We’re a greasy galaxy

Science Daily reveals that the Milky Way is more like the Greasy Way, with the discovery of lots of “grease-like molecules” floating in the void between the stars:

Astronomers at the University of New South Wales in Sydney (UNSW), and Ege University in Turkey used a laboratory to manufacture material with the same properties as interstellar dust and used their results to estimate the amount of ‘space grease’ found in the Milky Way. Their results appear in a paper in Monthly Notices of the Royal Astronomical Society.

Organic matter of different kinds contains carbon, an element considered essential for life. There is though real uncertainty over its abundance, and only half the carbon expected is found between the stars in its pure form. The rest is chemically bound in two main forms, grease-like (aliphatic) and mothball-like (aromatic).

The UNSW / Ege team used a laboratory to create material with the same properties as interstellar dust. They mimicked the process by which organic molecules are synthesised in the outflows of carbon stars, by expanding a carbon-containing plasma into a vacuum at low temperature. The material was collected and then analysed by a combination of techniques. Using magnetic resonance and spectroscopy (splitting light into its constituent wavelengths) they were able to determine how strongly the material absorbed light with a certain infrared wavelength, a marker for aliphatic carbon.

Schmidt is quick to dispel the comparison with anything edible: “This space grease is not the kind of thing you’d want to spread on a slice of toast! It’s dirty, likely toxic and only forms in the environment of interstellar space (and our laboratory). It’s also intriguing that organic material of this kind — material that gets incorporated into planetary systems — is so abundant.”