Wonder if this Human Cell Atlas could help us, given that it's mapping unknown stuff... https://www.bbc.co.uk/news/articles/c23829l8kzro
This is marketing rather than science, @Sasha. Any grown up scientist has known since student days that 'cell types' are just convenient rough groupings. Every cell is different in one way or another. Every brain cell has a different structure and function. People write this sort of stuff to sound clever and get awarded money for their research by others who play the same game. `we learn more gradually but there is no sudden new knowledge created by naming a new 'Project'.
Some articles today relating to this — Nature: A ‘Wikipedia for cells’: researchers get an updated look at the Human Cell Atlas, and it’s remarkable Nature: The Human Cell Atlas: towards a first draft atlas (links to other papers) Nature: The Human Cell Atlas from a cell census to a unified foundation model Nature: Single-cell integration reveals metaplasia in inflammatory gut diseases
An analogy might be making an atlas of all cities and claiming that it would lead to a new understanding of human society. Without all the details about who is in each city and all their interactions, there won't be any new understanding of society. The complexity of the interior of cells and all their interior interactions and exterior interactions probably rival the complexity of a city.