New here and curious...

[bbrock]

I suppose the problem I have with this idea is that metal rich is defined as anything heavier then helium. If a globular passes through the Milkey Way galactic plain and touches off a star burst -- creating a new open cluster of some 100 stars, granted there will be a high concentration of atoms heavier then helium.<br /><br />Now lets compare this concentration of heavy atoms in this relatively young open cluster to a globular cluster -- M13 or M3 or M53 or M92 etc etc. These guys have been around for over 10 billion years. Our Galaxy has robbed most of their stars. Thats a lot of fused hydrogen and a bunch of fused helium. Yet a property of a Globular cluster is low metalicity. A property of an open cluster is high metalicity. I really have a mental disconnect over this concept. <br /><br />Clear Skies<br />Bill

 

[yevaud]

Douglas:<br /><br />Well, our solar system is the beneficiary of many Gy of Supernovas occurring, which enriches the interstellar medium with heavy elements.<br /><br />So, when the original dust cloud that formed our solar system began to collapse, it naturally contained a higher proportion of those elements.<br /><br />Heavier elements were drawn inwards towards the protosun and protoplanets (which is why you see the rocky, solid bodies preferentially in the inner system, and gas giants preferentially in the outer).<br /><br />Since, of course, the sun and the planets were formed out of the same grab-bag of material, naturally Earth would share in the wealth (so to speak).<br /><br />That what you meant? <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>

 

[nexium]

I agree the close in giant planets found to date make the inner plants lost their gas theory seem doubtful. Do we have a good reason to think that the close giant planets we are finding have very thick atmospheres other that the precedent in our own solar system?<br /> I have been surprised when I circulate the water in a round swimming pool, by hurrying around just inside the side; that both the heavy and low density grits move to the center instead of the outside. Is it possible that this opposite of centrifuge action occurs in early solar systems which are circulated by the orbiting proto planets? If so this further cast doubts on explanations of how the solar systems, including ours, got the way they are. Neil

 

[yevaud]

As the first question, hard to say. Originally, they weren't even expecting to see bodies as large as they have, as close in to the primary. Not sure why this is, as yet, or so I have read.<br /><br />Hmm. Compound question. Well, in a proto-system, material is largely drawn inwards by gravity and electrostatic attraction (which is how it's believed the material begins to clump together in the first place).<br /><br />The coriolis force of the spinning disk of material will, yes, try to force material outwards, but there's also gravity pulling inwards. In the end, gravity wins enough for the heavier material to settle inwards, forming the inner system, and lighter materials settling outwards, hence the gas giants.<br /><br />Hope that answers your question(s). <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>

 

[Saiph]

sorry i haven't been around lately, i'm scoping out the university of wyoming for graduate school (they've thier own 2.3 m IR telescope!)<br /><br />Anyway, the reason earth is mostly heavy metals with almost no hydrogen and helium is a selection effect (similar to the centrifuge you compared it to). The lighter an atom is, the faster it moves at a given temperature. This is because at a given temperature, everything should have the same "average" kinetic energy (or at least the same distribution). since H and He are so light, they have more velocity in order to have the same kinetic energy as the heavier atoms.<br /><br />Now planets all have an escape velocity. Hydrogen and Helium's typical velocity distribution has a large fraction of them moving faster than earth's escape velocity. As such, they disappear into space, even if they were here after star formation.<br /><br />We don't know if most planets are the "hot jupiters" we've been finding, becuase that could be due to the selection effect caused by our methods of detecting them (the wobble method tends to find heavy, close orbiting planets).<br /><br />Anyway, I'm off to WIRO (that telescope)...I get to ride a snowcat for while! <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>

 

[jatslo]

I have observed Saiph to be the most knowledgeable, with respect to astronomy; however, I am fairly new too, so there could be more. Sorry I didn’t see this thread sooner. We obviously have a great deal to learn. Will you teach us?