Astrophysics

Dark Clumpuscules

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Science  23 Apr 2004:
Vol. 304, Issue 5670, pp. 491
DOI: 10.1126/science.304.5670.491c

The universe is about 73% dark energy and 36% dark matter. Dark matter tends to be clumpy, which is important for forming luminous structures, like stars and galaxies. About 4% of the dark matter is ordinary matter, consisting of elementary particles, such as protons and neutrons, that take part in strong interactions. Ordinary matter is hard to observe, but much of it might exist as clumpuscules of molecular hydrogen gas, structures of about 100 AU and with masses close to the mass of Jupiter.

Heithausen has resolved clumpuscules with the IRAM Plateau de Bure interferometer. They obey a fractal distribution and are very dense and overpressurized—significantly in excess of the pressure of the interstellar medium, so that it's hard to understand how these structures can survive. The clumpuscules are moving with a velocity similar to that of nearby molecular clouds, suggesting that the clumps are a natural and perhaps ubiquitous extension of the diffuse interstellar medium. — LR

Astrophys. J. 606, L13 (2004).

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