What is quantum tunneling? Neil deGrasse Tyson on Quantum Tunneling. In physics, quantum tunnelling, barrier penetration, or simply tunnelling is a quantum mechanical phenomenon in which an object such as an electron or atom passes through a potential energy barrier that, according to classical mechanics, the object does not have sufficient energy to enter or surmount. Related topics #physics #science #universe #neildegrassetyson #quantum #tunneling #quantummechanics