A Brief History of Timekeeping

I gave a guest lecture this morning in a colleague's sophomore seminar class about time. She's having them look at time from a variety of perspectives, and they just finished reading Longitude, so she asked me to talk about the physics of clocks and the measurement of time.

I've long considered using "A Brief History of Timekeeping" as the theme for a general education course-- there's a ton of interesting science in the notion of time and timekeeping. This was just a single class, though, so I didn't go into too much detail:

Kind of a lot for just 16 slides... I answered some more general questions as well, including one about the killer Higgs boson from The Future, and another about black holes. I had a good time, and I hope the students got something out of it.

This also represents an attempt on my part to be a little less bullet-point driven in my PowerPoints. This probably makes them less comprehensible on SlideShare, but that can't be helped.

More like this

Kudos on not missing John Harrison. I have always thought that was one of the most compelling and fascinating science stories ever. The Longitude book and miniseries were both fantastic.

May I recommend a book title 'Calendar'? Sorry, I can't remember the name of the author at the moment.

I found it a great read.

I did teach such a course several years ago - not just on time keeping, but notions of time... the second law... radioisotope dating... time in relativity... it makes for a great organizing theme to tie together a "Fun Topics in Physics" course

This is the kind of stuff that makes me doing undergrad would be fun.

I was also thinking that PowerPoint probably made this much better. In the dark ages when I was and undergrad, a presentation like this would have been visual aid free except for some seemingly random notations on the chalk board.

To understand this you don't need to be able to pull up a picture in your mind of a grandfather clock. That's got to be helpful to students who aren't working from the same cultural background that most other people are.

By katydid13 (not verified) on 15 Oct 2009 #permalink

Philosophy about Time and Quantum of Light.
/ My opinion./

Can Time Exist Without Matter?
1.
According to Newton the answer is â Yesâ.
2.
According to SRT and GRT the answer is â Noâ.
3.
Who is right? Who is wrong?
What is the resolution of this apparent paradox?
===========================..

There are two kinds of time:
a) the proper (individual) time and
b) the planetary time.
They are so familiar that we rarely give them thought.
Donât we know, that time for living being is limited
and the planetary time is absolute for them ? It is.
Maybe therefore Newton declared that time is absolute.
It â flows equably without relation to anything externalâ
he wrote in 1687. But Einstein had another opinion.
He wanted to know: â Where does the conception of time
come from?â, â What is the essence of time?â.
And to explain these questions he created two theories:
SRT and GRT and declared that time is relative, changeable.
1.
SRT explains behavior and the proper time of light
quanta /electron. Why do I think so?
a)
One law (postulate) of SRT says that speed of light quanta
is constant c=1. Second law ( postulate ) says no another particle
can reach this speed. So there are two incommensurable
quantities. Is it possible to bind them together? No. I was
taught at school from the first class that the incommensurable
quantities cannot be compared. The connection between these
incommensurable quantities is similar to the decision of a
problem: âWhat will be if the whale attacks the elephant?â
We can see whale in a ocean and elephant in a savanna,
but they never meet and fight in the same â frame of referenceâ.
And the same is about light quanta and another particles.
We cannot see them together in SRT. We can meet only the
light quanta in SRT and no other particles in it.
b)
SRT was born from Maxwell's theory and it is a continuation
of the electrodynamicsâ development . The electron is a main
and single hero in the Maxwell's theory and SRT. There
isn't the Maxwell's theory / SRT without electron.
It is not correct to compare electron/ light quanta with another
particles (protonsâ¦etc) and bodies (billiard balls, satellites,
astronauts, âtwinsâ) because they cannot produce electromagnetic
fields. The electron and the another particles are also incommensurable
quantities. They are absolutely different objects.
c)
Every epoch has its own delusion. Maxwell and Boltzmann
tried to explain electromagnetic fields using balls, wheels,
cog-wheels, springsâ¦etc. H. Hertz, who demonstrated the
existence of the electromagnetic waves, wrote that the
electromagnetic waves didnât have practice use. Etcâ¦.
Now we try to compare electron/photon
ability with astronautâs and âtwinsâ â opportunities.
It is mistaken, but what to do? We do it because this is
our way of cognition:
â From vague wish to the bright thoughtâ.
2.
So, how SRT explains time from electron/ light quanta point of view.
a)
When light quanta is in state of a rest its time is frozen,
and its own clock shows zero.
b)
When photon moves with constant speed c=1
its time is also frozen, and its own clock still shows zero.
c)
Only when photon moves with speed c>1 its zero time
changes and limited time appears. In this situation we
know photon as an electron. Photon works as an electron
and SRT and Lorentz transformations explain this process.
d)
And when , for example, electron emits from an atom and
interacts with Vacuum all its parameters change. Its limited
time ends and its own clock shows zero again. Now it lives
in infinite/ eternal Vacuum until new incarnation, until its new
work, maybe, in an atom (molecule), or in a cell, maybe, in a blade
of grass or in a tree, maybe, in an animal or in a person.
In another words:â We are living beings until Light quanta/
Electron is present and works in our body.â
Is it true? Yes, it is true. Why?
Because W. Pauli in 1924 wrote:" Each quantum state in the atom
is not limited of two electrons, but only one electron".
It means in the atom can be only one, single electron.
The electron manages the atom. If the atom contains more
than one electron (for example â two), this atom represents
â Siamese twinsâ. Save us God of having such atoms and cells.
And the living being begins its life from one, singe cell.
What I am introducing here is what ' thinking photon/ electron' exist .
I applied the quantum of light/ photon/ electron with a consciousness.
And His own consciousness is not static but can develop.
The development of conscious scale goes
" from vague wishes up to a clear thought ".
This evolution proceeds during hundred millions (billion) years.
e)
Trying to understand â the electrodynamics of moving bodiesâ
Einstein wrote that it is the result of time and space changes.
It is not exactly correct , because these changes are secondary
in SRT. And the first point of SRT is that Quantum of light changes
its spin. The former Planck/ Einsteinâs spin (h) changes in Goudsmit /
Uhlenbeck's spin (h = h / 2pi), and as a result of this act all its parameters
change and the time and new space appear.
3.
GRT explains the conditions of gravitation and the secret of
planetary time. Why do I think so?
a)
When Einstein worked on GRT, he asked astronomers:
â What is the average mass of matter in the Universe?â
The result was lamentable. The quantity of mass was
insignificantly small. It was impossible to keep gravitation
law with such insignificantly little mass and so, the Universe
must be âopenâ, endless. But what to do with the infinite
space, Einstein didnât know. Therefore he took (from the
heaven) â the cosmological constantâ in order to âcloseâ
the Universe. The taken mass was enough for creating the
condition of gravitation. Without â the cosmological constantâ
the Universe is endless.
b)
In 1922 Friedman wrote, that we could not take â the
cosmological constantâ in calculation. Instead of it, it is
enough to take âtimeâ and the Universe will be âclosedâ.
Friedman was correct, but why? Because âtimeâ, by its
nature, is a limited physical quantity and, be taken in
mathematical calculation, automatically gives âclosedâ result.
c)
So, the detected material mass of the
matter in the Universe is so small (the average density
of all substance in the Universe is approximately
p=10^-30 g/sm^3) that the gravitation law doesn't work.
Astronomers and astrophysicists know about this fact and
therefore (to save the gravitation law) invented new matter
a "dark matter", a new energy a âdark energyâ and another
abstract objects. This â inventionâ is only a result of our
mentality , which says: â If in a theory you meet infinity it
means the theory is nonsenseâ. It is very hard to take that
the Universe is infinite. It is no easy matter to give up
a lifetime of habit .
d)
On my opinion it is impossible to use GRT to Universe as
a whole. The Newton/ Einstein's gravitation laws are correct
only in the local parts of Vacuum. The Universe / Vacuum
as a whole is endless.
e)
So, how does GRT explain time?
According to GRT the time depends on the mass
and speed it means, of moving matter.
It means that different masses and speeds can create
different time. For example, our planet Earth has its
own time but for us it is absolute.
The other planets have another mass and speed and
therefore they have their own time. This time according
to GRT is relative. But their habitants will think that their
time is absolute. But if they know GRT they will
not make this mistake.
=============
According to SRT and GRT time is relative.
SRT says about proper/ individual time of an
electron/ light quanta.
GRT says about planetary time of a Planet..
The time cannot exist without matter and speed,
in another words, without moving matter. But
different reasons and different moving of a matter
create the proper and planetary time.
=================..
Is it possible to see the different manifestation of
time in a human being?
Here is an article â Even the time is pressed from fearâ
by Dr. Vadim Chernobrov (collaborator of MAI -
- Moscow Aviation Institute).
He wrote, that we usually think time is a constant quality.
But Einsteinâs relative theory says time is relative.
Question. Is it possible to check it in our life?
Answer. Russian and foreign researches say it is
possible. The documents (secret in the past) testify
that âcataclysm of timeâ, â phenomenon of timeâs
perversion â,â the changes (its deceleration) of timeâ
often is observed by people whose profession connected
with risk: astronauts, pilots, drivers, soldiers.
1.
The test pilot Mark Gallay wrote in his book
âThe test in the skyâ when his airplane was caught
with fire â the time began to go in another scale. The time
almost stopped. Every second took ability of expansion,
and in this situation it was possible to do many things.â
He confirms that tested such feeling many times.
2.
The test pilot Marina L. Popovich said the same,
in the dangerous, catastrophic situations â the time
is stretchesâ.
3.
In June 1989 the soviet airplane MIG-29 crashed near
Paris, in Le Bourget airport , in the time of its air show.
The notes of âthe black boxâ showed that during the
four (4)seconds the test pilot Anatoly Kvochur made as
many operations as in normal situation it would take some
minutes. The test pilot later said: â the time was stretchedâ.
4.
The captain N.Z.(fought in Afghanistan) remembers:
âthe fly of the bullet was so beautiful that I didnât guess
to evade from it, although I have enough time to do itâ.
5.
The sergeant V. Ch (fought in Afghanistan) told:
â The black barrel of gun seems very big, even enormous.
Time is stopped and full silence came. And I moved slowly
a step a side and the bullet passed close to me.â
6.
Etcâ¦
His conclusions.
The people in a critical situation, on the border of death,
suddenly for themselves begin to see everything as in the
slow down film and in this time their speed reaction and
power increase in tens and hundreds times. And this explains:
a) why a man who escaped from wolves, can quickly reach
up the top of the naked tree,
b) an old woman took out a big trunk from her burned house,
which later two strong firemen couldnât rise.
c) etcâ¦
=============..
My experience.
The speed on the curve was so fast that to keep the balance of
the car I went on other road line and flew straight at the
âforeheadâ of a green mercedes. The driver of the mercedes
was in panic, in horror. He threw the wheel and closed his face
with his hands. Suddenly the time stopped and the sound disappeared
for me and I made many actions before my car kicked only the side
back door of the mercedes. It was long time ago, but writing this article
I understood better what happened.
Our computer-brain works on a dualistic basis (on two different neurons
systems): 1) usually under logic program,
2) sometimes on intuition (subconscious).
Brain of a man approximately consists of sixteen milliards neurons.
All of them form the system that manages human body.
That is why that with the work of all the sixteen milliards neurons
of brain, a man cannot catch a single impulse of his Electron, of his
Quantum of light, of his Soul:
(mass of electron is equal 10^-31 kg., charge of electron is equal 10^-19 k.)
But in that time ( critical time ) most neurons of my brain stopped
their electric pulse (time almost stopped) and my Light Quanta/Electron
in this new condition (superconductivity) had possibility to increase
my speed reaction and power on a short period of time . So, as SRT says,
the Light Quanta in different systems ( even in our brain) can show us
a different Time. The Light Quanta plays major role in the Nature,
in the Physics, in our Life.
===============. .
Best wishes.
Israel Sadovnik. / Socratus.