The self repair forces of the ego selecting the tale with the highest praise for me, the chosen one, living at the end of time, made in gods image.

Statistically, size or quantity is a major part of significance. But that's not really the sense in which 'significant' is being used here... it's being used as a synonym of 'important' or 'meaningful'. In those terms, you have to ask the question, 'significant to whom?' Significance doesn't exist outside of somebody to attach meaning to it.

Most often, the answer is 'to me, the guy making the observation.'

In that sense, that tiny speck of dust in our corner of the galaxy is very significant. At least to me.

Size determines significance by definition of a population bottleneck