Why we can never travel faster than the speed of light

[stevil]

If you take science for it, the universe is 14 billion years old also, and no alien-race has developed technlogy to find us in all that time.

A few things here.
Humans haven't been around for 14 billion years.

If aliens visited Earth a billion years ago, they wouldn't have found any intelligent life. Some might say that if they visit us today they wouldn't find any either.

But we have only been broadcasting our presence for about 100 years or so.
Travelling at the speed of light our radiowaves have only travelled a very small fraction of what makes up the milky way galaxy. This is called the radioshere. It has a radius of 100 light years.
In comparrison, our Milky way galaxy is 100,000 light years across and 1,000 to 10,000 light years thick.
Our milky way is made up of about 100 billion stars.
But only 75 stars are within our radiosphere.
Those at the outer edge of the radio sphere will only just now have received our radio signals and it would talk another 100 years for them to send a signal back to us.

Because the universe is so large and has existed for so much time, it would be very hard for aliens to know we exist here and now.

 

[SelfSim]

If aliens visited Earth a billion years ago, they wouldn't have found any intelligent life. Some might say that if they visit us today they wouldn't find any either.
..
Because the universe is so large and has existed for so much time, it would be very hard for aliens to know we exist here and now.

If aliens exist at all .. which we don't know .. therefore any arguments made for/against, (or any argument whatsoever about aliens), are not founded on any evidence at hand.

Ie: the evidence for/against the existence of aliens is, itself, nonexistent.

 

[sjastro]

Hmm .. ok .. interesting.
Thanks!

The role of neural networks in AI can be seen in DeepSeek's taking on my layman explanation of dark energy k-essence.
It was done in Python code.

DeepSeek explains the role of its neural network in the response.

 

[SelfSim]

The role of neural networks in AI can be seen in DeepSeek's taking on my layman explanation of dark energy k-essence.
It was done in Python code.

View attachment 360764​

DeepSeek explains the role of its neural network in the response.

View attachment 360765​

Very interesting .. it relies on human capabilities along the way .. and in evaluating 'the physical relevance'.

IOW, its still an extension of the human mind's capabilities .. (and not another lifeform independent from the human mind).

Its capabilities, as a tool, are huge! .. I mean, what human could do what it does, in the way it does it, in the time spans it does and then communcate its results and conclusions, in a way humans can, (sort of/mostly), understand?

Soo impressive! Can it be used to finally understand quantum physics .. no wait! .. on second thoughts, let's not go down that rabbit hole, eh?

 

[sjastro]

Very interesting .. it relies on human capabilities along the way .. and in evaluating 'the physical relevance'.

IOW, its still an extension of the human mind's capabilities .. (and not another lifeform independent from the human mind).

Its capabilities, as a tool, are huge! .. I mean, what human could do what it does, in the way it does it, in the time spans it does and then communcate its results and conclusions, in a way humans can, (sort of/mostly), understand?

Soo impressive! Can it be used to finally understand quantum physics .. no wait! .. on second thoughts, let's not go down that rabbit hole, eh?

The human input AI was referring to was me.
While DeepSeek can generate Python code it cannot run it, its initial code had errors which I told it to fix.

The Python code and its output did not tell me anything why my layman explanation of K-essence was unsatisfactory.

While I can make sense of the top graph, the bottom graph is meaningless because I have never even heard of the term "Sound Speed Squared".
So the onus was put back on AI to explain the code and output in English an undergraduate in physics or applied mathematics can understand.

 

[SelfSim]

The human input AI was referring to was me.
While DeepSeek can generate Python code it cannot run it, its initial code had errors which I told it to fix.

The Python code and its output did not tell me anything why my layman explanation of K-essence was unsatisfactory.

View attachment 360767

While I can make sense of the top graph, the bottom graph is meaningless because I have never even heard of the term "Sound Speed Squared".
So the onus was put back on AI to explain the code and output in English an undergraduate in physics or applied mathematics can understand.

View attachment 360768​

I went for the Refined analogy .. but it lost me on the last bullet point .. then it lost me on the analogy supposedly demonstrating the interplay between the bullet points. ¯\_(ツ)_/¯

(Please Mr DeepSeek: don't sentence me to having to go back and do yet more undergrad physics and applied mathematics! )

 

[sjastro]

I went for the Refined analogy .. but it lost me on the last bullet point .. then it lost me on the analogy supposedly demonstrating the interplay between the bullet points. ¯\_(ツ)_/¯

(Please Mr DeepSeek: don't sentence me to having to go back and do yet more undergrad physics and applied mathematics! )

K-essence physics is very new, developed in 2000 and is very much in the field post doctorate research which tries to explain observations such as the emergence of dark energy around 6 billion years ago.
I doubt it has filtered down to undergraduate physics and applied maths except at a very elementary level.

I have requested DeepSeek to explain it to someone who doesn't even have a knowledge of basic physics.

First of all it thought about it....................................

​

Before giving its final explanation.

​

 

[Neogaia777]

I've decided I'm going to try this again?

You are moving along at 86% the speed of light. Time dilation at that speed is 50%, and then I am also assuming length contraction at that speed (86% of c) is also 50%, correct? For a total 75% effect overall, right?

Well, how can c always be (messured as) always being the same in everyones own frames of reference unless you can somehow make that 75% 86% in order for the math to pan out, or for the theory or idea that c is always the same in all reference frames to still be the same at that point, etc?

It would seem to me that inside of my own very, very simplistic understanding, that one of those two effects (either time dilation or length contraction) would need to be having a greater effect earlier on (in the percentage of speed of c that you were traveling) in order to make the math fit correctly or for the speed of c (when measured) to always be the same (when it is measured) inside of each ones owns reference frames, etc? Otherwise, they would be different, right? And we know that cannot be, because we already have proof that it is always the same, right?

That 75% effect needs to be made into 86% somehow, or the speed/length/time of c would be different when it is measured by; especially the one's moving at 86% of c, own reference frame, correct?

At 86% of c, time is affected by 50% for that one moving or in motion at that speed, and it's length is also affected by 50% at 86% of c, but isn't that only 75% when it would need to be 86% (of c)? What am I missing?

God Bless.

 

[Hans Blaster]

I've decided I'm going to try this again?

You are moving along at 86% the speed of light. Time dilation at that speed is 50%, and then I am also assuming length contraction at that speed (86% of c) is also 50%, correct? For a total 75% effect overall, right?

Well, how can c always be (messured as) always being the same in everyones own frames of reference unless you can somehow make that 75% 86% in order for the math to pan out, or for the theory or idea that c is always the same in all reference frames to still be the same at that point, etc?

It would seem to me that inside of my own very, very simplistic understanding, that one of those two effects (either time dilation or length contraction) would need to be having a greater effect earlier on (in the percentage of speed of c that you were traveling) in order to make the math fit correctly or for the speed of c (when measured) to always be the same (when it is measured) inside of each ones owns reference frames, etc? Otherwise, they would be different, right? And we know that cannot be, because we already have proof that it is always the same, right?

That 75% effect needs to be made into 86% somehow, or the speed/length/time of c would be different when it is measured by; especially the one's moving at 86% of c, own reference frame, correct?

At 86% of c, time is affected by 50% for that one moving or in motion at that speed, and it's length is also affected by 50% at 86% of c, but isn't that only 75% when it would need to be 86% (of c)? What am I missing?

God Bless.

Time dilation and length contraction are simultaneous effects of relativity that do not add (or multiply)

The common factor of 2 (or the reciprocal 1/2) that appears in this example is the Lorentz factor W which relates to the velocity v as such:

W = sqrt( 1/ ( 1-(v/c)^2))

Your "86%" is the v/c and it is a rounded version of sqrt(3/4) = 0.86602...

The formula for W needs us to square the v/c, in this case sqrt(3/4)*sqrt(3/4) = 3/4. Now

W = sqrt( 1/ (1-3/4) ) = sqrt( 1 / (1/4) ) = sqrt (4) = 2.

 

[SelfSim]

Looks like a case of attempting to apply intuition rather than following the mighty principle of: 'shut-up-and-calculate'?

 

[Neogaia777]

Time dilation and length contraction are simultaneous effects of relativity that do not add (or multiply)

The common factor of 2 (or the reciprocal 1/2) that appears in this example is the Lorentz factor W which relates to the velocity v as such:

W = sqrt( 1/ ( 1-(v/c)^2))

Your "86%" is the v/c and it is a rounded version of sqrt(3/4) = 0.86602...

The formula for W needs us to square the v/c, in this case sqrt(3/4)*sqrt(3/4) = 3/4. Now

W = sqrt( 1/ (1-3/4) ) = sqrt( 1 / (1/4) ) = sqrt (4) = 2.

I'm not understanding how this attempts to answer my question? To me it just sounds like restating my question, etc?

Let's say the length of a/the beam of light is 100, and the one who has been traveling at, or has already traveled that at 86% of that goes to measure it but his time is affected by 50% and so is his length by 50%, so he measures that 100 as being 25, correct? (although still 100 to him, etc) But, (and leaving that aside for a minute), he has traveled 86% of that, and so he should actually measure it as being (100-86) =14, correct? So what measurement does he actually measure or does he get? 25? or 14?

(And, yes, I realize 86% is rounded off, and maybe it should be 87%, but that's due to trying to keep this as simple as I possibly can, and also with him actually measuring it as 100, etc, it's due to trying to keep this as simple as I possibly can, etc) (The numbers themselves don't actually matter, but I've chosen the ones I have chosen for simplicities sake, and to better understand the ideas or concepts involved, etc)

Take Care.

 

[SelfSim]

I'm not understanding how this attempts to answer my question? To me it just sounds like restating my question, etc?

Let's say the length of a/the beam of light is 100, and the one who has been traveling at, or has already traveled that at 86% of that goes to measure it but his time is affected by 50% and so is his length by 50%, so he measures that 100 as being 25, correct? (although still 100 to him, etc) But, (and leaving that aside for a minute), he has traveled 86% of that, and so he should actually measure it as being (100-86) =14, correct? So what measurement does he actually measure or does he get? 25? or 14?

(And, yes, I realize 86% is rounded off, and maybe it should be 87%, but that's due to trying to keep this as simple as I possibly can, and also with him actually measuring it as 100, etc, it's due to trying to keep this as simple as I possibly can, etc).

Take Care.

Sheesh! Its counterintuitive enough to grapple with these concepts but its exponentially more difficult to grapple with your visualisations!
This appears as a sort of a cruel and unusual punishment you're determined to inflict on others, so I find myself asking: what is the benefit for others in trying to decode your visualisations such as 'the length of a beam of light'?.
Is that your intention here? (Ie: to inflict punishment upon others?) I really can't tell?
Would you kindly clarify?
Cheers

 

[Neogaia777]

Sheesh! Its counterintuitive enough to grapple with these concepts but its exponentially more difficult to grapple with your visualisations!
This appears as a sort of a cruel and unusual punishment you're determined to inflict on others, so I find myself asking: what is the benefit for others in trying to decode your visualisations such as 'the length of a beam of light'?.
Is that your intention here? (Ie: to inflict punishment upon others?) I really can't tell?
Would you kindly clarify?
Cheers

I thought some of you might think/have thought some of these kinds of things were/are actually kind of fun sometimes, etc?

Sorry if I am getting that wrong though.

I certainly don't want to putting others through a kind of quote/unquote "hell" like you are right now describing though, etc. Because that is not at all any of my intent, etc.

Take Care.

 

[SelfSim]

I thought some of you might think/have thought some of these kinds of things were/are actually kind of fun sometimes, etc?

Sorry if I am getting that wrong though.

I certainly don't want to putting others through a kind of quote/unquote "hell" like you are right now describing though, etc. Because that is not at all any of my intent, etc.

Take Care.

Ok .. thanks .. Others are free to choose for themselves.
I tend to look closely at posts containing syllogisms, (or mere assumptions posited as conditional truths).. especially when they're requests for accepting visualisations that don't make sense.

 

[Hans Blaster]

I'm not understanding how this attempts to answer my question? To me it just sounds like restating my question, etc?

Let's say the length of a/the beam of light is 100, and the one who has been traveling at, or has already traveled that at 86% of that goes to measure it but his time is affected by 50% and so is his length by 50%, so he measures that 100 as being 25, correct? (although still 100 to him, etc) But, (and leaving that aside for a minute), he has traveled 86% of that, and so he should actually measure it as being (100-86) =14, correct? So what measurement does he actually measure or does he get? 25? or 14?

no.

(And, yes, I realize 86% is rounded off, and maybe it should be 87%, but that's due to trying to keep this as simple as I possibly can, and also with him actually measuring it as 100, etc, it's due to trying to keep this as simple as I possibly can, etc) (The numbers themselves don't actually matter, but I've chosen the ones I have chosen for simplicities sake, and to better understand the ideas or concepts involved, etc)

Take Care.

 

[Mark Quayle]

I've decided I'm going to try this again?

You are moving along at 86% the speed of light. Time dilation at that speed is 50%, and then I am also assuming length contraction at that speed (86% of c) is also 50%, correct? For a total 75% effect overall, right?

Well, how can c always be (messured as) always being the same in everyones own frames of reference unless you can somehow make that 75% 86% in order for the math to pan out, or for the theory or idea that c is always the same in all reference frames to still be the same at that point, etc?

It would seem to me that inside of my own very, very simplistic understanding, that one of those two effects (either time dilation or length contraction) would need to be having a greater effect earlier on (in the percentage of speed of c that you were traveling) in order to make the math fit correctly or for the speed of c (when measured) to always be the same (when it is measured) inside of each ones owns reference frames, etc? Otherwise, they would be different, right? And we know that cannot be, because we already have proof that it is always the same, right?

That 75% effect needs to be made into 86% somehow, or the speed/length/time of c would be different when it is measured by; especially the one's moving at 86% of c, own reference frame, correct?

At 86% of c, time is affected by 50% for that one moving or in motion at that speed, and it's length is also affected by 50% at 86% of c, but isn't that only 75% when it would need to be 86% (of c)? What am I missing?

God Bless.

My answer would be, "[you are] missing" the frame of reference. But maybe that is the point you are making. Your talk is over my head.

I can't help but think something is going on here in this subject of light speed, that HAS TO assume some static point of reference. I can't see how it could be otherwise. And because of that, two things approaching one another at more than half the speed of light, are indeed traveling above the speed of light relative to each other. But, I've been shown I'm wrong, over and over, by those who seem to understand those explanations.

Beats me!

 

[SelfSim]

I can't help but think something is going on here in this subject of light speed, that HAS TO assume some static point of reference. I can't see how it could be otherwise.

Y'know I've had this same inkling myself, over the years of discussing the topic.

In my case, I've settled on the idea that its not 'a point' (as you're visualising there), .. its all relative to the 4 dimensionality of spacetime.

I'm willing to be corrected on this by say @sjastro or @Hans Blaster, maybe AI DeepSeek analogies(?) .. If I am corrected though, I'd like to know how there is another way of visualising it(?)

And because of that, two things approaching one another at more than half the speed of light, are indeed traveling above the speed of light relative to each other.

No.