Naked Science Forum

General Science => General Science => Topic started by: wolram on 01/03/2006 19:24:05

Title: Space time
Post by: wolram on 01/03/2006 19:24:05

What is it ? how can (some thing) that has no mechanical properties
be (bent) by gravity, the theory seems just so far fetched, but most
scientists seem to accept it.


A born optomist
Title: Re: Space time
Post by: Solvay_1927 on 02/03/2006 00:44:01
... but not a born speller

My (rather basic and limited) understanding is that spacetime is not bent BY gravity.  Gravity IS the bending of spacetime, gravity is the name we give to the effects of spacetime bending.

Spacetime is bent by the presence of matter or energy.

(I'll quietly shuffle away now before you ask "HOW/WHY does mass-energy warp spacetime" ...)



Maybe the easiest way of thinking about it is to consider general relativity as just a mathematical model - it gives us a set of rules to describe and predict how things are, but it doesn't tell us WHY those rules work.
Title: Re: Space time
Post by: wolram on 02/03/2006 00:55:10
quote:
Originally posted by Solvay_1927

... but not a born speller

My (rather basic and limited) understanding is that spacetime is not bent BY gravity.  Gravity IS the bending of spacetime, gravity is the name we give to the effects of spacetime bending.

Spacetime is bent by the presence of matter or energy.

(I'll quietly shuffle away now before you ask "HOW/WHY does mass-energy warp spacetime" ...)
how does mass enrgy distort space time





Maybe the easiest way of thinking about it is to consider general relativity as just a mathematical model - it gives us a set of rules to describe and predict how things are, but it doesn't tell us WHY those rules work.

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A born optomist
Title: Re: Space time
Post by: Xin on 02/03/2006 05:05:22
Think of "spacetime" as an extremely elastic piece of paper. By itself, it's flat and straight. But add some weight (aka a planet), and the paper bends where the weigh is. THAT is the bending of spacetime. Lame analogy, I know...but hopefully it explains the idea :)
Title: Re: Space time
Post by: wolram on 02/03/2006 15:03:11
quote:
Originally posted by Xin

Think of "spacetime" as an extremely elastic piece of paper. By itself, it's flat and straight. But add some weight (aka a planet), and the paper bends where the weigh is. THAT is the bending of spacetime. Lame analogy, I know...but hopefully it explains the idea :)

Hi Xin, i know the basic idea, i am just baffled as to what in (reality)
replaces the (elastic piece of paper).

A born optomist