Is the speed of light a constant? Or can it vary? If so, in what kinds of situations, or how much?

[Neogaia777]

My whole problem previously with getting up to the speed of light and/or being able to go beyond it, etc, was the infinite to near infinite mass increase, etc.

But if that's not at all the case, and the mass doesn't actually change, then why could we not get up to the speed of light, and/or maybe even go beyond it maybe, if we had an infinite amount of time to accelerate something, and kept on gradually accelerating something at a steady and stable and constant and consistent rate over time infinitely maybe, etc?

I mean, what's stopping us or preventing us from doing that, etc?

As far as I know, there's no actual or even theoretical barrier, etc?

And even if there was, maybe it's not all that important maybe, and is not unlike the sound barrier maybe, etc?

Take Care/God Bless.

 

[sjastro]

Let me bundle your posts together to make some selective responses.

(1) The simplest definition of infinite is unreachable as noted in the graph, for particles with mass which approach the speed of light, the centre of mass energy goes straight up without ever reaching or exceeding the speed of light.

(2) For a constant acceleration it doesn’t matter how the long acceleration is applied, the speed of light will never be reached by a particle with mass.

(3) Since the relativistic momentum p increases with increasing velocity but reaches a limit approaching the speed of light c, so does the energy E according to the equation.

The equations are supported by experimental data, particles with mass will never reach the speed of light.

 

[Neogaia777]

Let me bundle your posts together to make some selective responses.

(1) The simplest definition of infinite is unreachable as noted in the graph, for particles with mass which approach the speed of light, the centre of mass energy goes straight up without ever reaching or exceeding the speed of light.

View attachment 352726​

How does this slow a particle with mass down as it approaches the speed of light?

If it is not the mass that increases, but the energy, then does the energy have mass?

(2) For a constant acceleration it doesn’t matter how the long acceleration is applied, the speed of light will never be reached by a particle with mass.

View attachment 352727​

What stops or slows down the acceleration?

(3) Since the relativistic momentum p increases with increasing velocity but reaches a limit approaching the speed of light c, so does the energy E according to the equation.

View attachment 352728

But what's stopping it or causing it or preventing it though? Or why does such a limit at the speed of light exist, etc?

Or IOW's, It would seem to me that it would just continue accelerating if there was nothing slowing it down, or preventing it, etc?

So what's slowing it down, or preventing it?

The equations are supported by experimental data, particles with mass will never reach the speed of light.

I believe you, kind of, but am just trying to understand, and I thank you for bearing with me and putting up with me.

Take Care.

 

[KevinT]

What's that got to do with reality?

So he's some sort of physics crank, then?

Oh, good grief.

We have actual physics that explains these things. No need for Mr. Wolfram to make stuff up.

This was a bit of a rude reply in my mind. @Hans Blaster can discount the theory, but perhaps he could be more polite?

Which kind of "physics" are being referring to? The kind that says things are in two places at once? That denies realism? That believes that every quantum event spawns a new universe? Here is a listing of multiple interpretations of quantum mechanics that shows that there is still LOTS of room for people to still think about what is actually happening in "reality".

There are many in the "shut up and calculate" camp that are perfectly happy with the current formulas because they agree with experimental evidence to a large number of significant digits. Sabine Hossenfelder is a theoretical physicist and gadfly YouTuber and that has published many videos about quantum theory. She and many others have pointed out that quantum theory is incomplete; it is not compatible with relativity and breaks down around black holes. A theory of quantum gravity is needed, but today's brightest minds have not been able to figure it out. Why? I'm not a theoretical physicist but I wonder if it is because so many have been led down a path of thinking that end with a great set of formulas, but ultimately is not conducive to the next breakthrough.

So when someone decides to think outside the box, like Stephen Wolfram, it annoys me that @Hans Blaster calls him "some sort of physics crank." As if he is in a position to sit in judgement of him and his theories. From his post, @Hans Blaster don't seem to have much knowledge about what Wolfram is up to, but feel comfortable criticizing him for "making stuff up." I don't know who @Hans Blaster is or what his accomplishments are, but I respect that Wolfram is at least trying to push boundaries and trying something new.

KT

 

[sjastro]

How does this slow a particle with mass down as it approaches the speed of light?

If it is not the mass that increases, but the energy, then does the energy have mass?

What stops or slows down the acceleration?

But what's stopping it or causing it or preventing it though? Or why does such a limit at the speed of light exist, etc?

Or IOW's, It would seem to me that it would just continue accelerating if there was nothing slowing it down, or preventing it, etc?

So what's slowing it down, or preventing it?

I believe you, kind of, but am just trying to understand, and I thank you for bearing with me and putting up with me.

Take Care.

Since co-ordinate acceleration is the rate of change of velocity, the slowing down is due to time dilation.

Note from the graph the co-ordinate acceleration which is the gradient of the curve approaches zero as the particle approaches the speed of light.

 

[Hans Blaster]

This was a bit of a rude reply in my mind. @Hans Blaster can discount the theory, but perhaps he could be more polite?

No one has show here that Wolfram has anything that rises to the level of a theory.

Which kind of "physics" are being referring to? The kind that says things are in two places at once? That denies realism? That believes that every quantum event spawns a new universe? Here is a listing of multiple interpretations of quantum mechanics that shows that there is still LOTS of room for people to still think about what is actually happening in "reality".

Interpretations of QM are just that -- interpretations. If any of them gave an insight that changes how we compute things or the consequences, they would be used. Mostly it's just people arguing about what stuff "means".

There are many in the "shut up and calculate" camp that are perfectly happy with the current formulas because they agree with experimental evidence to a large number of significant digits.

Hardly a condemnation of a theory or a motivation for a new one.

Sabine Hossenfelder is a theoretical physicist and gadfly YouTuber and that has published many videos about quantum theory. She and many others have pointed out that quantum theory is incomplete; it is not compatible with relativity and breaks down around black holes.

Hardly the first to note such things. (And "gadfly" is a bit harsh.)

A theory of quantum gravity is needed, but today's brightest minds have not been able to figure it out. Why? I'm not a theoretical physicist but I wonder if it is because so many have been led down a path of thinking that end with a great set of formulas, but ultimately is not conducive to the next breakthrough.

There is no theory of quantum gravity because the standard tools used to build quantum field theories for the other forces don't work on the Einstein field equations.

So when someone decides to think outside the box, like Stephen Wolfram, it annoys me that @Hans Blaster calls him "some sort of physics crank." As if he is in a position to sit in judgement of him and his theories. From his post, @Hans Blaster don't seem to have much knowledge about what Wolfram is up to, but feel comfortable criticizing him for "making stuff up." I don't know who @Hans Blaster is or what his accomplishments are, but I respect that Wolfram is at least trying to push boundaries and trying something new.

KT

I've noticed people are interested in this "Wolfram idea" online, but I never looked into it. From your description it sounds rather silly.

 

[KevinT]

Sabine Hossenfelder is a theoretical physicist and gadfly YouTuber ...
Hardly the first to note such things. (And "gadfly" is a bit harsh.)

I went back and looked up the definition of gadfly:

an annoying person, especially one who provokes others into action by criticism. ... "always a gadfly, he attacked intellectual orthodoxies"​

So I was trying to use the term in a positive way, but I see that I overlooked the 'annoying' part. I meant to say that she is a person who calls people on their BS, and holds their feet to the fire. She feels that String Theory has been a huge waste of time / effort / money etc. I personally love her content, and didn't intend to demean her. She did a good review of Wolfram, along with others, here, where she essentially says, "I don't care about your theory of everything." I suspect you would agree with that sentiment. She concludes with:

I get a problem if theories that despite having turned out to be useless grow to large, tax-paid research programs that employ thousands of people, as it has happened with string theory and supersymmetry and grand unification. That creates a problem because it eats up resources and can entirely stall progress, which is what has happened in the foundations of physics.​

​

People like Lisi and Weinstein and Wolfram at least remind us that the big programs are not the only thing you can do with math. ​

So, odd as it sounds, while I don’t think their specific research avenue is any more promising than string theory, I’m glad they do it anyway. Indeed, physics can need more people like them who have the courage to go their own way, no matter how difficult.​

​

The brief summary is that if you hear something about a newly proposed theory of everything, do not ask whether the math is right. ​

Because many of the people who work on this are really smart and they know their math and it’s probably right. The question you, and all science journalists who report on such things, should ask is what reason do we have to think that this particular piece of math has anything to do with reality.​

There is no theory of quantum gravity because the standard tools used to build quantum field theories for the other forces don't work on the Einstein field equations.

Yes, thus the need for people to thrash about looking for explanations that can tie things together.

I've noticed people are interested in this "Wolfram idea" online, but I never looked into it. From your description it sounds rather silly.

If you are the type that is just looking for tools to work on existing problems, I can see that you might feel these guys stumbling around in the dark is a waste of time.
I, on the other hand, get frustrated when people tell me that everything is all figured out, and by the way reality doesn't really exist etc. So I like to see if there are alternative explanations that are consistent with facts, but are (in my mind) more rational.

If you wanted to look into Wolfram's ideas more, you could watch this video. It is a discussion between him, Brian Keating, and Eric Weinstein, but frankly it is way too long, and it is hard to listen to Wolfram go on and on about how he has everything figured out. But I think he is a smart guy, and I appreciate that he is trying something new.

Best wishes,

KT

 

[Hans Blaster]

I went back and looked up the definition of gadfly:

an annoying person, especially one who provokes others into action by criticism. ... "always a gadfly, he attacked intellectual orthodoxies"​

So I was trying to use the term in a positive way, but I see that I overlooked the 'annoying' part. I meant to say that she is a person who calls people on their BS, and holds their feet to the fire. She feels that String Theory has been a huge waste of time / effort / money etc.

It has.

I personally love her content, and didn't intend to demean her. She did a good review of Wolfram, along with others, here, where she essentially says, "I don't care about your theory of everything."

She said a little more: "not convincingly solved any actual problems in existing theories".

I suspect you would agree with that sentiment. She concludes with:

I get a problem if theories that despite having turned out to be useless grow to large, tax-paid research programs that employ thousands of people, as it has happened with string theory and supersymmetry and grand unification. That creates a problem because it eats up resources and can entirely stall progress, which is what has happened in the foundations of physics.​

​

People like Lisi and Weinstein and Wolfram at least remind us that the big programs are not the only thing you can do with math. ​

So, odd as it sounds, while I don’t think their specific research avenue is any more promising than string theory, I’m glad they do it anyway. Indeed, physics can need more people like them who have the courage to go their own way, no matter how difficult.​

​

The brief summary is that if you hear something about a newly proposed theory of everything, do not ask whether the math is right. ​

Because many of the people who work on this are really smart and they know their math and it’s probably right. The question you, and all science journalists who report on such things, should ask is what reason do we have to think that this particular piece of math has anything to do with reality.​

That is just her screed about "wasting money" on pretty math theories that don't work to the exclusion of everything else.

Yes, thus the need for people to thrash about looking for explanations that can tie things together.

The amateurs are welcome to waste their own time, but don't expect anything to come of it.

If you are the type that is just looking for tools to work on existing problems, I can see that you might feel these guys stumbling around in the dark is a waste of time.

There are lots of problems based on known physics, but there are also real discrepancies that need resolving and the pursuit of grand theories in the hope that it will solve the little ones has accomplished nothing. There is so much that needs work at the level below the grand unification that goes undone because resources are wasted on attempts to demonstrate how clever people are with math.

I, on the other hand, get frustrated when people tell me that everything is all figured out, and by the way reality doesn't really exist etc. So I like to see if there are alternative explanations that are consistent with facts, but are (in my mind) more rational.

Clearly not all is "figured out". I don't know where you are getting that or relating it to criticism of useless math theories.

If you wanted to look into Wolfram's ideas more, you could watch this video. It is a discussion between him, Brian Keating, and Eric Weinstein, but frankly it is way too long, and it is hard to listen to Wolfram go on and on about how he has everything figured out. But I think he is a smart guy, and I appreciate that he is trying something new.

Best wishes,

KT

Like Sabine, I do not wish to waste my time on their useless math.

 

[KevinT]

The amateurs are welcome to waste their own time, but don't expect anything to come of it.

Thanks for your reply. I'll just add that Wolfram is by no means an amateur. His first published paper was at age 15 yrs. Richard Feynman was on his PhD committee. From this source: by age 14, he had written three books on particle physics. He earned his Ph.D. at age 20 and began publishing research papers at the age of 18, some of which have been cited thousands of times. He developed the Mathematica software package, and is the founder of online Wolfram Alpha. From wikipedia: Following his PhD, Wolfram joined the faculty at Caltech and became the youngest recipient of a MacArthur Fellowship in 1981, at age 21.

If anyone has a chance of making some breakthrough, he at least has a chance.

KT

 

[Larniavc]

So, how does that happen? Does it just slow down for the people? The whole ship? Anything outside of the ship, etc?

Everything within its frame.

 

[Larniavc]

From the perspective of the planets watching the ship zip by, outsiders might see the ship appearing to burn through 1 unit of fuel every planet-based second.

The opposite is true.

 

[Hans Blaster]

Thanks for your reply. I'll just add that Wolfram is by no means an amateur. His first published paper was at age 15 yrs. Richard Feynman was on his PhD committee. From this source: by age 14, he had written three books on particle physics. He earned his Ph.D. at age 20 and began publishing research papers at the age of 18, some of which have been cited thousands of times. He developed the Mathematica software package, and is the founder of online Wolfram Alpha. From wikipedia: Following his PhD, Wolfram joined the faculty at Caltech and became the youngest recipient of a MacArthur Fellowship in 1981, at age 21.

If anyone has a chance of making some breakthrough, he at least has a chance.

KT

Does he work in physics? Where are his recent publications on this stuff?

 

[Neogaia777]

Since co-ordinate acceleration is the rate of change of velocity, the slowing down is due to time dilation.

View attachment 352736
Note from the graph the co-ordinate acceleration which is the gradient of the curve approaches zero as the particle approaches the speed of light.

Time dilation would probably do it, since we were leaving that part of it out of it temporarily.

Thanks for answering my questions.

Take Care/God Bless.

 

[Neogaia777]

Everything within its frame.

Or for every atom/particle in motion.

Thanks.

Take Care/God Bless.

 

[Neogaia777]

Time dilation would probably do it, since we were leaving that part of it out of it temporarily.

Thanks for answering my questions.

Take Care/God Bless.

I wonder if we had an outside source or way of accelerating it maybe, solar sails or something like that maybe, that it then maybe wouldn't require us applying more and more energy/thrust due to the effects of time dilation on it to accelerate it maybe?

All the processes for it would still be slower though, like it's converting that into energy, so I don't think that would probably work even then maybe?

Take Care/God Bless.

 

[KevinT]

Does he work in physics? Where are his recent publications on this stuff?

I'm going to assign you some homework: Read this. You are being very opinionated against this guy, and yet are putting, from what I can tell, zero effort on learning more on your own.

KT

 

[Tinker Grey]

I'm going to assign you some homework: Read this. You are being very opinionated against this guy, and yet are putting, from what I can tell, zero effort on learning more on your own.

KT

He seems the sort of fellow who lets math/theory drive his view of reality rather than vice versa.

 

[Hans Blaster]

I'm going to assign you some homework: Read this. You are being very opinionated against this guy, and yet are putting, from what I can tell, zero effort on learning more on your own.

KT

I already did a couple days ago. He runs that "mathematica" company.

Sure doesn't look like he is active in physics:

Astrophysics Data System

 

[KevinT]

I already did a couple days ago. He runs that "mathematica" company.

Sure doesn't look like he is active in physics:

Astrophysics Data System

He is doing work on the theoretical underpinnings of physics. That counts as being active in physics. And even the link you gave shows that his most recent publication was in 2023 on the subject of thermodynamics. Here is where his current efforts are being released:
Wolfram physics project technical documents

On a different approach, may I ask why you are so contrarian about this guy? I mean, what do you care if he wastes his time and spins his wheels? As above, Sabine dislikes it when wild-goose projects siphon money away from other researchers. But I am pretty sure Wolfram is self-funded. In that Weinsein / Wolfram / Keating video I linked to before, they had a discussion about why there was push back from many in the physics community. They wondered if it was because people were resentful of, or distrustful of, mavericks operating outside the usual channels etc. Wolfram (who I suspect is on the autism spectrum) denied that there was push back, but Weinstein assured him that there is. So I am wondering what your personal concerns are? I have demonstrated that Wolfram is smart, knows his math, and is working hard. He is publishing his work in an open source manner. And while, by the usual odds of the universe, he is likely wrong, that seems to be besides the point with you. I think you just don't like him on some fundamental level, and you don't seem to like someone coming along and claiming that they have figured something new out. Einstein was working as a clerk in a patent office when he was pondering relativity. Not everyone has to have a university position and follow the usual rank and file.

KT

 

[KevinT]

I'd like to add that I have come across as the #1 evangelist for Stephen Wolfram. This started when I described a simplistic model of the universe, very roughly linked to Wolfram's theories, that helps me conceptualize time slowing down with motion etc. @Hans Blaster attacked this concept and we have spiraled down a rabbit hole.

I personally think that Wolfram is very likely wrong, and he may well spend his life chasing a theory that ultimately is unprovable -- much like string theory. What I like about the approach is that it matches the way I think. But that doesn't have anything to do with reality.

I very much dislike the traditional Copenhagen interpretation of quantum mechanics, and it annoys me when it is presented as the gospel truth and alternative interpretations are side-lined. So I am delighted when someone is exploring concepts that may shed some light on ways to discredit Copenhagen-type thinking. And now I've shown my personal biases.

KT