unifying gravity and electromagnetism

[aggle-rithm]

I've been meaning to unify gravity and electromagnetism, but I've just been so busy...

 

[Dancing David]

We can straight away discard the idea of constant speed of light using the same twin flight experiment. Imagine that a beam of light with velocity ‘10C’ is shone towards the west. A west bound flight whose velocity is ‘2C’ will measure the velocity of light as only 8C unless its time gets dilated. Similarly the east bound flight with a velocity 2C will measure the speed of light as 12C unless its time runs faster. But we know that this was not the case from the above experiment.

We can straight away discard your experiment, how did you go at 2C, does this happen in reality at all?

 

[Dancing David]

I am not sure if the rest of the crowd also has the same limitations like you.

I would like to know how you go at 2c.

 

[aggle-rithm]

2.Twins paradox

a.Due to the expanding universe, we on this earth are already moving at close to the speed of light relative to the receding galaxies at the ‘far end’ of our universe. This should make us immortal!

b.Coming to the twins paradox, it is said that if one of the twins travels to the outer space at close to the speed of light, on his return from the space trip, because of time dilation, he would apparently be younger than his earth bound twin. But we could argue that the earth bound twin was also moving at the same speed relative to the space bound twin. So time should dilate for both them equally.

Wow! No one has EVER thought of this!

Oh, wait. Yes, they have.

Consider how the doppler effect would affect the perceived passage of time as one of the twins moves AWAY from the other than comes BACK.

If you never had that change of direction, then the time dilation would indeed be the same for both. This is why simultaneity has no meaning across great distances.

 

[Baloney]

Sounds like he could use a good dose of Staphysagria*. Among its other amazing homecraptic abilities is that of controlling anger.

-----------
* http://abchomeopathy.com/r.php/Staph

I love this disclaimer, right in the middle:
"Please remember though, this homeopathy materia medica is provided for information only, with no guarantee of accuracy; it is not intended as a substitute for medical advice, nor as a claim for the effectiveness of Staphysagria in treating any of the symptoms below. If symptoms persist, seek professional medical advice - minor symptoms can often be a sign of a more serious underlying condition. Homeopathic remedies are very dilute, and while the homeopathic remedy may be beneficial, the raw product may be harmful."

 

[Mashuna]

Time dilation has been ‘proved’ experimentally by running two flights with equal velocity in the opposite directions, one east wards and another west wards. It was 'noted' that the clock in the east bound flight recorded less time than that in the west bound flight ‘indicating’ time dilation. This is because, earth’s rotational velocity (as it spins towards east) gets added to the east bound flight making its relative velocity more than the west bound flight which runs opposite to the direction of the earth’s spin.

I'm sure I've seen someone use this fantastic argument before around here. I'll have to check the recent stundies.

 

[Complexity]

Homeopathy?



</thread>

 

[WhatRoughBeast]

I hate to point this out, as it may encourage him, but drgsrinivas is actually close to correct on one point:

a.Due to the expanding universe, we on this earth are already moving at close to the speed of light relative to the receding galaxies at the ‘far end’ of our universe. This should make us immortal!

To observers on the far side of the universe, we do live longer. Time dilation does not apply in the frame of reference which is considered to be moving, only to the observer in another frame.

 

[MattusMaximus]

drgsrinivas, please present some kind of mathematical analysis for your ideas that the rest of us can scrutinize.

ETA: Incidentally, Einstein spent much of his career attempting to unify gravity and electromagnetism, to no avail. And he even used math!

 

[Tubbythin]

I
To observers on the far side of the universe, we do live longer. Time dilation does not apply in the frame of reference which is considered to be moving, only to the observer in another frame.

That would never make us immortal to any observer though. We'd just live a very long life very slowly from their point of view.

 

[sol invictus]

To observers on the far side of the universe, we do live longer. Time dilation does not apply in the frame of reference which is considered to be moving, only to the observer in another frame.

It's more subtle than that. You cannot really talk about "frames" - which is usually short for "inertial reference frame" - in cosmology. There is no such thing as an inertial frame in a curved spacetime. And if instead you replace "inertial reference frame" by "coordinate system", your first statement is false. For instance, in standard, flat, FRW cosmology, the metric is

[latex]$-dt^2 + a(t)^2 d \vec x^2$[/latex]

If the earth is at x=0, an observer "on the far side of the universe" is at a*x=1/H, where H=(a dot)/a. But as you can see from that metric, time ticks at exactly the same rate everywhere.

You might wonder how that is possible, since after all, the universe is expanding and there must high relative velocities involved (indeed, if "velocity" means the time derivative of a*x, then for a*x>1/H the "velocity" is greater than c).

What's going on is that this metric describes a curved spacetime, and naive notions of time dilation - and even velocity and distance - simply do not apply to it. Instead, you should ask about physical experiments. For instance, if we looked at a (very) distant planet with some kind of super telescope, would we see the people on it living slowly? The answer is that we would, at least if H>0 - but how much of that is due to simple Doppler shift and how much is due to "true" time dilation is not at all clear (and in fact, not even a well-defined question).

 

[Tubbythin]

It's more subtle than that. You cannot really talk about "frames" - which is usually short for "inertial reference frame" - in cosmology. There is no such thing as an inertial frame in a curved spacetime. And if instead you replace "inertial reference frame" by "coordinate system", your first statement is false. For instance, in standard, flat, FRW cosmology, the metric is

[latex]$-dt^2 + a(t)^2 d \vec x^2$[/latex]

If the earth is at x=0, an observer "on the far side of the universe" is at a*x=1/H, where H=(a dot)/a. But as you can see from that metric, time ticks at exactly the same rate everywhere.

You might wonder how that is possible, since after all, the universe is expanding and there must high relative velocities involved (indeed, if "velocity" means the time derivative of a*x, then for a*x>1/H the "velocity" is greater than c).

What's going on is that this metric describes a curved spacetime, and naive notions of time dilation - and even velocity and distance - simply do not apply to it. Instead, you should ask about physical experiments. For instance, if we looked at a (very) distant planet with some kind of super telescope, would we see the people on it living slowly? The answer is that we would, at least if H>0 - but how much of that is due to simple Doppler shift and how much is due to "true" time dilation is not at all clear (and in fact, not even a well-defined question).

After my last post I started to wonder whether what I said was right (honest!). I realised the expansion of the Universe wasn't really special relativity and that I didn't really know how to describe the actual problem. I'm glad the actual answer isn't clear-cut though. Makes me feel better about my ignorance.

 

[drgsrinivas]

Thought experiment

I will make the thought experiment simpler for you, can’t see you all struggle so much on that.
We can straight away discard the idea of constant speed of light using the same twin flight experiment. Imagine that a beam of light with velocity ‘C’ is shone towards the west. A west bound flight whose velocity is ‘0.2C’ will measure the velocity of light as only ‘0.8C’ unless its time gets dilated. Similarly the east bound flight with a velocity ‘0.2C’ will measure the speed of light as ‘1.2C’ unless its time runs faster. But we know that this was not the case from the above experiment.

I said just imagine.
Lack of simple imagination power is not a limitation (with reference to the crowd here)

 

[drgsrinivas]

Thought experiment

I hope you will get past this tiny bit, so that I can answer to the rest of the arguments.

 

[dafydd]

I will make the thought experiment simpler for you, can’t see you all struggle so much on that.
We can straight away discard the idea of constant speed of light using the same twin flight experiment. Imagine that a beam of light with velocity ‘C’ is shone towards the west. A west bound flight whose velocity is ‘0.2C’ will measure the velocity of light as only ‘0.8C’ unless its time gets dilated. Similarly the east bound flight with a velocity ‘0.2C’ will measure the speed of light as ‘1.2C’ unless its time runs faster. But we know that this was not the case from the above experiment.

I said just imagine.
Lack of simple imagination power is not a limitation (with reference to the crowd here)

I'll just hang around until you win your Nobel prize.

 

[Roboramma]

But we know that this was not the case from the above experiment.

Wait, didn't you say that "the above experiment" demonstrated time dilation?

Sorry, I just don't seem to be following.

 

[dafydd]

Wait, didn't you say that "the above experiment" demonstrated time dilation?

Sorry, I just don't seem to be following.

There is nothing to follow.

 

[The Don]

I will make the thought experiment simpler for you, can’t see you all struggle so much on that.
We can straight away discard the idea of constant speed of light using the same twin flight experiment. Imagine that a beam of light with velocity ‘C’ is shone towards the west. A west bound flight whose velocity is ‘0.2C’ will measure the velocity of light as only ‘0.8C’ unless its time gets dilated. Similarly the east bound flight with a velocity ‘0.2C’ will measure the speed of light as ‘1.2C’ unless its time runs faster. But we know that this was not the case from the above experiment.

I said just imagine.
Lack of simple imagination power is not a limitation (with reference to the crowd here)

So we have to imagine that the laws of physics don't apply in order to understand your theories which revolutionise the laws of physics.

Both flights will note the same speed of light. The flight flying towards the light will notice a shift of frequency towards the blue spectrum, the flight flying away from the light will notice a shift of frequency towards the red spectrum.

 

[Fishstick]

I imagine if we put this guy and Maartenn in the same room, we would get some mindblowing new theories.

It would sound like putting two furbies across eachother, though.

 

[MRC_Hans]

I will make the thought experiment simpler for you, can’t see you all struggle so much on that.
We can straight away discard the idea of constant speed of light using the same twin flight experiment. Imagine that a beam of light with velocity ‘C’ is shone towards the west. A west bound flight whose velocity is ‘0.2C’ will measure the velocity of light as only ‘0.8C’ unless its time gets dilated. Similarly the east bound flight with a velocity ‘0.2C’ will measure the speed of light as ‘1.2C’ unless its time runs faster. But we know that this was not the case from the above experiment.

Yes, we know that this is not the case. Even if we move with a considerable fraction of c, we will still observe that light moves at c.

We need not imagine, because this is fact.

So, what will YOU conclude from this fact?

Hans