Why survive? Why SHOULD we do anything?

[SGOS]

Days actually DO last longer when you are a child.  An undiscovered relativity law (relative to adults)...  I have it on good authority that Hawkings is working on that very question.  He will undoubtedly call it the Hawkings Diminitive or something like that.

Don't know how credible this is, but I heard an interesting explanation of the phenomenon one time.  Because of our self-centered perception of time, when you are 10 years old, the last 10 years is perceived accurately as your lifetime.  It represents the sum total of your most familiar standard of time; One lifetime. 

But when you are 20, 10 years is perceived as only half a life time.  At 30, 10 years is a third of a lifetime, etc.  I suppose this presumes that least arbitrary biological clock is the one which compares time to our personal experience of time, the unit being most important to us being our experience of a life time. 

Concepts like one minute, one day, and one year, are man made and arbitrary.  The designations only have the value which are arbitrarily assigned to them.

I thought it was an interesting perspective.  Had I not heard that, I would have just said after 50 years, periods of time seems shorter, because we have experienced them so much, the wonder and excitement being drained away.  But I'm drawn to that other explanation.

[trdsf]

Days actually DO last longer when you are a child.  An undiscovered relativity law (relative to adults)...  I have it on good authority that Hawkings is working on that very question.  He will undoubtedly call it the Hawkings Diminitive or something like that.

Well, they would.  When you're a child, you're shorter, so you're deeper in the Earth's gravity well, and time actually *does* move a little slower relative to adults.

...well, okay, by something on the order of microfractions of a femtosecond, but the science is still there!!

[Cavebear]

Don't know how credible this is, but I heard an interesting explanation of the phenomenon one time.  Because of our self-centered perception of time, when you are 10 years old, the last 10 years is perceived accurately as your lifetime.  It represents the sum total of your most familiar standard of time; One lifetime. 

But when you are 20, 10 years is perceived as only half a life time.  At 30, 10 years is a third of a lifetime, etc.  I suppose this presumes that least arbitrary biological clock is the one which compares time to our personal experience of time, the unit being most important to us being our experience of a life time. 

Concepts like one minute, one day, and one year, are man made and arbitrary.  The designations only have the value which are arbitrarily assigned to them.

I thought it was an interesting perspective.  Had I not heard that, I would have just said after 50 years, periods of time seems shorter, because we have experienced them so much, the wonder and excitement being drained away.  But I'm drawn to that other explanation.

It goes the other way.  When you are 10, 10 years is a lifetime, when you are 20, 20 years is a lifetime, same for 30, 40, etc.  So when you are 40, a lifetime should seem longer, not shorter.

Life starts getting shorter the very first day you wonder "Am I getting old"?  Because then you are.

[SGOS]

It goes the other way.  When you are 10, 10 years is a lifetime, when you are 20, 20 years is a lifetime, same for 30, 40, etc.  So when you are 40, a lifetime should seem longer, not shorter.

The presumption is that a lifetime is the unit of measure; It's the basic unit of measure, not one year or one day.  Granted that unit would mathematically vary from one individual to another, and become a somewhat meaningless standard.  But the whole concept of life speeding up with age has nothing to do with mathematical measurement.  It's an illusion, and does not bind our mind by the boundaries of math.

As important as math is to physics, it does not change human illusions.  It can be used to disprove human illusions, but it does not change the psychological causes.

[Cavebear]

The presumption is that a lifetime is the unit of measure; It's the basic unit of measure, not one year or one day.  Granted that unit would mathematically vary from one individual to another, and become a somewhat meaningless standard.  But the whole concept of life speeding up with age has nothing to do with mathematical measurement.  It's an illusion, and does not bind our mind by the boundaries of math.

As important as math is to physics, it does not change human illusions.  It can be used to disprove human illusions, but it does not change the psychological causes.

Well trdsf suggested the opposite, so I was just showing another way of looking at our lifetimes.  And, not being cliche, but time (lifetime) IS all rather relative.  Some ancient ancestors would have considered living to 40 to be rather remarkable, yet I expect 80 to be expected. 

Even then, 40 or 80, it never seems long enough, yet can sometimes get to feel too long.  I suppose it is the length of enjoyable life that matters most.

[SGOS]

Even then, 40 or 80, it never seems long enough, yet can sometimes get to feel too long.  I suppose it is the length of enjoyable life that matters most.

Yes, I can't think of a better goal in life than that.

[Gawdzilla Sama]

My mailbox doesn't care if I get mail so why should I check it every day about 1pm?

Because that check from Nigeria has to come sooner or later, right?

[Baruch]

The presumption is that a lifetime is the unit of measure; It's the basic unit of measure, not one year or one day.  Granted that unit would mathematically vary from one individual to another, and become a somewhat meaningless standard.  But the whole concept of life speeding up with age has nothing to do with mathematical measurement.  It's an illusion, and does not bind our mind by the boundaries of math.

As important as math is to physics, it does not change human illusions.  It can be used to disprove human illusions, but it does not change the psychological causes.

In classical physics maybe ... but measuring rods are variable in Relativity, and the observer is crucial in Quantum Mechanics.  You are thinking of metrology standards like in 19th century France, with the perfect meter bar kept under glass at a fixed temperature, in Paris.  Measurements aren't random, they vary, but only as allowed in non-classical physics.

[Unbeliever]

I wonder what's the error margin for that bar? How far off is it, since it can't be exactly one meter. Unless, that is, the meter is simply defined as the length of that bar. Is that the case?

[SGOS]

I wonder what's the error margin for that bar? How far off is it, since it can't be exactly one meter. Unless, that is, the meter is simply defined as the length of that bar. Is that the case?

I think it used to be.  Maybe with new technology there is a more permanent baseline, but I haven't heard about it.

[Baruch]

I wonder what's the error margin for that bar? How far off is it, since it can't be exactly one meter. Unless, that is, the meter is simply defined as the length of that bar. Is that the case?

Yes ... that bar at such and such a temperature (Celsius of course).

[Baruch]

I think it used to be.  Maybe with new technology there is a more permanent baseline, but I haven't heard about it.

Old method replaced in 1960 ... then that newer method was replaced with a time standard plus a fixed numerical value for the speed of light.

http://physics.nist.gov/cuu/Units/meter.html

http://physics.nist.gov/cuu/Units/second.html

Time is more narrowly defined than length, hence this pragmatic change.  The speed of light in relativistic units = 1 anyway.  This means that if there is a successful test of light of varying speed in vacuum ... you have to do it with time variance.

https://www.sciencenews.org/article/speed-light-not-so-constant-after-all

This has to do with the difference between phase velocity and group velocity (usually significant in matter ... this is why you have an index of refraction) but pulsed light interferes with itself ... so it depends ;-)

[SGOS]

Old method replaced in 1960 ... then that newer method was replaced with a time standard plus a fixed numerical value for the speed of light.

That sounds familiar.  Maybe that's why I posted my comment.  Now we have to puzzle over whether or not time and speed of light are constants, and if not, do they fluctuate at some fixed ratio?  Maybe future generations will puzzle over why time seems to go slower as they get older.  Like if the universe starts to collapse.  OK, this is getting silly.

[Cavebear]

That sounds familiar.  Maybe that's why I posted my comment.  Now we have to puzzle over whether or not time and speed of light are constants, and if not, do they fluctuate at some fixed ratio?  Maybe future generations will puzzle over why time seems to go slower as they get older.  Like if the universe starts to collapse.  OK, this is getting silly.

Someday, humans will consider Einstein to be as wrong as Plato.

[Baruch]

Someday, humans will consider Einstein to be as wrong as Plato.

Anti-Semites in the 1930s already concluded that.  But they were wrong.  QM folks in the 1030s already concluded that ... and they may yet be proven right (spooky action at a distance does appear to be real ... so Einstein is losing).  But Plato wasn't even much of a mathematician, let alone a physicist (naturalist in those times).  Euclid was the mathematician, Aristotle was the naturalist, and Archimedes was the Eureka!