Why are the theories of galileo and Copernicus considered dangerous by the church

There is considerable uncertainty over the exact nature of the church's argument with Galileo. It has been suggested that his real crime was publicly to challenge the authority of a Catholic hierarchy that in fact included many who were sympathisers or supporters, or even that the heliocentric issue (Copernican Theory) was less of a problem than his atomic theories, which undermined the doctrine of transubstantiation (the conversion of the bread and wine into the body and spirit of Christ in the mass)