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Author Topic: 'Super' Earths may not be life friendly after all.  (Read 1913 times)

justboatonic

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'Super' Earths may not be life friendly after all.
« on: November 06, 2010, 07:34:31 PM »

H hum! Its seems possible that even if the Kepler Mission is successful in finding any Earth \ terrestrial like planets in the habitable zone of Sun like stars, these 'super' earths may be inhospitable to life! This would add even more credence to our solar system tending towards uniqueness.

Initial research has indicated that where a 'super' Earth is only a couple of times heavier than our earth, the planet's core may not be able to generate a magnetic field to protect any potential life from hazardous radiation.

ROCKY planets a few times heavier than Earth that we thought might be life-friendly may lack one vital feature: a protective magnetic field.

Planets are thought to owe their magnetic fields to an iron core that is at least partly molten. But a simulation of super-Earths between a few times and 10 times Earth's mass suggests that high pressures will keep the core solid, according to Guillaume Morard of the Institute of Mineralogy and Physics of Condensed Matter in Paris, France, and his team (arxiv.org/1010.5133).

Without a magnetic field, the planets would be bathed in harmful radiation, and their atmospheres would be eroded away by particles streaming from their stars. So life would have trouble getting started on super-Earths, even if they lie in the habitable zone around their stars.

However, Vlada Stamankovic of the German Aerospace Center in Berlin reckons it is too soon to rule out molten iron cores - and magnetic fields - for super-Earths. Their interiors might get hot enough to melt iron, he says. "Actual temperatures could be much larger than assumed - we simply do not know."
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dodgy geezer

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Re: 'Super' Earths may not be life friendly after all.
« Reply #1 on: November 06, 2010, 09:29:57 PM »

The most important words in this comment seem to be the last five....
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gondolier88

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Re: 'Super' Earths may not be life friendly after all.
« Reply #2 on: November 06, 2010, 09:47:17 PM »

I'll sleep now.
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dreadnought72

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Re: 'Super' Earths may not be life friendly after all.
« Reply #3 on: November 06, 2010, 10:05:11 PM »

The most important words in this comment seem to be the last five....

Oh yes.

And we could, if we were bothered, add that we don't know where life started on the Earth. If it were deep in the oceans at volcanic vents, as is possible, then the presence (or not) of an atmosphere or a magnetic field makes absolutely no difference to the basic chemistry.

I'll be borrowing Gondolier's pillow for the rest of this one.

Andy
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justboatonic

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Re: 'Super' Earths may not be life friendly after all.
« Reply #4 on: November 06, 2010, 10:22:23 PM »

Oh yes.

And we could, if we were bothered, add that we don't know where life started on the Earth. If it were deep in the oceans at volcanic vents, as is possible, then the presence (or not) of an atmosphere or a magnetic field makes absolutely no difference to the basic chemistry.

I'll be borrowing Gondolier's pillow for the rest of this one.

Andy

Actually, I think these are the most important "But a simulation of super-Earths between a few times and 10 times Earth's mass suggests that high pressures will keep the core solid, according to Guillaume Morard of the Institute of Mineralogy and Physics of Condensed Matter in Paris, France, and his team (arxiv.org/1010.5133)."

Interesting to note some people have instead used "Vlada Stamankovic of the German Aerospace Center in Berlin reckons it is too soon to rule out molten iron cores - and magnetic fields" instead!

as for saying "atmosphere or a magnetic field makes absolutely no difference to the basic chemistry" is just totally incredulous!
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Wasyl

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Re: 'Super' Earths may not be life friendly after all.
« Reply #5 on: November 07, 2010, 12:14:32 AM »

"Vlada Stamankovic of the German Aerospace Center in Berlin reckons it is too soon to rule out molten iron cores - and magnetic fields" instead!


these,academics  want to get a life,...the simple truth of the "matter"is,if you,re an RC,...one of the Ack Ack Gunners folowers,then you,ll believe in Adam and Eve and JC,....for them that believe in Darwin and his Evolution of Man theory,then they too are happy,....but the simple fact is ..irespective of who you believe in,is ...we are born...we live a long/short happy/sad life,then we pop our clogs,...then our loved one.s will come and clear out our lofts and garages of "all our keep in handies"....if we,re lucky some of our treasured models will be kept,...but most will be sold/or given to other club members,...and the rest will end upon ebay,....the days are counting down %%

Wullie
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dodgy geezer

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Re: 'Super' Earths may not be life friendly after all.
« Reply #6 on: November 07, 2010, 12:54:22 AM »


And we could, if we were bothered, add that we don't know where life started on the Earth. If it were deep in the oceans at volcanic vents, as is possible, then the presence (or not) of an atmosphere or a magnetic field makes absolutely no difference to the basic chemistry.


Correct. And we could also remember that a month ago, initial simulations suggesting that migrating HJs would make earth-like planets impossible turned out to be an exaggeration.  Simulations can be, and often are, way off beam.

The paper arXiv:1010.5133v1 [cond-mat.mtrl-sci]   http://arxiv.org/abs/1010.5133   comments that we know nothing about the iron melting curve under conditions corresponding to planets of several times Earth's mass. This is beyond our experimental capability. So they have performed theoretical calculations at the atomic level, and note that higher pressures make iron solidify at higher temperatures. They then match this theoretical curve to another theoretical curve for planetary adiabatic cooling, making assumptions about thermal barriers, and come up with a suggestion that cores will solidify quite rapidly for planets of 2xE and above. There is a lot of theory there, and a lot of assumptions.

They finally comment that precise conditions are, of course, unknown - temperatures will depend on the age of the planet and the precise alloy mix of the iron will affect the melting point. Finally, they comment that convection in a salty ocean may also generate a magnetic field, a suggestion which has been made for the one on Ganymede.

So the paper is highly theoretical, and many steps from saying that large earths will not have magnetic fields....
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justboatonic

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Re: 'Super' Earths may not be life friendly after all.
« Reply #7 on: November 07, 2010, 01:07:43 AM »

Well some inaccurate facts and backstroking going on again by a certain poster! He wants papers to support any theory. Then produces statements about the 'effects' of the Kepler mission virtually out of thin air. But the best bit is, he then bases his 'argument' on someone saying 'we just dont know!'

So he either wants papers to prove his case but at the same time then backstrokes and depends on the 'we just dont know' card and its all highly theoretical! Er, hello! What has he been basing his stance on todate? Theory!

Shame he cannot accept the simulation carried out by someone who is qualified in the simulation, Guillaume Morard of the Institute of Mineralogy and Physics of Condensed Matter no less, that 'super' earths may not be conducive to life after all. Incredible! He then attempts to argue the simulation is based on highly theoretical workings.

I could say pot, kettle, black but no doubt he'll do more backstroking!

Night, night, all.
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bilzin

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Re: 'Super' Earths may not be life friendly after all.
« Reply #8 on: November 07, 2010, 01:43:15 AM »

I am asolutely certain that I know where my ex mother-in came from..no doubt about it !!!  She had to be one of the unfriendliest alien life forms on Planet Earth, and she could not be classified as "super" in any way shape or form
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dodgy geezer

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Re: 'Super' Earths may not be life friendly after all.
« Reply #9 on: November 07, 2010, 09:56:08 AM »


... He wants papers to support any theory.



Yes, I do like to read the original papers. It means that you can see what was actually said, rather than just reproducing a journalist's interpretation.



"Shame he cannot accept the simulation carried out by someone who is qualified in the simulation, Guillaume Morard of the Institute of Mineralogy and Physics of Condensed Matter no less.."



Nobody is attacking the simulation per se, just pointing out that this is the first attempt to predict core properties on distant planets by using atomic theory, that many assumptions have had to be made to apply the theory to a practical instance, and that the result (that large planets are likely to have solid cores and no geomagnetic field) could be invalidated if the assumptions prove wrong, there were other heat sources(different radioactive potassium ratios, perhaps?), or an ocean were to provide such a field. So the paper cannot be taken to be the last word on the subject.

And the person who is pointing all this out? Not me. Guillaume Morard of the Institute of Mineralogy and Physics of Condensed Matter no less, in the original paper...
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justboatonic

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Re: 'Super' Earths may not be life friendly after all.
« Reply #10 on: November 07, 2010, 10:22:07 AM »

Here we go, more backstroking. Mark Spitz would be impressed at the level displayed.

The essence of the simulation, which I read up on, is, that 'super' Earths may have solid cores. That being the case, these 'super' Earths may not have a magnetic field which usually could be deemed conducive to life.

Instead we have to have someone who always wants to critique said articles on a web forum. Perhaps this should be done with the author of the study instead of here? Just a thought, like.

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dodgy geezer

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Re: 'Super' Earths may not be life friendly after all.
« Reply #11 on: November 07, 2010, 11:30:22 AM »


The essence of the simulation, which I read up on, is, that 'super' Earths may have solid cores. That being the case, these 'super' Earths may not have a magnetic field which usually could be deemed conducive to life.


Quite correct. That also makes 'We really do not know..." an accurate statement.


Instead we have to have someone who always wants to critique said articles on a web forum.

Why do you put these articles up on this web forum if not for us to critique them? But you rarely seem to respond in a positive manner. For instance, I noticed that your response to Dreadnought's critique was just that it was "totally incredulous", and would like to know the reasoning behind this...

Perhaps this should be done with the author of the study instead of here?

No need - I see this is already being done by Vlada Stamankovic. I am sure you will keep us informed on how the discussion goes...
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