That's the rumour. Press conference in 3 hours, apparently.

Live on Venus or live on Venus? I’m confused.

Uhwhat? do you mean they have actually found life on the second planet? or that a recently arrived probe will broadcast new insights?

Haha, life on Venus.

News explainer from Royal Astronomy Society in 127 minutes, or so...

isn't phosphine, like, toxic? how can it be evidence of the presence of a life it would destroy?

Toxic to some, waste product to others. Oxygen gas (photosynthetic waste product) was toxic to much of the early life on Earth, iirc.

Carolyn Porco (Cassini Mission to Saturn)

In other words, phosphine (which is easy to make geochemically) does not suggest life any more than finding any other geochemically common substance, like methane.

Quoting
Prof. Lee Cronin

@leecronin · 16m

I think we might need to teach some astrobiologists a bit of inorganic & physical chemistry starting with heats of formation & Hess’s law. To leap from we have found phosphine to life must make if with our understanding the surface of Venus & thermochemistry seems wild.

newolder wrote:Toxic to some, waste product to others. Oxygen gas (photosynthetic waste product) was toxic to much of the early life on Earth, iirc.

IIRC, it was the cause of the very first Mass Extinction, though we might never have noticed it because, at the time, life forms were still unicellular.

A big leap from "On Earth Phosphine is a product of biology" to "Phosphine on Venus must be a product of biology". Seems much more likely there are unknown non-biological processes making Phosphine on Venus than it being a product of unknown biological processes.

It's not aliens until it's aliens. I've seen discussion though that, if this turns out to be extant life, this is bad news for the Great Filter.

uh, what?

If there are microbes living in the high atmosphere of Venus, they're going to be seriously unusual from a biochemical standpoint. First, they're going to have to survive in an environment where the "moisture" droplets are actually 96% sulphuric acid. Under those conditions, normal aqueous biochemistry is right out of the window. If you want to find out why, drop some sugar in concentrated sulphuric acid and watch what happens. Quite simply, any molecules with a decent amount of -OH groups on them are going to have those -OH groups ripped off them in that environment, and as a corollary, a whole swathe of reaction pathways available to Earth microbes are ruled out, because these need intact -OH groups on key molecules.

Of course, our experience with organisms on Earth living in environments that aren't obviously hospitable to life, teaches us that strange organisms with unusual lifestyles are not only possible, but can be found in abundance in the right places. 20 years ago, no one would have thought nematode worms could live inside solid rock three kilometres below the earth's surface, but lo and behold, along came Halicephalobus mephisto to rewrite the rule book on that one.

Likewise, I've covered in some detail experiments demonstrating that tardigrades can survive for up to 21 days in the vacuum of space in low Earth orbit. A finding that could have some implications for an Israeli spacecraft that crashed on the Moon with a payload of tardigrades on board. I suspect some science fiction writers are already working that incident into some interesting stories.

Of course, we also need to exercise caution. Back in 1977, when the Viking landers arrived at Mars, they carried experiments intended, with the state of art of knowledge at the time, to detect any extant life there. We've since learned that some of the oxidation reactions that occurred in the Viking experiments threw up false positives because there are numerous strong oxidising agents in Martian soil, in the form of perchlorate salts. There's also detectable amounts of chromium in Martian soil, and in a strongly oxidising environment, some of that chromium could be in the form of hexavalent compounds, which are strong oxidising agents themselves, and bad news for most organisms with an Earth-type biochemistry.

Indeed, the question of whether Venus remained hospitable to indigenous life, long enough for some of that indigenous life to enter the atmosphere prior to the runaway greenhouse effect, is, I suspect, an open question.

Though there's something else to factor in here - phosphine is also present in the upper atmosphere of Jupiter. It's produced on Jupiter in the deep atmosphere, where a combination of high temperature and enormous pressure provides the thermodynamic gradient required. Although the surface of Venus is hot, it's a long way from the temperature of the deep Jovian atmosphere, and despite the atmospheric pressure on Venus being of the order of 200 bar at the surface, that's a long way short of the million or so bar in the deep Jovian atmosphere.

However, no one is considering phosphine in the Jovian atmosphere as indicative of indigenous microbes.

But, we know something odd is happening on Venus, in order for phosphine to be detectable in the upper atmosphere, because the currently known abiotic synthesis pathways do not appear to be available on Venus. At the moment, a new abiotic synthesis route seems more likely than microbes in the atmosphere, but until we send a suitable probe to look for the requisite processes, there's room for much speculation, including speculation that's a little on the wild side.

Indeed, one thought that crosses my mind, is that the large quantities of sulphuric acid in the Venusian atmosphere would provide any microbes capable of surviving the conditions in question, with a compelling reason to base their life processes on sulphur chemistry, in combination with ultraviolet photolysis processes. Phosphorus, on the other hand, strikes me as being very much a niche element on Venus.

Oh, really Cal. I've known there was life on Venus since I was 13. Dan Dare had a terrible time with the Mekon...



Sorry. Couldn't resist.

The Ghost of Mr Woodchuckles offers his apologies for the phospine in Venus' atmosphere. He was flying around the inner solar system and couldn't hold it any longer.


pic stolen from: https://astronomy.com/news/2017/02/groundhogs-day

Svartalf wrote:uh, what?

The Great Filter

https://www.nickbostrom.com/extraterrestrial.pdf

What has all this got to do with finding life on Mars? Consider the implications of discovering that life had evolved independently on Mars (or some other planet in our solar system). That discovery would suggest that the emergence of life is not a very improbable event. If it happened independently twice here in our own back yard, it must surely have happened millions times across the galaxy. This would mean that the Great Filter is less likely to occur in the early life of planets and is therefore more likely still to come.
If we discovered some very simple life forms on Mars in its soil or under the ice at the polar caps, it would show that the Great Filter must exist somewhere after that period in evolution. This would be disturbing, but we might still hope that the Great Filter was located in our past. If we discovered a more advanced life‐form, such as some kind of multi‐cellular organism, that would eliminate a much larger stretch of potential locations where the Great Filter could be. The effect would be to shift the probability more strongly to the hypothesis that the Great Filter is ahead of us, not behind us. And if we discovered the fossils of some very complex life form, such as of some vertebrate‐like creature, we would have to conclude that the probability is very great that the bulk of the Great Filter is ahead of us. Such a discovery would be a crushing blow. It would be by far the worst news ever printed on a newspaper cover.

The Fermi paradox, my favorite subject that I question is even a thing.
If we discover fossils of complex life forms on other planets, it will only increase the sample size to 2, still not enough to draw conclusions. Humans may never even reach the stage where we can look on other worlds for fossils.

Thinking about it though, we're having enough of a chore examining our own galaxy let alone the many billions of other galaxies, even if looking for type III civilisations.