The Most Foolish Theory in Physics

Well I'll give you *that*
made of a negative energy density[/quote]
No, that's wrong.


But the radiation is not at constant density over time where the DE, if a cosmological constant (which we don't know but presume currently is the case) is.


I do not know what this means. You need to use words more carefully if you're going to get physicists (I am one) to understand what you mean.


Well the CMB isn't even at a constant density so that's kind of pointless mentioning, and it's blatantly not vacuum energy anyway - the photons of it are as real as you and I and not in the slightest bit virtual.

You do not appear to understand what you are talking about.[/QUOTE]


First Lesson

1) -Have you heard of Radiation Pressure in the vacuum? For it excerts a negative force.

Second lesson

2) - The CMB according to the non-classical mathematical derivation is constant, that is why we represent it by the constant Lambda, which was that symbol i gave you [latex]\Lambda[/latex].

3) ... I don't appear to know what i am talking about. You don't seem to savvy yourself, if you don't mind me enquiring.
 
Well I'll give you *that*
made of a negative energy density[/quote]
No, that's wrong.


But the radiation is not at constant density over time where the DE, if a cosmological constant (which we don't know but presume currently is the case) is.


I do not know what this means. You need to use words more carefully if you're going to get physicists (I am one) to understand what you mean.


Well the CMB isn't even at a constant density so that's kind of pointless mentioning, and it's blatantly not vacuum energy anyway - the photons of it are as real as you and I and not in the slightest bit virtual.

You do not appear to understand what you are talking about.[/QUOTE]
May i ask something personal?

It appears quite a few people here don't actually know the quantum laws of physics very well - what age are you, and what levels of degrees do you have in the mechanics of physics, i.e any crudentials you could boast and put me to shame about?

For if this is true, then please, don't hesitate to provide my boring life with most possibly a boring answer.

Ball is in your court bub.
 
Learn to use quote tags properly.

1) -Have you heard of Radiation Pressure in the vacuum? For it excerts a negative force.

Nope. Radiation pressure from real photons is a positive pressure. The vacuum expectation value of the electromagnetic field (sometimes referred to as virtual photons) can produce a negative pressure (ie, the Casimir effect), but this is not called radiation pressure, because it doesn't behave the same way. The CMB is real photons. It exerts a positive pressure, not a negative pressure.

2) - The CMB according to the non-classical mathematical derivation is constant,

No it isn't. Not only are there slight inhomogeneities and anisotropies in it, it changes considerably over time. It explicitly decreases in strength as the universe expands.

that is why we represent it by the constant Lambda,

Except Lambda is not used to represent the CMB, because the CMB is not dark energy. Which should be obvious, because it's not dark.
 
2) The violation of the creation has been proven. Just google, ''Zero-Point Energy From Nothing.''

Thank you for the prompt response.


Ok ok.. Wikipedia isnt exactly my first choice in giving a proper "quote" but it will do for now as it appeared as the 3rd website when I googled the above as requested:


"Even though the zero point energy might be infinite, there is no theoretical basis or practical evidence to suggest that infinite amounts of zero point energy are available for use, that zero point energy can be withdrawn for free, or that zero point energy can be used in violation of conservation of energy."


Given that the first "link" is to http://www.calphysics.org/, is it this page you wanted me to read? http://www.calphysics.org/zpe.html I dont see any "proof" on that page, in fact not a single mention of conservation of energy.

I dont mean to be obtuse but I have been out of the field for a long time and I thought I would enquire as to your "backing" for the original statement, I am a bit rusty and thought perhaps I was missing something.
 
Zig, go away. You aren't contirbuting anything remotely to science, other than buzzwords stringed with no real meaning.
 
Thank you for the prompt response.


Ok ok.. Wikipedia isnt exactly my first choice in giving a proper "quote" but it will do for now as it appeared as the 3rd website when I googled the above as requested:


"Even though the zero point energy might be infinite, there is no theoretical basis or practical evidence to suggest that infinite amounts of zero point energy are available for use, that zero point energy can be withdrawn for free, or that zero point energy can be used in violation of conservation of energy."


Given that the first "link" is to http://www.calphysics.org/, is it this page you wanted me to read? http://www.calphysics.org/zpe.html I dont see any "proof" on that page, in fact not a single mention of conservation of energy.

I dont mean to be obtuse but I have been out of the field for a long time and I thought I would enquire as to your "backing" for the original statement, I am a bit rusty and thought perhaps I was missing something.

Exploiting Zero-Point Energy "One has to keep an open mind, but the concepts I've seen so far would violate energy conservation," Milonni concludes. In sizing up zero-point-energy ...
www.padrak.com/ine/ZPESCIAM.html - Cached - Similar -
 
Zig, go away. You aren't contirbuting anything remotely to science, other than buzzwords stringed with no real meaning.
IronyMeterSplode.jpg
 
Exploiting Zero-Point Energy "One has to keep an open mind, but the concepts I've seen so far would violate energy conservation," Milonni concludes. In sizing up zero-point-energy ...
www.padrak.com/ine/ZPESCIAM.html - Cached - Similar -


And the whole quote reads:


Certainly, there should be room for far-out, potentially revolutionary ideas, but not at the expense of solid science. "One has to keep an open mind, but the concepts I've seen so far would violate energy conservation," Milonni concludes. In sizing up zero-point-energy schemes, it may be best to keep in mind the old caveat emptor: if it sounds too good to be true, it probably is.


But as I said, I am out of touch with the field.... I would love to see a direct quote from a paper of his though that suggests he has evidence or good reason for breaking of conservation of energy.

http://www-spires.slac.stanford.edu/cgi-bin/spiface/find/hep/www?FORMAT=WWW&a=Peter+Milonni
 
=
2) - The CMB according to the non-classical mathematical derivation is constant, that is why we represent it by the constant Lambda, which was that symbol i gave you [latex]\Lambda[/latex].
Totally incorrect.
You don't seem to savvy yourself, if you don't mind me enquiring.

I'm a professional cosmologist. Like most professionals here I don't exactly throw my qualifications into the ring lightly, not least as there's a large number of highly knowledgeable laymen about.

You do not know what you are talking about, however.
 
It appears quite a few people here don't actually know the quantum laws of physics very well - what age are you, and what levels of degrees do you have in the mechanics of physics, i.e any crudentials you could boast and put me to shame about?

For if this is true, then please, don't hesitate to provide my boring life with most possibly a boring answer.

Ball is in your court bub.

Since you asked (which I previously suggested you didn't), I have a masters and PhD from a rather highly rated university. I've taught quantum mechanics at the university level, and cosmology, and astrophysics.

And even I bow to the superior knowledge in many areas of physics of other posters here such as Sol.
 
This is rude and off topic, please do not make posts like this.

Oh, let him. His post was unwarranted, but it only makes his cluelessness more obvious (which is all to the good), and it certainly isn't going to shut me up or hurt my feelings.
 
Since you asked (which I previously suggested you didn't), I have a masters and PhD from a rather highly rated university. I've taught quantum mechanics at the university level, and cosmology, and astrophysics.

And even I bow to the superior knowledge in many areas of physics of other posters here such as Sol.

Owned.
 
Not to derail, but could someone help out a USAian here?

No, i did my A-levels on physics a long time ago. The education gathered from doing physics for an HND is much more advanced.

Not that much more advanced. From University of the West of Scotland it appears that students with a Physics HND can join year three of their Physics course whereas students with three relevant A-Levels can join year two.

What levels of education are being discussed here?

In the USA, you go to high school (ages 14-18) and get a high school diploma. If you don’t complete high school, you can take tests and get a GED (General Educational Development) certificate that is (sort of) the same as a high school diploma.

After that, you can get an Associates Degree, which is usually a 2-year program from a community college, junior college, or business college. Or go to a college or university and get a Bachelors Degree, which is usually a 4-year program. This is usually what is meant by “going to college” and is for ages 19-22. Courses are usually coded 100, 200, 300, and 400 by level of complexity. So 101 is code for the most basic course in a field and is used as slang in casual conversation to describe something very simple (“cooking toast is like Culinary 101”).

After a Bachelors Degree, you can go to graduate school and get a Master Degree (2-3 years) and after that get PhD (another 2-3 years).

The way I read it, A-Level is like passing high school physics, three A-Levels would be like passing a college prep test to be able to skip a low level 100 college physics course, and HND would be like basic sophomore college level physics.

So where do A-Levels, HND, “three relevant A-Levels”, and such fit in to the USA system? :confused:


Also: Is “cojent” a valid spelling of “cogent” in Britain or Australia? Singularitarian used “cojent” and I have seen the spelling used a number of times in the past couple weeks. All were from writers outside of the USA. It is not a common word and on-line dictionaries did not show “cojent” as an alternative spelling, but the dictionaries are probably USA centric and the consistent spelling (or misspelling) struck me as odd. :confused:
 
It isnt that clear even for someone living in the UK as there are various levels and the education system in Scotland is not quite the same as in England and Wales.

Normally its school, leading up to (ages 14-16) GCSEs, then an optional (at the moment) further 2 years from 16-18 leading to (normally) A Levels, then perhaps move to university to study for a degree.

Degrees can differ quite a bit in difficulty across universities and subjects, but generally a BSc in a decent uni is 3 years work. Perhaps then followed by a Masters (MSc) for a year. Or then a PhD. (typically around 3 years), although I went straight to PhD after my BSc.

There is even a slight difference between say a BSc and a BSc (Hons.). Generally the honours degree is assumed to have been 'harder' or a higher standard pass.

A Levels are normally taken at ages 16-18, in a sixth form college or similar, after they have finished their secondary school education (normally leading to GCSE qualifications).

As I understand it students in Scotland take Highers and Advanced Highers of their version of the qualification, whereas those in England and Wales do "A Levels".

In Scotland and England the things we might quickly refer to as HND can mean slightly different things. Confusing eh?

In England HND, to me, means a BTEC qualification. In Scotland a good Higher National is supposedly as good as a year or two at uni.

We do have a national qualifications framework, which helps work out what is equivalent to what.

http://en.wikipedia.org/wiki/National_Qualifications_Framework

Be very careful though. My fiance teaches kids who are disadvantaged or have behavioural problems and go to a private firm that teaches them literacy, numeracy and vocational skills. I have seen some of their "qualifications" and certain levels of their maths certificates are supposed to be equal to a GCSE. Rubbish. On the framework the credit is equal, in practice the GCSE covers much much more ground and in much more detail. So it can be dangerous to just glance at such a table and say "this is the same as that".

Unfortunately there is no substitute for testing and demonstrating in depth knowledge of the subject matter and looking carefully at the exact requirements to pass the "qualification".

Most universities will be looking for good grades at A Level in order to enter for a course. The courses are not 'graded' 101, 102 etc like in the USA but will normally just have whatever name is chosen (when I did my degree it was just a description of the course matter, like "structure and evolution of stars").

It can be a little difficult to judge and compare difficulty of degrees without knowing the exact subject matter that was covered.

For example, I teach Further Mathematics at A Level and that covers what I have now seen in first and some second year courses at Uni. Although it is supposed to be a reasonably level playing field, the course content at a good uni will exceed that at one which is less well renowned. Such is life.

In my limited dealings with students from the USA the whole system seems to have a different emphasis. It certainly used to be the case that you studied some subjects in a narrower fashion here in the UK and thus delved a bit deeper than someone in the USA, I dont know if that is still true.



http://en.wikipedia.org/wiki/Higher_National_Diploma

http://en.wikipedia.org/wiki/GCE_Advanced_Level_in_the_United_Kingdom
 
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Not to derail, but could someone help out a USAian here?

What levels of education are being discussed here?

In the UK you must attend school until age 16. At that age you take GCSEs - General Certificates in Secondary Education. These are in a number of subjects some of which are compulsory. If you're smart you'd do about 8 to 10 of these. Not so smart, maybe 3 or 4. I think they are graded A through F and U (ungraded). (When I was at school, these exams were differentiated in to 'O (ordinary) levels' and CSE (Certificate of Secondary Education). Roughly speaking O levels are more academic and CSEs were more practical.)

you may choose to leave school at that age.

If you go on to 'sixth form', you'd do A (advanced) levels and leave at 18. Again, if you're smart you'd do 3 or 4 of these. No subjects are compulsory.

Then, you may choose to go to university and study a bachelors (BA, BSc, BEng ...) over 3 years or a Masters (MA, MSc, Meng) over 4. Or you could do a Masters separately after a bachelors. So that'd be ages 18-21 or 22

Alternatively after a Bachelors, you could study for a PhD over (at least) 3 years. So that'd finish around age 25.

There are variations on this, and it's become complicated by polytechnics (traditionally more trade-ful courses) becoming universities. Also Scottish education does a differently named exam at age 14 (scottish highers, IIRC).

Another alternative to A level is 'HND' Higher National Diploma. I'm not sure what purpose they serve now. It used to be you'd take these if you were intending either to work afterwards or attend technical college. Not university. My understanding is they're somewhere around 1st year undergraduate level. Also, if someone bails out of university before graduating, or fails finals really badly (but somehow managed not to get thrown out earlier) but has sufficient credit points from earlier years, they may be awarded a Diploma, hence my association of 'have Diploma' with 'failed degree'.

An (undifferentiated) graduate refers to someone who has (at least) bachelor's level qualification. We don't have the USian 'high school graduation' ceremony. The usual route to graduating university is GCSE, A levels, Bachelors. The usual route to becoming an academic is adding a PhD onto the end of that.

After that, you can get an Associates Degree, which is usually a 2-year program from a community college, junior college, or business college. Or go to a college or university and get a Bachelors Degree, which is usually a 4-year program. This is usually what is meant by “going to college” and is for ages 19-22. Courses are usually coded 100, 200, 300, and 400 by level of complexity. So 101 is code for the most basic course in a field and is used as slang in casual conversation to describe something very simple (“cooking toast is like Culinary 101”).

Same here. The requirements for award of a bachelors are something like 'at least 180 credit points at level 3 or higher'.

After a Bachelors Degree, you can go to graduate school and get a Master Degree (2-3 years) and after that get PhD (another 2-3 years).

As I mentioned above, there's no requirement to have a Masters to study for a PhD. But generally a PhD will take 3 + years full time.

The way I read it, A-Level is like passing high school physics, three A-Levels would be like passing a college prep test to be able to skip a low level 100 college physics course, and HND would be like basic sophomore college level physics.

Yes, I think that's right. My impression is that A-levels are more advanced than US high school, but not completely at 1st year university level. HNDs are at 1st year level. Note that doesn't mean having an HND will unconditionally get you into the 2nd year of a degree course. You'd have to negotiate that with the institution being applied for.

So where do A-Levels, HND, “three relevant A-Levels”, and such fit in to the USA system? :confused:

Hopefully the above is clear. To be accepted onto a university course, the minimum requirement is 2 A-levels at grade E (pretty damn easy.). However, if you're going for a Physics course at a decent university, they'd want to see one of your A levels being physics, and they'd probably want you to have 2A's and a B or something like that. There are equivalency conversions between A-levels and other awards, but they confuse university admissions, and they don't like them (I'm talking Russell[*] group, because that's what I know).

One of the difficulties with university admission, is one applies before you know your A level results, and thus the offers are all conditional based on predicted outcome. This leads to a noticeable skewing towards private schools who always predict high, rather than state schools who prefer to predict low. There is a drive to alleviate this in various ways.


Also: Is “cojent” a valid spelling of “cogent” in Britain or Australia?
No.

[*] as you might expect, there's a hierarchy of universities (by 'academicness'). From the top they go
1) Oxbridge (Oxford, Cambridge)
2) Russell Group 'older, but not that old' ~pre 1950 http://www.russellgroup.ac.uk/
3) Red-brick 'newer, but not as new as ...' ~post 1950
4) Ex-polytechnics
5) Oxford Brookes 'university' :)
 
Degrees can differ quite a bit in difficulty across universities and subjects, but generally a BSc in a decent uni is 3 years work. Perhaps then followed by a Masters (MSc) for a year. Or then a PhD. (typically around 3 years), although I went straight to PhD after my BSc.
Straight to PhD is the usual path (why mess about with an MSc in that case?)

There is even a slight difference between say a BSc and a BSc (Hons.). Generally the honours degree is assumed to have been 'harder' or a higher standard pass.

Correct. Although it's now moving towards just providing the % achieved, degree classifications are, with the grade boundaries as I recall them, for final year results.

* 1st >= 70%
* upper 2nd, (2:2) >= 65%
* lower 2nd (2:1) >= 60%
* 3rd >= 50%
* ordinary >= 40%

ordinary means without honours, all the others implicitly mean with honours. You wouldn't be considered for a PhD without either a first or upper second.
 

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