature. R, is called the Ricci scalar, and is also a measure of curvature - so the Einstein Tensor is a measure of curvature. Suppose we have a dust of particles then Tuv is called its called the stress energy tensor of the particles, and T00 in flat space-time is the mass density. So we have the amazing result - space-time is curved by mass.

Its virtually inescapable if you follow where the math leads.

Thanks
Bill

 

[itfitmewelltoo]

No its a theory believe it or not about symmetry. The link I gave before explains it:
http://www2.physics.umd.edu/~yakovenk/teaching/Lorentz.pdf

But you need math you probably do not have yet to understand it - you need to build up to it.
Well exist is a very philosophically loaded word in this contest best to not use it.

Here is a better way of looking at it.

Imagine you have a rod wider than your door you want to get through it. How do you do it? You rotate it - then it will fit. Now a watch you carry around with you is like the rod. All velocity does is rotate it so its smaller as seen by the door. In fact mathematically, by what's called hyperbolic rotation, that's just what is going on.

Using this view is time dilation real - that's a philosophical question. The theory doesn't answer that - it just tells you the results - like the rod is smaller in the direction of the width of the door if you rotate it.

How is the twin paradox resolved - well for one twin they are subject to accelerations - and that, at rock bottom is the answer. But you can read the detailed answer here::
http://www1.phys.vt.edu/~jhs/faq/twins.html

What is the rock bottom explanation of GR - simply that when gravity is present space-time is curved. Once you accept that then GR more or less falls out - but the mathematics of why is not trivial.

Thamks
Bill

Excellent. You hit on the two fundamental issues that people run into.

The first is they want to skip the bachelor's and master's material and jump right to the philosophical questions. And the can't, it simply doesn't work that way. You know, and I know, what are the philosophical questions because we studied the science.

The second, which you've implied, is what the twin paradox is. Many are under the false understanding that is a conclusion about reality that Relativity claims. It is the complete opposite. It is a paradox, and understood error that the logic of Special Relativity runs up against. Every system of logic will have a paradox that cannot be resolved within it. (No reference) General Relativity resolves the conflict by incorporating acceleration and gravity. It is the acceleration of one twin that accounts for time dialation. Even this resolved, Einstein remained concerned that the conclusion of the existence of the black holes was an unresolved paradox from General Relativity.

Now, as you said, the math of this is untenable. There is simply no satisfactory explanation of GR that a thoughtful person can have without the BS and MS material that comes before.

 

[PeterDonis]

Many are under the false understanding that is a conclusion about reality that Relativity claims. It is the complete opposite. It is a paradox, and understood error that the logic of Special Relativity runs up against.

This is not correct. The twin "paradox" is not an actual paradox in SR. It is an illustration of how SR spacetime geometry works. You do not need GR to explain the result in the standard setting of the paradox, which is in flat spacetime with no gravity.

 

[phyzguy]

The answer to your long post #29 is that the universe could work this way, in which there is a universal time which is independent of the observer's state of motion. However, this is not the universe that we live in. In our universe, when the spaceship arrives at Proxima, his clock will only read about 2024.9, not 2026. A vast number of experiments have confirmed the validity of relativity theory. You need to accept that there are things you don't understand and start studying.

 

[bhobba]

It is a paradox, and understood error that the logic of Special Relativity runs up against. Every system of logic will have a paradox that cannot be resolved within it.

Its not a paradox. The only issue is if you can use SR to resolve it or you need the full GR formalism. There is some debate I have seen about it, but the general answer is no - either way its not a paradox.

These days you don't really need Masters level material to do GR - senior undergrad is good enough.

Others likely will not agree with me but I believe you could teach it to senior HS students - but that is a whole thread by itself.

Thanks
Bill

 

[PeterDonis]

I will go and learn the mathematics, but hell guys, please just explain where Tine started to run slower or faster, because I see that the explanations by Physicists is only a description on how light is observed, and not that time dilates?

We can't "explain" your scenario as you give it because you got the numbers wrong. Here is a correct set of numbers for the scenario as you set it up. Just to be clear: the scenario is that a ship leaves Earth when Earth clocks say 2018 and the ship's clock says 2018; it travels at 0.5c relative to Earth until it reaches Proxima; then it turns around and travels back to Earth at 0.5c relative to Earth. For purposes of this scenario, we assume Proxima and Earth are exactly 4 light-years apart in an inertial frame in which they are both at rest.

Here are the correct times given the above:

Departure from Earth
Earth's clock reads 2018.
Spaceship's clock reads 2018.
Earth and spaceship see an image of Proxima's clock reading 2014.
In the Earth/Proxima frame, Proxima's clock reads 2018 and Proxima sees an image of Earth's and spaceship's clock reading 2014.
In the spaceship frame, Proxima's clock reads 2020 and Proxima sees an image of Earth's clock reading 2016 and spaceship's clock reading 2016. Why? Relativity of simultaneity; the event on Proxima's worldline that is simultaneous with the ship leaving Earth is different in the spaceship frame than in the Earth frame.

Arrival at Proxima
Proxima's clock reads 2026.
Spaceship's clock reads 2024.9 (time dilation factor of about 1.15).
Proxima and spaceship see an image of Earth's clock reading 2022.
In the Earth/Proxima frame, Earth's clock reads 2026 and Earth sees an image of Proxima's clock reading 2022 and an image of spaceship's clock reading 2022.62 (because the ship is in transit when this light is emitted, plus time dilation).
In the spaceship frame, Earth's clock reads 2024 and Earth sees an image of Proxima's clock reading 2020 and an image of spaceship's clock reading 2021.46 (again, because the ship is in transit, plus time dilation).

Return to Earth
Earth's clock reads 2034.
Spaceship's clock reads 2031.8 (time dilation).
Earth and spaceship see an image of Proxima's clock reading 2030.
In the Earth/Proxima frame, Proxima's clock reads 2034, and Proxima sees an image of Earth's clock reading 2030 and an image of spaceship's clock reading 2028.52.
In the spaceship frame, Proxima's clock reads 2032, and Proxima sees an image of Earth's clock reading 2028 and an image of spaceship's clock reading 2027.36.

With these correct numbers, it should be obvious how the spaceship "loses time" relative to Earth and Proxima.