Time : It's not what it used to be.
What gets us into trouble is not what we don't know.
It's what we know for sure that just ain't so.- - Samuel Langhorne Clemens, AKA Mark Twain
Contrary to what you may have been told: A day, a year, swinging pendulums (pendula), et cetera are not periodic in time. A basketball does not travel along a parabolic path when thrown. The gravitational force is not proportional to 1/r2. Momentum is not proportional to velocity, and kinetic energy is not proportional to the square of velocity.
I could add examples from other disciplines, but that is someone else's responsibility. The above are simply examples of approximations to Reality. If you did not learn this while in school, your teachers were either too ill prepared, too busy doing administrivia, or too lazy to teach you properly.
Yesterday some astute readers (/users/Not Henry Kissinger, /users/jwa13, /users/HenryWallace, /users/LapsedLawyer, and /user/Hawkfish) engaged me in a discussion concerning the nature of time.
/users/Not Henry Kissinger started it all with "I'm Sparticles!". As is usually the case, the discussion quickly spiraled into the stratosphere. Also, as is usually the case, the very "simplest" exposition did not occur to me until very early this morning, thank you very much.
The truth is, time doesn't work the way you have been taught. If you are in the top floor of a building you age more quickly than if you are in the bottom floor of that building. Ah, but not as fast as you might expect because the building is (probably) on a spinning Earth hence, you are moving faster standing in the top floor compared to your speed if you are standing in the bottom floor. While all this is quite straight forward, actually verifying this can be quite (experimentally) tedious, and expensive.
Funny Story: When the original GPS system was about to be deployed the scientists and managers of the project had a disagreement. The scientists wanted the computer code to include an "aging more quickly" correction code along with the "aging more slowly" segment. The managers insisted that only the "aging more slowly" code would be needed. So, the satellites were deployed with the "aging more quickly" code sequestered. As it became obvious that the very expensive system couldn't work, the scientists sent a set of commands to activate the additional code and the system immediately started to function properly.
It is because "time" is "distorted" as described and a much more interesting "distortion" of "space" occurs, that objects move approximately along parabolic paths when thrown.
Comments
Reading “The Three Body Problem” trilogy by Cixin Liu
certainly stretched my mind and taxed my ideas about where physics is heading, way beyond the primitive Heinlein-libertarian 1950s–1960s science fiction I grew up with.
If they don’t get long-term hibernation working soon, what chance will someone of my generation have to experience humanity’s next leap forward?
Great, another series to read . . .
. . . and a movie is in the works.
Bob Forward wrote some really good stuff. Timemaster is my favorite. Bob even included TimeSpace diagrams in the text.
You are very diplomatic to name me, PriceRip, but I don't
think "I just need to know when to start work" and being concerned that this season of Big Bang Theory might not be good qualifies as having engaged a physicist in a discussion about time. I know a bit about the history of the Ancient Roman, Julian and Gregorian calendars, but that is all. This is so far over my head that my eyelashes hurt. I just plant rice. I will leave the genius stuff to you and the other posters you named.
Thanks again for placing my name in that company, though!
You may understand far more than you know.
I started reading science fiction as well as "hard" science when I was eight years old. Understanding came as I realized the disconnect between "learning to do the subject" and "practicing the discipline". You could say, "It's a zen thing." Children are natural scientists, and most parents (though ignorance rather than malice) stifle those innate tendencies. I was fortunate to have a dad (much like Richard Feynman's) who, while not knowing much science, knew how to think like a scientist.
My job for the past 35 years was to create an environment in which young adults were encouraged to regain that former state of mind. My experience has been: Most are actually far more capable than they had come to believe. But of course there is the flip-side: Far too many (even if a small number) were privileged and weren't really interested in the discipline.
A primary factor in understanding Reality (read Physics) is the willingness to become passionate about the
subjectdiscipline. This is, of course, true for any discipline.So who ages faster?
The people who drive around in RVs going 45 mph or the speed demons who dodge speed traps at 80 mph?
Beware the bullshit factories.
Dunno, but, for the first time in my life, I'm glad I'm not in
the penthouse!
j/k. I never cared about the penthouse.
Serious Response
From the hitchhiker's point of view the RV ages faster than the Speeding vehicles. Remember, it's all relative.
Mental wall for me
From the point of view of the hitchhiker, the vehicles are moving and therefore aging faster (?????) yet relatively, the vehicles might as well be stationary and the hitchhiker moving, in which case the hitchhiker is aging faster. So everybody is aging faster than everybody else. WTF?
Beware the bullshit factories.
Resolution of Dilemma
This is the standard twin "paradox". It is resolved by noting the two are only able to verify the "truth" if they arrange to compare their clock while at rest with each other.
I have a set of articles I could publish here. I had them up at TOP but few people were interested.
Say they're on a giant oval racetrack.
One person is at the start line in a car and the other is standing next to the start line. They synchronize their clocks and the car driver then zooms around the track a few million times coming to a rest next to the standing observer and they compare clocks again? Will the clocks show a difference?
Beware the bullshit factories.
Yes
The moving clock will read a smaller value than the stationary clock. That is if this starts at 12:00:00 for both and stops so the stationary clock reads 12:20:00 the clock that took the trip would read 12:19:XX where XX is less that 60.
Still see a paradox
If their speeds are relative to each other, how do you define which person is stationary and which person is moving and therefore which person's clock will have moved faster?
Beware the bullshit factories.
One is accelerating while the other is not accelerating.
If you do not like my "solution", "One is accelerating while the other is not accelerating." you are in good company. A few decades ago David Mermin and I got into a pissing contest (angry words were typed) in a usenet news group and we never interacted again.
Just seems a little less depressing to talk about
Then hurricanes and fascism and corruption and police states and climate change. Sorry for being difficult.
Beware the bullshit factories.
This keeps me sane.
You can't.
Neither person is stationary. Everything is in motion so every clock runs at its own time rate.
There can no objective 'third party' observation, because by definition the third party's clocks would also be moving at a rate relative to the other two clocks. Any additional layers of observers just adds to the complexity.
All that's really observable is the interaction between the two initial people. You can define what each person experiences when looking at the other person and then deduce who appears faster and who slower. But there is no 'objective' measurement of the different rates of time.
The current working assumption appears to be that our Shroedinger's Cat system is still alive. But what if we all suspect it's not, and the real problem is we just can't bring ourselves to open the box?
One Tiny Quibble
Other observers may "see" different time spans on the clocks, but all other observers will agree that the "moving clock" runs at a slower rate than the "stationary clock".
True.
But the measure of that difference will most likely be different for each observer.
The current working assumption appears to be that our Shroedinger's Cat system is still alive. But what if we all suspect it's not, and the real problem is we just can't bring ourselves to open the box?
Indubitably My Friend
Right you are, and, the weird bit is that they will all agree the "moving clock" ticks more slowly than the "stationary clock" even as they will not agree about the particular values.
Irrelevant, since the speed demons will die younger.
Significantly younger. Especially if they are speed demons of color who will attract police who don't like anyone who defies the law. So drive your RV at 45 and enjoy the scenery. In the right-hand lane, though, so you don't block traffic and become a victim of road rage (probably mine)!
Please check out Pet Vet Help, consider joining us to help pets, and follow me @ElenaCarlena on Twitter! Thank you.
This is the level of my contribution. Love, Penny
[video:https://www.youtube.com/watch?v=-w0WPkB3XJ4]
[video:https://www.youtube.com/watch?v=IGj-ASVFvm0]
(needs more cow bell)
[video:https://www.youtube.com/watch?v=CsBwBct0_5U]
(chosen only for its title)
[video:https://www.youtube.com/watch?v=tBuUUBrC9eQ]
Gravity and space time
Since the sun and moon also exert a (very!) small gravitational force with many periodicities ... oh never mind.
See Shakspeare:
... from Alls Well.
See also Shakspeare's Astrology.
There are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns – the ones we don't know we don't know.
More Fundamental than Measurement.
Newton's law of universal gravitation is an approximation. We know that gravitational fields are more properly described using general relativity. So while the usual differential equations are "good enough for government" and nicely get us to the moon and beyond. The real process is more than just mid course corrections to account for uncertainties in initial conditions and the effects of the gravitational interactions with other bodies. So, sure, from a "practical" point of view we do not need to be concerned with the fact that the "classical" calculations are less than perfect.
My point is that the concepts of interest do not come from experiments and finely tuned measurements. Our understanding is very much a product of abstractions we create that do not contradict what can be observed. The mathematical constructs are by their very nature approximations describing what are in reality complex systems.
While the physical sciences must conform to observations, observation does not reveal what is true as much at it delineates what is not true. This distinction may not be of any interest to anyone else, it is central to understanding processes of interest to me.
So as you say . . . oh never mind.
"Observation delineates what is not true". I
Of course! Very often, that is how important discoveries are made!
But sometimes (see GR, below) theory --> crazy result --> better observations --> Eureka! moment
Other examples:
See:
anomalies in Uranus' orbit --> LeVerrier --> Neptune --> Lowell --> Pluto
Orbit of Mercury Einstein GR
Discovery of J/psi --> Standard Model
Sudbury Neutrino Observatory --> neutrinos have mass and lepton eigenstates are not mass eigenstates neutrino mixing finite neutrino 1/2-lives --> ???
So I'm not sure why your realization that
is so earth-shattering.
I was a "theoretical experimentalist", if there's such a creature any more, so I was always on the outlook for an experimental result that might point me to a new way of looking at things.
Alas, that attitude did not always work well in the highly competitive "publish or perish" environment of then science faculties. Colleagues, my foot.
Always enjoyable to read your posts!
There are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns – the ones we don't know we don't know.
"is so earth-shattering." not so much.
I have, for 35 years, interacted with students indoctrinated to believe science is grounded in experimentalism. And have been in the middle of every "it's just a theory" fight you can imagine. So, for me getting just the right sentence structure transcends my innate OCD tendencies. One of the nice aspects of this little corner of the Matrix is that I have been able to workout some important (to me) details of the presentation suite I am constructing for my target audience.
Thanks for commenting, you always provide well constructed "challenges" in an otherwise sanguine world. I find face-to-face (and sometime in your face) interactions to be very helpful, but this on-line mode is still a lot alien to me.
Re: your examples, I could turn each one into a one hour discussion probing lots of themes and variations. Or to be more precise: I intend to do just that sort of thing at the OLLI center in Medford.
I would very much like to hear
your extensive discussion of my "off the top of my head" examples, and I wish you luck!
There are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns – the ones we don't know we don't know.
Off the top of your head examples.
I envy people that are able to do that. My brain doesn't work that way. Or maybe I should write, "My brain doesn't work that well." Either way I have always been disadvantaged compared to my colleagues. For me to produce a relevent list like this would require much more than an "off the top of my head" effort.
I was fortunate that as an undergraduate, Paul Stephas saw that (even though I passed an little more than half his exams) I had potential. For me doing physics is a bit like exploring the Eagle Cap Wilderness in the Wallowa Mountains with a very thick fog in the High Lakes basins. I bumble about building a mental map of the terrain while using the peaks, distinctive ridge structures, and sounds from the many streams to anchor said map. In other words I "see" pictures rather than "do" calculations or "remember" calculational details. So, for me, the orbit of Mercury was on my mind as I wrote my bits but the others were not even on my radar at the time. I would have (maybe) included them all if I had tried to construct a (much longer) list, except for the J/ψ example . . . I think I would have missed that one. So, good "get" my friend.
Thanks man!
I appreciate the mention.
I don't pretend to any special training in this stuff, but as I work on my "hard sci fi" novel, the Time research is leading me in some very strange directions.
Time dilation, the change in rates of time between objects, is a long proven phenomenon. Yet I think we significantly underestimate its effects.
We completely take for granted that, across the entire surface of the earth, similar objects at similar altitudes experience similar time rates.
This consistency is true even though objects at earth's equator are rotating faster than objects at higher latitudes (more speed = slower time).
The difference is precisely compensated for by the higher lattude's closer proximity to the poles. (Closer to pole or center of momentum = slower time)
Since these two time rate factors exactly offset, the rate of time is consistent everywhere on the sphere of the earth.
So basically our Earth creates its own time rate, and we here on the surface all share in that.
The current working assumption appears to be that our Shroedinger's Cat system is still alive. But what if we all suspect it's not, and the real problem is we just can't bring ourselves to open the box?
Fun Factoid
If such were not true we would feel a tiny tug toward the surface region of "slower time", albeit too tiny to be of any real consequence (to many degrees of approximation) during the the age of the universe. This sort of "force" would only be noticeable for processes near blackholes (and maybe neutron stars).