You undermine your own argument here. The Higgs boson was a possibility mathematically described by several individual scientists to fill in a hole in a vast mathematical scaffolding known as the Standard Model. The particle’s characteristics were minutely laid out so that it was findable in the same fashion as a host of other previously unknown particles. Compare that to Pasta’s explanation that a - the - speed of light falls out of our understanding of 4D space-time and nothing, not any of zillions of experiments, contradict this. Knowns come out of knowns and take their place in a gigantic structure. The speed of light has just as much substantiation as your height. Just because one is harder for a layman to measure is irrelevant. And your height is known to far less precision.
“As far as we know” in this instance is essentially a denial of all science, just as much as proclaiming that the earth is flat. “As far as we know” the earth is spherical. Not much to argue there either. Anyone appending the qualifier makes a statement about themselves, but not about science.
Just an addendum on this, there are some pairs of events that are not related to each other via cause and effect, in either direction. For instance, from American history, there was no causal relation between the Treaty of Ghent and the Battle of New Orleans. There couldn’t be, because given the limitations on communication at the time, even though the treaty happened first, there was no way for a message to travel from Ghent to New Orleans in time. And because of that limit on the speed of messages, and the impossibility of a cause-effect relationship between those two events, history would have been basically the same if the Battle of New Orleans had happened before the Treaty of Ghent.
In a similar way, there can be events in spacetime that can’t have a causal effect on each other, because information can’t travel from one to the other quickly enough. And from any given reference frame, one of those events might have happened at an earlier time than the other. But it’s possible to rotate your point of view such that, in the rotated point of view, the other one happened first, and it doesn’t make any difference, so long as it’s still impossible for information to travel from one of the events to the other.
To clarify, are you saying the specific units we use (meters, miles, etc. for distance and seconds, years, etc. for time) are arbitrary, or that the idea of distance and time, regardless of the units we use, are arbitrary?
I’m just saying that if the value of 299,792,458 m/s seems an odd number to pick out of the air, like some kind of constant like pi…well, it isn’t. From a physicist’s point of view, this is the only non-arbitrary speed and should ideally be 1. 1.0 standard distance per standard time.
c is just a funny number because we’ve defined space in terms of things like a man’s stride and time in terms of how human attention works and finding something that divided into nice anti-primes like 60.
And yes I understand that there is a deeper question underneath though of why this mapping? I’m just separating out the notion that it’s a particular strange number.
In terms of the deeper question, AIUI if c were infinite, a lot of physics would break down e.g. electromagnetic fields would be able to self-interact to create an infinite runaway force…or something like that. IANA physicist (clearly).
That in itself doesn’t answer it though. Why should the universe care about having an infinite runaway force? And if the relationship between distance and time is indeed finite, why the exact relationship it is? I don’t think we know.
By the time you’re asking questions like that, you’re definitely in the realm of philosophy, not physics. You might as well answer “Because God wanted to the Universe to not tear itself apart”.
You can certainly return to the anthropic principle there. If c was infinite and the Universe promptly shredded itself right after the Big Bang, … well … we would not be here to watch it unfolding as it does.
So the fact we’re watching is one reason c isn’t infinite. Not a “reason” in the causal sense, but a reason in the necessary condition sense.
Sure, and IMO it’s fine of course to say “this is far as we can go with science” and/or “at a certain level, we have to just accept that it just is this way” as long as we don’t confuse statements like this for explanations.
It’s just a personal bugbear of mine when people (including noted scientists) say things like “Maybe the explanation is that the universe ‘just is’?” …That’s not an explanation. That’s a rephrasing of an admission of not having an explanation.
And maybe no explanation is possible, but that doesn’t make the lack of an explanation suddenly something that gives us understanding; something that gives us predictive or inferential power.
(All IMO of course, and happy to make a new thread of this kicks off a bit of a tangent)
Why questions are inherently ambiguous, meaning they cover a lot of territory. One way of interpreting them is the counterfactual. There are others.
The counterfactual asks what would happen if the phenomenon in question did not exist. The answer tells you the significance of the phenomenon. Nobel economist Robert Fogel used this technique to debunk the view that railroads were absolutely critical to US growth in the 1800s. Here, I interpreted the question to mean, “Well, what if c had some sort of other limit?”
Even that is ambiguous though. Chronus noted that the speed is tied to arbitrary metrics like “Mile” and “Second”. Stranger noted that if it was a lot faster chemistry wouldn’t work as we know it (because the size of the atoms would change???) and if it was very much slower space would expand faster than the speed of light over proportionally smaller regions of space (thanks to Francis for the clarification).
Another approach might be, “What is the origin of c?”, or “Where did it come from?” Sort of like, “Why is there money?”, or “Why are there 3 sequels to Jaws?” Some of these assume a person or a group doing something: this interpretation is close to nonsensical in a scientific context when describing natural phenomenon. I think the What If approach is better, though again a range of approaches are acceptable because Why questions are inherently ambiguous: they cover a range of meanings.
Bonus question: What’s a good textbook on relativistic and quantum mechanics that has fewer than one equation per page but more than 10 equations in the book? And a math appendix for anything beyond calculus.
I’ve read two Sean Carrol books in the last year and when he’s talking calculus I understand but then he gets into Differential Equations, which I barely passed in college.
For books, Susskind’s Minimum Theoretical xxx series are not bad. But I speak as a non-physicist.
The books were based on his lecture series directed at graduates from other disciplines. Many of the lectures are also on YouTube. He is very much an old school chalk and talk guy.
The laws of physics as seen by an observer are unchanged when the observer does any of the following:
moves to a new location
moves to a new time
rotates themselves to a new angle/orientation
gives themselves a fixed velocity relative to the physical system they’re watching.
Also:
Cause-and-effect is a well-defined concept.
I don’t think anyone finds these to be counter-intuitive or arbitrary seeming. No one is giving a shrug of “I guess it just is, then” with these points.
These “starting assumptions” yield quite compelling consequences. For instance, momentum and energy conservation are direct consequences of the first two items. “Why should momentum be conserved?” is not answered with “It just is, I guess” but rather with “Because the laws of physics are independent of spatial position.” It’s certainly not obvious to a non-expert that this connection is there, but it is.
All that relativity adds is a specific but simple 4D spacetime geometry. Could it have been something else, like a 3D space and a separate time dimension that never talks to the spatial behavior? Humans tried that idea. It didn’t work. Fortunately, something else quite tidy and elegant does work.
The non-offensive rules/expectations bulleted above still hold. And in order for them to all hold when physics is embedded in this 4D geometry, some other compelling consequences come out. A speed limit is one. But this non-intuitive consequence shouldn’t take any “I guess it’s just that way” flak. It’s all tied back to things that are much less arbitrary seeming. One could point at the underlying assumptions and continue the discussion, and at some point you hit the axioms, but if the axioms aren’t too weird or controversial (like those above), you might be happy that we found them.
Just a personal grumble. Fogel and his collaborator Stanley Engerman are extremely important for their role in introducing cliometrics to the study of history, which meant doing massive research into economic and numeric data rather than personal views and recollections. They both were teaching at my college while I was there and were stars.
The problem was that trying to turn history into science runs into issues that historians were unfamiliar with but that the scientific community continually faces. If you’re the only one to run an experiment how do others determine whether you’ve gotten it right? All your math might check out but maybe your data field was incomplete.
Sixty years on we know that was the case for much of what the early cliometricians wrote. They dug into what data was available but decades of work has uncovered far more than they could have imaged existed. Worse, data alone does not determine human actions. It must be placed into the context of the times and that piece of history cannot be ignored.
Context brings my meandering back to this thread. People try to put the physics of the universe into the context of their lives on Earth, a place where daily experiences encompass a small fraction of a percent of the possibilities. All of humanity marshaled their thoughts to fit within daily experiences until the 20th century, and even then only a small fraction of a percent of educated people understood enough about the very big and very small and very fast to attempt to translate the concept into the common language. I read a lot of books trying to accomplish that; I’ve come to realize that the metaphors and analogies used in the late 20th century have been superseded by a new collection that almost refute the older tellings.
Refusing to accept concepts that don’t make sense is normally intelligent. But why? is normally a proper response. Modern physics dumps on normal, partially because it deals with the abnormal, or better, tells us that we live abnormal lives. Who wants to hear that?
It seems to me that the “I guess it’s just that way” isn’t about why there is a speed limit at all. It’s about why the speed limit is the specific limit that it is. That has been elaborated on above, but I at least don’t have enough training in advanced math and physics to understand the explanations as to why that number is what it is.
ETA: Although I do understand (or at least I think I do) that the universe doesn’t like infinities (figuratively, not literally ), and this is one more place that demonstrates that dislike of infinities.
YouTube physics commentator Sabine Hossenfelder has become so disenchanted with the physicists’ search for highly speculative physics based on mathematical elegance that she has reacted by becoming an empiricist: declaring that maybe physics simply is awkward and arbitrary at bottom and that there’s no deeper level of understanding to be found.
If the limit was different, we’d be different. We’re not.
if the limit was significantly different the universe would not function at all. It might well be a near-eternal empty void or a seething mass of energy. But what it would not have is macroscopic clumps of matter like stars, planets, etc.
Who is to say those other places with other c values don’t or didn’t or won’t exist (taking liberties with the idea of time itself across differing universes)? They might. We just can’t say with any confidence.
), and this is one more place that demonstrates that dislike of infinities.