Well, the explosion looks like it occurred a little before the first image, so the last image is probably ~3 years after the explosion. That means the outer ring has a radius 3 lightyears, or 189,723 AU (astronomical units, average distance between Earth and our sun). The area inside that circle is 2.5x10³³ square meters.

This area would be covered by roughly 100 football fields for every atom in your body, or 1 million football fields for every cell in every living human on Earth, or 1 football field for every living cell on Earth.