Quantum Tunnelling has nothing to do with passing through physical barriers, it refers to a spontaneous change in energy state which a particle should not be able to do due to insufficient energy.
Think of it like a ball spontaneously borrowing energy to roll up a hill. When it gets over the hill, it will roll down far enough to repay the energy cost of it getting up the hill. But it still shouldn’t be possible!
Quantum Tunnelling has nothing to do with passing through physical barriers, it refers to a spontaneous change in energy state which a particle should not be able to do due to insufficient energy.
Think of it like a ball spontaneously borrowing energy to roll up a hill. When it gets over the hill, it will roll down far enough to repay the energy cost of it getting up the hill. But it still shouldn’t be possible!