Energy equals mass times speed of light squared, is the same as: E = mc².
The former is more accessible to a general public audience (reader).
to be clear, I was referring to use of percentages rather than "Astronomical Unit" vs AU
I could understand wanting to explain what AU stands for, and what an Astronomical Unit represents, it just seemed weird to then convert everything into percentages as well
i agree, it's a bit weird. personally I'd use 0.5 rather than 50% to record the facts, and 50% to make a salient point/summary, since the latter is a higher level of abstraction (perhaps even anthropocentric)