Thursday, August 23, 2007

Diamonds Are Almost Forever

In the Jack Hills of Western Australia, geologists have identified the oldest diamonds ever found, more than 4 billion years old. Diamonds offer clues to Earth's early history. We saw August 6 in Meteor Science that zircon crystals help determine how long a body was molten. Zircons in meteorites showed that asteroid Vesta cooled within the first 10 million years of its existence.

Zircon crytals are resistant to melting, and provide clues to ancient events. Analysis of zircons containing the Australian diamonds indicate that Earth cooled within 300 million years of formation. Diamonds require enormous pressures to form, needing a thick continental crust. These diamonds indicate that Earth's crust and oceans could be 4.4 billion years old.

There are many mysteries about the planet beneath our feet. How Earth condensed from a gas has long been a mystery. Particles colliding at orbital velocity will not attract each other gravitationally unless those particles have the mass of mountains. One way to start a planet forming would via with a tiny Black Hole with the mass of a mountain.

This week Planetary Society Blog hosts the Carnival Of Space!

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2 Comments:

Anonymous Anonymous said...

This may be off-topic with respect to diamonds,
but
have you seen the arXiv paper 0704.0908 whose abstract says:
"... our results suggest that the dip in extragalactic brightness and number counts and the WMAP cold spot are physically related, i.e., that the coincidence is neither a statistical anomaly nor a WMAP foreground correction problem ...
To create the magnitude and angular size of the WMAP cold spot requires a 140 Mpc radius completely empty void at z less than or equal to 1 along this line of sight.
This is far outside the current expectations of the concordance cosmology,
and adds to the anomalies seen in the CMB. ...".

There is also an NRAO press release with color pictures at
www.nrao.edu/pr/2007/coldspot/index.shtml

Tony Smith

5:08 AM  
Blogger L. Riofrio said...

Welcome Tony, your comments are most welcome. I have indeed read about the "hole." It is VERY exciting and I am writing a post about it.

"This is far outside the current expectations of the concordance cosmology, and adds to the anomalies seen in the CMB."

The Concorde cosmology is ready to crash.

5:52 AM  

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