Northern Lights

The Northern Lights (Aurora Borealis) light up our northern hemisphere sky and appear alive as they dance across the night sky. The truth of the matter is, that dance is a protective one, that speaks of the invisible shield at the upper most layer of our atmosphere that the charged particles from the Sun collides with.
Two nights ago the Aurora Borealis display brought me to thinking about how we each have our own shields of protection. It may be in the form of visible "armour" (clothes etc.) or a shield that is invisible to the eye, one that is worn within us. Our protective mechanisms are created (and evolve) over the course of our lifetime, some discarded when the need is no longer apparent, others are held onto. 
How do we know when our protective "armour" no longer serves in a positive way and in fact has become a barrier to our being able to live a healthy balanced life?
A question that can be pondered over a cup of tea while looking at the many amazing photos of the recent Aurora Borealis display!