Radioactive decay is known to be a pure quantum effect, the particle from the nucleus is in a superposition until we measure it (according to collapse interpretations). In the Sch. cat experiment the radioactive particle gets entangled with a macroscopic object (Geiger counter) and so the macroscopic object is also in a superposition before the decoherence and collapse. Now my question is, by which mechanism something so small effects something so big like an ordinary object and how does a similar effect happen in the environment of atoms in ordinary objects? It seems like nearby macroscopic objects very often enter the superposition state "affected by radiation/not affected by radiation" because of the uncertainty of the nucleus position, just like a measuring device for radiation experiences similar behavior. Is this true and how is it possible? Thanks in advance.