My most humble apologies. Here it is on a Sunday: what kills galaxies, and could life form on Saturn’s moons?
In the first chapter of our life and death volume, scientists from the University of Cambridge, UK have solved the mystery of the biggest killer of galaxies. Strangulation of a galaxy occurs when the supply of cold gas necessary for the formation of new stars is slowly choked off. Through fusion, which takes plase within stars, heavier elements are formed, including metals. By analysing the elemental make up of dying galaxies, Dr. Yingjie Peng and group have gathered evidence that dead galaxies contain more metals than live ones, and through the use of computer modelling claim that the only way this ratio is possible is is the galaxies are being strangled. However, the mechanism that causes strangulation is still very poorly understood.
On a lighter note, data sent back from the Cassini probe has left scientists at Sapienza Università, Italy thinking that one of Saturns larger moons, Enceladus, might be capable of fostering life. Conditions on the moon are harsh, with a surface temperature of -180 °C (-292 °F) and a covering of a sheet of ice 30-40 kilometers (19-25 miles) thick, very alkaline water (pH 12). Cassini has sent back pictures of Enceladus showing jets of water emerging from its south pole. This are thought to be froma large reservoir of water inder the surface. Because of the alkaline rocks thought to be under the surface making the water so alkaline, researchers think that this could release molecular hydrogen, which is important in driving prebiotic reactions to form the molecules of life (amino acids etc.). The hydrogen would also provide energy for any microbes living in the water on the moon, useful for a rock far from the sun with little light!
Image credit: NASA