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Mars, Mercury May Have Formed From Earth and Venus
goran72 sends along a report on a radical new theory of planet formation that suggests that Mars and Mercury were formed from the scraps of Earth and Venus. The theory has testable predictions — for example that the compositions of the rocky inner planets should be more similar than the current theory of planet formation would have them.
Venus and Earth are not even married! And now they are trying to say that Mars and Mercury are illegitimate children of a lesbian union of planets?!
NO! I will not accept it! GOD DID IT! Things are the way they are because God did it that way and need no further explanation!
Sometimes when a mommy planet and a daddy planet love each other very much...
"It is a miracle that curiosity survives formal education." -Albert Einstein
Also, I wonder how they get the protoplanetary disk to break up into bands. Saturn's rings aren't really banded as much as you might think. The degree to which they are is largely due to moons (or their on-going generation). Left to themselves, the rings should spread and homogenize.
Very true but the 4 inner planets have almost circular orbits.
Any planet that get flung around will have a very eliptical orbit.
The Hot Jupiters are a different thing. They are caused by the system having enough material to cause drag and slow them down enough to collapse the orbit.
Very true but the 4 inner planets have almost circular orbits.
Any planet that get flung around will have a very eliptical orbit.
Orbits get circularized by a number of effects over time, both orbital and viscoelastic coupling. Hot-Jupiter orbits somehow get circularized, after all, and they're much harder to circularize than smaller planet orbits.
The Hot Jupiters are a different thing. They are caused by the system having enough material to cause drag and slow them down enough to collapse the orbit.
Any process that can move Jupiter and super-Jupiter size planets will easily reposition smaller planets.
http://www.geoffreylandis.com
The Structure of Scientific Revolutions, Thomas Kuhn's magnum opus, should be required reading before engaging in a debate on science. There's an aphorism that goes "all theories are wrong, but some are useful." We can and do use theories we know have flaws because in the vast majority of cases, they predict and explain what happens in nature. When a better theory comes along to explain the observations, we begin to use that one instead.
It's absolutely useless to say "this theory is wrong!" as long as the theory, however flawed in some cases, works well in the general case. What do you propose to replace it? Does your replacement make specific, verifiable assertions about nature that are more correct or accurate than those of the prevailing theory? I thought not.
(On the off chance that it does, and you can provide evidence, please, submit an article to Science or Nature; you'll be famous for generations.)
The more petty among you will read what I said and decide (entirely without consulting me) what alternative theory I believe in and will probably proceed to make a contest of it because you cannot grasp the simple essence of "this is an open question" and therefore cannot conceive of anything except one ideology versus another. It's alright not to know; sometimes there is great freedom in it.
The problem with just "not knowing" is what do you do then? I agree we shouldn't treat these theories as absolute truth, but that doesn't mean they're not useful. The scientific method works by making a hypothesis, making predictions from that hypothesis, testing them, and modifying the hypothesis if necessary. But you have to start somewhere. Make some guesses, even if they're bad guesses. If you just shrug your shoulders and say "I dunno", you'll never get anywhere.
Give me Classic Slashdot or give me death!
Actually, it's the reverse. If you put a planet in the disk, it tries to open a gap. (See the Keeler and Encke gaps in Saturn's A ring for examples.)
So that's not it. (And besides, it sounds like these guys are positing the bands form FIRST.)
Your comment on frozen lines in plasma not withstanding. Its an approximation, that works well for a lot of cases. And anyone in the field will tell you that. Newer models allow this to be relaxed more and more. But really it doesn't change things that much with typical astronomical plasmas.
And the different redshift thing? Could you be more specific? There are really no theories that predict the comsmic microwave background and isotope ratios other than the big bang. Which also leads to the standard red shift interpretation. There really nothing else we have come up with that works. We have just have so much red shift data now. There really are no alternative that explain this without some serious arm waving.
and are humble enough to admit that maybe you don't know
I'm sure you are humble enough for both of us.
The Grey Goo disaster happened 3 billion years ago. This rock is covered in self replicating machines!
Last I checked, the solar wind isn't a stream of electrons.
It's roughly equal numbers of electrons and protons, as I recall, with a very small amount of helium nuclei in the mix.
Some good graphs here
http://www.geoffreylandis.com
Then, perhaps you should elaborate in what alternative you believe in instead of making pronouncements about how wrong a theory is without offering a more valid alternative.
There is no "-1 offended" or "-1 you don't agree with me" mod options for a reason.
Eccentric orbit's are destabalized during the process of circularization which then either ejects them OR crashes the orbit. But it is also true the eccentric orbits tend to be a bit more stable than true circular ones...but only a little.
I never said the sol system had a hot jupiter. But it had been cited in the grandparent therefore I was adressing the issue. Hot Jupiters happen in specific conditions where the gas that formed the original system was thick enough to not get blown away quickly. Therefore the jupiter sized planet, with it greater porportional size and gravitational field effect due to lower density, are disporportinaly slowed through friction. As they slow they eat or eject all inner planets until they get close enough so that the solar wind HAS cleared everything out.
The sol system did not have these conditions therefore no hot Jupiter.
With the higher density but smaller size of rocky planets they are not as likley to experience the slowing effect before they clear the neighboring space therefore any moving will probably be due to colision or near collision with other large bodies and will be entierly random.
The reason Venus, Earth and Mars probably haven't moved is because the planets chemistries match theory fairly closely. Planetary genesis theories suggest that there will be subtly chemical differences at varius altitudes from the star. Mercury has unexpected chemistry which could come from collision (there is evidence for such an event) or being moved
Jupiter sized planets can only form out past the "Snow line" where water can form ice. Otherwise you get terrestrial planets that max out a few times bigger than earth.
When a jupiter sized planet moves into a terrestrial orbit it EATS the planet already there.
Since the earth is still here, no hot jupiter ever existed in sol system.
When astronomy has a crisis in the next 5-10 years or so, perhaps most of you will be surprised. For a good starting point to see what I am talking about, do some research on black holes and what Schwartzchild really said vs. what is commonly attributed to him in colleges and textbooks everywhere (ask yourself if the most amateur of journalists would report so inaccurately). Or research Edwin Hubble and the fact that there are two equally valid interpretations of the redshift equation and we have settled the question of which to use by making an assumption. Or explain to me how a star that is powered by an internal thermonuclear reaction could have an atmosphere that is many times hotter than its surface (if you think that's a simple matter, you do not appreciate the question). Or why it is that a steady, flowing stream of charged particles is called an electric current everywhere it is found, unless those charged particles come from the sun and compose what is called the solar wind? Or why Hannes Alfven, the originator of what is now called magnetohydrodynamics, has thoroughly discredited his own theory, including during his Nobel Prize speech (especially the part about magnetic field lines being "frozen" in plasma), yet scientists continue to use this discredited theory to come up with fanciful ideas like "magnetic reconnection"? It's time to come up with new ideas instead of unscientifically shoring up old, failed ones in the name of preserving your funding.
The first two statements are insinuations and don't actually say anything (I'm not going to spend many hours reading Schwartzchild, Hubble, etc based on a vague insinuation). As for the high energy of the Sun's corona, the entire Sun is a rotating ball of plasma with strong magnetic fields and a power source in the center. That makes numerous opportunities to create highly energetic particles and throw them out. A steady flowing stream of charged particles is not an electric current because we haven't assertained the most important characterist of a current, namely that there is a net flow of charge. For example, water is a flowing stream of charged particles. However, the charges are tightly bound to each other so there's no EM effect until you almost touch the water. The Solar Wind contains a lot of charged particles, but it is electrically neutral, there is no net flow of charge. It is a plasma without an electric current.
Hannes Alfven hasn't "thoroughly discredited" magnetohydrodynamics. And "appreciating" a question like "How did the universe get here?" doesn't mean the question is well-defined. It implies that there's some process that makes universes. There may well be no such thing.
Having said that, you have mentioned a large variety of subjects: the Sun and its plasma environment, black holes, origin and current dynamics of the universe, and plasma dynamics. A lot of that we really don't have a good grasp on and it is likely that we'll see serious challenges to our understanding of these phenomena.
Eccentric orbit's are destabalized during the process of circularization which then either ejects them OR crashes the orbit.
I can't make any sense out of this statement. "Circularization" is by definition decreasing the eccentricity of an orbit. Decreasing the eccentricity of an orbit will not "eject" or "crash" the orbit; you have to increase the orbital eccentricity to do that. You can't "destabilize" an orbit by "circularizing" it; the two things are opposites.
But it is also true the eccentric orbits tend to be a bit more stable than true circular ones...but only a little.
I have not the slightest notion what you mean here. Circular orbits are not unstable! About the most you can stay is that circular orbits are "destabilized" into elliptical ones, but I can't see how that makes them "less stable" that orbits that start out elliptical in the first place.
I never said the sol system had a hot jupiter. But it had been cited in the grandparent therefore I was adressing the issue. Hot Jupiters happen in specific conditions where the gas that formed the original system was thick enough to not get blown away quickly. Therefore the jupiter sized planet, with it greater porportional size and gravitational field effect due to lower density, are disporportinaly slowed through friction.
I don't know what model you're assuming, and I don't know what you mean by "disproportionately" or what sort of scaling law you're assuming. About the best I can say here is that it is extremely model dependent.
As they slow they eat or eject all inner planets until they get close enough so that the solar wind HAS cleared everything out.
The sol system did not have these conditions therefore no hot Jupiter.
With the higher density but smaller size of rocky planets they are not as likley to experience the slowing effect before they clear the neighboring space
about all I can say is that this is extremely model dependent. If the small rocky planets are clearing their region, as you note, the amount by which they move in reaction is going to be inversely proportional to the planet's mass, and hence smaller planets will move more, not less. Have you actually calculated a scaling law? It will depend on what you assume to be the dominant effect, but it's not at all clear that the mechanism vanishes with small planets.
therefore any moving will probably be due to colision or near collision with other large bodies and will be entierly random.
Random, yes.
The reason Venus, Earth and Mars probably haven't moved is because the planets chemistries match theory fairly closely. Planetary genesis theories suggest that there will be subtly chemical differences at varius altitudes from the star. Mercury has unexpected chemistry which could come from collision (there is evidence for such an event) or being moved
There is not enough chemical knowledge of the composition of the inner planets to definitively base this statement on experimental data. (Venus in particular is very poorly characterized). The chemistry seen on the surface is highly affected by the planetary differentiation (that is, what got segregated to the core), and we currently know little about the cores of Mars, Venus, or Mercury.
http://www.geoffreylandis.com
Mars is from Earth, Mercury is from Venus.
...and methane is from Uranus.
Sorry..
You just got troll'd!