Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Uniform vs progressive solar system formation

  1. Mar 26, 2003 #1
    If some of the people that frequent this area of PF could please post their findings and or opinions on this debate I would appreciate the input very much.

    Did the planets of our solar system form uniformly; basically at the same time, out of the same solar material? Or, did some form sooner than others... and did some actually come from the mass of super planets like Jupiter... as was proposed by Velichovsky during the 20th century?
    Last edited: Mar 27, 2003
  2. jcsd
  3. Mar 29, 2003 #2


    User Avatar

    Staff: Mentor

    There are essentially 3 possibilites.

    1. All the planets (and the sun) formed from the same disc of dust and gas at roughly the same time.
    2. Some formed at one time from some initial matter, some from new matter later.
    3. Some fomed from matter "blown off" or left over from other planets.

    For #2 to be possible, there would need to be a considerable amount of new matter floating around in space for our solar system to "sweep up." There isn't.

    For #3 to be possible, you'd need to rewrite the laws of Newtonian phsics to allow matter to somehow get from Jupiter's orbit to Earth's orbit on its on and end up in a stable orbit.

    #1 is the most likely scenario for how the solar system formed.
  4. Mar 29, 2003 #3


    User Avatar
    Science Advisor

    Greetings !

    I think that the "natural" order is the formation
    of the star - first, as a result of the collapse
    of matter in the center of the accretion disk.
    I guess the way it happens is friction that
    increases the mass at the center of the disk.

    I believe the Earth is said to've formed about
    4 billion years ago (half a billion years after
    the Sun).

    I'm not certain about the other planets, but
    I believe they formed within the first billion
    years after the Sun's formation.

    Live long and prosper.
  5. Mar 29, 2003 #4
    I propose that a planet's orbital radius and its mass are determined mostly by the local density (~molecular weight) of the dust cloud and chaotic equilibrium dynamics associated with that evolving disk.

    The terrestrial planets formed from the metallic compounds that migrated under friction and gravitation toward the Sun, as the light molecules tended away from the Sun to form the gaseous planets. The asteroids represent a terrestrial planetoid(s) caught in an orbit originally favorable to such a satellite but later tolerable to only a more pliant body.

    Real planets swept up debris from their orbital paths; the farther from the Sun and more isolated the planet, the more dust they tended to accumulate until the disk became tenuous at large radius. The "seeds" for planets may have originated from the shock wave caused by the thermonuclear ignition of the Sun.
  6. Mar 29, 2003 #5
    These are all interesting views of "planetogenesis"... (not a real word!!!)

    After a some more posts I'd like to bring some quotes from Velichovski that concern planet formation to show another side to this story.

    He uses measurements of planet radiation and comparisomes between how much radiation a planet absorbs from the sun as compared to how much radiation (heat) a planet radiates.

    Jupiter, for example, radiates much more heat that it absorbs.

    Thank you!

    I learnink.
  7. Mar 30, 2003 #6


    User Avatar
    Science Advisor

    Greetings !
    How would that explain observation of so "many"
    gas giants very close to their stars in other
    star systems. Why would metallic compounds migrate
    towards the star and the light molecules away from it ?

    Live long and prosper.
  8. Mar 30, 2003 #7


    User Avatar

    Staff: Mentor

    One problem with that - the outer planets are believed to have solid/liquid cores. Tink of it like an earth with a jupiter wrapped around it. That would suggest the dust was roughly evenly distributed around the solar system.
  9. Mar 30, 2003 #8
    I may be wrong, but under frictional influence within the cloud, denser material is more likely to gravitate toward the formative parent star. We don't have enough optical resolution to determine the order of terrestrial vs gaseous planets in other systems. In fact, we observe that which we are able - thus close in, large gas giants which more likely intersect their parent star. Chaotic equilibrium is just that, two neighboring states (similar disks) evolve into very different though stable configurations. My guess is that in the star systems you mention, terrestrial planets, if they exist, have an even closer orbit than gaseous ones; or if not present, the parent stars in most such systems will show higher levels of heavier metals than those systems typical to ours-Testable prediction!

    As with any suspension, the original homogeneously distributed elements separate only partially over time. One might more productively compare planet densities (elemental distribution and self-gravitation) against their mass origins (disk attenuation and orbital radius "swept").
  10. Mar 31, 2003 #9


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Ok, but fair warning. Velichovski is considered to be a crackpot. Be prepared for rebuttles.
  11. Mar 31, 2003 #10

    Yes, I've heard about the crackpot status.

    Here's a conversation Velikovsky had with Einstein about Velikovsky's critics and what Einstein agreed was a form of suppression being employed at the time of the first publications Velikovsky put into the public arena.

    "On May 20, 1954 I went to see Einstein. This time I asked to see him. I wished to ask him to read a part of my Earth in Upheaval in manuscript. There was also another subject that I thought I ought to discuss with him.

    A few days before a correspondent in California drew my attention to an article in Astounding Science Fiction in which I was accused of inventing my sources. I realized the damage done by the Harvard group had spread into pulp magazines read by common people.

    I had not complained to Einstein before about the campaign of suppression and vilification carried on by some groups of scientists against my theory and myself.

    He received us this time in his study on the second floor, which has a large window overlooking the garden in the backyard. It was about the time before sunset. He asked:

    ?Would you like our conversation between four eyes or between eight??

    ?Between eight,? I replied, my wife and Miss Dukas being admitted.

    ?The women will listen but not participate,? he said, expecting something important to discuss with me.

    ?Like in a synagogue,? I remarked. But then I corrected myself. ?No, I feel myself here as Solomon Molcho must have felt in the palace of Pope Clement VII.? I explained that this marrano, i.e, a Jew from a family that had been forcibly converted to Christianity, was sentenced to die for reverting to Judaism and was burned as a heretic in Rome by the Inquisition; but the next day he was alive in the inner chambers of the Vatican discussing philosophical problems with the Pope.

    The Pope had let another heretic be burned and hid Solomon Molcho. If only the Holy Inquisition knew where he was! This was my way of referring to what my opponents and detractors among the scientists might think and feel were they to know where I was spending that evening.

    ?Is he a gentleman who permanently turns his pockets out to show that he did not steal?? I quoted Vladimir Jabotinsky. I could not spend all my time proving that I have not misquoted or otherwise misused my sources. But silence on the part of the accused is understood as admission of guilt.

    Einstein agreed with me. And thinking of injustice to a man, he mentioned Oppenheimer, whose removal from the advisory committee to the Atomic Energy Commission caused at that time great agitation.

    ?But you do not do better,? I said.
    Einstein?s face expressed surprise. ?I do not think of you personally, but of your colleagues, the scientists.? He wished to know more. I went down and brought from the car a file with some of the letters exchanged between Harlow Shapley and the Macmillan Publishers.

    (Einstein) read them with great interest. But we did not proceed far enough; we had not come to read the letter of Whipple to Blackiston Publishers in Philadelphia, or the statement of Shapley in the Harvard Crimson.1

    Einstein was obviously impressed and did not spare harsh words in characterizing some of the actors in the campaign of suppression.

    Einstein advised me to make the material public. I should, he said, find somebody with a talent for dramatic writing and entrust him with the task of presenting the case. He was obviously impressed and indignant. ?This is worse than Oppenheimer?s case.? (said Einstein)

    I mentioned that in Germany the church also opposed me, and in fact suppressed Worlds in Collision at the hands of its publisher (Kohlhammer of Stuttgart). As in America the book had a great success, and went through five printings in less than a year when the lid fell down.

    ?But what should the church people have against the book?? asked Einstein, and turned his face to me (as often during our conversations, he was sitting to my left). The opposition of the churches to a work that provoked furor among the scientists must have appeared to him incongruous. All this must have been thought, not said, for my answer followed immediately:

    ?The church opposed my interpretation of miracles as natural phenomena.? Einstein laughed with his loud, hearty laugh. He wished to read more in the file. But now I was interested in taking up the problem that really occupied my mind?my theories.

    Already at one of our earlier meetings, Einstein said to me: ?I know how to explain the great global catastrophes that occurred in the past.?

    (Einstein) spoke then of vestiges of an ice cover that were observed in the tropics and referred to an unpublished theory of Charles Hapgood, who thought that growing ice caps can cause a slippage of the terrestrial crust relative to the interior, thus displacing the poles.

    This evening Einstein returned to the same idea and said that terrestrial causes could have been responsible for the catastrophes. I told him that the problem of the displacement of the terrestrial pole was already much discussed in the last century by astronomers and geologists. ?By whom and where?? he asked. ?Here,? I said, about to leave, and showed him the second (of three) files of the manuscript of Earth in Upheaval,

    ?Here you may find the arguments of that old discussion.? First he was reluctant to take another manuscript for reading. The daily mail alone takes so much of his time, he said, and standing at the top of the staircase, while I was a few steps down, showed with his hands how thick was the bundle of his daily mail.

    But, hearing that the physical problem of the terrestrial crust moving over the core is discussed in that file, (Einstein) took my manuscript."

    Emmanuel Velikovsky
    Last edited: Apr 4, 2003
  12. Apr 4, 2003 #11
    Formation at Different Times

    "In 1950 most scientists firmly believed that all the planets were formed in their present orbits; many of them ridiculed Velikovsky for suggesting otherwise. However, by 1960 W.H. McCrea, who at the time was President of the Royal Astronomical Society, published a theoretical argument that no planet could originally have formed from a solar nebula any closer to the Sun than the orbit of Jupiter.

    Later J.G. Hills attempted to show that no planet could initially have formed outside the orbit of Saturn. Between the appearances of these papers, H. Alfven, who later received the Nobel Prize in Physics, theorized that the giant planets may have been formed before the "terrestrial (smaller) planets. He also presented arguments for the inverse order of events. Either way, within a very few years at least three respected scientists argued that all the planets need have been formed neither at the same time nor in their present orbits.

    If no planet initially formed inside Jupiters orbit or outside Saturn's, then major orbital changes must have taken place since most of the plantets were formed. Hills explicitly suggests that the planets now outside the orbit of Saturn may have been knocked into their orbit by encounters with other planets.

    This has already been proposed that events of this type have recently been explained theoretically. As early as 1953. R.A. Lyttleton, a noted British cosmologist, explained an orbital change of the type which some of his colleagues had, for at least three years, been claiming to be impossible."

    (From: "The Age Of Velikovsky" by Dr. C.J.Ransom, copyright, 1976)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook