Aeschylus

Is there any realm of science where the question might not be 'meaningless' ?

Not really, relativty must be taken into account.

i thought electron volts were energy units, not mass.

Rest energy = mc^2, so it is entirely consistent to give 'mass' units of energy infact the natural units of relativity c is taken as 1 and unitless (as time is measured in the units of distance).

You are uneducated on Chandrasekhar limit theory.

Rubbish, Flak is their really any need for this. All the Chandreskar limit staes is that it is impossible for white dwarves to exist beyond a certain mass.

The Chandrasekhar limit says nothing about black holes, I've said it before! Infact orginally the Chandrasekhar limit did not even consider relativstic effects and the black hole comes entirely from the genral theory of relativity.

The local coordinate velcoity of a photon always has a length of c in general relativty, this is simply a result of the postulates of GR. The Oppenheimer limit or the Chandrasekhar limit offere no insights into how black holes 'work' (infact the original limit did not take into account general relativity).

If a star goes over the limit' date=' that suggests to me that the limit no longer applies to it.

 

What with it being a limit and all.[/quote']

 

Correct, you'd aslo have to examine the Oppenheimer-Volkoff limit to determine hetehr graviational collapse into a black hole will take place.

 

AS I said before the Chandrasekhar limit applies only to white dwarves, read the link I posted, Flak.

The effects of special relativty do apply as indeed they apply to everything (the Lorentz invaraince is beleived to be a fundmanatal property of nature within it's limits).

BUT in special relativty a frame of reference cannot be defined for a photon. One of looking at is that any MCIF (a momentarily co-moving refrenc frame i.e. the frame in which a partcile considers itself to be at rest at any 'instant' of time, this is a generalization of an inertial frame as it allows us to consider the frames of objects that are accelartng too) has the property, by defintion, that the particle considered is at rest, yet it is a postulate of special relativty that the velcoity of a photon is c in all MCIFs so it CANNOT be at rest in any MCIF and therefore cannot have a rest frame.

Therefore it is meaningless in special relativity to talk about the 'photon's perspective'.

Currently trying to develop a technology that will make me able to kick Aeschylus without move from home.

very good.

If an star go over the Chandrasekhar limit it can became a black hole, it is STATED there. Or I have to scan and post the whole theory here?

.......Yet the Chandreskar limit refers to white dwarves. Infact the Chandrasekhar limit in itself does not provide a mechanism for a white dwarf to become a balck hole as it does not consider the degeneracy pressure between neutrons.

I said that Chandrasekhar limit can be aplicated to Black Holes and so on, unless you only want to tell me that I´m wrong. It seems that someone[/i'] needs to check about if not..

The Chandrasskhar limit cannot be applied to black holes! As I've said several times the Chandrasekhar limit appliues to white dwarves only!

Is clear that you only want to make me upset by kidding.

Though I might be being more than a little rude, I'm offereing you genuine advice: simple treatments of special relativty aren't that hard!

= this smilie is labelled "roll eyes (Sarcastic)"

Yes I'm aware yo are being sarcastic, nevertheless the Chandrasekhar limit refers speciifcally to white dwarfs which is why what you said earlier is incorrect

I had "examined" it... (I wont put any smilie to not confuse you again)

No you haven't, that is clear.

...really?

Yes, really:

Around 1930, S. Chandrasekhar studied astrophysical models of white dwarf stars and came to the conclusion that no white dwarf can be more massive than about 1.2 solar masses (). This became known as the Chandrasekhar limit.

http://scienceworld.wolfram.com/physics/ChandrasekharLimit.html

Now you could infer from this that a simlair limit may exist for neutron stars, but the Chandrasekhar limit refers specifically to white dwarfs.

Typically...

Simple mechanical treatments of special relativty aren't difficult at all and by examining them you will find out why lightspeed is a 'barrier' (infact calling lightspeed a barrier is really a very superficial, misleading precis of special relativity)

Chandrasekhar limit' date=' also have aplication on Black Holes, Neutronic Stars and

Supernovas.[/quote']

 

The Chandrasekhar limit refers specifically to white dwarfs.

 

 

 

I think you didnt read my post above yours.

 

Wheter you are "checking other possibilties" or not you still don't have clue about relativity and therefore lack the skills to evalute different possibilties.

I think there is a big difference between uneducated by the subject and not agree with some aspect of it, as a note I`m dont desagree with all the theory.

maybe, but you are undeducate don the subject, that is very clear.

You have absolutely no reason to disagree with special re;ativty besides which ypu should find out wjat special relativty is before you disagree with it.

As I said before. Massless objects or energy? For me is not the same. Do you have a diagram with the complete structure of the photon?. I`m not making inane statements, dont you think that say that the photon "CAN NOT HAVE MASS" is inane? As said before you have SOLID information to say that the photon dont have mass?

A massless object is not equivalent to energy, though a massless object may have energy. As far as is known photons have no structure. That photons cannot have mass is basic physics, thoguh you might want to read about this experiment:

http://www.aip.org/enews/physnews/2003/split/625-2.html

Seconmdly if a photon had mass the electric force would not obey an inverse square law.

About if I`m uneducated, the stated above about black holes (ONLY THAT, SURE) comes from the studies of Chandrasekhar (wich later Oppenheimer expanded) on the limit of the star. I want to know if you even remember that RIGHT NOW.

I guess what you are talking about is the Chandrasekar limit which places a definte maximum mass on the size of a white dwarf (subject to oher factors such as it's angular momentum), due to the force of gravity overcoming the degenracy pressure between elcectrons and protons. The Oppenheimer-Volkoff limit is analgous to the Chandrasekhar limit but refers to neutron stars instead of white dwarfs. But this pretty much irrelevant as you seem quite happy to except the existamnce of black holes (even if you do not know a great dela about them) yet you cannot accept the foundation that is necessary for the theory of black holes and indeed nearly all of modern physics - special relativity.

I'll say it again - learn about special relativty - basic special relativty is not hard and anyone with highschool maths should at least be able to undrestand the fundamentals.

What he syas though is misledaing to the point of being correct and I don't thoink it's a case of imprecise language.

Anyway it is pretty much accepted that to say that decoherence causes the collapse of the wavefunction is incorrect.

Uneducated on the subject.. please stop doing such coments' date=' I`m not a kid and I asume there are no kids here (at least not much) so dont use this type of argument. Better come here and put your toughts about the subject, that will be more interesting.

 

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Going back to the subject, if photons are pure energy without mass:

 

1) Why when they got a massive object, like an star, they got deviated?

2) Why the photons got affected by gravity if they dont have mass?

 

On this last I want to talk about. I was researching by myself for explanations about and I got responses or info that dont convince me.

For example, the light got absorved by a black hole due of strong gravity, so it have to have any kind of mass for that. An interesting note: when light got absorved by a black hole it got invisible, the explanation is that the black hole dont let the light to go out. However if this is true there should be a manifestaion of light before get into the hole, some kind of "funnel".

Personally, due of strongs gravitational forces on the black hole, the photons near it got attracted at speeds higher than the lightspeed, for that it got invisible.

 

Comments, suggestions welcome (as soon it is not like the one exampled at start of this message)[/quote']

 

You are uneducated on the subject, that is a simple and very plain fact, what you shouyld do is try to become educated on the subject, especially before you start to make pronouncements on it.

 

Photons have no mass by the defintion of mass, this does not mean that they will not be affected by gravity, infact in GR it is clear that even massless objects must be affected by gravity. Of course if you'd bothered to find this out for yourself inm the first place, you would not be here making inane statements.

What you are talking about is the Dirac sea, which is basically an infinite number (making them usuually unoticeable) of electrons filling all the negative energy states (thus making it impossible for a 'normal' elctron to sponaeously emit a photon and move down into one of these negative staes because of the Pauli exclusion principle). In this mdoel the creation of an elctron positron pair from a photon can simply be viewed as the absorption of a photon by one of these negative energy state electrons which then moves up into a vacant postive energy state creating a 'normal' electron and also a vacant negative enrgy state. This vacant negative energy state behaves just like a particle in it's own right - this particle is a positron.

Of course these days we do not think of things in terms of the Dirac sea, instaed we think of elctrons and psotirons in terms of the Dirac field.

Einstein used the most fast speed available in the universe wich manifestate itself. You cannot use higher values of speed on the formula listed above, so that formula says that highert velocities of speedlight are not posible and that formula also said that the photon cant have mass. My point is that there is posible higher velocities, and by this the photon can have mass.

Incorrect all EInstein assumed is:

1) the laws of physics are the same in all inertial frames (something that is true in Gallilean relativity).

2) the speed of light is constant in all inertial frames, strongly suggested by E&M and experimentally verifed many, many times.

Using these two postulates alone (tho' possibly having to postulate on the four momentum as the form we use is not the only one that gives the correct non-relativistic limit) you can derive the fact that:

a) anything with real non-zero mass must travel below the speed of light in any MCIF (momenatrily co-moving inertial frame)

b) that photons have no mass.

The formula I guess you are talking about is Einstein compostion of veolcites formula., this is a derived formula and you must look at the axioms and more fundamental formulas to find out why lightspeed is a 'barrier'.

Sorry' date=' i surely ment the geneal relativity :-D i say, i always make lots of misprints :-DD

sr is not what interests me much[/quote']

 

If you want to know about GR you better make sure you know about SR first as SR really is just the degenerate case of GR.

hehe' date=' i seem to have come to a wrong place, but i was just curious

Simply speaking:

Travelling at a speed.gt.c is not forbidden (mathematically), but crossing the very barrier of c is impossible due to singularities. Though i must say some of modern theories (mostly raw and incomplete) keep trying to develop methods to 'avoid' this singularity. And again i must say - that is only maths, we never know what is real, for math is just a kinda language (and we often make mistakes and misprints in it, like i do for instance ))))

First of all, ppl have to make sure, that special relativity (u remember what it states, don't u. adbout the equality of masses ;-)))has a right to exist, for it has only been indirectly prooved in experiments. And that is what i would suggest you to think over, 4 it is interesting indeed.[/quote']

 

Singularities in what? Gravitational singularites? special relativty does not deal with gravity, so no gravitaional singularities occur in SR which is what we are discussing. What do you mean special relativty has only been 'indirectly proven'?

Yes alot of what is posted here is not true

One of the most common mistakes is that time does not pass for a photon. You might as well say that a photon sees magic monkeys in it's frame as objects with null world lines do not have MCIFs.

Exactly. The sound speed was a barrier to human technology and now it is not more a barrier. Light speed is a barrier aswell now and some day it wont be anymore.

 

About the formula' date=' ed84c, the Relativity is based with the light speed as a limit.

 

Time is not stoped by lightspeed. If on astronomy you check the bright of an star 90 years light of distance this is because the photons took 90 years to reach here.[/quote']

WRONG! the 'lightspeed barrier' is not a technological barrier, it is a theoretical barrier.

Exlpain yourself' date=' I know about some theories about, but when aplicated their are wrong.

 

The fact is that a lot of publications, (that I will find the correct source so I can foward you) explain that lightspeed can be doubled, even go 10 times its speed, by the simply concept that is not the limit of speed.[/quote']

 

Special relativity underpins nearly all of modern physics and it is one of the mosted tested theories in physics, it says in no unceratin terms that aan object with real rest mass must travel at less than c in any inertial frame.

 

You must first famalirize yourself with the framework of relativity, before declaring it incorrect.

On the general science forum there was a thread about if we can go faster than light speed or not. I wanted to reply posting why it isnt a barrier but the thread was closed. I think no matter if it is like other threads' date=' I come here to talk if not I will spend time on the library in silence.

 

The point is: we can travel faster than light speed?. Yes.

 

Speed/aceleration is acumulative, it depends on mass and energy. The lightspeed is only the barrier of the "showed" speed, faster than that is not noticiable so we dont know what move faster than light.[/quote']

 

This is not the case, you do not understand why lightspeed is a 'barrier', investigate special relativty and you'll find out why.

The point is that you can transport the quantum state with 100% fidelity. Swansont keeps making the point that you are only transfering information, but I regard this as a little unfair - you destroy one quantum state and 100% faithfully reproduce it at the other end (with the help of a classical signal, as you say). Since quantum states are indistinguishable if they have the same quantum numbers there is no reason why one should not consider it as 'the same'. I could imagine that being rather useful.

Yes, but the information contained within the state must be transferred via classical means.

so are you saying that if i was travelling at C minus 1 mph then if i turned on a light, the light would travel faster than C?

I assume your using SI units (as for convience c is usually taken as 1 in natural units in special relativity). If you are travelling with a constantvelocity of m,magnitude 0.99999 c in some inertial frame and you turned on the lights, from th epoint of view of an observer in that frame the light would travel at c relative to them. BUT importantly from your point of view the light would travel at c relative to your ship.

i know, i was saying theoretically, if you were travelling at C+1, i did say remember that it was impossible

No, what I'm saying is you can't even say theortically what would happen.