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Post by silverdragon on Jul 30, 2016 5:55:03 GMT
Ceres is a carbonaceous asteroid, meaning that it is made from frozen gases like hydrogen, helium nitrogen and oxygen with other trace elements and molecules in similar abundance to the conditions in the early Solar System. It is also the only body in the asteroid belt has enough gravity to form a spherical shape, and heating in the interior due to that gravity has probably produced the energy for these cryovolcanoes. If the surface is "frozen", and the centre maybe molten, maybe there is significant geothermal geology that shifts the surface "crust" frequently, in the same way we get continental drift here, but not enough to create mountains, just absorb craters, or even fill them out, because the crust isnt that thick yet, and asteroid hits break through into the molten inners, that just instantly fill those craters?..
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Post by mrfatso on Jul 30, 2016 6:31:31 GMT
Ceres is a carbonaceous asteroid, meaning that it is made from frozen gases like hydrogen, helium nitrogen and oxygen with other trace elements and molecules in similar abundance to the conditions in the early Solar System. It is also the only body in the asteroid belt has enough gravity to form a spherical shape, and heating in the interior due to that gravity has probably produced the energy for these cryovolcanoes. If the surface is "frozen", and the centre maybe molten, maybe there is significant geothermal geology that shifts the surface "crust" frequently, in the same way we get continental drift here, but not enough to create mountains, just absorb craters, or even fill them out, because the crust isnt that thick yet, and asteroid hits break through into the molten inners, that just instantly fill those craters?.. If there was activity then mountains would be quite significant features on the surface compared to its size I think. From what I remember of the theories that I read the lower the gravity of a planet or other body then the tendency become a regular sphere is weaker, there's less 'pull' towards the centre. So protrusions are more significant. That's why Olympus Mons is so,very large on Mars, and if you remember the film Interstellar they found a world that Earth like but had a significantly greater mass it was far flatter with an ocean over the entire surface that allows huge waves to travel upon it. That planet was based on papers I read whilst I was a student. I don't belive therefore that there is significant plate tectonics going on on Ceres, features would be much more prominent, you do not see any of features such as transverse faults, volcanic ridges, subduction zones etc. I do recall that some Geophysicists and Geochemists suggest that in order for plate tectonics to work as on our planet you need liquid water to act as a kind of lubricant. There are other models for how geothermal upwelling would remodel the surface, but not through plate tectonics and continental drift.
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Post by silverdragon on Jul 30, 2016 6:37:52 GMT
Plate tectonics as you suggest require the planet to have a significant crust... If the crust or mantle is not that thick, its maybe just the crust, say the same significance as the skin on a pout of cooling custard. If the crust is minimally thick because of the inner warmth, and is maybe no more than the frozen surface of a pond or river in winter, any protrusions would quickly sink?.. or not be that high to be visible from the distances we have managed to see it from yet?.. mere wrinkles, "laughter lines" in a young planet?..
There may be significant up-wellings of such volume they flood over that surface crust and sink that crust on a frequent basis?.. forming a new crust as they go, and thus the older crust gets deeper, and then melted in to the core of the planet?..
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Post by mrfatso on Jul 30, 2016 7:24:35 GMT
A similar mechanism to Flip Flop Salt tectonics . sp.lyellcollection.org/content/363/1/245.abstractCrust as thick as a skin on a custard that's thick, for the earth think more a postage stamp on a football thickness. But the point is due to Ceres low gravity if they were there they would be prominent features and we would see them if that form of activity was taking place. The Dawn probe would see them.
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Post by silverdragon on Jul 30, 2016 7:39:01 GMT
A similar mechanism to Flip Flop Salt tectonics . sp.lyellcollection.org/content/363/1/245.abstractCrust as thick as a skin on a custard that's thick, for the earth think more a postage stamp on a football thickness. But the point is due to Ceres low gravity if they were there they would be prominent features and we would see them if that form of activity was taking place. The Dawn probe would see them. Took some working out, but, is this sort of what your inferring?...
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Post by mrfatso on Aug 3, 2016 6:18:23 GMT
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Post by WhutScreenName on Aug 8, 2016 15:28:22 GMT
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Post by the light works on Aug 8, 2016 17:11:15 GMT
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Post by silverdragon on Aug 9, 2016 5:56:35 GMT
Quite a good view of what is happening inside the "flame". I wonder how this is going to affect the making of fuel and how it burns...
On that subject, if you watch a Jet engine from a military fast jet, it has the row of diamonds out back... One of my workmates from back when, would check the row of diamonds on all the jets he saw, and make a note of them, because the number and spacing of them would tell him if it needed a service....
So, I have to ask, if the row of diamonds on a jet engine's exhaust tells you how perfect the combustion is, why isnt there the same thing on a rocket engine?..
Or is this a case of "We just dont know", and hence science begins?.
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Post by the light works on Aug 9, 2016 14:15:58 GMT
Quite a good view of what is happening inside the "flame". I wonder how this is going to affect the making of fuel and how it burns... On that subject, if you watch a Jet engine from a military fast jet, it has the row of diamonds out back... One of my workmates from back when, would check the row of diamonds on all the jets he saw, and make a note of them, because the number and spacing of them would tell him if it needed a service.... So, I have to ask, if the row of diamonds on a jet engine's exhaust tells you how perfect the combustion is, why isnt there the same thing on a rocket engine?.. Or is this a case of "We just dont know", and hence science begins?. I'd say the rocket one starts with "couldn't see them before now"
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Post by wvengineer on Aug 9, 2016 20:20:40 GMT
Quite a good view of what is happening inside the "flame". I wonder how this is going to affect the making of fuel and how it burns... On that subject, if you watch a Jet engine from a military fast jet, it has the row of diamonds out back... One of my workmates from back when, would check the row of diamonds on all the jets he saw, and make a note of them, because the number and spacing of them would tell him if it needed a service.... So, I have to ask, if the row of diamonds on a jet engine's exhaust tells you how perfect the combustion is, why isnt there the same thing on a rocket engine?.. Or is this a case of "We just dont know", and hence science begins?. They are called shock diamonds. They are a result of the supersonic exhaust of the engine going though several shock wave steps in order to slow down to subsonic ambient speeds. They are not a direct result of combustion, but of the speed of the exhaust telling a trained mechanic how fast and therefore how well the engine is performing. Weather or not the shock diamonds are visible is a based on how "clean" the exhaust is. On engines that run very basic fuel mix lie oxygen/hydrogen, you will see those diamonds. YOu can see them if you look at the engines on the space shuttle or like the ones on the Saturn 5. A solid fuel booster runs a very complex chemistry of ingredients. The white smoke from those engines is actually the powdered aluminum that is one of those ingredients. Because of that mix, the exhaust is so cloudy that you can't make out anything. To Silver's questions, I actually think that if you could clean out the exhaust, you actual could see the shock diamonds. The problem is that shock diamonds are int he middle of the flow, surrounded by lots of very turbulent air. In the case of that engine, i would be willing to bet that if you could somehow see into the middle of the flow, you would see them. But as we see it there, we are looking at the turbulent outer layers of the exhaust that is obscuring the core.
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Post by Lokifan on Aug 11, 2016 15:02:51 GMT
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Post by the light works on Aug 11, 2016 15:37:55 GMT
they seem pretty convinced something hi it to put it in that orbit. I think it would be more likely that we picked it up somewhere, and it may just be passing through, in a non-orbital trajectory, if they've not watched it complete an orbit.
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Post by GTCGreg on Aug 11, 2016 15:53:33 GMT
"They" can't explain a small hunk of ice in our own solar system, yet they can tell you exactly how the entire universe formed from a "bang" 14 billion years ago.
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Post by OziRiS on Aug 12, 2016 1:21:56 GMT
they seem pretty convinced something hi it to put it in that orbit. I think it would be more likely that we picked it up somewhere, and it may just be passing through, in a non-orbital trajectory, if they've not watched it complete an orbit. Well, seeing as Neptune has an orbital period of 165 years, they probably haven't seen it complete an orbit. Not unless someone has been watching it for 165+ years or it's going ridiculously fast.
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Post by wvengineer on Aug 12, 2016 13:07:00 GMT
they seem pretty convinced something hi it to put it in that orbit. I think it would be more likely that we picked it up somewhere, and it may just be passing through, in a non-orbital trajectory, if they've not watched it complete an orbit. You don't need watch a full orbit to determine where it is going. All you need is 3 or 4 different observations where you can get a good 3-d fix on it's position in space that are a reasonable length of time apart, usually a few weeks or a month. Once you have that, you can determine its position, direction, and speed. With that info, it is a fairly simple mater of plugging those values into the correct formulas to determine what the full orbit will look like. The physics that dictate all that isn't too complex.
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Post by the light works on Aug 12, 2016 13:53:05 GMT
they seem pretty convinced something hi it to put it in that orbit. I think it would be more likely that we picked it up somewhere, and it may just be passing through, in a non-orbital trajectory, if they've not watched it complete an orbit. You don't need watch a full orbit to determine where it is going. All you need is 3 or 4 different observations where you can get a good 3-d fix on it's position in space that are a reasonable length of time apart, usually a few weeks or a month. Once you have that, you can determine its position, direction, and speed. With that info, it is a fairly simple mater of plugging those values into the correct formulas to determine what the full orbit will look like. The physics that dictate all that isn't too complex. on something with a 100+ year orbit at that distance, can you get a good enough 3D fix on its position to reduce your margin of error to less than light years?
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Post by wvengineer on Aug 12, 2016 15:22:17 GMT
Sigh, fighting the IT setting on my work computer... Lost my first post. For a good summary: spaceplace.nasa.gov/review/dr-marc-solar-system/planet-distances.htmlUsing normal visual observations, you use several observations over a period of time and then use trig to calculate the distance based on the chance in angle of your observation using the distance the earth travels in a given time as a known base to calculate from. Cassini used this to measure the distance to Mars in 1672 to withing a million miles. For higher precision, you can use high powered RADAR. Since the speed of the radar wave is a known constant, you can time the return signal for very good accuracy. For something in the Trans-neptunain region, accuracy of a million miles (0.00000017 ly) is common. The longer you do observations, the ore accurate you can get. 6 months will give you the best results since you can use the fill diameter of the earth's orbit as your base for calculation.
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Post by the light works on Aug 12, 2016 15:36:50 GMT
Sigh, fighting the IT setting on my work computer... Lost my first post. For a good summary: spaceplace.nasa.gov/review/dr-marc-solar-system/planet-distances.htmlUsing normal visual observations, you use several observations over a period of time and then use trig to calculate the distance based on the chance in angle of your observation using the distance the earth travels in a given time as a known base to calculate from. Cassini used this to measure the distance to Mars in 1672 to withing a million miles. For higher precision, you can use high powered RADAR. Since the speed of the radar wave is a known constant, you can time the return signal for very good accuracy. For something in the Trans-neptunain region, accuracy of a million miles (0.00000017 ly) is common. The longer you do observations, the ore accurate you can get. 6 months will give you the best results since you can use the fill diameter of the earth's orbit as your base for calculation. I can understand half a bubble off on a level. not sure how much margin of error in calculating an orbit accuracy to within a million miles makes. it's outside the scale I'm accustomed to.
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Post by Lokifan on Aug 12, 2016 16:23:58 GMT
Neptune's orbit is 2.8 billion miles from the Sun.
Assuming a circular orbit, that means the circumference is about 18 billion miles.
And the object is even further.
With those numbers, a million miles is pretty insignificant.
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