What If Missing Particles and Stuff Cannot Be Found?

[wolram]

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

In particle physics, supersymmetry is a hypothetical symmetry that relates bosons and fermions. In supersymmetric theories, every fundamental fermion has a superpartner which is a boson and vice versa. Although supersymmetry has yet to be observed in the real world it remains a vital part of many proposed theories of physics, including various extensions to the Standard Model as well as modern superstring theories. The mathematical structure of supersymmetry, invented in a particle-physics context, has been applied with useful results in other areas, ranging from quantum mechanics to classical statistical physics. SUSY is the acronym preferred for whichever grammatical variation of supersymmetry occurs in a sentence. Experimentalists have not yet found any superpartners for known particles, possibly because they are too massive to be created in our current particle accelerators. Hopefully, by the year 2007 the Large Hadron Collider at CERN should be ready for use, producing collisions at sufficiently high energies to detect the superpartners many theorists expect to see.
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So if L Smolin is correct the missing stuff just got less.

 

[wolram]

http://en.wikipedia.org/wiki/Integrated_Sachs_Wolfe_effect
Integrated Sachs Wolfe effect
From Wikipedia, the free encyclopedia.

The integrated Sachs Wolfe effect is a change in the fluctuations of the temperature of the cosmic microwave background due to evolution of the Universe according to the standard Big Bang model.

It is due to the gravitational redshift induced by photons falling into and climbing out of regions of space with different density, called potential wells, in between the Earth and the surface of last scattering (close to the particle horizon). The non-integrated Sachs-Wolfe effect is also due to gravitational redshift, but is the effect only at the surface of last scattering itself.

There are two main contributions to the integrated effect. The first occurs shortly after photons leave the last scattering surface, and is due to the evolution of the potential wells as the universe changes from being dominated by radiation to being dominated by matter. The second, sometimes called the 'late-time integrated Sachs Wolfe effect', arises much later as the evolution starts to feel the effect of the cosmological constant (or, more generally, dark energy), or curvature of the Universe if it is not flat. The latter effect has an observational signature in the amplitude of the large scale perturbations of the cosmic microwave background and their correlation with large scale structures in the universe.

 

[wolram]

http://www.space.com/scienceastronomy/string_systems_030226.html

Just ahead of a bandwagon of theoreticians suggesting the discovery of extra dimensions might be just around the corner, a streetwise inquiry into the potential effects of these additional "spaces" has come up as empty as a gas tank during an oil embargo.

Theorists are unlikely to be sobered by the new study of possible effects on gravity in tiny spaces, however. The research is useful in that it puts an upper limit on the distance at which strange new physical behaviors might yet be detected. Further, it explored only one possible manifestation of extra dimensions.

 

[wolram]

http://www.math.columbia.edu/~woit/blog/archives/2005_04.html

A link to NOT EVEN WRONG .

Lots of information on how string theory is progressing?

 

[wolram]

http://arxiv.org/PS_cache/hep-ph/pdf/0504/0504059.pdf

New mass limit on the Axion.

 

[ohwilleke]

In support of the argument that I'm not the only person comparing 1905 and 2005 in terms of the state of physics.

http://www.msnbc.msn.com/id/7327050/?GT1=6428

 

[SpaceTiger]

I must say this is a very interesting thread. Let me add a few other ideas. Sorry if I accidentally repeat anything:

- Quark stars
- Magnetic monopoles
- primordial black holes
- Oort cloud
- quantum gravity
- "ejected" planets (planets not bound to stars)
- white holes
- wormholes
- GZK cutoff (maybe resolved)
- Cosmological Neutrino Background (CNB)
- Tachyons
- Source of cosmic rays
- Intermediate Mass Black Holes (maybe seen)

 

[Billy T]

I must say this is a very interesting thread. Let me add a few other ideas. Sorry if I accidentally repeat anything:

- Quark stars
- Magnetic monopoles
- primordial black holes
- Oort cloud
- quantum gravity
- "ejected" planets (planets not bound to stars)
- white holes
- wormholes
- GZK cutoff (maybe resolved)
- Cosmological Neutrino Background (CNB)
- Tachyons
- Source of cosmic rays
- Intermediate Mass Black Holes (maybe seen)

Me too, and your's is an interesting list - thanks. I have questions about four of your items:

On Magnetic monopoles - I am confused about how heavy they are. I saw a website in google search that set floor by fact none have been produced in accelerators. That "floor" is many OM below theory predictions I have seen which tend to put the mass at least 10^15 times the proton mass. (some as high as 10^21 times!)

I have also seen site suggesting an interesting reason why they have not been seen - I.e. suggestion that even one Mag. Monopole may be so heavy and so compact that it is a black hole (some how stabilized by the magnetic field) or was a BH that long ago evaporated. A third idea (mine, but perhaps not original) is that a N & S Mag. Monopole would attract over long ranges much more rapidly than gravity assembled matter into stars and might be able to form a stable "hydrogenic like" atom. It would need to call upon quantum mechanics to escape the death spiral of radiation loss, just as the electron accelerating around the nucleus does. Any comments?

On "ejected planets" - I would bet that any planets that could slowly form from matter that did not end up in star would be in stable nearly circular orbits ad not likely to be ejected by any "sister" planets unless there were a pair of stars. Paired stars are quite common, if not more common than single stars. Perhaps two stars mutually orbiting could resonately "pump up" from a gravitation well of one a planet. So I limit my bet to the single star case. Obviously a third body on an open trajectory could gravitationally quickly eject a planet. (This is what happens to the sun's outer planets when the "dark visitor" of my book by same name passes.) Can you think of any other mechanism that can eject planets or reject my "bet" ? (I.e. claim that chaos in solar systems can eventually eject weakly bound planets of single star even though their orbits were stable long enough for difuse matter to collect into a planet.)

On tachyons - Their mass becomes infinite if they were to slow down to speed of light, so they never will or could. If one were inside our equipment's "light cone" now, at for example the left side of our light cone and headed towards the right side, I think we could get to it. I.e. we could have it and our measuring equipment at the same point in our space, but at (or very near) this common point it would only be passing thru our light cone so quickly that nothing could be measured. Is this correct? If it is, they could exist and never be observed, but like gravity "escaping" from a black hole, their gravity might be felt - could it be the "dark matter?

On Intermediate Mass Black Holes - Your comment "maybe seen" interests me greatly - what did you mean by this?

The implosion of a star large enough to have formed an iron core before imploding is, IMHO, very unlikely to be the spherically symmetric implosion always assumed for mathematical convenience. (It is quite a fine art to implode even the very uniform and small critical mass of uranium to make a A-bomb, without blowing it into pieces.)

Because only the extreme "Maxwellian tail" of the velocity distribution is energetic enough to be fusing in nuclear collisions in the active region of a star, I would think that despite what must be high thermal conductivity, some regions of the active fusing region of a star are slightly hotter than others. This would be a self amplifying instability that is only limited by the density decrease of the hotter region. This true because the fusion rate should be decreasing only quadratically with density decrease, which would be linear with the temperature increase, but the fusion rate is increasing exponentially with temperature. (I am assuming that the velocity of light is not limiting the increase of velocity, even at iron forming temperatures, but the instability effect I am tying to describe must still exist even if it is, only the strong quadratics exponential proportions I have stated would be less strong.)

Thus, I think it highly likely that some parts of the "active fusing region" get closer to the iron end point before others. If true, the implosions compressing a large and inhomogeneous mass - much harder to do than symmetrically compress a small uniform shell of uranium, and of course there is no one trying hard to make it a symmetric collapse. This is why I think that when the final implosion comes, it is very unlike to be the symmetric event assumed in most if not all models.

Since the first generation of stars (and perhaps most of the second generation too - all those that had already started to assemble) were roughly at least 100 times the solar mass, it seems to me that several of your "intermediate mass black holes" and lots of planet size chunks of iron could have separated in the blast of an asymmetric implosion.

Some "implosion pieces" and smaller BHs that formed during the implosion would would no doubt be recaptured by the larger BHs created, but if some of the "trans iron elements" that now exist were "built up" or "slow cooked" inside active stars by baryon capture, as I understand accepted theory teaches, and these atoms escaped (some are inside me now) then surely some of the larger pieces that were separated in an asymmetric and inhomogeneous implosions could also.

Thus, I think one can plausibly argue along these lines (and also noting that there were several generations of large stars before our sun was born) that there are more of your "intermediate black holes" than there are currently active stars. (A number that has been estimated to be greater than all the grains of sand on Earth's beaches!) Next paragraph provides one answer to the question: Where are they?

We should not be able to see them, unless they were close to our sun because:
(1) Their "weak quasar" radiation would not been seen, probably not even from the "night side" of a planet orbiting a star until it enters the solar wind of that star as the density in "empty" intra stellar space is so low.
(2) Even if one were to pass very close to Barnyard's star (I think that is the closest star's name) it would not be detectable or resolved from the stellar radiation, if only a few stellar masses.

This reasoning is why I assigned only 2.2 solar masses to the "dark visitor," I presumed to be now about 130 AU from the sun, still undetected, but headed our way. Any comments?

 

[SpaceTiger]

Man, Billy, you always have to make me work, don't you?

On Magnetic monopoles - I am confused about how heavy they are.

Not at all my area, unfortunately, so there's not much I can say about it. If I get around to it, I may do some more research on the subject and make a comment.

On "ejected planets" - I would bet that any planets that could slowly form from matter that did not end up in star would be in stable nearly circular orbits ad not likely to be ejected by any "sister" planets unless there were a pair of stars.

If a planet the size of Pluto were to pass close to a planet like Jupiter, it could be very easily slingshotted out of the system. This would likely only eject small planets, however, so they'd be hard to see. The longterm stability of multi-planet systems is an extremely complicated problem that is still in the process of being answered, so a more complicated analysis of your bet will have to wait.

On tachyons - Their mass becomes infinite if they were to slow down to speed of light, so they never will or could. If one were inside our equipment's "light cone" now, at for example the left side of our light cone and headed towards the right side, I think we could get to it. I.e. we could have it and our measuring equipment at the same point in our space, but at (or very near) this common point it would only be passing thru our light cone so quickly that nothing could be measured. Is this correct? If it is, they could exist and never be observed

From what I know, that all sounds right.

but like gravity "escaping" from a black hole, their gravity might be felt - could it be the "dark matter?

I don't know the answer to this question, but I suspect the answer is no. I believe that tachyons are hypothesized to have negative mass, so that would imply that they could instead be used to explain dark energy.

On Intermediate Mass Black Holes - Your comment "maybe seen" interests me greatly - what did you mean by this?

The inferred masses of Ultraluminous X-ray Sources (ULXs) are in the intermediate mass black hole range (~10⁴ solar masses). I suggest a google or ads search.

...This is why I think that when the final implosion comes, it is very unlike to be the symmetric event assumed in most if not all models.

Asymmetric supernova explosions are a popular explanation for "neutron star kicks". I believe that the popular theory right now involves acoustic pulsations in the core. Again, I suggest a search.

Thus, I think one can plausibly argue along these lines (and also noting that there were several generations of large stars before our sun was born) that there are more of your "intermediate black holes" than there are currently active stars.

This can't make up a significant component of the matter in our galaxy because of a combination of microlensing and CMB measurements.

 

[Billy T]

Man, Billy, you always have to make me work, don't you?

Did not mean for only you to try to answer my questions or make comments on ideas in my post 43. Perhaps someone can enlighten us both on mass of mag. monopole etc.

If a planet the size of Pluto were to pass close to a planet like Jupiter, it could be very easily slingshotted out of the system. ...

I knew this and of course agree, but don't think it likely that planets formed far apart as the pair you mentioned were, would ever get close. I spoke of the long planet formation period (and need for stable orbits while doing so) plus the tendency for orbits to be come circular as I think that small planets that are forming near a larger one are very likely to dissipate energy either in the still uncollected matter they formed from or by tides and end up as bound moons, not ejected planets. - just guessing - I don't know.

The inferred masses of Ultraluminous X-ray Sources (ULXs) are in the intermediate mass black hole range (~10⁴ solar masses).

We had different size black holes in mind when speaking of the "intermediate mass black hole range." I intended 5 to 50 solar masses - BHs, that might have formed from iron core star collapses, even symmetric ones. For me this is "intermediate between Hawking's "babies" and those at the center of typical galaxy. I doubt the lens effects of many 5 to 50 solar mass BH would do much we would be able to notice and continue to think the total number of them is the same OM as all the current stars (for reason stated in my last post) at least until some one offers a creditable counter argument.

Asymmetric supernova explosions are a popular explanation for "neutron star kicks". I believe that the popular theory right now involves acoustic pulsations in the core. ...

I was vaguely aware of this "neutron star kicks" -it partially caused my thoughts about the asymmetric collapse of a black hole forming star, but the "fusion instability" producing inhomogeneity in the core of a BH forming star is IMHO more important than some sound waves producing regions of temporarily different fusion rates as the pressure wave peaks passes and both heats and compresses the reacting / fusing matter.

The mechanism I suggested is a growing instability that saturates at a higher level of reaction rate, not transitory until it starts to run out of fuel. It could makes some core regions a moderately high percent iron while others are still only slightly iron. Perhaps it could even initiate a black hole collapse of only that region in a 100 solar mass star -blowing apart other still iron forming regions of the core etc. with the sudden release of a lot of gravitational energy. - Admittedly only wild ideas until someone does some numerical evaluations to show them reasonable or wrong. In first and second generation stars, where I suspect many 5 to 50 solar mass BHs may have been made, these "meganova" events are vastly greater than the nova (or even supernova of our later generation stars) - Certainly when this event is compared to the "kick" during the formation of a neutron star, it is like comparing that of a flea to that of a horse!

This can't make up a significant component of the matter in our galaxy because of a combination of microlensing and CMB measurements.

I'll take your word on this, but I was speaking of BHs of 5 to 50 solar masses, with most typical around 10, not your 10,000 solar mass ones. Does your comment still apply?

 

[SpaceTiger]

I'll take your word on this, but I was speaking of BHs of 5 to 50 solar masses, with most typical around 10, not your 10,000 solar mass ones. Does your comment still apply?

Actually, it only applies to the 5 - 50 solar mass objects, not to the 10,000 solar mass ones. I inferred that you were thinking of a different mass range at the end of your post. The black holes you're thinking of would be considered stellar-mass black holes. They're observed to exist in small numbers and are likely the explanation for "microquasar" behavior in nearby systems (like SS433).

I hope you'll take no offense if I don't try to further analyze your supernova theory. That subject is extremely complicated. Unless you're specifically referring to somebody else's work on the subject, I find it highly unlikely that your basic conceptual arguments would hold.

 

[Chronos]

I second that notion. I think it's very improbably any naive new ideas in cosmological phenomenon are likely to hold these days. The observational and theoretical constraints are just too sophisticated for anyone but a professional to properly grasp - and even then, only within a narrow range of specialization. Most of the lottery picks are taken. I think it's going to take a lot of sophisticated nibbling around the edges to usher in any new physics.

 

[turbo]

I second that notion. I think it's very improbably any naive new ideas in cosmological phenomenon are likely to hold these days. The observational and theoretical constraints are just too sophisticated for anyone but a professional to properly grasp - and even then, only within a narrow range of specialization. Most of the lottery picks are taken. I think it's going to take a lot of sophisticated nibbling around the edges to usher in any new physics.

I think that you're mistaken, here. Specialization often leads to systemic myopia. A particle physicist trying to set detection limits on the Higgs Boson is probably not the person who is best equipped to describe a model of the Universe in which the Higgs Boson is unnecessary, although I must say that Rocky Kolb seems quite open-minded about such things.

Einstein's theories started out not as mathematical representations, but as thought experiments - just the kind of logical associations that most people today would dismiss as crackpot ideas.

 

[Billy T]

I second that notion. I think it's very improbably any naive new ideas in cosmological phenomenon are likely to hold these days. The observational and theoretical constraints are just too sophisticated for anyone but a professional to properly grasp - and even then, only within a narrow range of specialization. Most of the lottery picks are taken. I think it's going to take a lot of sophisticated nibbling around the edges to usher in any new physics.

I agree with both you and spacetiger on this. It is highly improbable that I would intuitively guess (even with considerable knowledge of physics) a correct answer to such a complicated and mathematically complex (and still in early development stages) problem as the implosion of a superstar (first = "generation III") "meganova." I don't have the time, inclination or background to adequately defend my speculations.

None the less, I think it useful to point out that the assumption of a spherically symmetric meganova collapse is made out of mathematical necessity. It is not based on physics. The physics indicates just the opposite - a highly asymmetric collapse, at least as I understand it, and for the reasons I gave in prior post. (I would be please if someone can find fault with my reasons, especially the "fusion instability" reason I described.)

The current analysis, mathematically limited to the assumed symmetric collapse, is sort of like the drunk looking for his lost keys in the light under a lamp post because that is the only place where he can see, despite the fact that he thinks he lost them in the dark parking lot. Because I think this assumption of a spherically symmetric collapse high improbable, for reasons of physics given in prior posts (mainly the growing then saturating instability of the fusion rate in sub regions of the stellar core, but not limited to this), I think the current predictions, are based on a foundation that is very likely only mathematically convenient, but physically wrong. Thus some speculation, based on explained physics as I have, is justified, but one must be careful to admit, as I do, that it is only that. Not results sustained by mathematical analysis.

Changing subject, but still in a simular line of speculative suggestion, I wounder if the term "neutron star" does not belong in the same class of physics misnomers that "tidal wave" does. This thought was stimulated by ST's inclusion in his list of missing stuff "quark star."

Is there any reason to believe that the three quarks that make up neutrons would retain the same close association with each other they had when they were more widely separated, clearly a unique particle, in a nucleus after they are so tightly compressed one against another "adjacent neutron" that forces (presumbably exchange of virtual particles) are interacting between different neutrons and preventing further collapse? That is, is there some reason to believe that a quark in one neutron interacting by virtual particle exchange with the quarks of a "very adjacent" neutron would continue to only exchange virtual particles with the other two in its original neutron? (I.e. do the neutrons retain their original identity?) If the answer is "yes" each quark only interacts with its original two "sisters", then my question becomes: "What is preventing further collapse into a black hole?" ( and how does it recognize its "sister quark" from the original neutron if there is an identical quark in the "adjacent neutron" exchanging virtual particle with it to produce a force that resists further collapse? Is there some new force (not the repulsive region of the strong force) acting to prevent further collapse?

I don't know enough high energy nuclear physics to even speculate an response to these questions, but do find it at least plausible that once the the collapse has occurred and a "neutron star" has formed, that what really has formed is a "quark star." I.e. the quarks of a "quark star" no longer "belong" to a particular neutron just as the valence electrons in a metal no longer belong to any particular atom. If this is the case, then "quark star" probably should be removed from ST's list and "neutron star" added.

This is another example of where I think it is useful to use the physics one does understands to speculate about questions one can not answer. It is both interesting to do so, and may provoke someone with more knowledge to think about the questions raised. Surely this must be considered useful and appropriate here. I am NOT trying to defend baseless speculation, but speculation based on accepted physics seems to me to be both useful and fun. Would you agree?

Does anyone out there in cyberspace know enough high energy physics to comment on my speculation that "neutron stars" may really be "quark stars"?

PS by "edit" - While I was writing, Turbo -1 made his post and I think he makes a very good point. To some extent, it is the same point I was making when I noted that speculation may prompt someone with more knowledge to think about the questions raised, but Turbo-1 expressed it better than I did. To put it more poeticly - Sometimes the blind can lead the sighted.

 

[Garth]

To put it more poeticly - Sometimes the blind can lead the sighted.

In fog for example?

Garth

 

[ohwilleke]

In fog for example?

Garth

A brilliant analogy, and arguably one applicable now.

 

[wolram]

Nice to see this thread still active, i started it because i think astro phys
is in the doldrums, may be i am wrong, which is not unusual, but it seems
to me that the main stream view is some what out of explanations, and
looks to some outlandish reasons why.
It could be that a eureka moment is just around the corner but i won't
hold my breath.

 

[SpaceTiger]

i started it because i think astro phys
is in the doldrums

Astrophysics is in its prime. With cosmology, we're only just now figuring out the basic parameters of the universe. At the same time, a revolution is going in our galaxy, as we're discovering the first planets outside of the solar system. If anything, the field is progressing too fast for the small contingent of astrophysical theoretists to keep up. Professors in the physics department here are nudging their students towards astrophysics because of all the opportunities available, while things like particle physics are being discouraged.

I don't know if we're about to have a "eureka", but there is sure to be lots of excitement in the field in the next 10 - 20 years.

 

[wolram]

Space Tiger.
Astrophysics is in its prime. With cosmology, we're only just now figuring out the basic parameters of the universe. At the same time, a revolution is going in our galaxy, as we're discovering the first planets outside of the solar system. If anything, the field is progressing too fast for the small contingent of astrophysical theoretists to keep up. Professors in the physics department here are nudging their students towards astrophysics because of all the opportunities available, while things like particle physics are being discouraged.
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It gives me a warm feeling that people are being nudged toward astro phys,
also a feeling of envy, just think you may discover some new **********
that explains the U, What is the state of funding these days?

 

[SpaceTiger]

What is the state of funding these days?

Eh, not so good. The problem is that our field is mainly the pursuit of "pure knowledge", so we can't really make money for anyone or contribute to political dominance. The budget juggling at NASA has been particularly problematic because our missions keep getting cancelled.

 

[wolram]

Maybe we should start a PFs collection

 

[Billy T]

Eh, not so good. The problem is that our field is mainly the pursuit of "pure knowledge", so we can't really make money for anyone or contribute to political dominance. The budget juggling at NASA has been particularly problematic because our missions keep getting cancelled.

I would be glad to donate the proceeds from my book, but unfortunately I always tell how to read it for free so after deducting the expenses, the proceeds are negative! Perhaps you should borrow a page form it and try to scare people into doing more for astro physics. - i.e. make them worry about really possible (if improbable) astro disasters and / or enjoy astro delights.

One encouraging thing to note on this last idea is that some wonderful Hubble photos are in todays newspaper (even here in Sao Paulo!) - that may help get funding for Hubble's repair. The problem is same one I had. - How to get those that are not already interested, interested. In your case, especially the ones and groups with money. (I only wanted to get more science students.)

Percival Lowell was rich and interested in finding "planet X" so he built the observatory now named after him at Flagstaff AZ. Some how more of that money that is wasted on weapons, etc. needs to be put into pure research where at least it is not likely to do any harm. More beautiful space photos, like those in today's paper will help recruit science students too.

 

[wolram]

why does politics have to infringe on science, it is neither one nor the other
science should be divorced from politics, it may be advantageous to let a fight
b in politics, but in science every one should be united.

 

[Billy T]

why does politics have to infringe on science, it is neither one nor the other
science should be divorced from politics, it may be advantageous to let a fight
b in politics, but in science every one should be united.

the answer in a word is: MONEY.

But this reminds me of an old university joke - The university administrator was complaining to the physics dept director: "Every year you ask for more money! Why can't you be more like the math department. - All they ever ask for is paper, pencils and trash baskets, or better yet be like the philosophy department - they publish everything they write and don't even need the trash baskets."

 

[turbo]

why does politics have to infringe on science, it is neither one nor the other
science should be divorced from politics, it may be advantageous to let a fight
b in politics, but in science every one should be united.

In an ideal world, maybe everyone in science would be united and working toward a common goal, BUT there is the little matter of funding. Major sources of funding originate in the public sector. Scientists, or perhaps more properly, the directors and administrators of the programs the scientists work in, fight turf wars to establish their programs as "worthy" and obtain funding. They regard this funding as a limited resource that must be battled over, and the "concordance view" researchers tend to get the lion's share of the funding. They often can and do wield political leverage in pursuit of funding, bringing politics and ideology into the mix.

For example, stem cell research has shown some promise in combating diseases arising from genetic deficiencies and may perhaps help slow, halt, or even reverse neurological damage resulting from injuries or diseases. The US government is presently dominated by the Republican party, which is heavily indebted (politically) to right-wing Christian fundamentalists. These people usually link any discussion on stem-cell research to abortion, and some hold views that ANY viable human life at any stage of development (even extending to uncombined sperm and eggs) is exactly equivalent to a living breathing human. Under these circumstances, political pressures will make it nearly impossible for stem-cell researchers to gain public funding in the US. I do not bring this up to take one side or the other, or to inject any political view into the mix, but to illustrate that politics is a powerful force that can derail any scientific endeavor, no matter how lofty the goals. If scientists are unwilling or unable to sway the Luddites and the creationists, etc, we will continue to be hampered by their political influence. Has anybody noticed the nice new Hubble Telescope pictures being circulated these past few days? John Q. Public is being courted heavily to keep HST alive. I hope it works. HST can do things that no ground-based scope can do, and Webb can only compliment it, not replace it. Write to your representatives in Congress. A few thousand well-expressed letters, including letters to your local newspapers, can do more good than you may realize. Rant mode OFF.

 

[Chronos]

I think that you're mistaken, here. Specialization often leads to systemic myopia. A particle physicist trying to set detection limits on the Higgs Boson is probably not the person who is best equipped to describe a model of the Universe in which the Higgs Boson is unnecessary, although I must say that Rocky Kolb seems quite open-minded about such things.

Huh? Do you have a study in mind that supports your assertion that specialization often leads to systemic myopia? That sounds like an unsupported, sweeping generalization. I hear cowbells ringing.

Einstein's theories started out not as mathematical representations, but as thought experiments - just the kind of logical associations that most people today would dismiss as crackpot ideas.

Oh please, that is absurd.

 

[turbo]

Huh? Do you have a study in mind that supports your assertion that specialization often leads to systemic myopia? That sounds like an unsupported, sweeping generalization.

Do you need a peer-reviewed paper to convince you that overspecialization leads to systemic myopia? I urge you to look at the medical field for an equivalent example. Generalists are in terribly short supply, especially in rural areas where they are most needed. Specialists can make a ton of money, especially if they enter fields like ophtalmology, cardiology, neurology, etc, so specialists abound, and small towns cry out for competent family doctors.

Oh please, that is absurd.

You should read about Einstein a bit. His theories started as gedankenexperimenten (thought experiments), generally as a first step toward simplifying a problem or explaining something illogical under existing physics. The mathematical modeling came later. If you have any source that explains how Einstein was playing with math problems and stumbled across SR, GR, or the photoelectric effect, please post them here. That's not how he worked.

 

[Billy T]

...You should read about Einstein a bit. His theories started as gedankenexperimenten (thought experiments), generally as a first step toward simplifying a problem or explaining something illogical under existing physics. The mathematical modeling came later. If you have any source that explains how Einstein was playing with math problems and stumbled across SR, GR, or the photoelectric effect, please post them here. That's not how he worked.

I can't agree with Chronos that your statement is absurd, but it certainly is overly broad.

Einstein, like most of us, worked in various ways. For example his now little read, but very important, at least at the time(1905) paper on Brownian motion was (as I understand it) motivated by the following mystery.

The velocity of the Brownian motion became slower the more accurately you measured it. (as they though at the time about how you should measure accurately - i.e. use more time difference between start and stop times to reduce % error in measurements of time difference and displacment.) Yet the Brownian movement never stopped!

You also must realize that in 1905, the continuum theory of matter was much more widely accepted than the atomic concept - hard to believe now that five years olds speak of atoms, but back then few physicists thought atoms much more than a strange speculation. Assume a small one existed, why could you not cut it in half and make two even smaller ones? - surely the reason had only to due with how sharp you could make your knife.

Einstein not only exhibited that random motion would indeed slow down (the accumulated displacement being proportional to the square root of the time difference) but also predicted how the density gradient of pollen grains (Brown was a biologist) in the vertical direction of the fluid would vary if the motion was the result of random collisions with particles too small to be seen (what we now call atoms).

He was not very important yet so it took several years of difficult experimental work by a French team (sorry but can't recall their names) to experimentally confirm this predicted density variation. Only after the French results confirmed E's predictions, did the physics community beginning to think that atoms might be indivisible.

Not to be too long in this post, I also quickly note that the classical idea of "equal partition of energy" and fact that no shortest wavelength exists in Maxwell's EM equations, lead to what was called the "ultraviolet castrophy" - catastrophic failure of classic physics to explain the fall off of radiation coming from a small hole in an isothermal cavity (a practical version of a Black body, even today). Again as I understand it, Plank had the experimental curve that now bears his name, and was "playing around" with math tyring to see how it could be fit when he found he could do so by quantizing (for no gedankenexperimenten reasons) the number of radiation states. Certainly Einstein used the gedankenexperimenten appproch, but not it alone.

 

[wolram]

Have made an attemt to understand pop 111 stars, it seems to me that
if they exist, then there should not be any conditions in our universe that
is time dependant for these things to form, ie if solar mass is a limiting
factor now why would it be different at an earlier stage of the Us
formation, it seems to me that gravity is a constant that is beyond doubt.

 

[Billy T]

Have made an attemt to understand pop 111 stars, it seems to me that
if they exist, then there should not be any conditions in our universe that
is time dependant for these things to form, ie if solar mass is a limiting
factor now why would it be different at an earlier stage of the Us
formation, it seems to me that gravity is a constant that is beyond doubt.

Not sure I understand your question and others such as Spacetiger can give you more informed infro, but there are a few comments that may be helpful I can make:

When the first stars began to form, the universe volume was about 35 times smaller and of course no stars had converted hydrogen into other elements, so the gas clouds, when they had cooled enough to let gravity collect them into smaller subregions, converted their potential energy into velocity/thermal energy as the gas mutually fell down the potential well it was forming.

The temperature required for these masses (much larger that the sun by factor of approximately 100), which were assembling from only Hydrogen (and a little helium) to fuse the hydrogen was essentially the same as it is today and far above that required to ionize all the then existing atoms completely. Fully ionized material does not radiate well compared to the radiation form transitions between states of bound electrons.

These large stars ran thru their life cycles quickly compared to the sun. When they died most, if not all, left black holes behind but what is important for your question is the tremendous gravitational energy released by a large mass collapsing into a BH, not the BH itself. What I like to call "meganova" event, as contrasted to the supernovas of this latter stage of the universe, It blasted shock waves thru the outer parts of the dying star of such force that all the elements with greater atomic numbers than iron could form in the collisions of lesser element nuclei. (iron itself and lesser atomic number element nuclei were formed in successive fusing stages inside the star before the meganova event {and a little "trans iron" also but you can forget about it.})

The subsequent generations of stars thus could form from gas clouds that contained many different atomic number atoms, not all completely ionized a few thousand (?) years (or less) after the meganova event that formed them. As these later "want to be" stars began to condense into smaller space under their mutual gravity, intense radiation began to be emitted from those partially ionized atoms. This did not happen in the formation of first generation stars that were assembling only from hydrogen and helium to any comparable degree as these two element are much easier to full ionized than the "trans iron" elements with many electrons.

I caution you now that I am less sure about how it works in detail, but the general idea is that this radiation exerts a pressure on the more distant gas of the cloud that would otherwise have also fallen into the forming star, blowing it away. Consequently, the second and later generations stars, as you suggest have the same gravity acting, but counter balancing it is this radiation pressure that at some radius in some stage of the contraction exceeds the gravity. Both the gravity and radiation fall off as inverse square so this radius may not be too well defined, but the effect of it is to limit the total mass of the star that can form to much lower value than could form before these "trans iron" elements existed.

I hope ST, or others, better versed than I am, will correct my errors, but at least you now have the general picture and an answer to your questions. If you alread knew most of this, please take no offense - others who may know less may have benfited.

 

[SpaceTiger]

if solar mass is a limiting
factor now why would it be different at an earlier stage of the Us
formation, it seems to me that gravity is a constant that is beyond doubt.

Gravity is assumed to be constant, but as Billy T said, there would be fewer "metals" (elements heavier than helium) in the primordial gas. The reasons they expect this to lead to massive stars are fairly complicated, but can be summarized as follows:

1) The size of the star is determined by the scale on which the initial molecular cloud fragments. The initial molecular clouds will be composed only of H₂, so the scale on which they fragment will be determined by the properties of this molecule. This molecule is a less effective coolant than, for example, CO, so the cloud will fragment on a larger scale. This leads to more massive stars.
2) Once the stars are formed, their opacities (their tendency to absorb radiation) are decreased by the fact that dust can't be formed in the atmosphere. Decreased opacity means decreased mass loss (as in stellar winds), which means that the star can maintain its initially large mass.

There is still some debate as to whether all Pop III stars must be massive. This is important because subsolar mass Pop III stars would still be around in the present day. If no such stars are formed, it would be no surprise that we don't observe them in the local universe.

 

[Chronos]

There are no pop III stars around today because the ISM is heavily polluted with metals. We need to work on that problem first.

 

[wolram]

Thanks for replies, BILLY T, SPACE TIGER.

Sorry to jump around from subject to subject, but the existence of
magnetic monopoles was mentioned, if anyone wants to flick through
a few papers try this.
http://www.google.co.uk/search?hl=en&lr=&q=+site:arxiv.org+magnetic+monopoles+2005

 

[wolram]

There are no pop III stars around today because the ISM is heavily polluted with metals. We need to work on that problem first.

Another difficult problem Chronos, this paper is 81 pages and recent
http://xxx.lanl.gov/PS_cache/astro-ph/pdf/0504/0504193.pdf

It seems that galactocentric distance could be more important than
age for metal abundances.

 

[Chronos]

Agreed. That is a good read. It took some time to load and read [I'm on dial up]. Thanks for that one. I like your references, they are solid.