# [bi|sur|in]jective coordinates

Discussion in 'Physics & Math' started by RJBeery, Sep 29, 2010.

Not open for further replies.
1. ### temurman of no wordsRegistered Senior Member

Messages:
1,330
Please answer my question. I want to know your background and also see the will to learn, not to use the answer to hold against others in an argument. Otherwise it will be a complete waste of time.

3. ### Green DestinyBannedBanned

Messages:
1,211
Forgive me. I posted that post near enough at the same time. I hadn't seen your question. Hold on.

5. ### Green DestinyBannedBanned

Messages:
1,211
They are spacelike coordinates. I guess there could be a fourth, a timelike coordinate...

7. ### temurman of no wordsRegistered Senior Member

Messages:
1,330
Yes, 4 coordinates. Let us leave the t-coordinate for now. What are the remaining 3 coordinates? What is the range of each of them? For example, the Cartesian coordinates x,y,z in the usual 3-d space all run from -infinity to +infinity.

8. ### AlphaNumericFully ionizedRegistered Senior Member

Messages:
6,697
Most people don't pass A Level physics because most people don't take it.

And no matter how many times you assert what you think my views are that doesn't make it so. If you're incapable of holding a rational discussion don't be surprised when people treat you as such.

Except that the mistakes we make are mostly small slips in memory or minor algebraic mistakes. None of us are claiming to understand work we don't. You've been caught lying too many times and now you're having a hissy fit.

Your 'pet theory' thread in pseudo. You didn't correct yourself on the scalar/vector issue, in fact you said things like "If you didn't respond to that part then I'll assume I'm right", which you weren't.

Yes, everyday I make algebraic mistakes in my work and then have to quickly correct myself or I code up an algorithm which doesn't do what I wanted or I forget some result I'd previously known but which might be applicable to the work I'm doing. But I typically quickly discover my mistake, correct it and learn from it. And I continue to read and learn and talk to other people doing the same thing. No, not on forums, in real life.

I know you want us to think we're perfect so you can throw insults at us but reality differs from your perception of it. As you should have realised given how often your delusions about your abilities are exposed.

Your hissy fit response says otherwise. And its not like you've been called on stuff in only one thread, is it?

Yes, having a rational and informed view of science is tiresome.....

To a grandmother in a way which conveys the details. The concept of what the Dirac equation covers is easy, its matter like the electron or quark or neutrino.

Didn't you say something a few posts back about how its terrible we supposedly lie about you and yet, here you are lying about me. The fact you said 'hypocritical bullshit' makes it all the more ironic.

Please provide instances where we have stated things which we have presented as our own answers which we came up with when in fact we've been parroting someone else. Specifically where have we clearly tried to pass something off as our own work?

It wouldn't appear so. Perhaps if you understood this stuff you'd not need to defer to Temur, you could discuss the matter yourself? Its that difference between parroting and understanding again...

That the best you got? You tried calling me 'rocket scientist' as an insult and it backfired because one of the projects I'm currently involved in does involve rockets. Yes, I love my job.

How about you give some examples rather than just claiming they exist? Its easy to say such things exist if you don't provide any examples.

And I don't come here to post 'pet theories', my day to day work has nothing to do with what I post here. If someone is presenting a pet theory and is serious about wanting to get it into the mainstream then they should be prepared to have every little mistake highlighted. That's what a journal reviewing the work would do. That's what goes on during a PhD viva. The back and forth between an author and a journal can last more than 6 months before a paper is published if the paper contains lots of things which need clarification or correction. If you aren't prepared to put in the effort to meet basic standards why are you even bothering to post pet work?

That's the 'Farsight attitude', that if you get the concepts right the mathematical details are something minor to worry about afterwards. Its nonsense when it comes to theoretical physics.

If you'd read a little bit of the literature you'd be aware of that.

And your evidence for this is.....? I mean, other than your own wish it went different. I'm using it as the standard example of how you talk about concepts over your head, you name drop mathematical things which it turns out you don't know anything about and you delude yourself into thinking you are 'doing physics' when in fact you're just spouting buzzwords. The thread on tensors is another example. Or your pet theory about electromagnetism. In all of them you got basic things wrong and until someone forced you to face up to that you went about as if you understood them properly.

Now you're deluding yourself again saying "Oh he's mentioning that example too much, obviously he's worried about it so it didn't go his way".

Sorta how I commented a few times I'd as nicely as possible tell you to not jump ahead of your current understanding, else you'll only be hurting your own learning and yet you continued posting crap?

Perhaps your problem is that you don't understand the difference between being wrong a few time on small things while being intellectually honest compared to trying to deceive people about your level of understanding and lying about your knowledge?

As I said above, this is an example of why understanding is important. You just parroted Temur and you failed to understand the context and the specifics of his post. You didn't understand that he wasn't contradicting me nor I him. Instead you just saw "is ''injective''" and did a copy and paste. If you understood the specifics about coordinates and even basic geometry on spheres you'd have seen my example was perfectly valid and you'd have understood Temur's reply in the correct context. Instead you're jump head first in with "Look, look what Temur said!! You can't be right 'Mr rocket scientist'!!' only to mash your head on the bottom of the 6 inch deep pool.

If you were a touch more intellectually honest and tried to understand things rather than just 'pass them on' you might not put your foot in your mouth so often.

9. ### NeverflyBannedBanned

Messages:
3,576
You may need to repost this in a little while. He and Alphanumeric are gonna do the Tom and Jerry thing for a bit and he may forget to answer your question.

10. ### Green DestinyBannedBanned

Messages:
1,211
Sorry, that was like 3:00am in the morning I was kept up, and I needed to retire.

Back now!

What are the remaining 3 coordinates?

The three vectors of spacetime, $x$, $y$ and $z$.

What is the range of each of them? For example, the Cartesian coordinates x,y,z in the usual 3-d space all run from -infinity to +infinity

I vaguely remember that Kruskal coordinates are from $-\infty < t < \infty$, would that apply as the range for the vectors?

11. ### Green DestinyBannedBanned

Messages:
1,211
If you would be so good, as to wait until me and temur is finished, so it's not too cluttered. Then I'll get back to you.

12. ### temurman of no wordsRegistered Senior Member

Messages:
1,330
We are talking about the Schwarzschild coordinate system. If you leave the t-coordinate out, what are the remaining 3 coordinates of the Schwarzschild coordinate system?

What is the range of each of the coordinates (except the t-coordinate for now) in the Schwarzschild coordinate system?

13. ### Green DestinyBannedBanned

Messages:
1,211
The spatial coordinates? I don't know what else you would call them.

If I wasn't right the first time, I surely do not know.

Last edited: Oct 10, 2010
14. ### temurman of no wordsRegistered Senior Member

Messages:
1,330
More details. What are the letters usually used to denote the coordinates in the Schwarzschild system? What are the intuitive meanings of each of the coordinates?

You talked about Kruskal in your answer, so I was repeating the question to remind you that we are talking about Schwarzschild. What are the ranges?

15. ### Green DestinyBannedBanned

Messages:
1,211
I'm going to have to do some guessing here, and admit I had a little look round the internet, but do you mean the spatial coordinates make up $r_0=(x,y,z)$, or if I am wrong, I would love to know the answer now.

And as for the ranges I will stick with the original answer. $-\infty < t< \infty$.

I'm probably wrong.

16. ### temurman of no wordsRegistered Senior Member

Messages:
1,330
In the Schwarzschild coordinate system are the spatial coordinates usually called (x,y,z)? What is the meaning of x, for example? What is it measuring?

Messages:
6,697

18. ### Green DestinyBannedBanned

Messages:
1,211
It's not that I am unwilling, but perhaps a but unfair.

I should have probably told temur I would be away the next three days. But, then again, My life does not revolve around this place.

Secondly, I did reply to temur. Now I am going to answer him again.

19. ### Green DestinyBannedBanned

Messages:
1,211
$x$ would imply spatial coordinate $v_1$, and $y$, $v_2$ and $v_3$ obviously $z$. No?

and then I will modify what I said slighty different, and remove the time variable, because you did say afterall, we where not going to take that into consideration.

simply from $-\infty <x,y,z<\infty$.

20. ### temurman of no wordsRegistered Senior Member

Messages:
1,330
I think you don't know anything about Schwarzschild coordinates, but don't worry I will guide you through questions. Just answer my questions.

Now the second set of questions. What is polar coordinates on the plane? What are the coordinates usually labeled? What are the ranges? What is the meaning of each of those coordinates?

21. ### Green DestinyBannedBanned

Messages:
1,211
Yes, I really don't know much. We did assertain that earlier on, but thanks for the continuation. I am willing to learn.

The polar coordinates I think are the most convenient reference frame (according to sources I have read). The poloar coordinates are extended into three spatial dimensions, so I see how they apply.

I think the two polar coordinates are represented by $r$ and $\theta$ and in some cases can be converted into Cartesian Coordinates. I am not sure about the ranges.

22. ### temurman of no wordsRegistered Senior Member

Messages:
1,330
Do you know what $r$ and $\theta$ represent?

23. ### Green DestinyBannedBanned

Messages:
1,211
Not really. $r$ generally denotes a radius. $\theta$ usually denotes an angle, but I am unsure if this is what they imply in polar coordinates.

Some teaching is required.