Asteroids may be a byproduct of planet formation rather
than planetary building blocks, according to a recent
paper in Nature.
Research done at Purdue University and Massachusetts
Institute of Technology suggests collisions of planetary
embryos — the seeds to the planets in our solar system
that existed 4 billion years ago — could be the origin of
the material that formed asteroids.
When part of an asteroid falls onto the Earth, it is called a
meteorite. For more than a century scientists have studied
the tiny bead-like grains of solidified melted rock called
“chondrules” found in meteorites, but the origin of these
grains remained a mystery, says Jay Melosh, a distinguished professor of earth, atmospheric and planetary
sciences.
“Understanding the origin of chondrules is like looking
through the keyhole of a door; while we can’t see all that is
happening behind the door, it gives us a clear view of one
part of the room and a glimpse into the very beginnings of
our solar system,” says Melosh, who also is a professor of
physics and aerospace engineering.
“Chondrule-bearing meteorites have long been thought to
be similar to the building blocks of planets,” adds David
Minton, an assistant professor of earth, atmospheric and
planetary science. “This study suggests that instead chondrules might actually be byproducts of impacts between
objects of an earlier generation, and meteorites may not be
representative of the material that made planets.”
Purdue professors of earth, atmospheric and planetary sciences David Minton, left, and Jay Melosh
with a section of meteorite showing the round chondrules within it. Melosh and Minton were part
of a research team that studied chondrules, tiny beads of solidified melted rock that are some of
the solar system's earliest solids, and suggests they were created through collisions of planetary
embryos. (Purdue University photo/John Underwood)
David Minton, left, and Jay Melosh
Keck Foundation to Fund Purdue Research
into Spectroscopic Imaging
A team of Purdue University researchers has been awarded a $1 million
W.M. Keck Foundation grant to develop a new type of imaging technology for cell and tissue analysis.
Central to the concept is the invention of a new way to perform
in vivo spectroscopy, or using a pulsing laser light to determine the
precise chemical content of tissues in living organisms.
The lead researcher is Ji-Xin Cheng, a professor in Purdue’s
Weldon School of Biomedical Engineering and Department of
Chemistry and scientific director of Label-Free Imaging at Purdue’s
Discovery Park.
"This work is potentially very important because if we know the
chemical content of tissue we can do early detection of disease with
biomarker sensitivity, and this is not possible with current medical
imaging technologies," Cheng says. It is currently not practical to
use in vivo spectroscopy — the analysis of how light interacts with
molecules in living tissue — because photons scatter when light
shines on tissues, making for inefficient detection of the photons.
The new in vivo imaging technology hinges on a
technique called modulation-multiplexed stimulated
Raman scattering microscopy.
“We will convert Raman spectroscopy, generally used to
study molecules in solutions
or fixed tissues, to an in vivo
imaging platform that is able
to monitor how a living cell
executes its functions in real
time,” says Cheng, who is
collaborating with Andrew
Weiner, the Scifres Family
Distinguished Professor of
Electrical and Computer
Engineering; and Mingji Dai,
an assistant professor in the
Department of Chemistry.
Meteorite Material Born in Molten
Spray as Embryo Planets Collided
Ji-Xin Cheng
