Astronomers study the interstellar medium, to better understand how stars exchange matter with their ambient surroundings as they evolve. Though the area near our Sun has been surveyed at many wavelengths, the picture is far from complete or clearly understood. This image of the new interstellar map accompanies the data catalog compiled by the team.
Map of partially ionized interstellar gas within 300 parsecs around the Sun, as viewed in the Galactic plane. Triangles represent the sight-line positions of the stars used to produce the map. White to dark shading represents the low to high values of the gas density, and orange shading is for areas with no reliable measurement. The Local Cavity is shown as the white area of low density gas that surrounds the Sun at about 80 parsecs. Image credit: by B. Y. Welsh, R. Lallement, J.-L. Vergely, and S. Raimond.
The press release was almost too technical for me to understand, so I wandered a ways along the Net to find readable background information.
Here is a a college course introduction (PDF) to the interstellar medium, by Richard W. Pogge, Professor of Astronomy at the Ohio State University, Department of Astronomy.
This new study has been reported by many science bloggers and news websites already, so I won't go into further detail here.
According to historical information from the press release:
The most widely accepted theories about the the space-stuff that fills the non-void between the stars predict that it is bumpy and pock-marked with large, less-dense regions that were generated by supernova events combined with outflowing winds from clusters of hot, newborn stars. Many scientists speculate that a series of supernova explosions produced our Sun's Local Cavity about 15 million years ago, followed by cooling and re-heating (the most recent re-heating happening about 3 million years ago).
What are your favorite resources and references about the interstellar medium?
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