Mary Johnson-Groh discussed the methodological cross-over act from biology to cosmology with the attempt, recently, of astronomers to build the family tree of the stars in our galaxy, the Milky Way Galaxy, akin to methodologies found in biology to classify species, and families, orders, and so on.
With the classification in biology as taxonomy, the field of biology has become much more complex with the increase in evidence. However, the ability to catalogue provides a systematised manner in which to find and classify species, whether new or old.
This has been termed the family tree in terms of the tracing of the lineages of organisms. Apparently, astronomers are beginning to borrow from biology to catalogue and organise, in a systematic way, the stars.
In particular, this is being used for the Milky Way Galaxy. In a way, the information encoded into DNA can be used to decipher the lineage of an organism and the relationship of one organism to another, in that tree of life.
The chemical composition of the elements within stars can be used to determine its history. What fuel is it burning? Hydrogen, Helium, Iron? There are proxies as to the composition and age of the stars based on their spectra because some fuels emit different electromagnetic radiation – or light – than others.
Anyway, this can give a tree of the evolution of the Milky Way Galaxy.
The laws governing galactic evolution and stellar evolution, or the evolution of the galaxy and the stars, differ from those of organisms, but the information is passed down in a general way – and in this general passing down can be used in similar way, in an analogous way, with the stars in the galaxy.
Some have termed this “astrocladistics” after cladistics. It is a way to determine the characteristics inherited by stars over time in the galaxy. So astrocladistics deals with the formation and evolution of stars over time, or stellar evolution and formation. For this particular example, the Milky Way Galaxy that we inhabit.
The younger stars are to be found in the central thin desk of the Galaxy with the older stars in the thicker disk. The thickness of the disks differs for the young and the old stars. The thick disk, apparently, is said to be like a “diffuse cloud.”
However, researchers found a third category of stars, or stellar family. This raises questions. What is the origin of the newly found family of stars? As things move through the ‘heavens,’ we can see the trajectory and the age of the stars.
Did they form within the Galaxy or outside of it? The third category appears to be a family of stars termed “late-bloomers” because of their apparent formation from a possible galactic merger or the “collision” of two (or more) galaxies into one.
However, there are difficulties in the appropriate translation of the methodologies found in the biological sciences to the astronomical sciences, but the generalised analogous methodologies are used to suss out the general information about the family of stars in our Galaxy.
In that, the researchers found three classifications: the young and the old from within the original galaxy, and the late-bloomers from the collision of one (or more) galaxies together.