[SOLVED] space-time and matter/energy

[Michael Hell]

Would it be correct to say that space and time are two sides of the
same coin, and matter and energy are two sides of another coin?

Are space-time and matter/energy considered "primary" concepts?

[Oh No]

Thus spake Michael Hell <mobydikc@gmail.com>
>Would it be correct to say that space and time are two sides of the
>same coin, and matter and energy are two sides of another coin?

Yes. In relativity 3 dimensional space is replaced with 4 dimensional
space time, and classical 3 vectors get replaced with 4-vectors. Time is
the fourth (or, these days, the zeroth component) of a 4-vector with
three space components and, likewise, Energy is the zeroth component of
a vector whose other three parts are classical momentum.
>
>Are space-time and matter/energy considered "primary" concepts?
>
Yes (at least in fundamental scientific theory so far).


Regards

--
Charles Francis
substitute charles for NotI to email

[Cyberkatru]

Michael Hell wrote:
> Would it be correct to say that space and time are two sides of the
> same coin, and matter and energy are two sides of another coin?
>
> Are space-time and matter/energy considered "primary" concepts?

In a sense yes. In relativity, space and time are unified in a specific
conception of spacetime mathematically embodied in the notion of a
Lorentz manifold.
However, the distinction between time and space survives to some extent
in the notions of lightlike, spacelike and lightlike. There is a field
of future oriented light cones (that roughly point into the "future").
There remains slightly subtle notions "absolute past/future" and
"absolute elsewhere". See http://en.wikipedia.org/wiki/Light_cone

There are several Newtonian notions that are synthesized in relativity.
For example, from that vantage, mass/energy and momentum are frame
dependent components of a geometrical reality which is the
energy-momentum 4-vector.

(E/c, p_1, p_2, p_3)