PCA was invented in 1901. It hardly qualifies as AI.
Are you sure? From the same article on CNA:
> This is the first time we have used machine learning to fill in the gaps where we don't have data
After PCA, they used some gradient descent for the next steps.
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Sorry, edit: there are more components of AI which I understood (in the not fully analytical reading of the two divulgative articles and a brief skim of the research article): right above «machine learning» is said to be used to «fill in the gaps», and elsewhere it seems that a data interpreter is built to go from the obeservational data from the telescope to the results, qualitative and quantitative (e.g. shape and mass of the object - as you read in the other post).