Thursday, August 23, 2007

What Can a 4.25 Billion-Year-Old Diamond Tell Us?

For starters, the fact that a 4.25 billion-year-old diamond exists tells us a lot. Around the time such a thing would have formed, the general scientific consensus is that the earth was still a glowing sphere of bubbling magma. But according to a recent Scientific American report, diamonds four-and-a-quarter billion years old have been found, and scientists are questioning traditional assumptions.

The text book story goes that the Earth coalesced into that glowing hot ball-thing I described earlier around 4.5 billion years ago. For the next 500 million years, the Earth was supposed to stay that way before cooling so that land and oceans could form. But these new diamonds may set the time Earth started cooling back about 250 million years.

Diamonds can form in a number of ways. For example, meteors can slam into rock with enough intensity to form diamonds, and pressure at certain depths of the Earth’s crust are enough to do it, too. In the case of the super-old diamonds that have recently been studied, it’s likely that they were formed by pressure in the crust. And the Earth would have had to do a lot of cooling to make a crust thick enough to create the pressure needed to make diamonds. So the earth may have started cooling some time before 4.25 billion years.

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I started pound360 to channel my obsession with vitamins, running and the five senses. Eventually, I got bored focusing on all that stuff, so I came back from a one month hiatus in May of 2007 (one year after launching Pound360) and broadened my mumblings here to include all science.