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

Entry: General Theory Of Relativty - A73254648
Author: EnergeticRobb978 - U14573969

This article is all about Einstein's general theory of relativity and other things assosciated with it.

Hi energeticRobb, welcome to PR. We already have an edited article on this subject, A287381 Relativity.
Unless your article contains anything different, in which case it would be an update to the original, then we don't duplicate articles for the edited guide.
You can remove this by clicking on the small x next to your name in the list.


BMT Scout

Beg to differ.

1. The existing Entry is very brief. This is significantly more comrehensive.
2. There are two theories of course, the Special and the General. This new Entry is about the General Theory. The original one alludes to both, but actually refers more to the Special, albeit in a shallow and uninformative way.

That's not to say that Energyrobb's offering is EG-fit. It needs critical help to improve it, and it needs specific things (like the inclusion of images as an obvious example) fixing.

Let's not go thinking that the Edited Guide already has an adequate Entry on Relativity though. This is an important subject for inclusion, and all we've got at the moment is triviality with the right title.

Pin (also a Scout, if a half-hearted one)

Hi Pin, I did say it could be an update to the original which does away with the duplication issue.
I personally think an update is the way to go but I'll wait and see what others say.

BMT Scout

But that shouldn't be the first thing we say in cases where the original is weak. Hardly encouraging is it?

And I think you're wrong anyway. General Theory is original.

As always, I'll go along with the concensus so I'll wait for others to comment and take it from there.

BMT

I must concur with Pinniped on all points.

Something I like to see in math oriented articles, nothing taken for granted, as one might with a specialized audience, everything properly explained and defined, considerations especially important when writing for an educated and intelligent general audience as with the Guide. This article rates markedly better than the mean on these points.

This is where I'm going to take some time out to carefully read both articles.

By the by, Pinniped is absolutely correct about the need to differentiate between Special and General Relativity.

IMO This Entry should be treated as an Update to the original Entry on 'Relativity' which, as has been pointed out, is exceedingly trivial!

If the original Entry has anything which hasn't been explicityl stated in this Entry, then perhaps it could be included in the opening section 'History'...

In which case, perhaps the opening section should be re-titled 'Relativity'

This looks like the making of a gfood, interesting and useful Entry

with it

Thank you very much guys, your comments are much appreciated. I did know of the other article, but that one was about relativity.
My article was about a type of relativity.

Hi Energetic Robb,

Welcome into PeerReview. I hope you enjoy the experience

I can't pretend to understand what you have written, but I do know that blobs (pictures) you have included need to be removed. Only those approved by the Eds are permitted into Edited Guide Entries.

I have only skimmed over the article and have found this little typo >>Suggestions Made By Relativty<< = Relativity

Hopefully, those with a better knowledge than I will be able to help you through to the next stage


lil xx

Coming along on my re-study of the two articles. Hopefully will be ready to post a little tonight. (7:30am PST here.)

The number one thing I'd like to see more of is hyperlink explanatory notes on the math notes. Hyperlink notes represent a revolution in literary technology.

Please bear with me, critique about 2/3 done.

Its going to take a little longer. System crashed and dumped my work. Some kind of internet trouble, 'Jakatoa west of Krakow'. Everything including the cell has been going flooey since the last Java update. A regular recurrence people have been complaining about for years.

Church tomorrow and laundry to do tonight. Back to this tomorrow afternoon.

There's a problem of tone with this article. The prose sections are written as though aimed at a medium-ability 12 year old, but then tensors are casually introduced without any explanation whatever. The wild swings back and forth between Janet and John phrases like "Einstein put his magnificent brain to work" and "Oh no,it predicted something that makes any star look like a complete wimp when talking about curvature" on the one hand, and the concepts like the cosmological constant and curvature tensors on the other, make it hard to identify the intended audience. Anyone who can understand the concepts discussed (and to be honest this is a pretty small proportion of the population) is likely to be put off by the childlike language.

Perhaps the language usage can be improved, and the presentation simplified somewhat, to reach a median level with which h2g2 editorial will be happy.

Rather than attempting to do the critique complete this time (and risking another 'dump') I'm simply going to take it section by section.

Remember, you're not obligated to accept anything suggested here.




Section 1, History




...line by line...




1st sen. Rather than "...history..." I'd make this "...publication of Albert Einstein's..."

3rd sen. "...the speed of light..." This should read "...the speed of light in a vacuum..." [This is a good place for a hyperlink with an exposition on Einstein's proof that objects with a positive rest mass cannot be accelerated to the speed of light in a vacuum.]





Though may seem excessively pedantical, it is an important qualification on Einstein's Special and General Relativity people need to be regularly reminded of lest they make the naive mistake of confounding the speed of light constant with a universal invariant*. Albert Einstein's reference to the Fizeau effect** in his book on Special Relativity was made to the purpose of reinforcing the point that his arguments only held good in a vacuum well removed from nearby gravitational sources. Fizeau had proved that the speed of light varies with the mass density of the medium through which it propagates and the direction of motion of that medium. One could make a case that a major part of the reason Einstein was awarded his second Nobel prize, for General Relativity, was his proof that the speed of light varies with local gravitation flux densities.




5th and 6th sen. I'd combine and condense these two sentences, "...imagine the..." becomes "...conceptualize...", the word "...the..." from "...and the 1..." deleted, "...This allowed him to create..." deleted, insert; "...as..." space-time.

7th sen. hyphenate "...space time..."

8th sen. "...bend..." becomes "...bending..."

9th sen. (So far as I know, there has never been a direct measurement of the speed of propagation of gravity made. All determinations I know to date depend on electromagnetic observation.)




*The speed of light is a 'constant', 'k', in the sense that it mediates the mass/energy equivalency and many other important physical relationships. It is not, though a 'universal invariant', and does vary with mass density of the medium through which it propagates, the direction of motion of that medium relative the direction of the propagation of the light itself and local gravitational flux densities. It also varies over cosmological time since all of those factors also vary with cosmological time. Unless one has a clear idea of the difference between a 'constant' which mediates a physical relationship, and a 'universal invariant', something unchanging irrespective of conditions in which the determination is made, one will also have problems with more advanced relativistic concepts like the Cerenkov effect and emerging technologies like quantum teleportation.




**On Fizeau:

http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Fizeau.html

http://renshaw.teleinc.com/papers/fizeau4b/fizeau4b.stm

Fizeau was an important pre-relativistic pioneer ranking with Michaelson, Morley and Lorentz and Fitzgerald. The later experiments of Michelson and Morley disproving the existence of the 'ether' were based on Fizeau's work.




On section 2, Theory




This is the section that's got people excited. You have here a gem in the rough which can be developed and expanded into a standalone article. I'm hoping you'll carefully detail it with hyperlink expansions and expositions on each of the given terms and expressions embodied in it.

Supporting hyperlink expositions allow you to be rigorously pedantic with disrupting the flow of the narrative, allowing the reader to reference the technical details at their convenience.

I find this entry interesting too - I did a module in General Relativity at University, many moons ago. I found it quite hard going (I've forgotten much of what I learned about the theory behind the equation) but I particularly liked the discussion of Unified Field Theory.

The main typo I spotted is in the title - Relativity.

We need to modify the existing entry so that it explains that there are two theories of relativity and that it is only about the special one.

Then we need to get an entry about General Relativity to explain the topic. But I don't think this is such an entry, without a lot of work, as it doesn't explain anything. I don't think that an ignorant person reading it will be any less ignorant afterwards.

Try and rewrite the entry so that an intelligent person who knows nothing about the topic can read it and learn. We have plenty of very intelligent people here who don't know anything about relativity. If they learn something, then you will have succeeeded.

From a semi-ignorant point of view, I must say a lot of this sounds rather different from what I've read. Firstly, the thing about special relativity imho is that it explains how the speed of light is always constant regardless of the observer, and also how gravity can be explained as matter following the geodesic along curved spacetime. I can't say this entry communicates that sort of stuff.

That's because this isn't about Special Relativity, it is about the other sort.