- 4436 - MARS ROBOTS - what have they found?
------------------------- 4436 - MARS ROBOTS - what have they found?
- Perseverance is a rover on Mars. It finds its “dream rock”. A specific type of rock so important that it
holds convincing clues to Mars’ ancient habitability. If scientists could design the perfect rock
for Perseverance to find, it would be one that displayed evidence of ancient
water and was the type that preserves ancient organic material.
-
- The Perseverance rover may have found it as
it explores the “Margin Unit”, a geologic region on the inner edge of Jezero
Crater’s rim. The Margin Unit was one of the reasons Jezero Crater was selected
for Perseverance’s mission. This is the
kind of rock we had hoped to find when we decided to investigate Jezero Crater.
-
- The “Margin Unit” is in a narrow band
along the crater’s western rim. Orbital observations showed that it’s one of
the most carbonate-rich regions on the planet.
Its presence, along with the adjacent fluvial delta, made Jezero crater
the most compelling landing site for the Mars 2020 Perseverance mission.
-
- “Bunsen Peak” caught scientists’
attention because it stands tall compared to its surroundings. One of the
rock’s faces also has an interesting texture. Scientists thought the rock would
allow for nice cross-sections, and since it stood vertically, there’d be less
dust when working on it. Surface dust is a problem for Perseverance because it
can obscure the rock’s chemistry.
-
- The Perseverance team decided to scan the
rock’s surface with SuperCam and PIXL, the rover’s spectrometers. Then, they
abraded the rock’s surface and scanned it again. The results show that Bunsen
Peak is 75% carbonate grains cemented together by nearly pure silica.
-
- Nearly all the minerals in the rock just
sampled were made in water; on Earth, water-deposited minerals are often good
at trapping and preserving ancient organic material and biosignatures. The rock
can even tell us about Mars’s climate conditions that were present when it was
formed.
-
- Here on our planet, carbonate minerals can
form directly around microbe cells. Once encapsulated, the cells can quickly
become fossils, and are preserved for a long time. This is what happened to
stromatolites here on Earth, and they now constitute some of the earliest
evidence of life on our planet.
-
- These minerals are a high priority for
return to Earth. Sample is number 24,
named Comet Geyser, because everything gets a name when you intend to transport
it to Earth from another planet.
-
- There’s something specific that makes this
sample even more intriguing. They’re microcrystalline rocks, meaning they’re
made of crystals so small that only microscopes can see them. On Earth,
microcrystalline rocks like Precambrian chert hold fossilized cyanobacteria.
-
- The silica and parts of the carbonate appear
microcrystalline, which makes them extremely good at trapping and preserving
signs of microbial life that might have once lived in this environment. That makes this sample great for
biosignature studies if returned to Earth. Additionally, the sample might be
one of the older cores collected so far by Perseverance, and that is important
because Mars was at its most habitable early in its history.
-
- The samples support what scientists thought
about Jezero Crater before Perseverance landed there: it was once a
paleolake. The hypothesis is that the
rocks here formed along the shores of an ancient lake.
-
- There was no intelligent life, but there may
have been simple life in those lakes. Once we get Comet Geyser and the other
samples back to Earth, we may find out for sure.
-
- If there’s a Holy Grail on Mars, it’s
probably a specific type of rock: A rock so important that it holds convincing
clues to Mars’ ancient habitability.
Nearly all the minerals in the rock
were made in water; on Earth, water-deposited minerals are often good at
trapping and preserving ancient organic material and biosignatures. The rock
can even tell us about Mars’s climate conditions that were present when it was
formed.
-
- The sample contains about 75% carbonate
minerals cemented by almost pure silica. Here on our planet, carbonate minerals
can form directly around microbe cells. Once encapsulated, the cells can
quickly become fossils, and are preserved for a long time. This is what
happened to stromatolites here on Earth, and they now constitute some of the
earliest evidence of life on our planet.
-
- These minerals are a high priority for
return to Earth. Sample is number 24,
named Comet Geyser, because everything gets a name when you intend to transport
it to Earth from another planet. There’s
something specific that makes this sample even more intriguing. They’re
microcrystalline rocks, meaning they’re made of crystals so small that only
microscopes can see them. On Earth, microcrystalline rocks like Precambrian
chert hold fossilized cyanobacteria.
-
- There’s still more work to do, but the
samples support what scientists thought about Jezero Crater before Perseverance
landed there: it was once a “paleolake”.
They are still exploring the margin and gathering data, but results so
far may support our hypothesis that the rocks here formed along the shores of
an ancient lake.
-
-
April 17, 2023 MARS ROBOTS
- what have they found? 4436
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------ “Jim Detrick” -----------
--------------------- --- Wednesday, April 17,
2024
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