On the first Tuesday of each month, I write an
astronomy-related column piece for the Oklahoman newspaper. On the following
day, I post that same column to my blog page.
This is reprinted by permission form the Oklahoman and
newsok.com.
Purveyors of fine jewelry might be salivating over two recent scientific reports. Or perhaps they are worried that the bottom may fall out of the diamond market.
Astronomers study the universe
all across the electromagnetic spectrum, from the low frequency radio waves to
high energy gamma rays. They can usually identify whatever they find by
studying the spectrum, the way it looks at different wavelengths. For decades,
astronomers have observed some unknown objects that emit a particular set of frequencies
of microwave light, which they refer to as AME. They know it comes from some
kind of rapidly spinning nanoparticles, but didn’t know what they were.
Astronomers have long known that
a class of organic molecules in space, known as polycyclic aromatic
hydrocarbons (PAHs), emitted diffuse infrared radiation, and many thought they
were also responsible for the AME. A given material can shine in many different
wavelength bands.
"Though we know that some
type of particle is responsible for this microwave light, its precise source
has been a puzzle since it was first detected nearly 20 years ago," said
Jane Greaves, an astronomer at Cardiff University in Wales and lead author on a
paper announcing this result in Nature Astronomy.
The new study, led by Greaves, found
an IR glow around three star systems that come from nanodiamonds. These stars also
emitted AME, leading the astronomers to the realization that the nanodiamonds
created both types of radiation. Stars that have PAH IR-radiation don’t also
show AME. Stars that do have AME contain about 1000 times Earth’s mass in
diamond dust.
Geologists know much about the composition
of Earth’s interior, even though we have never been there to study it directly.
They gain knowledge of the interior of our planet by analyzing seismic
data. With enough data, they can
accurately determine what types of rock or mineral lies at all points beneath
the surface of our planet.
A craton is the deepest part of
the stable interior of a continent. These extend as far as 200 miles deep into
the mantle and represent the oldest existing rock on our planet. By studying
the seismic data, scientists estimate that 1-2% of the cratons below each
continent consists of diamond. That's according to a new study published by a
team of researchers from MIT, Harvard, the University of California at
Berkeley, and other institutions.
"This shows that diamond is
not perhaps this exotic mineral, but on the [geological] scale of things, it's
relatively common," said Ulrich Faul, a research scientist in MIT's
Department of Earth, Atmospheric, and Planetary Sciences who helped write the study.
"We can't get at them, but still, there is much more diamond there than we
have ever thought before."
The team estimates that more
than a quadrillion tons of diamonds exist at the bottom of cratons. As of now,
it’s far beyond our technological ability to get them, but in time, some will
slowly work their way to the surface. Future jewelers need not worry about
their livelihood.
