Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: macrocosmos on 20/09/2007 09:38:37
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Firstly Hi, I am new to the board so please try and be tolerant.
I have been reading various articles and I am somewhat confused?
To the best of my knowledge all of the planets in our system where created during the formation of the Solar body we call the Sun.
As the Sun formed and attempted to achieve a relatively stable fusion process it may have expanded and contracted a number of times (at least eight times) and expelled protoplasmic matter into the cloud of matter that Sun itself is formed from.
This Protoplasmic expulsion of solar matter as it travelled through the matter, energy and gas cloud accumulated additional mass.
Now the composition of that cloud would have changed dramatically as each cosmic hiccough consumed the available matter, energy, gas and all of the primary states would have been involved: Plasma, Gas, Liquid, Solid ,Transition and therefore the composition of the planets formed out of that process and the available components would differ very much as our planets differ.
This is not difficult to understand so is there a different explanation I know nothing about?
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Macrocosmos you are clearly very confused where did you find the information about plantary formation you have described because the nomenclature and processes do not match current theories.
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This topic has been split ,with the removed section being placed in the New Theories section.Unfortunately some of the posts needed to be deleted or edited in order for the remaining to make sense.
It would now be helpful if someone could answer or post a link to the original question using something which is based on current scientific theory.
If anyone has any problems with what i have done then please PM me or post a reply here.
http://www.thenakedscientists.com/forum/index.php?board=3.0
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This is a precis of star and planet formation as currently understood and this model is well supported by a wide range of scientific evidence including observations of stars and planetary systems in the process of formation and deep time evidence from observations of the earth and other planets and asteroids in the solar system.
Stars form by the slow collapse of large cool clouds of gas and dust under their own gravitation. Because these clouds have usually originated from the explosions of other stars as supernovae they are often turbulent on a very large scale so the clouds contain significant quantities of angular momentum and as the cloud contracts it begins to rotate.
Angular momentum (rotation) like energy is always conserved so as the cloud contracts the rotation speeds up. This is a bit like the process where the water going down the plughole of an initially quite still bath eventually forms a rapidly rotating vortex.
This rotation of the cloud means that it is often not possible to form a star without the cloud losing this angular momentum in some way. One of the ways this may be done is for the cloud to split into several pieces and form several stars in a binary or multiple star system and very many stars are like this. Another way is for the star to form a planetary system like our sun. If all the planets and their mass and angular momentum were suddenly dumped into the sun the mass would not have a great deal of effect on the sun but the angular momentum would be so great that the sun would be rotating too fast to be stable.
The process for the formation of the planets is that during the collapse the rotating cloud goes from a spherical blob to a disc and then condensations "planetesimals" form in this disc These then gradually coalesce into a planetary system an over time planets migrate to areas where there respective orbits allow long term stability. Initially the solar system with its ordered almost circular orbits was our only example but recent observations of exoplanets with a wide range of orbit types suggest that there may be several types of planetary systems.
The nature of the planets that condense out of the cloud is likely to be dependant on their distance from the primary star with planets close to the star being mainly rocky because light elements like hydrogen and helium have been driven from them by the heat of the star and those far out and cooler containing more volatile elements. It is also quite likely that one planet will be much larger than all the others (like Jupiter in our solar system)and dominate the others by its gravitational effects. large planets that can retain hydrogen and helium are called gas giants. Sometimes it appears that during the formation of the system these planets can migrate to be quite close to the primary star. We have seen a lot of systems like this because large planets that are close to their parent star are the easiest sort to detect. As yet it is still not quieter possible to detect earth like planets but in a few years when improved techniques become available this will be possible ant hen we will learn a lot more about the nature and origin of planetary systems.
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Cheers Ian
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Planetary formation part 2 The basic composition of the clouds from which the stars condense is mostly hydrogen and helium with a small quantity of a wide range of heavy elements that have come from the gas and dust blown of from ageing stars novae and supernovae The oldest stars contain very little heavy metals. the heavy metals are in the form of dust grains coated with ice but they probably have quite a wide range of different composition depending on their sources. It would be very interesting to get some Oort cloud material before it has been exposed to the high temperatures of the inner solar system and examine it in detail to see its fine structure. The initial process of condensation of the material in the cloud from isolated atoms to small clumps to grains has already taken place over many millions of yearsThe star formation process once it is initiated (probably by a shock wave from a nearby supernova compressing the cloud a bit. To condense the cloud has to be quite cool. The collisions of the hydrogen and helium atoms with the grains and their subsequent radiation of long wave infra red radiation is the critical process that allows this to happen. the grains are slower moving and can stick together more easily than the hydrogen and helium and these probably form the first structures that gain enough mass to pull things together gravitationally and form planetesimals. The reason the disc forms is that it is easier to collapse along the line of the axis of the cloud than across it and the disk then tends to hold itself to gether gravitationally.
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To be honest this seems a little to pat and seems very cosy, is this based on hard data? or is it based on theoretical supposition? a star has to have a certain density to guarantee its gravitational mass, are you saying that a fusion process based on hydrogen/helium would create sufficient mass to produce a sol type gravity field or sufficient mass to collapse to a neutron state or singular state
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The sound of a penny hitting the bottom of the bucket.
I have been wracking my poor old brain to try and remember where I heard this explanation before.
This was first postulated by Swedenborg and then taken on-board by Kant.
A 260 years old hypothesis based on an ordered view of the Universe, still unproven by hard data.
why would you present this as if it were fact?
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To be honest this seems a little to pat and seems very cosy, is this based on hard data? or is it based on theoretical supposition?
Yes it is based on hard data, and yes it is based on theoretical supposition. Curiously that is how science works.
We have a wealth of observational data that ranges all the way from GMCs (Giant Molecular Clouds) through to other solar systems. We can witness each stage in the formation of stars and new planetary systems and these observations match the theoretical postulates - hardly surprising since the theory is based upon the observations.
We know the compositions of the stars, of the GMCs,of accretion discs. We can determine, with FEA type software, the dynamics of such clouds, witness their collapse into disces, and their assembly into planets and protoplanets.
There is still a lot of detailed, and exciting, work to do in this field, but the basics are well understood and accepted.a star has to have a certain density to guarantee its gravitational mass, are you saying that a fusion process based on hydrogen/helium would create sufficient mass to produce a sol type gravity field or sufficient mass to collapse to a neutron state or singular state
Why would any of us say that? The fusion process does not create the gravity field. The collapsing cloud of gas and dust provides the gravity field. Stars of solar mass do not collapse to neutron stars or balck holes.
You go on to say:
"I have been wracking my poor old brain to try and remember where I heard this explanation before.
This was first postulated by Swedenborg and then taken on-board by Kant.
A 260 years old hypothesis based on an ordered view of the Universe, still unproven by hard data."
The theory has changed greatly in detail since Kant and Laplace played with it. We are still using many of Newton's findings every day, so being 260 years old is not automatically a weakness.
You also ask:
" why would you present this as if it were fact?"
Largely because, in scientific terms, it is a fact. The theory, at the risk of being boringly repetitive, is well validated by observation and by simulation. No other theory offers anything like the answers to detailed questions that this one does. It's close to as solid as plate tectonics as bing factual.
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The processes involved in the formation and functioning of normal stars and planets are pretty well understood and backed up by laboratory experiments and a vast amount of observational evidence. In many cases the same information can be obtained by different and independant experimental techniques,
The composition and density of interstellar material can easily be found by its spectrum in visible light infra red and radio observations.
The behaviour of hydrogen and helium gas contracting under gravity is analysable by experiment and predictable from the kinetic theory of gases.
The nuclear reactions that happen in the centre of stars were observed in detail many years ago using accelerator experiments and some of them have been tested in both thermonuclear weapons and fusion experiments like JET.
The nucleosyntheses that created the primordial mix of hydrogen, helium and a few other light elements fits the big bang model very well.
Putting this together creates a model for stars of different masses with temperatures and brightnesses.
The colour, brightness and life cycle of a star is purely determined by the mass of material that it contains and nothing else. (there are some slight adgustments for stars that contain very few "metals" because the formed from clean primordial big bang materials)
This exactly fits the observational evidence from the main sequence of stars this was first observed using spectroscopic analysis of stars in both open and globular clusters and have been confirmed accurately by many the measurement of accurate distances using parallax via the Hipparchos satellite. This now means that the spectral type of a star will accurately indicate its size brightness and distance and in many cases its approximate age.
There are some cases where there is mass transfer bettween binaries and short term states in very large stars these need more study.
A good book to read on the subject is Astronomy A physical Perspective by Marc l. Kutner
ISBN 0 521 52927 1
This is not complacency just very good and very painstaking science involving thousands of man years of work.
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I have no problem with the initial formation of a Star , However planetary formation is not cut and dried otherwise there would not be several differing theories and collisional aggregation has not been pr oven as viable, if you bang rocks together you get a larger quantity of smaller rocks, I also understand that the initial energy to start the whole process may come from an external source, however the initial kick start to the whole processing of universal formation is still in doubt and the source of that initial energy is not pr oven and is still conjecture.
Our planet has a hot core collisional aggregation does not explain this.
Please amplify.
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A few more moments in a very busy schedule.
For ophiolite
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I always admire certainty in an uncertain universe I am pleased that you feel that you know all that you need to know.
I was under the impression that science was fluidic rather than static thank you for correcting this.
I would of course direct your attention to the March edition of the journal of science and to the article that deals with the current estimation of the planets core temperature.
I ave not had as yet time to calculate the Entropic ramifications of this new estimate, but I will Get back to you.
As to the scientific method
Quote Common Mistakes in Applying the Scientific Method
As the scientific method attempts to minimize the influence of the scientist's bias on the outcome of an experiment. That is, when testing an hypothesis or a theory, the scientist may have a preference for one outcome or another, and it is important that this preference not bias the results or their interpretation. The most fundamental error is to mistake the hypothesis for an explanation of a phenomenon, without performing experimental tests. Sometimes "common sense" and "logic" tempt us into believing that no test is needed. There are numerous examples of this, dating from the Greek philosophers to the present day.
Another common mistake is to ignore or rule out data which do not support the hypothesis. Ideally, the experimenter is open to the possibility that the hypothesis is correct or incorrect. Sometimes, however, a scientist may have a strong belief that the hypothesis is true (or false), or feels internal or external pressure to get a specific result. In that case, there may be a psychological tendency to find "something wrong", such as systematic effects, with data which do not support the scientist's expectations, while data which do agree with those expectations may not be checked as carefully. The lesson is that all data must be handled in the same way.
Another common mistake arises from the failure to estimate quantitatively systematic errors (and all errors). There are many examples of discoveries which were missed by experimenters whose data contained a new phenomenon, but who explained it away as a systematic background. Conversely, there are many examples of alleged "new discoveries" which later proved to be due to systematic errors not accounted for by the "discoverers."
In a field where there is active experimentation and open communication among members of the scientific community, the biases of individuals or groups may cancel out, because experimental tests are repeated by different scientists who may have different biases. In addition, different types of experimental setups have different sources of systematic errors.
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The hot core of our planet is largely be explained by the energy released by the residual radioactivity in the rocks. The energy of formation of the planet was enough to melt it and cause the layers to differentiate but most of that has been lost into space by radiation.
I agree that one needs to have an open mind to new ideas but just having a different idea and saying that is not enough you have to take this idea and add a lot of detail to show clearly how this idea fits the available evidence better than the current idea and propose and conduct if possible experiments or observations that will prove your idea.
Mistakes can be made and good things missed but this in my extensive experience is very rare. it is important also to understand fully the current theory too because you may find that the effect of your idea has already been included as a minor or significant part of the theory.
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Than you Soul Surfer I do not enjoy being shouted at by anyone in reality my physical appearance tends to deter that sort of behaviour.
Just one small thing further.
I feel that it is being implied that during the formation of a Star it is the sort of event that you could invite an elderly relative to watch, have a game of bowls and a cream tea while the star formed.
I on the other hand have formed the impression that it is violent and nasty and that during the formation process a lot of matter is ejected so that rotational stability can be achieved and that as this ejected matter accreted further mass and forms a cooler surface which insulates the hotter ejaculate the gravity from these planetesimals slows the rotation of the primary, of course i am always open to definitive proof
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Planetary formation is clearly a complex process and there are probably several effects related to the creation and disruption of condensations within an accretion disc surrounding a forming star. I am quite happy to entertain several theories simultaneously and expect that the type of planetary system that is formed will depend on several things notably
The initial composition of the cloud ie amount of dust and radioactvity
The amount of angular momentum it possesses
whether or not multiple gravitationally bound stars form from the cloud (likely to inhibit planet formation)
The size and orbital position of the largest planetesimal as it is forming.
The behaviour of the central star as it is forming
The magnetic field entrained by the cloud
The planetary systems that are formed will depend on the balance between these and other significant properties but it is now clear from observation that planetary and asteroid systems clearly do frequently form around stars and are probably a feature of almost all stellar systems.
The rings around the major planets show some interesting features that may be a guide to condensation from clouds, for example the "shepherd moons" process.
You have not given a very clear indication of your favoured and maybe non orthodox theory in this topic. If it coincides with that given in the topic moved to new theories it is flawed in many ways. Remember, Laplace's "nebular hypothesis" (the old theory which is in some ways nearest the currently favoured theory) was rejected for many years because there was not an adequate explanation of the processes by which the collapsing gas could shed its angular momentum to the planets and near stellar collisions (extremely rare events) and stellar mass ejections were favourites earlier in 20th century when I first studied astronomy.
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A lot of matter is ejected during star formation it is ejected from THE POLES of the rotating clouds (NOT the equator at one might initially expect) and bipolar flows in areas where stars are forming are a good indicator of places where collapsing clouds are forming stars and planets.
I find part of your final paragraph
"during the formation process a lot of matter is ejected so that rotational stability can be achieved and that as this ejected matter accreted further mass and forms a cooler surface which insulates the hotter ejaculate the gravity from these planetesimals slows the rotation of the primary"
completely non understandable. It does nor appear to relate to any physical process of which I am familiar can you please try to explain it carefully and thoroughly.
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Ok.
So we start with a mess of gas and a variety of elements which have formed a roughly spherical shape.
This sphere has a total mass and therefore a total gravity which it cannot exceed
This Sphere has angular momentum possibly gained from an external source.
Most of its heavier elements have migrated to its centre and therefore the overall gravity is the same but it has changed its location in space to a more central position.
This change has added to the compression being experienced by the core elements.
Pressure and gravity cause changes in the core Elements with the end result that they have to release energy and much of this energy is transformed into heat.
This released energy causes further change
Also because of the change in Gravity the sphere undergoes Bi-Polar collapse which causes the sphere to change from a sphere to a disc.
So we now have a central core which has most of the mass.
Most of the gravity.
Most of the angular momentum.
Most of available working energy.
Please explain How For example Our Sun Only has two percent of our total solar mass without having released some of its mass into the disc or possibly discs?
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I have decided to leave.
I find that those who claim expertise are simply declaring finite Knowledge.
I like to learn new things, but to learn new things you have to take apart the established facts and look at them from a different perspective.
I like to look at a problem in terms of MESTI.
I have beliefs that form my model of the universe and I like to compare that model with the model of others.
I declare a belief because I do not fear anything especially ridicule.
I expect others to present a different view of reality.
In this way, I can keep my model fluid.
I like to pick at things.
Imagine being given a pullover by a maiden Aunt.
She has gathered the Materials and the Tools She has the time, energy and information to create something from a skein, which became a ball that becomes a hopefully recognisable item.
She sends this Item with love, which as you know cannot be quantified.
I ungrateful bastard that I am hate the way it looks but decide to unpick it.
However when I get to the final stitch I decide to make a skein.
I do not leave it there I make a ball, then I extrapolate further and discover the wool came from a sheep and was not man made, now my interest is peaked and I look further still.
Well long story short I could have simply accepted the pullover as a gift and placed it out of view.
That however is not my nature.
Many areas of this forum seem to be holding a wake for the late great Marcel Marceau
So Adieu and Bon Chance
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CANT PLEASE SOME PEOPLE
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Microcosmos on the whole your description is approximately correct except that some of your words are a bit ambiguous for example your statement "Our Sun Only has two percent of our total solar mass" is obviously incorrect, so I am trying to answer the question that I think you are trying to ask which is why is why the sun ends up with all the mass and very little of the angular momentum in the solar system which clearly stayed in the disk. Note also that the denser material (dust) would not necessarily end up at the centre immediately because it hangs on to its angular momentum more effectively. What you have forgotten though, is the effect of the magnetic field in the cloud. The contraction of the cloud strengthens the field that permeates the galaxy and the differential rotation winds up the field. This tends to put the brakes on the more rapidly spinning centre of the cloud and allows it to contract while concentrating the angular momentum into the accretion disc around the cloud. This effect was first explained by Fred Hoyle back in the 1950s and brought the currently preferred theory of planetary origins back into favour.
I am sorry that you do not seem to be prepared to engage in rational discussion. Clearly the presence of properly written scientific argument has scared you off because you can't peddle half truths as genius and get away with it unchallenged. I am all prepared to listen to innovative theories and am interested in them and have some myself. but you need to study and understand the current theories fully before you have any right to call those who have gone before you in science as blinkered idiots and I can assure you that they are not.
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For ophiolite
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I always admire certainty in an uncertain universe I am pleased that you feel that you know all that you need to know.
This is offensive on two grounds: a)the snide superiority in your choice of wording, and b) it wholly misrepresents what I wrote. May we hold this discussion on the basis of facts and not personal, emotional attacks.
For the record, amongst other things, I stated: "There is still a lot of detailed, and exciting, work to do in this field, but the basics are well understood and accepted."
That statement alones demonstrates your claim that I 'feel I know all I need to know' is wholly erroneous.
The most fundamental error is to mistake the hypothesis for an explanation of a phenomenon, without performing experimental tests.
You imply, though you do not appear to state, that I (or science) is guilty of this error in regard to the current theory of planetary formation. Again, you appear not to have read what I have written. Astronomy, like geology, is largely an observational science. The experiments we would like to carry out have already been conducted by nature. In the case of stellar and planetary formation we are blessed with the opportunity to observe the process at many points along the way, in different systems. Further we can then build models of this process, which we can test in simulations, which lead us to make predictions, which we can validate against further observation.
There is no violation of scientific method here, macrocosmos.
You go on to talk about bias, again implying that such is responsible for being wedded to the current planetary formation hypothesis. Yet in your final paragraph you explain exactly why this is irrelevant.
"In a field where there is active experimentation and open communication among members of the scientific community, the biases of individuals or groups may cancel out, because experimental tests are repeated by different scientists who may have different biases."
I was at pains to point out that this hypothesis is not the work of a couple of groups of individuals, but of many researchers from diverse backgrounds within astronomy, all submitting peer reviewed data to reputable journals.
I would of course direct your attention to the March edition of the journal of science and to the article that deals with the current estimation of the planets core temperature.
I ave not had as yet time to calculate the Entropic ramifications of this new estimate, but I will Get back to you.
I look forward to it, for at present I cannot see what relevance it has to the issue. Since I see you intend to abandon the forum - purely it seems, because your ideas have been challenged - perhaps I shall have a long wait.