Re: Time Flow
- From: socratus <israelsad@xxxxxxxxxxxx>
- Date: Mon, 18 Aug 2008 18:24:44 -0700 (PDT)
On Aug 19, 12:08 am, "Sue..." <suzysewns...@xxxxxxxxxxxx> wrote:
On Aug 18, 4:52 pm, socratus <israel...@xxxxxxxxxxxx> wrote:
Time. /My opinion./
” It's not so much that there's something strange about time,
the thing that's strange is what's going on inside time.
We will first understand how simple the universe is when
we recognize how strange time is. “
/ J. A. Wheeler /http://en.wikipedia.org/wiki/John_Archibald_Wheeler
=========.
Time. /My opinion./
===
There are two kinds of time:
a) the proper (individual) time and
b) the planetary time.
Can you cite some references where physicists
respect this distinction? Do they use symbols
like t_I and t_P in calculations?
I suspect you intended to compare philosopy
with the OP rather than offer argument for or
against a farily solid physical concept
of time offered in my post.
<< invariance with respect to time translation
gives the well known law of conservation of energy>>http://en.wikipedia.org/wiki/Noether's_theorem#Applications
Sue...
Noether's theorem has become a fundamental tool of modern theoretical
physics and the calculus of variations. Noether's theorem allows a far-
reaching generalization of earlier work on constants of motion in
Lagrangian and Hamiltonian mechanics.
My point of view.
1.
a)
In mechanics, a constant of motion is a quantity that is conserved
throughout the motion, imposing in effect a constraint on the motion.
However, it is a mathematical constraint, the natural consequence of
the equations of motion, rather than a physical constraint (which
would require extra constraint forces). Common examples include
energy, linear momentum, angular momentum and the Laplace-Runge-Lenz
vector (for inverse-square force laws).
b)
In SRT and QM a constant of motion is a speed of light quanta: c=1.
2.
a)
Lagrangian mechanics is a re-formulation of classical mechanics that
combines conservation of momentum with conservation of energy. It was
introduced by Joseph Louis Lagrange in 1788.
Lagrange's equation for the classical mechanics is the difference
between
kinetic and potential energy.
b)
For the QM this difference between kinetic and potential energy
describes by formula: E=Mc^2.
3.
a)
Hamiltonian mechanics is a re-formulation of classical mechanics that
was introduced in 1833 by Irish mathematician William Rowan Hamilton.
It arose from Lagrangian mechanics, a previous re-formulation of
classical mechanics introduced by Joseph Louis Lagrange in 1788, but
can be formulated without recourse to Lagrangian mechanics using
"symplectic spaces" (See Mathematical formalism, below). The
Hamiltonian method differs from the Lagrangian method in that instead
of expressing second-order differential constraints on an n-
dimensional coordinate space, it expresses first-order constraints on
a 2n-dimensional phase space[1].
As with Lagrangian mechanics, Hamilton's equations provide a new and
equivalent way of looking at classical mechanics. Generally, these
equations do not provide a more convenient way of solving a particular
problem. Rather, they provide deeper insights into both the general
structure of classical mechanics and its connection to quantum
mechanics as understood through Hamiltonian mechanics, as well as its
connection to other areas of science.
b)
Hamiltonian mechanics and Lagrangian mechanics are equivalent .
Israel Sadovnik.
.
- References:
- Time Flow
- From: Quantum Ranger
- Re: Time Flow
- From: Sue...
- Re: Time Flow
- From: socratus
- Re: Time Flow
- From: Sue...
- Time Flow
- Prev by Date: Re: If lightspeed were constant to all frames
- Next by Date: Re: If lightspeed were constant to all frames
- Previous by thread: Re: Time Flow
- Next by thread: Re: Time Flow
- Index(es):
Relevant Pages
|
