Possible Origin of Mysterious Red and
Blue Lights in the Milky Way
Galaxy
8/2/06
NASA's Goddard Space Flight Center, Greenbelt, Md., in collaboration
with university scientists, have solved yet another mystery.
For years, scientists have observed unstructured silicate particles in
space, but could not pinpoint the origin of recent observation of wide
presence of crystalline silicates or their role in the Milky Way Galaxy.
The work of Ashraf Ali from Goddard, Shiv N. Khanna from Virginia
Commonwealth University, Richmond, and A.W. Castleman, Jr. from
Pennsylvania State University, University Park., have successfully created
nanoclusters of silicates. They were also able to predict that these
particles have absorption features from the red and blue lights found
throughout the Galaxy, and could be the original building blocks of Earth
and other planets in our solar system.
To further understand these silicon oxide nanoparticles (tiny
particles), Castleman and his colleagues undertook studies of cluster
formation and their growth under expanding plasma-jet conditions (ionized
gas) and followed the changing composition of these clusters.
The experiments were designed to enable insights into formation
mechanisms operative in the regions of circumstellar environments (the
space around stars) where silicates are often found. By exposing silicon
monoxide to the plasma conditions, they were able to convert silicon oxide
gas to clusters of silicon oxide nanoparticles.
The formation of these particles had never been observed or proven,
that is, before Ali, Castleman, Khanna and their coworkers began their
study. Employing theoretical methods to study the growth of silicon oxide
nanoparticles, Khanna and his colleagues obtained direct insight into
mechanisms and unraveled two puzzling mysteries. First, they demonstrated
the mechanisms that might be responsible for the formation of silicates
providing another step towards the understanding of the history of the
formation of our solar system.
Secondly, the silicon oxide nanoparticles have electronic properties
that allow the absorption of the blue and red light and it might relate to
the absorption of starlight and emission of red and blue light known as
Extended Red Emission and Blue Luminescence consequently. Astronomers have
long observed the red lights in the Milky Way Galaxy but have never been
able to determine the exact nature of particles that were responsible for
the emission.
"To understand the chemical evolution of the formation of planets,
we have to understand the composition and degree of crystallinity of
grains in interstellar space" said Ali.
By determining the role of the chemical processes involved in the
formation of solids, scientists understand more of the mechanics that
inspired the creation of Earth and its neighboring planets. The particles
discovered likely played a major role in dust formation process in
circumstellar environments of young and evolved stars.
Ali and his colleagues conducted their experimental research at the
Pennsylvania State University Chemical Physics Laboratories in University
Park, Penn., and the theoretical work in the Physics Department of The
Virginia Commonwealth University. The investigations were made possible by
funding from NASA, the U.S. Air Force and the Department of Energy.
The results were published in the June 19 American Chemical Society's
Nanoletters journal (Nanoletters, vol 6, p1190)
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