*Christopher Johnson asked the Naked Scientists:* My name is Chris Johnson from West Virginia in the US.

Love your show - and all the other naked scientist podcasts. I have a question, and as I am a mathematician and don't know any astronomical physists, I would love your thoughts.

I did my master's thesis on weighted alpha shapes and persistent homology. Basically, this is where you take a 3d point set, each with a radius, and build a triagulation. You then use Persistent Homology to find the number of components, tunnels, and voids in the structure. This has been applied to images (removing noise) and to proteins.

I have written the software to compute these structures, and I am interested in applying this type of analysis to stars. With a dataset of a region of stars and using the mass of the star as the weight, I can show where there are disconnections, tunnels, and voids in the gravity of a region of space. I am curious to get physists opinions on the benefit of this. What kinds of questions might you ask, having this type of information about a region of space?

Also, I am not sure where to find a complete database of all the stars in a particular region with their position, diameter, and mass. I have looked at a few online, but the ones I found so far did not have complete and consistent data.

I appreciate your time, and I would appreciate any thoughts you have.

Thanks,

Chris Johnson

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