The formation of solar systems

[CalliArcale]

This is a topic that has come up frequently lately, so it is obviously of great interest. It can't be properly dealt with in most of the other threads without stomping on the topics of those other threads, so I'm starting a fresh thread where we can really get down to business on the subject.<br /><br />The formation of solar systems.<br /><br />The most popular model nowadays is accretion. There are several flavors of this model; it is not entirely accurate to say that because one has issues with one of them, they must all be wrong, and it's important to know this. I'm hopeful that one of our resident astronomy students (perhaps Saiph) can help outline various models in more detail, because it's not something I know a lot about myself. I only understand it on a high level. And of course I don't get the EU version at all, so perhaps someone who is well-versed in that can give a brief summary of that one too.<br /><br />The basic gist of accretion, in all its flavors, is that particles in a sufficiently dense cloud will randomly encounter one another. Some of them will stick together, at first probably through nuclear forces or static electricity, but once there are enough, they'll start to capture other particles through gravity. As the clump of particles grows, it becomes stronger and better able to both capture and retain particles. Given enough time and enough particles, it could become a planet, or even a star. When a star forms, it begins to put out a powerful solar wind. It is expected that this blasts away a great deal of the remaining material, slowing or even halting planet formation. Our own solar system has few volatiles in the inner solar system (with Earth's vast water oceans being a notable and curious exception), and it has long been presumed that the ignition of the Sun had something to do with that. However, the discovery of Hot Jupiters poses a potential problem for that. (So does the Earth itself; one must explain where the oceans came from <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[telfrow]

Calli:<br /><br />I found the following article concerning 'Hot Jupiter' Systems. The article notes that simulations point to the possibility these systems might harbor "Earth-like" planets. <br /><br />Just food for thought. <div class="Discussion_UserSignature"> <strong><font color="#3366ff">Made weak by time and fate, but strong in will to strive, to seek, to find and not to yeild.</font> - <font color="#3366ff"><em>Tennyson</em></font></strong> </div>

 

[CalliArcale]

That is very interesting indeed. Thank you for sharing that!<br /><br />Probably the biggest challenge in this field is that planetary formation is doubless very complex. Tiny changes in the intial state of the protoplanetary cloud would result in very dramatic changes in the end product. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[telfrow]

More food for thought concerning the formation of solar systems: The locked migration of giant protoplanets <div class="Discussion_UserSignature"> <strong><font color="#3366ff">Made weak by time and fate, but strong in will to strive, to seek, to find and not to yeild.</font> - <font color="#3366ff"><em>Tennyson</em></font></strong> </div>

 

[bonzelite]

i like this idea from the article: <br /><br /><font color="yellow">the astronomers propose several possible solutions. One may be that several generations of planets form and that only the ones that form as the disc dissipates survive the formation process. This may make it harder to form gas giants, as the disc is depleted of the material from which gas giant planets form. (Gas giant formation may still be possible though, if enough gas lies outside the planets’ orbits, since new material may sweep inward to be accreted by the forming planet). Another solution might be related to the physical properties of the protoplanetary disc. In their simulations, the astronomers assumed that the protoplanetary disc is smooth and non-turbulent, but of course this might not be the case. Large parts of the disc could be more turbulent (as a consequence of instabilities caused by magnetic fields), which may prevent inward migration over long time periods. </font><br /><br />this suggests that the solar system was very different early on, not even necessarily containing the same amount of major planets as observed today. their studies suggest a dynamic and changing solar system, with some planets ceasing to exist, remaining undetectable today. i tend to believe, in some way, either the way they suggest or otherwise, that this is true. <br /><br />i have a notion, too, that perhaps the terrestrial planets such as mercury, venus, earth, and mars, may have been the rocky cores of gas giants. that is, all planets may start off as gas planets, such as saturn or neptune, and then settle into a more advanced state, such as seen in the stratification of planetary types that we see in our solar system.

 

[CalliArcale]

Assuming of course that gas giants have rocky cores. There's so little known about the interiors of those huge planets, and it's very difficult to study their insides. Even the Sun's interior is easier to study, thanks to helioseismology.<br /><br />Of course, it's also possible that there is more than one kind of gas giant. We lump them all together, but is it really fair to call all large low-density worlds "Jovian"? It's not easy to answer that right now; it comes back to the same problem I alluded to above. It's just not easy to study these monsters. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[vogon13]

Astronomers are acquiring more stats on planet/star configurations all the time. In our own solar system, we have the curious pair of Jupiter and Uranus to contemplate.<br /><br />Neglecting Miranda for the moment, Uranus and its four large satellites approximates a scale model of Jupiter and it's 4 largest satellites. Mass ratios, distances, etc. are actually scaled quite closely. I can't help but think this is trying to tell us something. Perhaps scaling effects work around other stars too. Perhaps there are some patterns and commonalities to consider too.<br /><br />Currently, the technology strongly favors detecting the close in 'hot Jupiters'. As the techniques improve we can (hopefully) expect to see more far out 'cold Jupiters' too.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[siriusmre]

A message board is not really the best way to try to introduce someone to a completely different paradigm. I would urge those who are curious about what the Electric Universe is about to check out this site: The Electric Universe.<br /><br />Essentially, though, it goes something like this:<br /><br /><font color="yellow">Plasma physicists argue that stars are formed by an electromagnetic "pinch" effect on widely dispersed gas and dust. The "pinch" is created by the magnetic force between parallel current filaments that are part of the huge electric currents flowing inside a galaxy. It is far more effective than gravity in concentrating matter and, unlike gravity, it can remove excess angular momentum that tends to prevent collapse. Stars will form like beads on a wire until gravity takes over. The late Ralph Juergens, an engineer from Flagstaff, Arizona, in the 1970's took the next mental leap to suggest that the electrical input doesn't stop there and that stars are not thermonuclear engines! This is obvious when the Sun is looked at from an electrical discharge perspective. The galactic currents that create the stars persist to power them. Stars behave as electrodes in a galactic glow discharge. Bright stars like our Sun are great concentrated balls of lightning! The matter inside stars becomes positively charged as electrons drift toward the surface. The resulting internal electrostatic forces prevent stars from collapsing gravitationally and occasionally cause them to "give birth" by electrical fissioning to form companion stars and gas giant planets. Sudden brightening, or a nova outburst marks such an event. That elucidates why stars commonly have partners and why most of the giant planets so far detected closely orbit their parent star. Stellar evolution theory and the age of stars is an elaborate fiction. The appearance of a star is determined largely by its electrical environment and can</font> <div class="Discussion_UserSignature"> </div>

 

[bonzelite]

right. i'm not bought into the idea that all gas giants have rocky cores. they may or may not. some scientists are of the belief that jupiter, for example, is homogeneous. <br /><br />we're getting into "i have no idea" territory.

 

[bonzelite]

<font color="yellow">Note that the Titus-Bode relationship is harmonic which is not inconsistent with nodes of a shock wave.</font><br /><br />wow. you're one observant and smart dude. <br /><br />that has huge ramifications. the planets may have been expelled from a stellar explosion; a birth-giving model similar to you-know-what theory.

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>right. i'm not bought into the idea that all gas giants have rocky cores. they may or may not. some scientists are of the belief that jupiter, for example, is homogeneous.<br /><br />we're getting into "i have no idea" territory. <p><hr /></p></p></blockquote><br /><br />Very much so. There are some way-cool bits of speculation on the subject, though. Some of the more aesthetically pleasing ideas include a core of metallic liquid hydrogen (hydrogen, when too hot to be a solid but too dense to be a gas or a normal liquid, forms a metallic state) and a diamond the size of the Earth (since carbon is known to exist in Jupiter, and would tend to sink, and becomes diamond when subjected to sufficient pressures and temperature). But nobody really has a practically testable idea at this point. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[bonzelite]

you mention diamond. didn't i read somewhere a few years ago that astronomers believe, have good reasons to suspect, that it may precipitate (rain) diamonds in the atmosphere of neptune or uranus? imagine that. raining diamonds! that would totally destroy your car! <br /><br />

 

[CalliArcale]

Worse than hail. <img src="/images/icons/wink.gif" /><br /><br />It's speculative; they know carbon should be precipitating out of Uranus' clouds. It strikes me as somewhat wishful thinking to imagine the carbon forming diamonds, but it's not really a topic I'm very good with. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[derekmcd]

Don't tell anyones wife that... there would be a mass exodus of husbands going to jupiter. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[bonzelite]

right. <br /><br />

 

[mikeemmert]

I think I agree somewhat with borman on this. I think a standing sound wave through the tenuous gases of the solar nebula had a great deal to do with the formation of the solar system.<br /><br />Shock and sound waves have significant differences. Sound gets into standing nodes a little easier, and the nodes last longer.<br /><br />I spent a frustrating day yesterday getting conflicting figures for the amount of energy it takes to cause (diatomic) molecular hydrogen to break down into atomic hydrogen (where the molecules consist of single atoms). It takes a lot of energy to do this; when it happens, that energy is absorbed. The temperatures, though, are within range of a Jupiter or smaller mass collapsing under gravitational forces. Once this energy starts being absorbed, the collapse proceeds in a runaway fashion, since the cloud is not heated by compression beyond the temperature of molecular hydrogen and so won't bounce back until the molecular hydrogen has been converted into the atomic form. It's like a shock absorber. Actually more like a sound absorber.<br /><br />This is known to be a factor in the collapse of stars. If there is added compression from sound or shock waves (which have similarities as well as differences) then perhaps a smaller mass will collapse.<br /><br />In previous years, numeric modeling incorporating electrostatic forces, magnetic fields, sound and shock waves, phase changes, chemical reactions, and perhaps other factors, were too complicated for the computers of the day. They might still be. But this is the reason astronomers started with gravitation, the main force involved. I think the other effects are important.

 

[bonzelite]

<font color="yellow"> The study of these relic frequencies might be thought of as sort of a <b><i>paleohelioseismology. </i></b></font>/b><br /><br />i love your point of view of stuff. you're very creative and imaginative, noticeably very visual, yet seemingly within context of convincing scientific reason.

 

[CalliArcale]

I love reading borman's posts. I haven't the background to know this stuff, and I like his eloquent style. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[mikeemmert]

<blockquote><font class="small">In reply to:</font><hr /><p>Uranus and its four large satellites approximates a scale model of Jupiter and it's 4 largest satellites. Mass ratios, distances, etc. are actually scaled quite closely. I can't help but think this is trying to tell us something.<p><hr /></p></p></blockquote>I think Saturn fits in your pattern, vogon. My basis for this is the idea that Titan formed at the Sun/Saturn Lagrange points L4 and L5, and later collided to form one object. Saturn has very little noble gas except argon, a decay product of potassium. Likely it has lost it's original atmosphere.<br /><br />So it's not a part of the original system. Of the moons that are left, Enceladus has demonstratably shrunk over the years. So Enceladus, Tethys, Dione, and Rhea are the Gallilean-style moons of Saturn.<br /><br />Mimas, Uranus' Miranda, and Neptune's Proteus are in another class which is somewhat analogous to the terrestrial planets. Mimas and Miranda are considerably smaller than the Gallilean class moons of those planets.<br /><br />Neptune could also have fit into that scenario at one time. The capture of Triton messed it all up and now there's no way to tell what it used to look like.<br /><br />So we have a pattern of a central large object orbited by four planets/moons in this solar system, if you throw in Lagrangians.