tag:blogger.com,1999:blog-9094742788006644220.post1645523697220679425..comments2020-11-09T07_43_07.776-08_00Comments on Mike Brown's Planets: Snow balls in spaceUnknownnoreply@blogger.comBlogger39125tag:blogger.com,1999:blog-9094742788006644220.post-21640682679084892122015-01-27T13_16_56.834-08_002015-01-27T13_16_56.834-08_00Well, Haumea is football-shaped, so odd-shaped bod...Well, Haumea is football-shaped, so odd-shaped bodies are plausible. But if 2002 UX25 is a close binary, then there should be a considerable variation in its / their luminosity with time, according to the rotational / orbital period. More than you&#39;d expect for a single body with two different sides.<br /><br />I should think that something similar to the programs which find planets around stars by luminosity variation, would make sense of this. If one body is eclipsed or occulted, then the total luminosity drops; and for two non-luminous bodies the change should be appreciable. And since it&#39;s probably a higher frequency than the orbit of a planet around a star, it would take a relatively short time to gather the data for the program. And if it is a single body, then the shape of the luminosity curve would probably be different from two bodies occulting, so that should be resolved as well.<br /><br />Now, all we need is an astronomer with a telescope...Reggiehttps://www.blogger.com/profile/17478546089651522517noreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-81166772446532480962015-01-27T03_53_19.100-08_002015-01-27T03_53_19.100-08_00What if 2002 UX25 not binary, but triple? It&#39;s...What if 2002 UX25 not binary, but triple? It&#39;s central body is close binary system. Two objects with high density, but as don&#39;t resolved, looks like one big object with low density.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-83729241919732393412015-01-06T12_47_45.938-08_002015-01-06T12_47_45.938-08_00On the other hand, the &quot;rocks&quot; could be ...On the other hand, the &quot;rocks&quot; could be volumes of ice allotropes which are denser than water. I haven&#39;t (yet) found a phase diagram showing all the allotropes (Isomorphs) of ice, but at least some are denser. So above a certain pressure (planetoid diameter), the regular ice could be collapsing into Ice II or Ice III &quot;rocks&quot;, which would increase the total density.Reggiehttps://www.blogger.com/profile/17478546089651522517noreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-31480999533387700222014-09-27T13_21_40.926-07_002014-09-27T13_21_40.926-07_00be fun to play snowballs, I miss ... :)be fun to play snowballs, I miss ... :)drochmadyhttp://www.drochmady.comnoreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-37546375394809541312014-07-27T20_21_31.572-07_002014-07-27T20_21_31.572-07_00You keep mentioning &quot;water ice&quot;. Are the...You keep mentioning &quot;water ice&quot;. Are there other volatiles which could be present in large, nonporous quantities, yet be lighter than water ice thus lowering the overall density? Or perhaps some allotrope of water ice that is stable at super-low temperatures and pressures? Ice already has many allotropes; another would not be much of a surprise.Reggiehttps://www.blogger.com/profile/17478546089651522517noreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-41870649969288430212014-06-02T14_27_32.057-07_002014-06-02T14_27_32.057-07_00Just another entirely baseless speculation about w... Just another entirely baseless speculation about way out type objects.<br /><br /> Given that the galaxies formed in a small time compared to the known lifetime of the observable universe, is the space between the galaxies empty ( except for rogue hydrogen atoms ) ? Could there have been a significant amount of material left over, after construction of the galaxies, which then evolved in some manner similar to proto-planetary or proto-stellar disks, eventually forming comets, asteroids, planetoids, gas giants, brown dwarf stars and Chevy Impalas? I vote for the Impalas. What was their big hit recording in about 1959 ? Oh, wait ! Weren&#39;t we talking about astronomy ? Well, at least, I thought I was.<br /><br /> If that intergalactic space contained a large enough density of objects, perhaps that would be detected due to the resulting haze blocking our view of the galaxies or some of them or the ones sufficiently far away. So that seems to indicate that few such objects are out there. Way out there.<br /><br /> But if intergalactic space contained rather large objects, perhaps the size of asteroids or of our gas giant planets, maybe those objects would not be visible [ assuming, for no logical reason, that there were a relative few of those larger objects ].<br /><br /> How could such things be existing, there in intergalactic space?<br /><br /> Could stuff be gravitationally ejected from the fringes of galaxies, forming something like our Oort cloud objects or our Kuiper belt objects, which may be found around other stars in the Milky Way galaxy and which may be shared by nearby stars rather like the conduction band of electrons in an electrical conductor: objects with no legal home.<br /><br /> Is this possibly a part of the missing 95 % of the mass of our universe? Perhaps 1 % of 1 % of the missing mass ?<br /><br /> Just thought I&#39;d ask. I have always been interested in the possibility of fairly large objects just wandering around completely unsuspected and uninspected, in intergalactic space. Just kinda fun to speculate about.<br /><br /> Thanks for your time &amp; patience.James Milton Martinnoreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-5638667098723676842014-05-20T13_27_53.450-07_002014-05-20T13_27_53.450-07_00The history of KBOs and Oort objects fascinates me... The history of KBOs and Oort objects fascinates me because I have long thought it likely that such objects may be remnants of objects formed in the early universe which may permeate the inter-galactic space as well, of course, as the intra-galactic or interstellar space. Which leads to my thought that these unusually dense KBOs (which may have cousins among the Oort objects) may have developed by mechanisms operating outside the solar system or outside either the Kuiper region or the Oort region.<br /><br /> Thus: an alternative origin for some of our KBO or Oort friends? { rocks which did not evolve by slow accretion of 2002 UX25-sized objects in the rather thinly populated and thus somewhat collision-free zones of the outer regions; rather, may they be fragments of previous planets or asteroids in previous solar systems ? }<br /><br /> Just speculating; I neither live nor die on this totally unfounded speculation. I merely find it fascinating to ponder the history of various objects which may have survived several solar systems and lived to tell about it.<br /><br /> Thank you for your time &amp; bandwidth.James Milton Martinnoreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-59846717242728803082014-04-09T14_39_18.694-07_002014-04-09T14_39_18.694-07_00Varda: diameter 705 km, density 1.27 g/cm^3Varda: diameter 705 km, density 1.27 g/cm^3Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-66749357903385717042014-02-21T16_32_47.616-08_002014-02-21T16_32_47.616-08_00If it&#39;s porous, then it doesn&#39;t have &quot...If it&#39;s porous, then it doesn&#39;t have &quot;sufficient mass for its self-gravity to overcome rigid body forces&quot;, so it can&#39;t be a dwarf planet. That throws a monkey wrench into your dwarf planets page calculus. It also flies against the Cole / Lineweaver-Norman calculations. Maybe it&#39;s Rama III :-)<br />David Tnoreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-46723962248980181482014-02-11T05_52_31.129-08_002014-02-11T05_52_31.129-08_00So far mainly two parameters have been used for cl...So far mainly two parameters have been used for classification:<br />size and density. Perhaps &quot;age&quot; might be an appropriate third<br />parameter, explaining the &quot;unusual&quot; nature of 2002 UX25.Ingo Althofernoreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-54524320010914230862013-12-28T23_01_53.334-08_002013-12-28T23_01_53.334-08_00A little late here (found u thru @carolynporco fan...A little late here (found u thru @carolynporco fan page) but have you heard of Paul Hoffman @ Harvard Uni? He had some snowball earth theories about icy objects, he&#39;s a geologist Andrew Zolnai Bloghttps://www.blogger.com/profile/14579698318895235779noreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-49340658934036236832013-12-12T16_45_49.230-08_002013-12-12T16_45_49.230-08_00The only problem with that theory is that, when th...The only problem with that theory is that, when the Heavy Late bombardment happened, the asteroids hit the planets because they had a large gravitational pull towards them, but in the Kuiper belt, for one thing, the area is much less dense, so there aren&#39;t many small projectiles to fling around, and the bodies have nearly no gravitational pull except to immediately close objects. Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-26322943579157026452013-11-28T11_59_38.637-08_002013-11-28T11_59_38.637-08_00Let me try my personal theory! In the inner sola...Let me try my personal theory! <br /><br />In the inner solar system apparently we had a long &quot;stable&quot; period, that allowed to the inner planets to grow and &quot;clear the neighborhood around their orbit&quot;. Then about 4 B years ago, there was a disruptive &quot;Heavy late bombardment&quot;.<br /><br />Maybe the same sequence happened in the Kuiper belt: there was a long period of stable growth of planetesimals resulting in several &quot;large&quot; bodies (Pluto or Eris-sized) that differentiated with a rocky core and ice crust and &quot;cleared their neighborood&quot; so that there was almost no material left. <br /><br />Eventually an event (the same that caused the HLB maybe) perturbed the &quot;stable and safe&quot; orbits of the large bodies resulting in several collisions; but somehow the average dynamic of these collisions (slow relative velocity) did not shatter completely the bodies but generated mostly debris from the ice crusts leaving the rocky core intact. Eventually the ice debris reassembeld as &quot;rubble piles&quot; and never had enough gravitational pull or energy from decaying radioactive elements to melt and become compact ice spheres. <br /><br />I&#39;m trying to think about a way to test this... if the smaller bobies are in fact very irregular collections of ice chunks it could be possible to observe some variability in their light curves maybe... <br /><br /> Anonymoushttps://www.blogger.com/profile/04637291486305232932noreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-27083647974292039302013-11-22T16_50_13.076-08_002013-11-22T16_50_13.076-08_00nice share mike !!! Thanks.. Good Job.. nice share mike !!! Thanks.. Good Job..<br /><br /><br />Camera.co.id Toko Kamera Murah di Indonesiahttp://mranggendemak.blogspot.com/2013/11/cameracoid-toko-kamera-murah-di.htmlnoreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-4567946993863697042013-11-16T11_19_55.251-08_002013-11-16T11_19_55.251-08_00link to nature/news article: http://www.nature.com...link to nature/news article:<br />http://www.nature.com/news/astronomers-surprised-by-large-space-rock-less-dense-than-water-1.14135agmartinhttps://www.blogger.com/profile/14559477374723896051noreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-16470016529635827302013-11-16T11_18_36.633-08_002013-11-16T11_18_36.633-08_00Alternate theory from nature/news article: big obj...Alternate theory from nature/news article: big objects formed first, small objects formed from debris produced by impacts between large objects. Steps required: <br /><br />1a) form large objects directly from eddies in early nebula<br />1b) avoid forming &#39;small&#39; objects (d&lt;700km) at same time<br /><br />2) differentiate large objects<br /><br />3) produce enough debris from collisions of large objects to make population of small objects from debris that is not re-accreted by large objects<br /><br />I have my doubts about steps 1b) and 3) working<br />agmartinhttps://www.blogger.com/profile/14559477374723896051noreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-60589004807638174752013-11-12T08_13_38.275-08_002013-11-12T08_13_38.275-08_00...and then the debris from the breakup of the int......and then the debris from the breakup of the intruders eliminates the small icy bodies. Oops,I killed the Kuiper belt.agmartinhttps://www.blogger.com/profile/14559477374723896051noreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-12675053007561836392013-11-09T09_33_25.980-08_002013-11-09T09_33_25.980-08_00Almost forgot about this, Gonzalo Tancredi analyze...Almost forgot about this, Gonzalo Tancredi analyzed the light curves of a bunch of potential dwarf planets several years ago and concluded that2002 UX25 wasn&#39;t one of them.<br />http://adsabs.harvard.edu/abs/2008Icar..195..851T<br />http://www.astronomia.edu.uy/dwarfplanet/list.htmlAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-36327866222898771102013-11-09T09_27_53.847-08_002013-11-09T09_27_53.847-08_00Yeah, I wondered about that. You also get the adv...Yeah, I wondered about that. You also get the advantage that there are fewer small objects to bash the porosity out with collisions (you want enough medium objects around to make the big ones - normally you&#39;d expect even more small ones). Also, if there&#39;s lots of carbon monoxide, nitrogen, methane etc in there to start with, you don&#39;t need porosity at first. If the bodies warm up slowly (radioactivity, increasing heat from the sun) then the CO, N2, CH4 can quietly leave, giving you a nice big lightweight body. Hence my comment about clathrates above.David Frankishttps://www.blogger.com/profile/09586713131483488218noreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-41716679915620132332013-11-09T06_38_59.067-08_002013-11-09T06_38_59.067-08_00Could it be that in the early process of formation...Could it be that in the early process of formation there were objects with more rock in them and those with less, and that the ones with more rock were more likely to withstand the harder collisions, causing them to grow and melt in the process, making them less porous over time, while those in the other group would either undergo hard collisions and shatter, or would only grow by relatively soft collisions that would not melt them, leaving them more porous?<br /><br />Another question: it seems after 2007 no really big objects beyond Neptune were discovered. What&#39;s the reason for that? Are most objects in the mass range found, or are astronomers concentrating on other stuff, or did the criteria to publish a discovery get more difficult?Ambi Valenthttps://www.blogger.com/profile/03488247852564879628noreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-75437686612883812382013-11-08T09_37_13.717-08_002013-11-08T09_37_13.717-08_00If the objects up to 2002 UX25&#39;s size formed d...If the objects up to 2002 UX25&#39;s size formed directly from the disk as described here: http://arxiv.org/pdf/1004.0270v1.pdf would they start out colder? If colder means stronger they would be able to support a larger porosity. I note that Iapetus has the shape of an object with a rotation period of ten hours which I understand was acquired early and was preserved after its it acquired a thick crust crust as it cooled.agmartinhttps://www.blogger.com/profile/14559477374723896051noreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-18575840663432628692013-11-07T20_31_42.824-08_002013-11-07T20_31_42.824-08_00Well, Tethys appears to have a large, recent crate...Well, Tethys appears to have a large, recent crater on it, which would leave a large part of its interior molten. I&#39;m not sure how that would affect the density, and apparently there is an undersea ocean in it, which later turned to mostly ice (leaving large bubbles, possibly?) in it. The ocean probably hasn&#39;t entirely frozen over, leaving parts of it full of water.<br />Also, I&#39;ve had a dumb question I&#39;d asked myself since I was a little kid, and haven&#39;t been able to find an adequate answer to: What would a moon&#39;s moon be, is it even possible? If so, is there anything interesting it would have about it that other planets, minor planets, and moons, don&#39;t tend to have?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-15946764543503487942013-11-07T14_31_02.437-08_002013-11-07T14_31_02.437-08_00In response to Mr. Brown&#39;s comment about the o...In response to Mr. Brown&#39;s comment about the origin of Saturn&#39;s moons, it seems peculiar that some of the IAU&#39;s definitions of a dwarf planet are &quot;has not cleared the neighborhood around its orbit&quot; and &quot;is not a [natural] satellite.&quot; So how can ordinary planets such as Saturn not clear their neighborhood of lesser objects i.e. planets with such gravitational force should fling all bodies that come near it off into deep space (and not have moons).<br /><br />What conditions must be necessary for a planet or other body to collect objects (capture into orbit) rather than scattering them about the Solar System?<br /><br />If a large TNO drifted towards one of the gas giants, would they just bounce off it and drift away, would they be hurled off rapidly into space or would they be captured? Perhaps some moons were created out of materials that formed the primary planet? But it seems counterintuitive for a planet with great gravitational force to cast other bodies off; after all, it is the Sun that keeps the other Solar System objects from just drifting about; gravity is the force that pulls things towards the center.<br /><br />P. S. Skip the movie &quot;Gravity,&quot; in this case it makes perfect sense to be repelled off into space. George Smithnoreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-12145261451090368182013-11-07T08_28_34.125-08_002013-11-07T08_28_34.125-08_00Saturn&#39;s moons are funny things. Their origin ...Saturn&#39;s moons are funny things. Their origin is still controversial, I think.Mike Brownhttps://www.blogger.com/profile/04402191029077523538noreply@blogger.comtag:blogger.com,1999:blog-9094742788006644220.post-3601800218720578272013-11-07T08_27_53.063-08_002013-11-07T08_27_53.063-08_00KBOs and comets are indeed the same. The interesti...KBOs and comets are indeed the same. The interesting thing about KBOs that we see, though, is that they are hundreds of kilometers across and thus have significant gravitational compression on their insides. While you could get away with having a fluffy snowball sitting on the surface, the interior would still be quite compressed, and the overall porosity would have to be low.Mike Brownhttps://www.blogger.com/profile/04402191029077523538noreply@blogger.com