School of Life Sciences

Astrobiology Paper Explores the Link Between Terrestrial Extinctions and the Milky Way

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A new paper exploring the link between terrestrial extinctions and the Milky Way galaxy has been published by Dr Michael Gillman (School of Life Sciences, University of Lincoln), Dr Hilary Erenler (University of Northampton) and Dr Phil Sutton (School of Mathematics & Physics, University of Lincoln).

The paper, Mapping the location of terrestrial impacts and extinctions onto the spiral arm structure of the Milky Way, was published in the International Journal of Astrobiology and looks at data from asteroid impacts, as well as other significant historic changes in the climate of Earth, and the location of the Solar System in the Milkyway galaxy. It was found that asteroid impacts, relating to mass extinction events on Earth, were clustered around the passages through the higher density regions of the spiral arms.


High-density regions within the spiral arms are expected to have profound effects on passing stars. Understanding of the potential effects on the Earth and our Solar System is dependent on a robust model of arm passage dynamics. Using a novel combination of data, we derive a model of the timings of the Solar System through the spiral arms and the relationship to arm tracers such as methanol masers. This reveals that asteroid/comet impacts are significantly clustered near the spiral arms and within specific locations of an average arm structure. The end-Permian and end-Cretaceous extinctions emerge as being located within a small star-formation region in two different arms. The start of the Solar System, greater than 4.5 Ga, occurs in the same region in a third arm. The model complements geo-chemical data in determining the relative importance of extra-Solar events in the diversification and extinction of life on Earth.

Image of spiral galaxy NGC 3344 taken by the Hubble Space Telescope.


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