> I hope it's all fungi and I hope it's edible.

That reminds me of a passage from H.G. Wells's «The First Men In The Moon», where the narrator protagonist is so hungry that he can't help but take a bite out of some fungi-like lunar vegetation, and convinces his colleague Cavor to indulge in it as well... but the fungi happens to be psychoactive!

If anyone's interested, it's at the end of Chapter XI, «The Mooncalf Pastures», from the paragraph that begins “We roused ourselves...” onward: https://www.gutenberg.org/files/1013/1013-h/1013-h.htm#chap1...

I'd be disappointed if lunar fungi weren't psychoactive....

Other images show the "sphericals" as being hollow and easily crushed by the treads, and having stalks, and growing together. The "growth" photos which could be possibly explained in isolation by wind exposing round pebbles on previously existing stones doesn't explain the appearance of additional sphericals in the 3 sol period of the same size as the ones being "revealed". If it was just that photo sequence I could understand that argument but the rest of the evidence really pushes towards organic growth as the most likely scenario.

"Other images show the "sphericals" as being hollow and easily crushed by the treads, and having stalks, and growing together."

This is an example of "proving too much". If Mars had plant life developed to the point of having stalks and visibly growing in macroscopic amounts over this time frame, we wouldn't be "debating" life on Mars because it would be plainly obvious that it has life, if life was that active.

This is why we discuss whether or not it has a micro-organism based ecology that it is hiding, rather than discussing whether or not it has forests that we just haven't found yet.

I've noticed this is one of the key signs you can use to identify cranks massively overfitting data about life being here or there.

Fungi (and lichen) is known to be able to survive in places where plants cannot. So it's entirely possible that fungi could survive on Mars while trees/moss/grass could not. We also know where this happens on Earth[1][2]. We didn't discover these life forms from orbit or even by standing and looking at them.

[1]: https://en.wikipedia.org/wiki/Biological_soil_crust [2]: https://www.wbur.org/hereandnow/2021/02/15/antarctic-ice-new...

> So it's entirely possible that fungi could survive on Mars while trees/moss/grass could not

Nope, there is no real chance to find fungi living at -50C to -70C, with no liquid water. There is no life on Earth that lives at such low temperatures, and there is no way for life as we know it to work without liquid water (or perhaps other liquid solvents, though that is highly speculative).

Also note, fungi in particular can't deal with extreme cold, the coldest I've read about any kinds of fungi living is ~0C. There are bacteria and other prokaryotes that survive at temperatures below that, but even then only at high pressures that allow liquid water to exist at very low temperatures - whereas Mars has extremely low pressure, much lower than anyone on the Earth's surface (Martian atmospheric pressure is comparable to Earth's upper atmosphere).

Whether life could survive is entirely orthogonal to my point, and sneaky life surviving that we can't even see is exactly what I said could still be on Mars. What can't be on Mars is life with stalks (it may not sound like much to a Earth-bound human in 2021, but that's actually quite sophisticated for life) that grows macroscopically over the course of just a few days. There'd be evidence of their metabolites, probably color and spectra changes like Earth's greenness as something uses sunlight, all kinds of things. Macroscopic plants are way too much to claim on the basis of a few photos. I mean, if nothing else, we ought to see lots of them.

I assume you're referring to Fig 31. (I was referring to Fig 32)

"Spherical" clumps of blue dust would crush just the same. Mars is reeeeally cold a lot of the time and has a bit less gravity. Dust can clump. Again, not a geologist.

What's important to me is that they're presenting crossing tracks as evidence of before/after, when it's not. They don't have two images of the same area separated by X days, they have one image of two tracks separated by X days, and are interpreting the crest-clumping as "new". This is a somewhat disingenuous way to present, if I'm reading it right.

I'm into sending a robot to grab some, don't get me wrong, but I'm also not privy to all the details to make an intelligent prioritization of the robots' time.

> the rest of the evidence really pushes towards organic growth as the most likely scenario

We know next to nothing about geological processes that can happen at low temperatures and extremely low air pressure. Biological explanations are never 'the simplest', as there is no kind of geological formation that comes even close to the complexity of a single cell, nevermind the complexity of a multicellular organism.

Everyone is attacking the author's credentials, but I'd like to see what people have to say about image 30.

Even if it's not organic, they are pretty odd looking formations that I haven't seen on Earth in any inorganic way.

Sure, but you also haven't seen geological processes working at -50C at pressures similar to the upper atmosphere, have you?

By that logic, we should not be able to interpret anything we see at all.

Nevertheless, the image on picture 30 looks like something that grew out of the ground because it's on a stem.

> which show that there's a bunch of dark stuff under the surface that shows when you disturb the surface. Interpreting fresh impact imagery with a fungii story would be "Rocks impacting the surface cause fungii growth" which makes very little sense. Even dust devils strip off the surface enough to show the dark stuff.

there was a link here or on reddit a few days ago studying the link between mushroom growth and the lightning. they claimed just using small electrical charges (1/billion of the power of a lightning) they could get up to %10 more growth

> I hope it's all fungi and I hope it's edible.

I'm not sure I do. If we can eat it, it can eat us.

Well this got real quickly.

> I hope it's all fungi and I hope it's edible.

Whoa, imagine being the first human to eat alien mushroom stew.

as for page 41, sand eroding from pebble is not a convincing argument imho. page 41 is sufficient proof for me.