When observations do not fit into tradition

I have mentioned several times that the Hubble classification is a traditional approach of classification that is not adapted to modern data. I have also noticed that in the astrophysical literature modern statistical tools of clustering are often used in the sole purpose of retrieving the Hubble sequence without using the eyes. Or course, this […]


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Progress Report

Today, I have finished the chapter called “Diversification” which is fundamental to Astrocladistics since it explains why such a phylogenetic tool can be applied to galaxies (and beyond). With already completed chapters “Classification” and “Cladistics”, I have given all the concepts necessary to understand what is behind Astrocladistics. The next step is to go into […]

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Evolutionary cost

Cladistics looks for the relationships between taxa in terms of an evolutionary cost. By minimizing this cost, it is expected to find an evolutionary scenario that closely matches the hierarchical diversification processĀ  through transmission with modification. In other words, inheritance of innovations from common ancestors is the simplest way to explain diversity. To understand why […]

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Cladistics and the Hubble sequence

Hubble discovered galaxies in 1922. He found elliptically shaped objects and disky ones showing spiral arms sometimes with a bar at the center. He also thought that because of Jean’s law, elliptical galaxies would flatten into a disk, so the elliptical galaxies are the most ancestral ones. We can code Hubble’s initial observation with to […]

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Opposite walks

Biologists have been confronted, right at the beginning (2000 years ago or so) , to the diversity of the living organisms on Earth. They had to do statistics and classification (systematics). Thanks to the progress of technology, they are now able to investigate the very detailed functioning of cells and molecules, asking physicists and chemists […]

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Astrocladistics is about cladistics in astrophysics, or classification of complex astrophysical objects in evolution, particularly galaxies. This is my research subject since 2001. This blog, created August 1st, 2011, is intended to be the place where I present and explain the concepts, the techniques, the results, the failures, of astrocladistics, in a different way than […]

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