Re: plzz... guys tell me why mass curves space-time?
- From: Henning Makholm <henning@xxxxxxxxxxx>
- Date: Mon, 20 Mar 2006 13:49:22 +0100
Scripsit "eye-n-stein" <physickboy@xxxxxxxxxxx>
1. why does mass curve space time ?
Nobody knows. Assuming it seems to be a valid way of describing how
the world behaves, but nobody have the foggiest idea about _why_ the
world behaves in that way.
2. why is space time imagined as a sort of linen cloth warped by the
presence of mass?
It's the best analogy that is readily available to authors of popular
science books. That does not stop it from being a horribly inaccurate
analogy, and I don't think anybody have been able to use it to reach
conclusions they did not already know to be true in advance. In order
to get anything useful out of general relativity one has to dispense
with the bedsheet analogy and learn the real math behind it (which is
hard).
[More technically, the bedsheet picture is, as far as I understand, a
fair representation of the *spatial* part of the spacetime metric
outside a heavy mass, using Schwarzschild coordinates. It fails on two
counts: (1) It completely ignores the time part of the metric, which
is immensely more important than the spatial part so far as slow
motion is concerned. (2) Unless we're talking about black holes or
something close to it, the indentations in the bedsheet should be
*extremely* shallow, and invisible to the naked eye.]
--
Henning Makholm "Khanivore is climbing out of its life-support pod."
.
- References:
- plzz... guys tell me why mass curves space-time?
- From: eye-n-stein
- plzz... guys tell me why mass curves space-time?
- Prev by Date: Re: The speed of light can not be physically constant to all
- Next by Date: Re: Taylor approximations
- Previous by thread: Re: plzz... guys tell me why mass curves space-time?
- Next by thread: Re: plzz... guys tell me why mass curves space-time?
- Index(es):
Relevant Pages
|
