Star System Soaked With 'Rain'

[h2ouniverse]

Andrew,<br />In reply to: "would they not <br />be detectable by ... COG of the Solar System measurements "<br />---------------<br />A super-Earth at 800AU would shift indeed the COG of Solar System by about 2 million km. But, with a period larger than 20000 years, i.e. about one arcmin per year.<br />Not sure they can detect such a slow component in the COG. And even so, are they even trying?<br /><br />Cheers<br />

 

[3488]

Thanks Joel.<br /><br />A 2 milion KM shift in Solar System CoG is well within the capabilities of modern equipment.<br /><br />The one arc minute per year shift though would be extremely difficult to detect.<br /><br />It is good point though, IS any one actually bothering to monitor this?<br /><br />AFAIK, the Kuiper Belt objects had a theoretical upper size limit, due to the low speed<br />of the formative material, hence my theory that Eris, Triton & Pluto, perhaps being<br />close to the upper size limits for KBOs.<br /><br />As for really large objects in this region, IMO it would either mean, that our current ideas<br />for the formative processes in this region are wrong / or they may be captured <br />'rogue' planets, escapees from other solar systems, much like the idea being <br />bantered around for Sedna. That WOULD be very exciting.<br /><br />I am probably wrong though!!!!!<br /><br />Regarding Triton, I certainly cannot think of any other explanation. A large moon, in a <br />retrograde, highly inclined orbit, cannot think of anything else.<br /><br />The rather, reatively crater free ice surface, does suggest that Triton, was <br />violently heated up internally, during the initial capture & eccentric orbit, stretching & <br />squeezing the globe (much like Io around Jupiter), but refroze when the orbit circularized.<br /><br />Below, 'Ice Bridge' between two frozen 'lakes' on Triton.<br /><br />Voyager 2.<br /><br />NASA / JPL.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[h2ouniverse]

"theoretical upper size limit, due to the low speed <br />of the formative material, ":<br />you are right, as far as local formation is concerned provided that the mass there has been correctly assessed.<br />Actually what I had in mind was something that would have formed far closer to Sun and be deported during the migration phase. One planet or big planetesimal planet out of two is said to be statistically ejected. Some may reach the liberation speed from Sun's gravity well. But some others may simply have been injected into higher eccentric orbits by close encounters.<br /><br />Just another theory, waiting for a detection...<br /><br />Best regards.

 

[robnissen]

Considering how common water is, is it likely that pure water planets are common?

 

[3488]

Sorry Joel.<br /><br />I did not understand what you meant. I thought you meant large icy orbjects formed<br />in situ, not put out there from closer in.<br /><br />Hi RobNissen,<br /><br />IMO why not?? The Saturn moon Mimas is almost pure ice. <br /><br />I do not see why considerably larger water ice bodies could not have formed.<br /><br />Perhaps H20universe will know more about this.<br /><br />Below Mimas. A water ice 'iceball'. 397 KM diameter.<br /><br />NASA / JPL.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[h2ouniverse]

Rob, Andrew,<br /><br />Actually I do not know whether it is possible.<br />I would expect that it cannot be. <br />Small bodies like Mimas ok. Or the big chunks stripped off from the external ice layers of EL61.<br />But a very large body composed only of water would have a gravity sufficient to collect other substances on its way. Especially the ones denser than water, that once accreted would sink and form a rocky and metallic core anyway.<br />There are areas in space with few water: close to stars within the frost line. But there is no mechanism IMHO that would deplete a region of space from rocky material. So it should be collected by a large body along with H2O.<br /><br />The proportion of H2O in a large planet can for sure be high: Uranus and Neptune have a huge porportion of their mass in the form of H2O.<br /><br />What I hope will be found one day is a super-Earth far from Sun, because something intermediate between Uranus or Neptune (supercritical ocean) and an Earth placed by thought far from Sun (thus giving a frozen ocean) should have a very deep liquid ocean with an ice-free surface. The bottom might be ice VII instead of rock though, but if the ocean upper limit is wiith the atmosphere, organic materials can make their way.<br /><br />Best regards.

 

[MeteorWayne]

"The proportion of H2O in a large planet can for sure be high: Uranus and Neptune have a huge porportion of their mass in the form of H2O. "<br /><br />Any idea of what theat precentage is?<br /><br />AFAIK, it is not that high, but I don't know for sure.<br /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[h2ouniverse]

Andrew,<br /><br />Fantastic picture of Mimas!<br /><br />Btw Varuna is said to have a density of 1. And a diameter />800km (although we need to be cautious with TNO diameters, generally overestimated).<br />I would assume however that a minimum quantity of rock should be be present at least in a dispersed way, à la Callisto. Unless there is heat stored in Varuna, and Varuna is, unexpectedly, differentiated. If only we could get images of this spinner!!<br /><br />Best regards.

 

[h2ouniverse]

MW,<br /><br />AFAIK, Uranus is core + mantle + gaseous atmosphere, <br />with the following mass distribution:<br />* core less than 5%<br />* mantle about 85, 90%<br />* atmosphere between 5 and 10%<br />The "mantle" is thought to include essentially ices of water and ammonia, and a supercritical ocean of water+ammonia mix. Some methane expected but not in majority.<br />This being said, as Andrew rightly complains, nobody will know until we send a probe!<br /><br />Best regards.<br /><br />Best regards.

 

[h2ouniverse]

Andrew,<br /><br />In reply to: "I thought you meant large icy orbjects formed in situ, not put out there from closer in."<br />------------------<br />Well actually I meant both. In my previous post page 1 I said indeed that it may be part of the 30-50 Earth masses of the initial KB. In that case, that stands for an in-situ in the inner part of this primordial KB, at about, say, 15 AU. Uranus and Neptune are said to have formed far closer to Sun with 14 to 17 E-masses. So just a little bit further from Uranus-Neptune formation zone, it was surely possible to form Earth-massed planets. <br />The inner part of the primordial KB might have be extermely perturbated. So if such planets existed, they would have been expelled from their craddle. Logically with more strength than the outer bodies (perturbated by the giants just at the end of their migration).<br /><br />Best regards

 

[brellis]

<font color="yellow">The "mantle" is thought to include essentially ices of water and ammonia, and a supercritical ocean of water+ammonia mix. Some methane expected but not in majority.<br />This being said, as Andrew rightly complains, nobody will know until we send a probe! </font><br /><br />I'm following the water <img src="/images/icons/cool.gif" /> on this one <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>