Hello, friends! Welcome to Sciency Words, a special series here on Planet Pailly where we take a closer look at some interesting and new scientific term so we can expand our scientific vocabularies together. Today’s Sciency Word is:
You don’t mind if I do one more post about Venus, do you? Venus is my favorite planet, after all, and the detection of phosphine (a possible biosignature!) in Venus’s atmosphere has got me really excited. I’ve been reading lots of papers and articles about Venus lately, and many of those papers and articles mention something called VIRA.
VIRA stands for Venus International Reference Atmosphere. VIRA is actually a book, originally published in 1985 by an international committee on space research. The purpose of VIRA was to consolidate everything we knew about Venus’s atmosphere at that time into a single, easy to use reference guide. As planetary scientist David Grinspoon describes it in his book Venus Revealed:
Although not exactly a best-seller, [VIRA] is a cherished reference among students of Venus’s atmosphere, and many a copy has become dog-eared and worn. The tables and summaries of atmospheric data found therein are still the standard on Earth for Venus models, and the wide use of this standard allows us to make sure that we are comparing apples with apples, when making models and sharing new results.
One thing I don’t understand: why are Venus researchers still relying so heavily on a reference guide from 1985? I’ve found several scientific papers (like this one or this one or this one) offering updates and improvements to VIRA. And yet, unless I’m missing something (I feel like I must be missing something), it sounds like the original 1985 VIRA is still used as the gold standard for modeling Venus’s atmosphere.
Anyway, when people say we can’t explain where Venus’s phosphine comes from, in a sense, what they mean is that there’s nothing in VIRA that helps explain it. So maybe the discovery of phosphine in Venus’s atmosphere will finally give scientists the push they need to update VIRA for the 21st Century.
P.S.: According to this paper, there’s also a Mars International Reference Atmosphere, or MIRA. And I’m guessing there are similar reference atmospheres for other planets and moons in our Solar System as well.