Getting scipy.cKDTree to return everything with a given meter radius

I want to find everything within a 0.1 meter radius.
I’m confused on exactly how query_ball_point is getting distance. I’m using decimal degree coordinates when creating the cKDTree, ie. [(-73.52610659993773, 40.99738620279574), (-73.52610659993992, 40.99738620279341), etc].

This currently works in my real life use cases but it was just testing different numbers until it did. I read the cKDTree documentation and I’m having a hard time understanding how it’s getting the distance and how different units come into play. I feel like I might be overthinking this but was hoping someone could give some clarity for someone with no understanding of geography.

new_tree = spatial.cKDTree(decimal_degree_coords)
found_points = new_tree.query_ball_point(check_feature, .00001)

found_points = new_tree.query_ball_point(check_feature, .0000009)