Jump to content


Senior Members
  • Content Count

  • Joined

  • Last visited

Everything posted by Aeschylus

  1. Not really, relativty must be taken into account.
  2. 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).
  3. 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.
  4. 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.
  5. 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).
  6. 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'.
  7. very good. .......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.
  8. The Chandrasskhar limit cannot be applied to black holes! As I've said several times the Chandrasekhar limit appliues to white dwarves only! 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!
  9. 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.
  10. Yes, really: 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. 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)
  11. 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.
  12. 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. 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. 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.
  13. 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.
  14. 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.
  15. 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'.
  16. 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.
  17. Yes, but the information contained within the state must be transferred via classical means.
  18. 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. No, what I'm saying is you can't even say theortically what would happen.
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.