h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: Newton's Conjecture - A26853663
Author: antimather - U9649944

Mathematical equations offer no sure guide to their proper interpretation. Dimensional analysis gives a better insight into the physical workings of natural forces

Your point being what, precisely?

The answer Felonious is in the article accompanying my entry.

It's not a very clear point, though, is it? h2g2 Entries are not supposed to require a degree in physics to understand. They should be easily readable by the average well-educated man in the street. This is going to require a lot of work to bring it up to that standard.

When you've done that, I'll be able to tell whether the point you are making is a valid one or not.

The implication Gnomon is that you want the standard of argument brought down to the level of an average well-educated man. In fact the article was not written with the benefit of a degree in physics, only a degree of lateral thinking, which I invite you to try.

Felonious Monk, I have been grappling all day with the problem of how to distil the point I am making as succinctly as possible. I suppose the essence of it is that the more simply an algebraic statement is made, the easier it is to make it mean precisely what you want it mean and nobody can contradict you. The wool has been successfully pulled over many people's heads by both Newton's inverse-square law and Einstein's famous E=mc2. The best defence is to examine exactly what the various symbols represent. So in Newton's case his d is for distance between centres, believing that is where the force originates, whereas Hooke had used it to signify the diameter of a notional sphere, the centre of which is the focal point of an external force. The symbols in Einstein's equation are treated as unrelated to any measurable quantity, and c2 as a dimensionless very large number. They can in fact tell a very different story if treated as real dimensions in the physical universe instead of a metaphysical world of make-believe. The proper field for that is the mystical oriental religions.

>>only a degree in lateral thinking, which I invite you to try.

No, I'm not going to try that. I'm not reviewing this for the purpose of expanding my brain, which is big enough thank you. I'm reviewing its suitability to be in the Edited Guide.

It isn't suitable as it stands.

Looking through some of the earlier entries on the subject of gravity, Gnomon, I am left wondering how the average well-educated man in the street was able to cope with some of the more scholarly of the entries. The general standard seems to cover a very wide spectrum of intellects

From what I can distil from your argument, it appears to be making a mountain out of a molehill. Gravitation operates according to an inverse square law, so do lots of other physical phenomena, so what?

If this is what you are trying to say it (a) isn't very profound and (b) isn't very clearly communicated. If you want tosee how to write an Entry on a physics subject, try A26384385. Written and edited by both me and Gnomon, as it happens.

Antimather - please read the following page and expand your mind a little:

Writing-Guidelines

c^2 isn't dimensionless. c is a speed. In fundamental dimensions, it's measured in distance/time. In that case, c^2 is measured in distance^2/time^2. To put some sample units on that, you could measure c^2 in metres^2/seconds^2. It's certainly a very large number.

TRiG.

I was being charitable earlier. It is conceivable that this writer knows what he is talking about but is too careless to put it down in words, or is not a good enough writer to express it in terms we can understand. It's unlikely, though. There are just too many pieces of wooly-headed thinking in this.

I've read it through several times and I haven't the faintest as to what he's trying to say.

TRIG Yes c is a dimension, but what is the dimension of the square of speed? Acres per square second? What I am saying is that could represent the rate of expansion of a spherical wave-front, if that were the intention, but it is clearly not.

Why are you asking this question, antimather, did you not understand Trig's answer?

No, c is *not* a dimension - it *has* dimensions, exactly as stated in Trig's post 11

Gnomon, No, I certainly did not understand how TRiG proposed to measure square speed

h5ringer, ...but we were not talking about c but c2

Antimather, do you agree with these 3 statements?

1. c is a speed

2. speed is expressed as a unit of distance divided by a unit of time. The actual units don't matter; speed is speed whether it is expressed in metres per second, or furlongs per fortnight.

3. c squared is c multiplied by c, i.e. c x c

If so, then since c has dimensions of distance divided by time, i.e. [d]/[t], then c squared (c x c) must have dimensions of [d]/[t] x [d]/[t], i.e. ([d] squared) divided by ([t] squared)

Just add your own preferred unit of distance and your own preferred unit of time.

E=mc^2

c^2 has units m^2.s^-2
m has the unit kg
E has the unit kg.m^2.s^-2 ...otherwise known as a Joule.