How does the automatic garbage collection mechanism determine that an object is no longer accessible and should be deleted?

The automatic garbage collection (GC) mechanism in Go determines that an object is unreachable based on its reachability from root set points. Root points include global variables, local variables of current goroutines, and call stacks. If an object is not reachable through a chain of references from these root points, it is considered 'dead' and eligible for removal.

For example, if a variable references an object, GC considers it alive. If the reference is removed or goes out of scope, the object becomes unreachable and can be collected.

Thus, GC periodically traverses the object graph starting from the roots and marks all reachable objects. All other objects are considered garbage and are freed.