"Death Spiral:" Finally, the End of Core Accretion?

[siriusmre]

How many times have I (and a few others here) asserted that the core accretion model of solar system formation is in trouble? Now, it seems to be dead.<br /><br />Despite this recent puzzling finding, I'm sure that there will be some who will write this off as being just another "adjustment" in the standard model as a result of new data. Others, like me, point to this as clear evidence that the core accretion model has finally been falsified.<br /><br />From the recent SPACE.com feature article:<br /><font color="yellow"><b>For scientists who spend time thinking about how planets form, life would be simpler if gas giants like Jupiter and Saturn didn’t exist.</b><br /><br />According to the standard model of planet formation, called "core accretion," planets form over millions of years as enormous blocks of rock and ice smash together to form planetary embryos, called "protoplanets," and eventually full-fledged planets.<br /><br />Most scientists agree that core accretion is how terrestrial planets such as Earth and Mars were created, <b>but the model can’t convincingly explain how gas giant planets like Jupiter and Saturn came to be.</b><br /><br />One major problem is that developing gas giants through core accretion takes too long. <b>According to the best current models, the process requires several million years—longer than the typical observed lifetime of the stellar gas disks from which planets are born.</b><br /><br />The other main difficulty is the so-called "migration" problem. Protoplanets are not sitting stationary in the gas disks as they bulk up. <b>Due to gravitational interactions with the disks, the protoplanets swirl rapidly inwards toward their central stars in what scientists call "Type 1" migration.</b> Models predict that this death spiral can take as little as 100,000 years.<br /><br /><b>This so-called "migration" problem is the toughest challenge facing theorists trying to explain gas giant formation through core accretion</b>, said Alan Boss, a planet forma</font> <div class="Discussion_UserSignature"> </div>

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>How many times have I (and a few others here) asserted that the core accretion model of solar system formation is in trouble? Now, it seems to be dead. <p><hr /></p></p></blockquote><br /><br />I find it curious indeed that you would make this claim, since not only does the article not support your claim, but a great many scientists are still working on accretion. Methinks you are greatly exaggerating a rumor of its demise. <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>

 

[yevaud]

A major problem here, Sirius: the "Plasma Cosmology" model cannot remotely explain how planets form. So instead of resolving this issue, you've substituted a much weaker model. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[siriusmre]

<blockquote><font class="small">In reply to:</font><hr /><p>the "Plasma Cosmology" model cannot remotely explain how planets form.<p><hr /></p></p></blockquote><br />So say you. Others would beg to differ, however. Understanding it, though, requires that you step outside of your intellectual bubble of certitude about what is and is not possible...in a universal sense.<br /><br /><font color="yellow">So let's examine a second major plank of standard theory - that we understand where planets come from. The nebula theory of the origin of planets is so problematic that it only survives because no one has been able to come up with a better idea. A many-body system controlled by a single force, gravity, is inherently unstable and should fly to pieces. In an Electric Universe the model is simple. Planets are "born" from stars in a descending hierarchy of size by the highly efficient expedient of electrical splitting of an unstable positively charged core. That is why the majority of stars have partners. It explains why many of the extra-solar planets orbit their star extremely closely - that is where they were created. It is why Jupiter and Saturn have a large number of close-orbiting moons. Close orbits are normal. Distant or highly eccentric orbits are more likely to be a result of capture. An exchange between orbital and electrical energy quickly stabilizes orbits.</font><br /><br />More: Other stars, other worlds, other life?<br /><br />Cassini's Homecoming also makes some compelling points. I encourage all those ignorant of this paradigm--but willing to at least understand what it is--to follow all of the links within those pages. It is a radically different--and yet holistically sound--way to view our cosmos. <br /><br />Whether you agree with the EU point of view or not, one thing is certain: the core accretion model has <div class="Discussion_UserSignature"> </div>

 

[yevaud]

<i>Understanding it, though, requires that you step outside of your intellectual bubble of certitude about what is and is not possible...in a universal sense.</i><br /><br /><img src="/images/icons/rolleyes.gif" /><br /><br />***/Ahhh, never mind. Pointless/*** <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[siriusmre]

<blockquote><font class="small">In reply to:</font><hr /><p>Core accretion is not "dead" at all, just in need of some revision to explain how some gas giants get so large. But core accretion explains the formation of terrestrial planets and smaller gas giants quite well.<p><hr /></p></p></blockquote><br />OK. So, you're sicking with the it's-not-wrong-it's-just-incomplete excuse? How's that working out? If the model "can't make solar systems," as the title of the article--which I did read in its entirety, btw--states, then doesn't that pretty much falsify it? Who cares if it *seems* to work in a few specific cases? It should work in all cases, no?<br /><br />Of course they're going to say, "The program is sound; never speak ill of the program." The alternative is absolutely terrifying: They've been wrong about so much for so long. <div class="Discussion_UserSignature"> </div>

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>Whether you agree with the EU point of view or not, one thing is certain: the core accretion model has some big--perhaps fatal--problems.<p><hr /></p></p></blockquote><br /><br />Of course it's not perfect. No theory is perfect. However, it is intellectually dishonest to equate imperfection with absolute falsehood -- and it's very rude to insinuate that those who do not agree with you are close-minded (i.e. not stepping outside their "intellectual bubbles"), merely because they dare have their own thoughts on the matter.<br /><br />Let us return to the subject at hand. Explain why you think core accretion is "dead". Explain these "perhaps fatal" problems, rather than merely hinting that they exist. Remember, this is a science forum. If you do not wish to adhere to these sorts of principles, I can move this thread to Phenomena, where there is less intellectual rigor.<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>A many-body system controlled by a single force, gravity, is inherently unstable and should fly to pieces.<p><hr /></p></p></blockquote><br /><br />What makes you think this? The calculations actually work out very well for a many-body system held in place by gravity -- and have done so for centuries. <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>

 

[siriusmre]

<blockquote><font class="small">In reply to:</font><hr /><p>Yes, once again, being informed that $60,000 tuition was worth crap - because a website you read says so.<p><hr /></p></p></blockquote><br />This is the inertia of prior belief and the abject terror that I posted about.<br /><br />Your high-priced education was perfectly effective...in indoctrinating you into a particular way of thinking. The big price tag and the years spent huddled with your nose in a book have conspired to convince you that what you learned was gospel. That you re the possessor of the knowledge of the One True Way. It is uncomfortable in the extreme, I'm sure, to ponder the possibility that it was all for nought. That what you have become expert in is attempting to solidify a series of sometimes inspired guesses into a dogma. A dogma that seems to "step in it" at almost every tricky turn.<br /><br /><img src="/images/icons/rolleyes.gif" /> indeed. <br /><br />Why not put your fears--and prejudices--aside and take an intellectually honest look at the material for yourself, instead of cheaply trying to belittle the source or the messenger? <div class="Discussion_UserSignature"> </div>

 

[yevaud]

You always assume that people do not read and contemplate the things you post. And when they decide for themselves, based on good science, that it hasn't proven itself, is when you come out with slurs and sly innuendos about being close-minded and indocrinated. It speaks volumes about you.<br /><br />Sorry, Bud, but I *do* read these things.<br /><br />And any indocrination hereabouts is contained within you, not me. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[siriusmre]

<blockquote><font class="small">In reply to:</font><hr /><p>Explain why you think core accretion is "dead". Explain these "perhaps fatal" problems, rather than merely hinting that they exist.<p><hr /></p></p></blockquote><br />Um...the headline reads "Death Spiral: Why Theorists Can't Make Solar Systems." Maybe that doesn't sound like a death knell to you, but it at least sounds like the model is on life support. And that life support comes in the form of even more fantastical guess-work: "Perhaps around a real star several generations of protoplanets form and only those that develop later—as the inner regions of the gas disk begins to dissipate—survive into planetary adulthood;" and "[a]nother solution might be that large parts of the gas disk are turbulent, and not smooth as the computer model assumed. The turbulence could be the result of magnetic field instabilities in the disk and would impede inward migration...But it’s unclear whether this could actually work in real life."<br /><br />Indeed. Is there any evidence for either hypothesis, I wonder?<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>What makes you think this? The calculations actually work out very well for a many-body system held in place by gravity -- and have done so for centuries.<p><hr /></p></p></blockquote><br />First, this is not my assertion. It is the assertion of the author of the Web site. Perhaps you should ask him. Second, are you telling me that there has NEVER been a problem with gravity in the theoretical formation of multi-body systems? Come on. <img src="/images/icons/rolleyes.gif" /><br /><br />Perhaps you should move this thread to the Phenomena forum; it's phenomenal to me that anyone would continue to defend this obviously broken model. <div class="Discussion_UserSignature"> </div>

 

[CalliArcale]

Actually, given the rapid rise of hostility in this thread so far, I no longer think it is fit for Phenomena. It is fit for locking.<br /><br />I do not grasp your insistence on insulting other members when they dare think differently than you, nor your apparent belief that it's okay to dismiss other views with prejudice -- but not okay for others to disagree with your view. <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>