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Tuesday, June 19, 2012

Discovery of an ultrafine powder that must be present in all parts of the universe

Science and techno world topic: Space
After several years of research, the team of physicist Tom Hill of Rice University in Houston, Texas, has managed to clear up a mystery that has baffled scientists involved in analyzing data collected by the Cassini spacecraft for NASA.

In the new study, Hill and his colleagues describe and interpret what they found in the data from the Cassini: A class of hitherto unknown space particles, nanoscale grains electrically charged dust. They further believe that these particles exist everywhere in the universe.

If, as seems, are correct, this study is the first time you get to measure and analyze such particles.

Measurements of nanoscale grains were conducted during three flybys of Enceladus, a small icy moon of Saturn. Enceladus was significant interest in the scientific community in 2005 when Cassini's camera captured in visible light a series of geysers erupting near its south pole. In addition to the dust particles of ice visible, geysers spew water vapor into space, and three flybys in 2008 and 2009 gave scientists the first opportunity to make measurements inside the plumes of the geysers.

"The common perception is that space is extremely empty, but this is inaccurate," he argues sharply Hill.

The sun emits a supersonic flow of particles, known as solar wind, and this flow extends throughout the solar system as a plasma of electrons and ions, electrically charged. Hill and his colleagues have presented a description of how the plasma in Saturn's magnetosphere interacts with nanoscale grains and imparts a negative charge as they move away from Enceladus. The powder grains in the tufts are clumps of water molecules present in a wide range of sizes, from small enough to correspond to only a few sets of water molecules, to as large matching the size of conventional smoke particles.

The nanoscale grain size is so peculiar to them gives a set of features not present in other types of materials. For example, nanoscale grains are strongly affected by both gravitational force and the electromagnetic. This contrasts sharply with the case of larger particles, which are dominated by gravity, and the smaller particles and electrically charged, which are dominated by the electromagnetic force.



It is not immediately clear what impact will the finding in astrophysics and cosmology, and how will that rewrite theories. However, some cosmologists had speculated that particles of nanometric size of these grains are part of the dense dust clouds where stars are born.

Hill, professor of physics and astronomy, is a researcher Plasma Spectrometer Cassini, or CAPS, an instrument designed to measure electrons and charged ions. The instrument was designed and built at Southwest Research Institute in San Antonio, Texas, United States, by an international team led by David Young.

Hill became involved in work related to the design and use of CAPS in mid-1980 when Cassini program scientists were still trying to raise funds to build the spacecraft.

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