In the news: Mineral evidence paints life friendly picture of earlyEarth ...

http://sfgate.com/cgi-bin/article.cg...NGGSCLJDN1.DTL

(via Jason Spaceman on talk.origins)

In message , Alfred A.
Aburto Jr. writes
http://sfgate.com/cgi-bin/article.cg...NGGSCLJDN1.DTL

(via Jason Spaceman on talk.origins)

Interesting! Was that before or after the formation of the Moon?
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Jonathan Silverlight wrote:
In message , Alfred A.
Aburto Jr. writes

http://sfgate.com/cgi-bin/article.cg...NGGSCLJDN1.DTL


(via Jason Spaceman on talk.origins)


Interesting! Was that before or after the formation of the Moon?

According to:

http://www-curator.jsc.nasa.gov/curator/lunar/lunar.htm

the Moon surface appears to be about 4.4 billion years old (from the
Apollo Program Lunar samples). The Solar System appears to be about 4.5
billion years old (from meteorite samples). So, if we can believe such
accuracy in these dates (and, well, I'd be a bit wary about that!), then
the Moon was formed 100 million years after the Earth formed and 100
million years after that, the Earth was in the position described in the
article above ... :-)

Alfred A. Aburto Jr. wrote:
Jonathan Silverlight wrote:

In message , Alfred A.
Aburto Jr. writes

http://sfgate.com/cgi-bin/article.cg...NGGSCLJDN1.DTL

(via Jason Spaceman on talk.origins)

Interesting! Was that before or after the formation of the Moon?

According to:

http://www-curator.jsc.nasa.gov/curator/lunar/lunar.htm

the Moon surface appears to be about 4.4 billion years old (from the
Apollo Program Lunar samples). The Solar System appears to be about 4.5
billion years old (from meteorite samples). So, if we can believe such
accuracy in these dates (and, well, I'd be a bit wary about that!), then
the Moon was formed 100 million years after the Earth formed and 100
million years after that, the Earth was in the position described in the
article above ... :-)

But at those ages, add +/- error bounds and they become as accurate as political polls.

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"Alfred A. Aburto Jr." wrote in message m...
http://sfgate.com/cgi-bin/article.cg...NGGSCLJDN1.DTL

(via Jason Spaceman on talk.origins)


From the article :

The oldest indeed date from about 4.1 billion to 4.3 billion years old, little more than 200 million years after the Earth itself
was formed and nearly a billion years before the oldest known fossils of living creatures.
More important, the two scientists used the titanium in the zircon crystals as a novel kind of thermometer to determine for the
first time that the zircon minerals formed into crystals at about 700 degrees Celsius, or nearly 1,300 degrees Fahrenheit. After
those early zircon crystals formed, temperatures on the Earth must have cooled quickly to more benign levels that allowed
water-containing granites to form in the planet's crust


Was the expectation that Earth would be even hotter than 700 degrees at 200million years of age ?
700 Degrees Celsius does not seem very 'life-friendly' yet.
And why do they conclude that Earth must have cooled down quickly ?
Wouldn't radio-active decay and tidal forces prevent rapid cooling ?
How fast does a Earth-size planet cool down any way ?

Rob Dekker wrote:
"Alfred A. Aburto Jr." wrote in message m...

http://sfgate.com/cgi-bin/article.cg...NGGSCLJDN1.DTL

(via Jason Spaceman on talk.origins)



From the article :


The oldest indeed date from about 4.1 billion to 4.3 billion years old, little more than 200 million years after the Earth itself
was formed and nearly a billion years before the oldest known fossils of living creatures.
More important, the two scientists used the titanium in the zircon crystals as a novel kind of thermometer to determine for the
first time that the zircon minerals formed into crystals at about 700 degrees Celsius, or nearly 1,300 degrees Fahrenheit. After
those early zircon crystals formed, temperatures on the Earth must have cooled quickly to more benign levels that allowed
water-containing granites to form in the planet's crust



Was the expectation that Earth would be even hotter than 700 degrees at 200million years of age ?
700 Degrees Celsius does not seem very 'life-friendly' yet.
And why do they conclude that Earth must have cooled down quickly ?
Wouldn't radio-active decay and tidal forces prevent rapid cooling ?
How fast does a Earth-size planet cool down any way ?


I don't understand the geology of it exactly. I will find the Science
article though and see what I can make of that.

From the SFGate article it appears that the zircon crystals formed at
700C but must have cooled rapidly ... that is, the zircons are embedded
in granite and the _granite_ must have cooled quickly ...

It was just the continental plates that cooled quickly ... not the Earth
itself, just the granite that forms the Earths surface plates ...

Is this NASA/Apollo stuff more of your conditional laws of physics,
soft-science and/or disinformation-R-us?

Since there's absolutely no hard-science as to our moon being made from
Earth, what about an icy moon of r=2000 km as arriving from the Sirius
Oort zone, or even from our own Oort zone?
~

GUTH Venus township, bridge and ET Park-n-Ride tarmac:
http://guthvenus.tripod.com/gv-town.htm
Russian LSE-CM/ISS (Lunar Space Elevator)
http://guthvenus.tripod.com/lunar-space-elevator.htm
A few other testy topics by; Brad Guth / GASA-IEIS
http://guthvenus.tripod.com/gv-topics.htm

"RD" == Rob Dekker writes:

RD From the article :

The oldest indeed date from about 4.1 billion to 4.3 billion years
old, little more than 200 million years after the Earth itself was
formed and nearly a billion years before the oldest known fossils
of living creatures. More important, the two scientists used the
titanium in the zircon crystals as a novel kind of thermometer to
determine for the first time that the zircon minerals formed into
crystals at about 700 degrees Celsius, or nearly 1,300 degrees
Fahrenheit. After those early zircon crystals formed, temperatures
on the Earth must have cooled quickly to more benign levels that
allowed water-containing granites to form in the planet's crust


RD Was the expectation that Earth would be even hotter than 700
RD degrees at 200million years of age ? 700 Degrees Celsius does not
RD seem very 'life-friendly' yet. And why do they conclude that
RD Earth must have cooled down quickly ? Wouldn't radio-active decay
RD and tidal forces prevent rapid cooling ? How fast does a
RD Earth-size planet cool down any way ?

You might want to see URL:
http://nai.arc.nasa.gov/news_stories...tail.cfm?ID=76 . My
understanding is that either zircons require water at some stage in
their formation process. It doesn't mean that the environment in
which the zircons formed was itself cool, but at some prior stage the
environment was cool.

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