According to my current knowledge, the earth's magnetic field formed due to the molten iron core that is spinning to create a magnetic field. This magnetic field is also what is protecting us from harmful bursts (solar plasma?) from the sun.
I don't understand one thing - why doesn't Mars have one?
rAgAv <ragav.pa...@googlemail.com> wrote in news:1ffef2dc-a033-410e-96f4- 4f0136740...@e6g2000prf.googlegroups.com:
> Hello,
> According to my current knowledge, the earth's magnetic field formed > due to the molten iron core that is spinning to create a magnetic > field. This magnetic field is also what is protecting us from harmful > bursts (solar plasma?) from the sun.
> I don't understand one thing - why doesn't Mars have one?
Mars is cold. Being smaller, it cooled quicker. It's liquid core froze eons ago thus shutting down its dynamo.
> rAgAv <ragav.pa...@googlemail.com> wrote in news:1ffef2dc-a033-410e-96f4- > 4f0136740...@e6g2000prf.googlegroups.com:
>> Hello,
>> According to my current knowledge, the earth's magnetic field formed >> due to the molten iron core that is spinning to create a magnetic >> field. This magnetic field is also what is protecting us from harmful >> bursts (solar plasma?) from the sun.
>> I don't understand one thing - why doesn't Mars have one?
> Mars is cold. Being smaller, it cooled quicker. It's liquid > core froze eons ago thus shutting down its dynamo.
But then why does Venus not have one? Being roughly the same size as Earth and all................ cheers Bill
Skywise <i...@oblivion.nothing.com> wrote: > Mars is cold. Being smaller, it cooled quicker. It's liquid > core froze eons ago thus shutting down its dynamo.
> Earth faces the same fate.
No so sure. Mars has an important volcanic activity which is at odd with the hypothesis that it is a dead cold planet:
-- Florian "Toute vérité passe par trois phases. D'abord, elle est ridiculisée; ensuite, elle rencontre une vive opposition avant d'être acceptée comme une totale évidence" - Arthur Schopenhauer
Landy wrote: > But then why does Venus not have one? Being roughly the same size as Earth > and all................
Perhaps the impact that created the Moon added the iron core of the impactor to Earth's core, causing it to be over an sized core (relative to Mars and Venus, and especially to the Moon, which has little), and also reheated the whole interior, causing it to still be warmer, today, than it otherwise would have been.
In article <gfWdnSyiUOCYYn3anZ2dnUVZ_u6rn...@comcast.com>, John Popelish <jpopel...@rica.net> wrote:
> Landy wrote:
> > But then why does Venus not have one? Being roughly the same size as Earth > > and all................
> Perhaps the impact that created the Moon added the iron core > of the impactor to Earth's core, causing it to be over an > sized core (relative to Mars and Venus, and especially to > the Moon, which has little), and also reheated the whole > interior, causing it to still be warmer, today, than it > otherwise would have been.
Not likely. The impactor, and thus its dense iron core, had a velocity that took it away from the Earth again (albeit probably in lots of little pieces). Why would that event suddenly leave the iron core in the Earth and not leave one in the moon?
And that hypothesis just begs the question: Where did the impactor get its iron core? Could not the proto-Earth have gotten one the same way?
-- Timberwoof <me at timberwoof dot com> http://www.timberwoof.com "When you post sewage, don't blame others for emptying chamber pots in your direction." ‹Chris L.
> -- > Florian > "Toute vérité passe par trois phases. D'abord, elle est ridiculisée; > ensuite, elle rencontre une vive opposition avant d'être acceptée comme > une totale évidence" - Arthur Schopenhauer
- - - - -<> <> - - - - - It had volcanic activity up to 100 million years ago. It has none, now, today, this minute, and is therefore presumed deceased. The author of the article is not, apparemntly, aware that a thousand million is a billion. Must be the metric system, billion in metric is a thousand million.
"We went to the moon using the inch pound foot system, so why do we need to change to the metric system? Those Europeans have not been to the moon." 1960's speach by US Senator that killed the "change to metric" movement in the USA - - - - -</> <\> - - - - -
According to a documentary that I watched, when earth was still in its molten state, the heavy iron present in the spinning planet moved into the center because of its heaviness and all the lighter substances moved to the crust thus giving rise to the spinning iron core of the earth. This spinning iron core gives rise to the magnetosphere.
So, just because Mars was a little bit smaller and was farther from the sun, it cooled away faster thus leaving the process of formation of the core at an immature status?
hmm...does Mars even have Iron in its composition? Anyway, where did the iron in Earth come from?
SBC Yahoo <atilla.the....@liberals.suck.net> wrote: > It had volcanic activity up to 100 million years ago. It has none, now, > today, this minute, and is therefore presumed deceased.
Do you seriously consider that the activity is now dead forever? That would be ludicrous.
-- Florian "Toute vérité passe par trois phases. D'abord, elle est ridiculisée; ensuite, elle rencontre une vive opposition avant d'être acceptée comme une totale évidence" - Arthur Schopenhauer
>> -- >> Florian >> "Toute vérité passe par trois phases. D'abord, elle est ridiculisée; >> ensuite, elle rencontre une vive opposition avant d'être acceptée comme >> une totale évidence" - Arthur Schopenhauer > - - - - -<> <> - - - - - > It had volcanic activity up to 100 million years ago.
Most planetary geologists would put the waning of volcanic activity on Mars at ~2 Ga. Don't know of a URL for this, but I know I've read it in several places (not on the www). cheers Bill
> In article <gfWdnSyiUOCYYn3anZ2dnUVZ_u6rn...@comcast.com>, > John Popelish <jpopel...@rica.net> wrote:
>> Landy wrote:
>> > But then why does Venus not have one? Being roughly the same size as >> > Earth >> > and all................
>> Perhaps the impact that created the Moon added the iron core >> of the impactor to Earth's core, causing it to be over an >> sized core (relative to Mars and Venus, and especially to >> the Moon, which has little), and also reheated the whole >> interior, causing it to still be warmer, today, than it >> otherwise would have been.
> Not likely. The impactor, and thus its dense iron core, had a velocity > that took it away from the Earth again (albeit probably in lots of > little pieces). Why would that event suddenly leave the iron core in the > Earth and not leave one in the moon?
Because it had greater momentum and was less likely to vapourise. cheers Bill
> > In article <gfWdnSyiUOCYYn3anZ2dnUVZ_u6rn...@comcast.com>, > > John Popelish <jpopel...@rica.net> wrote:
Why would that event suddenly leave the iron core in the
> > Earth and not leave one in the moon?
> Because it had greater momentum and was less likely to vapourise. > cheers > Bill
The sentence doesn't quite make sense. Do you mean momentum in the center of mass coordinate system of the two bodies? Furthermore, why would greater momentum make it less likely to vaporize? I saw a special describing the results of the simulation but they didn't try to explain the results in simpler terms. My first guess was that the two bodies merged for a short time into one giant liquid body, and partially equilibrated. Then, there would be forces that resembled buoyancy. Basically, the iron sunk to the bottom of the merged body. Wait, this doesn't work (?). The system would be far too turbulent. The Froude number would be too big to allow stratification. My second guess involves phase transitions. The joint body was gas. The iron, having a higher vaporization temperature, condensed into one massive liquid-body that sent all the momentum into the gas, which then recondensed into the moon. The elements with the small atomic number had larger vaporization point temperatures. Calculations have long shown, since the 1700s, that an inelastic collision between earth-like bodies would vaporize most of the material of both bodies. Therefore, I would hope the simulation included phase transitions in the dynamics. Did they? The verbal description only said they simulated the bodies as made of many small particles, and calculated separate trajectories. There are google squared ways to do this.
What bothers me is that the computer simulation never means anything by itself. It is the physical assumptions being made that make the computer simulation meaningful. You can't go, "Run a computer simulation," and believe everything that comes out. If you don't confined the physics before the run, you can make the physics do ANYTHING. It would be so nice if scientific documentaries included references to scientific papers, even if most of the audience don't care. I am sure that few of the audience care about the actors, writers and directors. Yet we have credits.
rAgAv wrote: > According to a documentary that I watched, when earth was still in its > molten state, the heavy iron present in the spinning planet moved into > the center because of its heaviness and all the lighter substances > moved to the crust thus giving rise to the spinning iron core of the > earth. This spinning iron core gives rise to the magnetosphere.
> So, just because Mars was a little bit smaller and was farther from > the sun, it cooled away faster thus leaving the process of formation > of the core at an immature status?
> hmm...does Mars even have Iron in its composition? Anyway, where did > the iron in Earth come from?
Earth: A likely scenario is that the two proto earths collided, the outer layers of each vaporized, went into orbit about the real earth, and later condensed into the moon. The heavy metals, being heavy, sank and formed the earth's core.
Mars: Mars is red because of rust. Yes, Mars cooled faster because it is smaller. Compare surface areas. Also, when solar systems are formed, the lighter stuff gets pushed farther out due to solar wind. The heavy stuff stays closer to the star. That is why gas giants tend to be far from the sun and rocky planets close to the star.
See if there is a library nearby or a school with a library nearby. You may want to try to find a few modern books about solar system formation. It is an interesting subject.
> Not likely. The impactor, and thus its dense iron core, had a velocity > that took it away from the Earth again (albeit probably in lots of > little pieces).
Huh? That's news to me. All the simulations I've seen show the impactor remains recolliding with the earth after about half and orbit. The impact reduced the impactors momentum below escape velocity of the barycenter. This 2nd impact further melted the earth and impactor thus allowing the two cores to merge and other materials to stratify.
> > It had volcanic activity up to 100 million years ago. It has none, now, > > today, this minute, and is therefore presumed deceased.
> Do you seriously consider that the activity is now dead forever? That > would be ludicrous.
Why? Where would the energy come from to heat things up again?
(Of course, the final answer will come when we have enough seismometers on Mars to measure its interior. Until then, it's informed hypothesis.)
-- Timberwoof <me at timberwoof dot com> http://www.timberwoof.com "When you post sewage, don't blame others for emptying chamber pots in your direction." ‹Chris L.
In article <3fa1c846-051d-47f9-9c03-a23472584...@d21g2000prf.googlegroups.com>,
rAgAv <ragav.pa...@googlemail.com> wrote: > According to a documentary that I watched, when earth was still in its > molten state, the heavy iron present in the spinning planet moved into > the center because of its heaviness and all the lighter substances > moved to the crust thus giving rise to the spinning iron core of the > earth. This spinning iron core gives rise to the magnetosphere.
> So, just because Mars was a little bit smaller and was farther from > the sun, it cooled away faster thus leaving the process of formation > of the core at an immature status?
> hmm...does Mars even have Iron in its composition? Anyway, where did > the iron in Earth come from?
You should go pick up a copy of Carl Sagan's "Cosmos" and read it cover to cover. There's a lot of basic knowledge you need to catch up on. :-)
-- Timberwoof <me at timberwoof dot com> http://www.timberwoof.com "When you post sewage, don't blame others for emptying chamber pots in your direction." ‹Chris L.
> > Not likely. The impactor, and thus its dense iron core, had a velocity > > that took it away from the Earth again (albeit probably in lots of > > little pieces).
> Huh? That's news to me. All the simulations I've seen show the > impactor remains recolliding with the earth after about half > and orbit. The impact reduced the impactors momentum below > escape velocity of the barycenter. This 2nd impact further > melted the earth and impactor thus allowing the two cores to > merge and other materials to stratify.
It appears I misremembered. :(
But in regards to a different discussion, that's certainly not an inelastic collision or orbital interaction!
-- Timberwoof <me at timberwoof dot com> http://www.timberwoof.com "When you post sewage, don't blame others for emptying chamber pots in your direction." ‹Chris L.
>> > In article <gfWdnSyiUOCYYn3anZ2dnUVZ_u6rn...@comcast.com>, >> > John Popelish <jpopel...@rica.net> wrote: > Why would that event suddenly leave the iron core in the >> > Earth and not leave one in the moon?
>> Because it had greater momentum and was less likely to vapourise. >> cheers >> Bill
> The sentence doesn't quite make sense. Do you mean momentum in the > center of mass coordinate system of the two bodies?
Think about density
>Furthermore, why > would greater momentum make it less likely to vaporize?
Nothing to do with the momentum - just the boiling point.
> I saw a special describing the results of the simulation but > they didn't try to explain the results in simpler terms. > My first guess was that the two bodies merged for a short time > into one giant liquid body, and partially equilibrated. Then, there > would be forces that resembled buoyancy. Basically, the iron sunk to > the bottom of the merged body. > Wait, this doesn't work (?). The system would be far too > turbulent. The Froude number would be too big to allow stratification.
It looks like the frequency of major events has increased. That is at odd with the statement that the activity on Mars is gone forever.
> (Of course, the final answer will come when we have enough seismometers > on Mars to measure its interior. Until then, it's informed hypothesis.)
Indeed.
-- Florian "Toute vérité passe par trois phases. D'abord, elle est ridiculisée; ensuite, elle rencontre une vive opposition avant d'être acceptée comme une totale évidence" - Arthur Schopenhauer
Darwin123 wrote: > It would be so nice if scientific documentaries included > references to scientific papers, even if most of the audience don't > care. I am sure that few of the audience care about the actors, > writers and directors. Yet we have credits.
Surely you don't think the credits are for the benefit of the viewer, do you?
> It looks like the frequency of major events has increased. That is at > odd with the statement that the activity on Mars is gone forever.
Umm, increased? Only if you read the graph upside down. According to the graph, between 3.7-4.2 bya there were some 3,500 volcanic episodes. Between 4.2-1.0 bya there were some 1,500 volcanic episodes. Around 500 mya there were about 400-800 volcanic episodes. About 300 mya there were about 200 volcanic episodes. About 100 mya there were about 100 episodes. I don't know of any that have definitely been identified as being current. By any measure, activity has significantly DECREASED, not increased. At this point, the issue of energy (as in "Where would the energy come from to heat things up again?") becomes a critical one.
> > It looks like the frequency of major events has increased. That is at > > odd with the statement that the activity on Mars is gone forever.
> Umm, increased? Only if you read the graph upside down. According to the > graph, between 3.7-4.2 bya there were some 3,500 volcanic episodes.
<eyes rolling>
George, confused as usual. Guess what? impact craters are NOT volcanic episodes...
-- Florian "Toute vérité passe par trois phases. D'abord, elle est ridiculisée; ensuite, elle rencontre une vive opposition avant d'être acceptée comme une totale évidence" - Arthur Schopenhauer
>>> It looks like the frequency of major events has increased. That is at >>> odd with the statement that the activity on Mars is gone forever. >> Umm, increased? Only if you read the graph upside down. According to the >> graph, between 3.7-4.2 bya there were some 3,500 volcanic episodes.
> <eyes rolling>
> George, confused as usual. Guess what? impact craters are NOT volcanic > episodes...
I read it the same as George. According to the legend, the little volcano pics with numbers represent "Major Episodes of Volcanic Activity." The curved line represents impact craters.
> >>> It looks like the frequency of major events has increased. That is at > >>> odd with the statement that the activity on Mars is gone forever. > >> Umm, increased? Only if you read the graph upside down. According to the > >> graph, between 3.7-4.2 bya there were some 3,500 volcanic episodes.
> > <eyes rolling>
> > George, confused as usual. Guess what? impact craters are NOT volcanic > > episodes...
> I read it the same as George. > According to the legend, the little volcano pics with numbers represent > "Major Episodes of Volcanic Activity."
LOL, the numbers represent the age of each Episode. Next time, read the full paper which was cited a few articles above ;-)
-- Florian "Toute vérité passe par trois phases. D'abord, elle est ridiculisée; ensuite, elle rencontre une vive opposition avant d'être acceptée comme une totale évidence" - Arthur Schopenhauer
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