FlingingGoronGonads t1_ixn5h3n wrote
All emphasis added is mine:
> The new Perseverance research is detailed in three extensive studies published Wednesday, one in the journal Science and two in the journal Science Advances. The journal reports are highly technical and devoid of hype — daring to be dull as dirt — but the scientists involved translate them into a more exciting tale.
You mean, like nearly every other science paper ever published? I don't think Ken Farley and the rover team had WaPo reporters in mind when they write them, and I sure wasn't taught to think about that sort of person when writing up either.
> “It’s amazing. In pretty much every rock we’re finding organics,” said Abigail Allwood, a geologist at the NASA Jet Propulsion Laboratory in Pasadena, which operates the rover and the broader Mars Sample Return mission.
Not the first time we've discovered organic material on Mars - MSL/Curiosity has detected the same, and we know that plenty of meteorites have them too. This is still big, though.
> One of the studies concluded that the rocks in the crater experienced three different events in which they were exposed to water.
In other words, it's not as simple as "we found volcanic minerals, never was any water here" or "the floor of this crater is covered in limestone and coral!!!1!". It's something in between, or even something completely different. Sounds about right for Mars.
> “Crucially, conditions in the rock during each time that water migrated through it could have supported small communities of microorganisms,” lead author Michael Tice, a geologist at Texas A&M University, said in an email.
> Even finding organics — life-friendly molecules with combinations of carbon, hydrogen and oxygen — is a far cry from discovering life or even proof of its presence in the past. Such molecules can be either biological or nonbiological in origin.
> One of the new papers more closely examining Mars’s chemistry has delivered a surprise for geologists. They had assumed that they were going to dig up a bunch of sedimentary rocks. Instead the rocks are volcanic.
> The shallow crater clearly had water in it long ago. This could be determined from orbital images showing the remnants of a delta where a river flowed into the lake.
This is not in question, and hasn't been for years. The crater floor rocks are lower than the river delta sedimentary rocks, which are at or near the crater rim.
> Planetary geologists had assumed the floor of the crater was covered in sedimentary rock, formed from dirt and debris that slowly accumulated at the bottom of the lake.
> If such sedimentary rock was ever there, it’s gone now. It may have eroded away, Tice said. The lack of sedimentary rock could mean that the lake didn’t last very long, which would be disappointing for the astrobiologists.
I'm no astrobiologist, but I fully respect their work. Nonetheless, I have two words for everyone involved: Earth bias. In fact, we already know that at least some rock once found in the region has eroded away (there were volcanic layers atop the olivine rocks in the lower crater floor formation).
> The volcanic rocks are not a disappointment, though, because they preserve loads of information about the Martian past, including the presence of organic molecules, scientists said.
> Mars’s magnetic field died, and then it became a different kind of planet. It lost almost all of its atmosphere. It became a frigid desert world. How quickly that happened is unknown, but that’s something that might be revealed by the volcanic rocks in the crater.
> Magma contains some amount of iron, which is sensitive to a planet’s magnetism. As lava cools, it crystallizes into igneous rock, freezing electrons within iron-bearing minerals into patterns that could reveal a magnetic field’s traits, such as its orientation.
> Benjamin Weiss, a planetary scientist at MIT and co-author of two of the papers, said in an email, “On balance, we are actually super lucky that there are igneous rocks in the crater, and that we happened to land right on them, since they are ideal for determining ages and studying the past history of Mars’ magnetic field.”
Ding ding ding Credit to the reporter for getting this part right! So we didn't find a muddy lake bottom or the Great Barrier Reef on the floor of Jezero, but what we found will be super useful in dating the stuff that we know did form under large amounts of water.
> The presence of organic material on Mars had been confirmed in previous missions, but their precise nature and chemistry can’t be discerned through this kind of long-distance research and will require laboratory scrutiny on Earth, according to Bethany Ehlmann, a planetary scientist at Caltech and co-author of two of the new papers.
> “Are they merely organics that kind of washed into the system — maybe from meteoritic material that was just part of the water? That would be the least exciting. Or are they little niches of microbial life living in the cavities of these rocks? That would be the most exciting,” Ehlmann said.
> She added that the rover “is collecting an awesome set of samples to reveal Mars’s environmental history in all of its forms — the volcanic history, the history of water, the relationship of organics to those water-rich environments.”
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