Yes, the assumption of a standard candle always seemed a little "assume a can opener"ish. Without it, seems like a lot of our current understanding of the universe is on shaky ground, no? (Its size, rate of expansion, eventual fate, and the whole % of dark matter plug-figure?)As the extent of my astronomical knowledge is scarcely more than knowing which tunes in Cosmos are performed by Vangelis, I've just gone on faith that astronomers were pretty certain about their standard candle. Now I'm all, "psshh... c'mon guys! Do we know this or not?"Unless I'm totally misunderstanding this, in which case, would love to understand if anyone wants to explain it better than the article did.