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Are Small Rocky Worlds Naked Gas Giants?
astroengine writes "The 'core accretion' model for planetary creation has been challenged (or, at least, modified) by a new theory from University of Leicester astrophysicists Seung-Hoon Cha and Sergei Nayakshin (abstract). Rather than small rocky worlds being built 'bottom-up' (i.e. the size of a planet depends on the amount of material available), perhaps they were once the cores of massive gas giant planets that had their thick atmospheres stripped after drifting too close to their parent stars? This 'top-down' mechanism may also help explain how smaller worlds were formed far from their stars only to drift inward toward the habitable zone."
I imagine this excludes Earth, but if not it would explain a lot of the smells.
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Here one can generalize: instead of being improved monkeys we may be restrictions of something higher. And entropy hints at our downward progress.
I've had this idea before. Thought that's what happened to Pluto, when I was was in 3rd grade. I don't see anyone nominating me for a Nobel prize!
For a long time the only planets we found were 'hot Jupiters'. Jupiter sized planets very close to their star (inside Mercury's orbit).
Why weren't these planets stripped of their atmosphere?
modified > challenged
no?
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Many of these extrasolar gas giants are in extremely small orbits very close to a star. So how could Earth and Mars have lost huge atmospheres?
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Your crust is showing. Slut.
I don't know. Why ask me? What on Earth makes you think I would know? Go ask an expert. Geesh.
Equine Mammals Are Considerably Smaller
How does this square with the idea that gas giants have materials like metallic hydrogen at their cores? I can see how accretion can occur without the necessity for a rocky core, and I can see how it would occur with one. Either way, isn't this hypothesis kind-of trivial in its conclusion? Matter accreted more matter. Equilibrium is reached. Constituent parts - gas, solid, ice are determined based on many variables. There is a centre of gravity. That's all.
(Disclaimer: I might have misunderstood the point!).
As this calculation for CoRoT-2b indicates, at 6M tons per second, a hot super-Jupiter would need more than 39B years (~3x the age of the universes) to be "blown/boiled away". Jupiter is ~1/3 the mass of CoRoT-2b, so at 6MT/s, it would last 13B years. The rate of loss of atmosphere would have to be at least a factor of 10 greater than on CoRoT-2b, or greater than 60MT/s just for a Jupiter mass planet to to reach an Earth mass core in 1.3B years. Our solar system is estimated to be ~5B years old and that Earth and Mars both appear to have been rocky for more than 2B years, so 1.3B years to blow off an atmosphere seems to be a generous estimate of quickly it must have happened.
Given that our sun is only converting ~600M tons/sec of hydrogen into ~594M tons of helium, a net loss of 6MT/s, therefore a Jupiter mass planet would need to be receiving a enough of the solar radiation to blow off 60MT/s. Yes, E=mc^2, and c^2 is large, but you're still talking about a lot of mass to move out of notable gravity well (first out of the Sun's gravity well, then move more mass out of Jupiter's gravity well). If jupiter were in earth's orbit, would it receive enough solar radiation to lose 60MT/s? Not from solar wind, the total solar wind mass is ~1.85MT/s. even if all 1.8MT were directed at Jupiter and Jupiter had no magnetopause to protect it from the solar wind, 1.8MT/s would not strip 60MT/s of atmosphere. So you have to come up with a theory where the EM radiation causes the the planet to eject it's own atmosphere, which is still going to be virtually impossible.
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And they magically entered stable orbits afterward. Of course.
I thought the solid surfaces of gas giants weren't rocky at all, but rather hydrogen compressed to a metallic state under extreme pressure? Without the pressure, the gas would melt and then boil away. I thought rocky planets were basically accretions of asteroid junk.
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Ah wait, it was just your mom.
Is that sail or sale? Or is that a sail sale? I suppose you can hold a sale around Neptune in a submarine having fun on Triton, especially if something like the Battleship Yamato actually makes the trip into space. If a battleship can do that, I suppose a submarine can too.
I also suppose these "scientists" haven't been able to really prove the existence of China to your satisfaction either. Yes, Marco Polo brought back some amazing legendary stories and a few trinkets he claims to have come from there. I guess the theory of China is just the figment in the imaginations of a whole bunch of people too, in spite of what the Sam Walton family has done with more trinkets supposedly discovered from that mythical place.
At those pressures, we ought to see a planet covered in diamonds, garnets, granulites, etc. - very high temperature metamorphic rocks. If the planet is made of other types of rock, then there probably wasn't that much pressure on it when the rock formed.
Disclaimer: I am not a xenogeologist.
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This seems to be the title of this post. Very unlikely don't you think. Are some? Sure, why not.
The general rule of thumb is that volatiles like water/hydrocarbons/helium get evaporated and blown out by the nascent star at the centre of a proto-planetary disk. So, many rocky planets will form from the remaining silicate and other non-volatile materials (such as Iron) that are left after most of the volatiles are gone. Will some gas giants migrate inwards and have their atmospheres evaporated and blown off..? Can't think of any reason why not especially given the number of hot jupiters we've discovered out there.
Why this post/article would bother suggesting that ALL rocky planets MUST be formed this way is beyond me, seeing as the authors themselves don't appear to be making this assertion. Whether a planet forms this way would depend on all sorts of factors, such as the composition of the proto-planetary disk and the temperature of the star among other things.
I'm also quite sure this isn't the first time I've heard this idea.
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Show me the simulation. It would make a nice screen saver and maybe explain the theory to those who haven't read TFA or imagined it previously.
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But not in the comments for this article.
Gas giants are wannabe stars. They are Pauly Shores of the night skies.
You can't handle the truth.
They can't really prove there is a distant planet revolving around a distant world.
You seem to have bought the 'distant world' theory, you're this close in believing the earth isn't flat. Do your parents know this?
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The Earth surrounded by Oxygen gas (and other gases) in the atmosphere, the only difference to us is that our eyes have evolved to see through the wavelength of oxygen making it appear 'invisible', but from the hypothetical alien point of view, an alien looking at earth might not have the eyes to see through the Oxygen and it would look like any other gassy planet from their perspective.
Maybe the technology can be developed to look through the gasses of other planets to see inside in the same way we can see though oxygen.
Sorry if there are any scientific errors in my theory, I'm not an expert, but unlike most the other posters on Slashdot, I don't even pretend to be one.
perhaps they were once the cores of massive gas giant planets that had their thick atmospheres stripped after drifting too close to their parent stars?
(emphasis mine)
Let's assume they did. How did they drift back out?
The three laws of thermodynamics:(1) You can't win. (2) You can't break even. (3) You can't even quit.
There's no made up math involved... it's an irrefutable conclusion from simple observation, plus judicious application of occam's razor. If you can come up with a simpler explanation that actually accounts for the observations ("just gas moving around" wouldn't cut it, I'm afraid... because that doesn't explain all the observations), then you may be in line for a nobel prize.
File under 'M' for 'Manic ranting'
Eureka moment....here is what I believe, if the clouds are like the cocoon of a moth, helping keep it safe until it transforms, then you could almost say that the cloud is there for a reason, and that the planet is now morphing into a solid planet ready for life. This would imply that the gas is great vs. anything damaging to a planet while forming....such as cosmic or gamma rays, solar winds, UV rays etc...whatever that might be ....we can also deduce that if the gas planets are the precursors to
formed planets...then we can assume there is an evolutionary path that forces the gas inside to condense while the gas outside stays there for protection...leading to believe that there are 2 types of gas...one for creation of , and one for defense....
Now that we know this, I think if we were to use that same information and look into the defense properties of that second gas, in order to define what it is made up of, and maybe replicate that someway for our development of mars, in essence helping the mars rock to become habitable (again or for the first time?) ...
it might help us create a second rock that can hold human life.