alt Hacker NewsI read the article but didn't watch the videos yet, but I'm curious as to what would be needed to make this a 3D map. That is, I'm assuming this 2D map records the position of all of these objects in the sky, but not the distance from Earth. But I thought that calculating the distance of objects is relatively straightforward, e.g. you hear all the time "Galaxy X is 2 billion lightyears away" or whatever. Would it just be really computationally expensive to calculate the distance to all of the 4 billion objects identified in the map?
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Celestia might be what you're looking for.
There are a lot of unknowns and processes that must be undone, which often require an unknown basis. Red shift, moving bodies, gravitational lensing and other processes distort light along its journey. Sometimes we don't know the exact magnitude of a star, etc. Spectroscopy helps a lot but is limited by the fidelity of our datasets.
They do this mostly with spectroscopy, breaking out the light by frequency. The longer the light has been travelling, the more frequency shifts into redder frequencies, because the universe is continually expanding.
But those distances are all built on top of the cosmic distance ladder (Terence Tao explaining on 3blue1brown)
https://youtu.be/YdOXS_9_P4U?is=jbkFbwWKgbn3yOjq
Maps like DESI add the 3d distances.
https://www.desi.lbl.gov/education-outreach/interactive-visu...