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?

Timberwoof <timberwoof.spam@inferNOnoSPAMsoft.com> wrote in
news:timberwoof.spam-30CDC8.09083319032008@nnrp-virt.nntp.sonic.net:

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 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.

hmm...does Mars even have Iron in its composition? Anyway, where did
the iron in Earth come from?

On Mar 19, 4:22 pm, "Landy" <no...@nowhere.net> wrote:
"Timberwoof" <timberwoof.s...@inferNOnoSPAMsoft.com> wrote in message

news:timberwoof.spam-30CDC8.09083319032008@nnrp-virt.nntp.sonic.net...



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.

In article
1ie2edr.1gqxazt1xwbh7eN%auxotectonics_deletethis@nachon_andthis.net>,
auxotectonics_deletethis@nachon_andthis.net (Florian) wrote:

SBC Yahoo <atilla.the.hun@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.

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.)

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?

Timberwoof <timberwoof.spam@inferNOnoSPAMsoft.com> wrote:

In article
1ie2edr.1gqxazt1xwbh7eN%auxotectonics_deletethis@nachon_andthis.net>,
auxotectonics_deletethis@nachon_andthis.net (Florian) wrote:

SBC Yahoo <atilla.the.hun@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.

Why? Where would the energy come from to heat things up again?

Leave the energy question on the side, and look at the chronology of the
major volcanic events:

http://www.esa.int/images/ChronologyModel_v02_H.jpg

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.

Leave the energy question on the side, and look at the chronology of the
major volcanic events:

http://www.esa.int/images/ChronologyModel_v02_H.jpg

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.

Florian wrote:
George <George@george.net> wrote:

Leave the energy question on the side, and look at the chronology of the
major volcanic events:

http://www.esa.int/images/ChronologyModel_v02_H.jpg

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."

George <George@george.net> wrote:

Leave the energy question on the side, and look at the chronology of the
major volcanic events:

http://www.esa.int/images/ChronologyModel_v02_H.jpg

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.

Paul <Paul@comcat.net> wrote:

Florian wrote:
George <George@george.net> wrote:

Leave the energy question on the side, and look at the chronology of the
major volcanic events:

http://www.esa.int/images/ChronologyModel_v02_H.jpg

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 ;-)

http://www.esa.int/esaCP/SEMCPLM5NDF_index_0.html

Florian wrote:
Paul <Paul@comcat.net> wrote:

Florian wrote:
George <George@george.net> wrote:

Leave the energy question on the side, and look at the chronology of
the
major volcanic events:

http://www.esa.int/images/ChronologyModel_v02_H.jpg

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 ;-)

http://www.esa.int/esaCP/SEMCPLM5NDF_index_0.html

You are right. Wow! That should have been obvious to me.
Definite brain glitch.

"Skywise" <i...@oblivion.nothing.com> wrote in message

news:13u10vvtoo55d71@corp.supernews.com...

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

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.