So much for that theory...

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I'm not trying to refute the entirety of your post...however...

Any correlation between the shrinking of intra-atomic space and the overall density of the black hole is false. Atoms of stars have no electrons. There is an energy threshold called ionization energy. After this energy stage is reached, as in our own sun for example (well below black hole energy states), the electrons are "burned" off and sent into space. I believe (although I am not certain) this is the major component of the solar winds.

 

Wow, I mentioned "point singularity" and look at where this thread leads...

Anyway, as a chemist, I have a very hard time buying the "infinite mass" theory. To me, all matter is composed of atoms. I can believe that such matter is compacted in such a manner as to overcome the barriers (electron clouds) that keep atoms separated. In such a scenario, you could reduce the volume of a given object by several tens of thousands, even millions of fold. However, to me, even if we are only speaking of the nuclei of the atoms, it seems to me that tens of billions of tons of matter would still take up a very measurable volume. Sure, you could have a star that was initially millions of kilometers in diameter contract to a size of just a few meters across, but that's still a finite volume.

On a side note, I don't see how it is possible for a star to be devoid of electons as LNT states. Certainly, the heat from the sun would be sufficent to provide the activation energy of pulling electrons from atoms, and the creation of free-radicals a plenty would occur. However, stars are fusion chambers. They start off as just hydrogen, which fuse to create a helium. A helium can fuse with a hydrogen to from lithium, or two heliums could fuse to form a boron. It is in this way that all the matter in the universe is produced. However, in the examples I have provided above, we are talking about very small atoms, with relatively small proton cores. These atoms are routinely found to exist in nature without some or all of thier electrons. Hydrogen is commonly found without any electrons, He2+1 is commonly found as is Li+1 and B+2. However, as you get to bigger and bigger atoms, it is increasingly easy to lose one or two electrons, but increasingly difficult to lose ALL of the electrons. For example, gold (Au) in its stable state has 79 protons and 79 electrons. Isomers of gold with 79 protons and 78 elctrons (Au+1) are common, however there is no mechanism known (even extreme heat) that would cause gold to lose ALL 79 electrons. I know this whole discussion is a bit off topic, but a star composed of countless atoms and at the same time being completely devoid of electrons seems a little far-fetched to me.

 

Well Aldeth, you are right to point out that a star will not lose ALL it's electrons...but what percent of the mass of a star is hydrogen? What percent is helium? In fact, the entire visible mass of the universe is 90% hydrogen and 9% helium. That's right...the universe. I would assume stars are similar...particulary at formation.

What is the ionization energy of hydrogen and helium? According to my chemistry book...1312 kJ/mole for H and 2372 kJ/mole for He. Lets cross-reference with fusion energies...damn...I don't have those in this book. Well you get the idea. Although I don't have the data...sigh...I'm pretty sure the fusion threshold is well above the ionization threshold.

Also...and this is where I am completely wandering off into my own theories which have no substance in experiment (since I have done none, heh)...has anyone ever measured the diameter of a proton? And not in the indirect sense...? Outside of electro-magnetic repulsion, is there any such thing as "mass" other than the effect of gravity? Just because two things seem to bounce off one another does not mean that is the case at the smallest scale. Assuming that atoms have definite borders may be an error Aldeth.


EDIT

BTW I am loving the Quick Reply! Good move Tal.

 

Late-night thinker is somewhat right if i remember my Physic (which I don't). as far as i remember the Sun (ours) starts out consisting of H and Isotopes H^2 and H^3 (referring to the numbers of how man neutrons there is in the core). the energi from the sun comes from H losing there electron and there by becoming H+(protons), but as far as I remember does protons, electrons and H(or one of its Isotopes) fuses and creates He Which then continues the process, until some point, I thinks it when it becomes Iron, at some point it will then go Red Giant.

 

This is correct. Stars at formation are nearly entirely hydrogen. I'd guess even more than the 90% you suggest. However, all known elements are produced through fusion in stars across the universe. So elements like aluminum, iron, gold, and even uranium are all formed through fusion. Obviously, as you get to the larger elements they are present in far smaller quantities than the smaller elements, as they require many more steps of fusion to create.

All I'm saying is that for the bigger elements, all will have many electrons. Let's take another example. Iron is present in almost all but the very youngest of stars. So what kind of ions do we see for Fe? Fe+1, Fe+2 and Fe+3 are all fairly common. How common is Fe+26? Don't forget every time you take away an electron the remaining electrons are held more tightly. So the ionization energy goes up every time you take away one more, and increases exponentially once you're talking about a bunch of them, especially penetrating another shell.

I do not doubt that the extreme energy in the sun would be able to fuel many ionization reactions. The only problem I have is of the solid matter in the universe (granted that's only around 1% of the total mass) it is common for many electrons to be present. So, unless there is a mechanism for matter to pick up additional electrons by chance following a supernova, the heavier atoms MUST have electrons while in the star.

 

yeah found a like that says the same that I said earlyer about the sound (wow I could remember something from physic)

The Sun's energy output (3.86e33 ergs/second or 386 billion billion megawatts) is produced by nuclear fusion reactions. Each second about 700,000,000 tons of hydrogen are converted to about 695,000,000 tons of helium and 5,000,000 tons (=3.86e33 ergs) of energy in the form of gamma rays. As it travels out toward the surface, the energy is continuously absorbed and re-emitted at lower and lower temperatures so that by the time it reaches the surface, it is primarily visible light. For the last 20% of the way to the surface the energy is carried more by convection than by radiation.

http://www.nineplanets.org/sol.html

 

Interesting. I, for a change, am a physicist – although General Relativity and Astrophysics is not my field of work. Still – it should be possible to add some information to this thread.

On suns and stars (simplified): We start with Interstellar Matter (Gas, Giant Molecular Clouds, …). Almost all of this will be hydrogen – although recent observations hint at amounts of up to 1% of carbon and other “heavy” atoms. Contraction of this matter forms a “protostar”. This is a cold object that doesn’t emit much. The contraction will go on until the gas is completely ionized plasma (not difficult: no iron at this stage ).

At some point the nuclear fusion will kick in, burning the hydrogen to helium (in what is called the pp-chain, proton-proton-chain): a star is born. For most of the time there are no heavy elements involved whatsoever. The star is called a ZAMS (Zero-Age-Main-Sequence-Star) at this point. The sun is such a star on its main sequence. There are electrons inside, however none in bound states and none in the core. Hence, when the elements fuse they already are without electrons, it is not necessary to strip them away from the atom cores.

The ratio of hydrogen to the products of the fusion will become more and more unfavourable for the pp-chain. The helium core will shrink; the surface of the star will expand: we have a red giant. Very soon now the burning of helium will begin (around 100,000,000° Kelvin) in the core, while in outer regions hydrogen is still fusing.

The star will afterwards reach something like a final state which depends on its mass. At the end of the CNO-cycle (carbon, oxygen and nitrogen are formed) our sun will become a white dwarf with only half its former mass. In bigger stars iron is created. Only super massive stars ending in a Supernova have the potential to create the really heavy elements up to uranium.

As the matter cools down after the end of the fusion processes, the atom cores will catch the remaining electrons and form electrically neutral isotopes.

Like I said – this abstract is highly simplified. Feel free to pm me if you are interested in de-tails (hopefully none of you is – it isn’t that fascinating anyway…).

Conclusion: for most of their lives stars don’t consist of many heavy atoms. And the atoms present are ionized (= without their electrons).

Next, where is this all related to black holes? Well, nowhere. Really. We don’t know yet what lies behind the event horizon. We have to be careful to distinguish between the theoretical side of the problem and how we lie to each other when we try to explain complicated things. Well, not exactly “lie”, but something close to that: every picture one uses to make a big idea fit into one small mind has to simplify matters somewhere. Knowingly. (Courtesy to Terry Pratchett’s “The Globe”)

What we call “black hole” (since 1967, 51 years after their theoretical “birth”) is basically a solution to the central equation of the General Theory of Relativity (GTR), Einstein’s Field Equations. These are ten nonlinear and coupled partial differential equations (for those of you who like it the hard way ) connecting the curved space-time to energy and mass. Highly complicated stuff. Einstein was therefore astonished when a guy called Schwarzschild came up with a first solution in 1916, only one year after the equations had been made public. This solution is static, spherical, and introduces the event horizon with the singularity inside al-ready addressed. Because of this solution we tend to think about black holes the way we do (cf. the above).

Additional solutions and generalizations of the static Schwarzschild-solution have been found, all with the same basic implications. Till this day, it is not even clear if the GTR is valid beyond the event horizon, because of quantum. Hence, people took into account quantum effects near the event horizon, which e.g. led Hawking to his proposition of the Hawking ra-diation.

(Side note: The main problem manifesting itself here is that there isn’t a unified theory for all four fundamental forces (gravitation, electro magnetism, weak and strong). Three of them have been tamed, but gravitation withstands all efforts to be incorporated into the other uni-fied forces. Einstein shed some tears about this. String Theory has made a good effort, but experimental verification is still missing. Besides, some implications of this theory really are beyond what would normally be tolerable, even amongst the weirdoes theoretical physicists normally are…)

Because of quantum mechanics (and what quantum mechanics has to say about information and its preservation), Hawking withdrew his theory of the parallel universe and offers now the explanation given in the article above. No time travel through wormholes, it seems.

But this is just an interpretation of the attributes of a black hole. What about the problem of infinite density? Hm. No one can imagine something packed into one point in space – hell, no one can even imagine one single point! Some highly respected scientists follow the mathe-matical implications of the field equations and just work with the singularities therein without trying to explain them. Other scientists, equally high in respect, expect a valid theory to be beautiful and aesthetically appealing. They argue that ugly outgrowths like singularities al-ways are indicators for the incompleteness of a theory.

There approaches that don’t lead to singularities when explaining black holes, namely the ones stemming from the String Theory. The objects proposed are similar in aspect, have all the necessary attributes of black holes and are called “holostars”. Unfortunately, string theory is not verified experimentally yet – GTR, on the other hand, is…

Last, for Spellbound: Your picture of a splashing rock is not that bad. Although an implosion leads to the creation of the black hole, there still is an explosion: a “shockwave” is running inwards with the collapsing matter, is reflected by the ultra dense core, and is then racing out in to the void. God of Thunder.

 

Thanks Darkthrone. I have a much better understanding of the situation now. I had not realized that most stars consist of nearly entirely hydrogen and helium for nearly their entire lives, and don't start producing heavier atoms until much later. Given that we're talking small atoms, it's also pretty easy to ionize such atoms as well (hydrogen is ridiculously easy to ionize for example). Helieum is still pretty tough compared to hydrogen, especially the second electron.

One more question Darkthrone:

Where did the other half of the mass go?

Also, in the case of red giants, are they simply much less dense versions of the old star? It seems if a star swells to many, many times it's original volume, it would become progressively less dense.

 

Black holes have fascinated people ever since theeir first postulation back in the before time (If I were hard pressed, I would say that Einstein first theorized them, but really, I have no idea!) These warpings of space have inspired some really funky science fiction stories and one of the worst Disney movies ever, not to mention all sorts of theorizing, bad jokes, and sophomoric allusions.

All that aside, though, I like the human element here. Hawking was willing to stand by his guns when he believed he was right, even though many other people in the scientific community disagreed with him. When he was confronted by data that made him realize he was wrong, he stood up and admitted it publicly. Now that's class and style that everyone should try to live up to.

 

A small portion of the mass is blown away into space by what is called solar wind. This consists of electrons, protons, neutrinos and stuff. However, most of the mass is transformed into energy through the fusion process itself. Fusion is an exothermatic process (for all elements up to iron) because the mass of the newly created atom is always smaller than the sum of the masses of the starting atoms. The difference in the masses before and after the fusion goes into the creation of photons. These reach the outer regions of the star after some 10,000 years (after being repeatedly reflected, absorbed and reemitted) and are sent into space as heat, light, and other forms of radiation.

As to the other question: the mass is of the star is never spread homogenously over the object. There is a hot core where the thermonuclear fusion happens (therefore most of the helium is in there) and we have a shell of lighter atoms (hydrogen). The whole star is in a hydrostatical equilibrium which changes over time because of the lost mass and changed gas pressure inside. The dense core shrinks and grows hotter - until the temperature for the burning of helium is reached. The outer shell swells and becomes indeed less dense than before - the temperature sinks (hence the spectral change to the red) and becomes constant at the surface when the new hydrostatical equilibrium is reached.

Ah, I did it again. Too many words where two small sentences would have sufficed. Alas, vanity is one of the pillars of the scientific community. The good Lord Keldin is right: you can't overestimate what Hawking has done in calling back his own theory... you don't see that too often in science. Some people even die with the knowledge of their theory being wrong - still defending every bit of it for dear life.

Edit: Interestingly enough, the first mention of black holes can be traced to the priest John Michell (1724 - 1793). He wrote in 1783 to the Royal Society "If the semi-diameter of a sphere of the same density as the Sun in the proportion of five hundred to one, and by supposing light to be attracted by the same force in proportion to its mass with other bodies, all light emitted from such a body would be made to return towards it, by its own proper gravity." Keen thinking, eh? Einstein had no real business with black holes, Schwarzschild found them in Einstein's theory. Until 1967 they where called "frozen stars" in the eastern hemisphere and "collapsed star" in the west. John Archibald Wheeler came up with the (PR wise) better name black holes.

 

I think these theories and field of expertise are very interesting. I'm far from a specialist on that field, but I'm intriguiged non the less.

I read this article about Hawkings new theorie around black holes.

http://www.guardian.co.uk/uk_news/story/0,3604,1266356,00.html

 

A couple questions for Darkthrone (I hope he enjoys explaining his field )...

OK...first off...I have come across a fact relating to relativity in a couple books but have not found an explanation I can understand. The speed of light is constant whether an object is traveling towards the source or away from it. I am fairly certain the solution has to do with the lack of absolute time as Einstein discovered. But that is as far as my understanding goes.... Is this something you could explain and if not, perhaps you could point me in the right direction? Are there any good physics books which actually go into the ugly details?

Secondly, do you know of any good books that explain electro-magnetism? Also, perhaps one which relates electro-magnetism to light.

I get the feeling I may just have to buy an expensive physics manual from a university...