this post was submitted on 21 Sep 2024
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[–] [email protected] 93 points 1 month ago (4 children)

Turns out rocks are rocks. (I'm a geologist I an I approve of this message)

[–] [email protected] 19 points 1 month ago* (last edited 1 month ago) (1 children)


Interesting that Dean Norris was on Mars and has a special interest in ~~rocks~~ minerals.

[–] [email protected] 3 points 1 month ago

Hey you show some got dang respect. He knew it was an ugly planet, a bug planet, and he did something about it. No more bugs on Mars. You're welcome.

[–] [email protected] 13 points 1 month ago (1 children)

Those particular rocks seem to be sandstone, though... which would pretty much be proof of liquid water having existed at some point.

Rocks are rocks, sure... but rocks tell stories, and these ones are telling a story that, while common and somewhat uninteresting on Earth, is quite interesting indeed when told on Mars.

[–] [email protected] 5 points 1 month ago* (last edited 1 month ago)

You are totally right. I was going to make a big post about how they actually formed but I deleted it halfway through. These rocks are definitely significant in that the same processes on earth happen on Mars so we can infer how they were deposited and formed. Hence my shitty first comment, rocks are rocks.

[–] [email protected] 5 points 1 month ago (1 children)
[–] [email protected] 5 points 1 month ago (1 children)
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[–] [email protected] 37 points 1 month ago (4 children)

Aren't the layers in the rock showing that water was definitely present on Mars, and that they're formed by sediment being deposited and forming into sedementary rock over time?

[–] [email protected] 16 points 1 month ago

I could be wrong, but I don't think so in this case. Water would likely create more variation in banding where some groupings of layers is present and distinct. What I see in the differences at higher levels appears to be from exposure to wind and solar temperature fluctuations due to exposure. It looks too linear from top to bottom. With water I expect those more distinct sections of banding like you see on the Earth pic side. Maybe there was a lot more or less rain for a time due to a mountain range that came and went, or a local sea or large water basin. Those layers are deep time and more like the slow accumulation of an average dust before wind patterns shift significantly or some event shifts the composition like exposure of a different large rock unit to winds regionally. It is hard for humans to grasp deep time like this.

[–] [email protected] 15 points 1 month ago (7 children)

I’m not a geologist but I’ve read up on it a fair bit.

This Mars photo appears to be sandstone.

On earth sandstone is usually associated with ancient rivers, lake shores, and sea shores. But also sand dune fields.

The thing with sandstone though, is it’s not just sand. Rather, it’s sand plus time plus pressure plus cementation.

Now, the time part is obvious. What’s sandstone now was sand a long ass time ago (usually).

Pressure? That’s a little harder to understand for me here. Has mars ever had tectonic stuff going on to bury it (and hence have pressure applied), followed by erosion and uplift? Or am I incorrect and pressure is not a necessary condition? Maybe sandstone without pressure is a thing it’s just weaker and/or less dense? Maybe layers of volcanic basalt or something could have a similar effect? I don’t know and would love to have someone more knowledgeable fill this part out.

Cementation? This part, I’m nearly certain, REQUIRES water. On earth anyway, this happens when ground water absorbs chemicals from other rock/stuff (for example carbonates from sea shells, but there’s lots of other chemicals that can do this), then flows through the beds of buried sand, and some of those chemicals are deposited along with magical chemistry stuff happening, and your sand becomes sand stone.

So I don’t 100% know that the short answer to your question is β€œyes”, but I’m leaning towards a solid β€œyeah, probably, but I’m not a real geologist and Mars isn’t a real Earth so I dunno”.

[–] [email protected] 13 points 1 month ago

Apparently, sandstone takes FAR less time to form than most people think. Apparently, some sandstone deposits have been found with roman artefacts inside. They were normal sand at the time and turned to sandstone since then.

Basically, it would take far less time than you would think to form sandstone on Mars. It's still proof of liquid water, but the lower end of the time estimate can be FAR shorter than you first think.

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[–] [email protected] 8 points 1 month ago

Yup!

Sediment gathers at the bottom of a lake or sea. Builds up deeper and deeper layers. Each layer is formed by a sediment deposition event. Each layer you go down is going further into the past of that former water body.

Because sedimentary rock requires standing bodies of liquid to form, they are only found on Earth and Mars (and maybe Dragonfly will find sedimentary deposits on Titan which would be very different in chemistry).

[–] [email protected] 7 points 1 month ago (1 children)

Think so. That's what I came here to ask

[–] [email protected] 4 points 1 month ago (1 children)

I came to ask which picture is which then noticed the blue sky duh πŸ˜‚

[–] [email protected] 5 points 1 month ago (1 children)
[–] [email protected] 6 points 1 month ago

OMG I'm being leftright-shamed

[–] [email protected] 31 points 1 month ago (2 children)
[–] [email protected] 6 points 1 month ago

It's just the ray tracing

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[–] [email protected] 27 points 1 month ago (3 children)
[–] [email protected] 6 points 1 month ago

Looking for a big rock

[–] [email protected] 4 points 1 month ago

They're gorn.

[–] [email protected] 4 points 1 month ago

I've been to the Vasquez Rocks where that was shot. It's right by a freeway that definitely also existed in the 60s. They had to use some very creative camera work in terms of where they pointed it. It's kind of impressive.

[–] [email protected] 19 points 1 month ago (5 children)

Those clouds are doing a lot of talking in the picture on the right

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[–] [email protected] 19 points 1 month ago

Looks like a nice day on Mars. Apart from it being -70C out.

[–] [email protected] 18 points 1 month ago (2 children)
[–] [email protected] 13 points 1 month ago* (last edited 1 month ago) (1 children)

If only he would tell us why he had to hide away, for so long :(

[–] [email protected] 9 points 1 month ago

Where did we go wrong?

[–] [email protected] 10 points 1 month ago

Mars has blue sunsets though.

[–] [email protected] 11 points 1 month ago

Aeolian erosion do be like that though.

[–] [email protected] 11 points 1 month ago (1 children)

I dont know what camera they used but that zoom is crazy

[–] [email protected] 9 points 1 month ago

Captured on my Samsung Galaxy s22

[–] [email protected] 11 points 1 month ago (1 children)

Mmmm that's some good choss! Do you happen to know where the photo on the right was taken? My geoguessr brain wants to put a pin on Kanab, Utah

[–] [email protected] 8 points 1 month ago (2 children)

I believe it's the Atacama desert in Chile, according to a reverse image search.

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[–] [email protected] 11 points 1 month ago

If you find this interesting, you would probably enjoy the Mars Guy youtube channel. Weekly updates on the latest rovings of Perseverance.

[–] [email protected] 9 points 1 month ago (1 children)

Mars looks like Southern California in Star Trek in the 60s.

[–] [email protected] 5 points 1 month ago

Says a lot for how much they were able to accomplish thematically with environments like that. Iconic

[–] [email protected] 6 points 1 month ago (3 children)

i wonder if humanoid aliens would be a common thing throughout the universe

like a mass effect sorta thing

[–] [email protected] 3 points 1 month ago (1 children)
[–] [email protected] 4 points 1 month ago (1 children)

i was thinking more on the convergent evolution side, since the worlds seem to be similar? but panspermia is a cool concept too.

[–] [email protected] 3 points 1 month ago (1 children)

If it's gonna be convergent evolution, all the aliens are probably crab people

[–] [email protected] 3 points 1 month ago

crab people crab people

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