Tag Archives: diamonds

Diamonds from space!

Researchers have discovered nano-sized diamonds inside a recovered meteorite that suggest a formation process deep within a planet at least the size of Mercury.

The researchers used transmission electron microscopes to determine their composition and morphology, and found that the diamonds contained inclusions (impurities) made of chromite, phosphate and iron-nickel sulfides.

These inclusions are common in diamonds formed underground here on Earth, but this marks the first time they’ve been found in alien rocks. That’s interesting enough on its own, but it has much bigger implications – the team calculated that these diamonds could only have formed under pressure of more than 20 gigapascals. That means they must have been born inside a planet at least as big as Mercury, and possibly up to the size of Mars.

But there’s still more to the story. The fact these diamonds made it to Earth implies that their home planet, whatever it may have been, is no longer with us, since it would take quite a cataclysm to wrench them out of their birthplace deep underground and fling them into space. Instead, the team believes the diamonds came from a planetary embryo.

Not so fast. Though the researchers themselves, in the released paper, assume that the diamonds could only have formed from inside a now destroyed large planet, this leaves out the possibility that the diamonds formed inside one of the existing terrestrial planets, were moved upward toward the surface by later geological process (as happens to diamonds are here on Earth), and then were thrown from the planet by a later nearby impact. This scenario is just as likely.

Nonetheless, this discovery is fascinating. More than anything, it illustrates the inconceivable amount of time that has passed in creating our solar system. Any of these scenarios requires time, time in quantities that no human can really understand or conceptualize.


A new technique for creating diamonds

In discovering a new solid state for carbon scientists have also discovered that it is a relatively inexpensive way to produce diamonds.

Professor Jay Narayan of North Carolina State University is the lead author of three papers describing the work that sees Q-carbon join the growing list of carbon solids, a list that includes graphite, graphene, fullerene, amorphous carbon and diamond. He has suggested that the only place Q-carbon might be found in the natural world is in the core of certain planets.

The researchers created Q-carbon by starting with a thin plate of sapphire (other substrates, such as glass or a plastic polymer, will also work). Using a high-power laser beam, they coated the sapphire with amorphous carbon, a carbon form with no defined crystalline structure. They then hit the carbon with the laser again, raising its temperature to about 4,000 Kelvin, and then rapidly cooled, or quenched, the melted carbon. This stage of quenching is where “Q” in Q-carbon comes from.

The researchers have found that, depending on the substrates, tiny diamonds will form within the Q-carbon, suggesting to me that they have actually discovered how diamonds are formed deep below the Earth. The hot high pressure environment there allows Q-carbon to naturally form, and in the process of its solidification diamonds are a byproduct.


A super Earth, made of diamonds

A super Earth, made of diamonds.

Astronomers also thought 55 Cancri e contained a substantial amount of super-heated water, based on the assumption that its chemical makeup was similar to Earth’s, Madhusudhan said. But the new research suggests the planet has no water at all, and appears to be composed primarily of carbon (as graphite and diamond), iron, silicon carbide, and, possibly, some silicates. The study estimates that at least a third of the planet’s mass — the equivalent of about three Earth masses — could be diamond. “By contrast, Earth’s interior is rich in oxygen, but extremely poor in carbon — less than a part in thousand by mass,” says co-author and Yale geophysicist Kanani Lee.