- 4544 - EXOPLANET LIFE - Perseverance Mars rover finds possible signs of ancient Red Planet life. On Earth, these types of features in rocks are often associated with the fossilized record of microbes living in the subsurface.
--------------------------------------------- 4544
- EXOPLANET LIFE
-
- NASA's Perseverance rover has discovered a
rock on Mars that may have once hosted microbial life. The rock, nicknamed
“Cheyava Falls”, has chemical compositions and structures that could have been
formed by ancient life, although non-biological processes cannot yet be ruled
out.
-
- The rover has come across an intriguing,
arrowhead-shaped rock that hosts chemical signatures and structures that could
have been formed by microbial life billions of years ago, when Mars was
significantly wetter than it is today. Inside the rock Perseverance's
instruments detected organic compounds, which are precursors to the chemistry
of life as we know it. Wisping through the length of the rock are veins of
calcium sulfate, which are mineral deposits that suggest water, essential for
life, once ran through the rock.
-
- The rover also found dozens of
millimeter-sized splotches, each surrounded by a black ring and mimicking the
appearance of leopard spots. These rings contain iron and phosphate, which are
also seen on Earth as a result of microbe-led chemical reactions.
-
- On Earth, these types of features in rocks
are often associated with the fossilized record of microbes living in the
subsurface. Cheyava Falls sits at the
edge of an ancient, 400-meter-wide river valley named “Neretva Vallis”.
Scientists suspect this ancient channel was carved out long ago due to water
gushing into Jezero Crater; Neretva Vallis runs along the inner wall of this
region.
-
- In one possible scenario, mud that already
possessed organic compounds got dumped into the valley and later cemented into
the Cheyava Falls rock, which Perseverance sampled on July 21, 2024. A second episode of water oozing into the
formed rock would have created the object's calcium sulfate veins and
black-ringed spots the team sees today.
-
- The rock's visible features aren’t
irrefutable evidence of ancient microbial life on Mars, not yet, at least. It
is possible, for instance, that the observed calcium sulfate entered the rock
at uninhabitably high temperatures, perhaps during a nearby volcanic event.
However, whether such non-biological chemical reactions could have resulted in
the observed black-ringed spots is an open question.
-
- We have zapped that rock with lasers and
X-rays and imaged it literally day and night from just about every angle
imaginable.
-
- Scientists are keen to get the Cheyava
Falls sample to Earth, where it can be scrutinized with powerful instruments
that Perseverance’s limited suite doesn't have. The complex Mars Sample Return effort,
however, has run into many snags in recent months after its costs spiked to $11
billion.
-
- In its current form, the program requires
multiple launches to Mars to place a vehicle on the Red Planet, after which
either Perseverance will travel to the vehicle and drop off its collected
samples, or pop those samples over to a retrieval helicopter that can complete
the handoff. Then, an ascender would launch the samples into orbit, where a
spacecraft would collect them and return them to Earth.
-
- On Earth, these types of features in rocks
are often associated with the fossilized record of microbes living in the
subsurface. The arrowhead-shaped rock
that hosts chemical signatures and structures that could have been formed by
microbial life billions of years ago, when Mars was significantly wetter than
it is today.
-
- Inside the rock Perseverance's instruments
detected organic compounds, which are precursors to the chemistry of life as we
know it. Wisping through the length of the rock are veins of calcium sulfate,
which are mineral deposits that suggest water once ran through the rock.
-
- The rover also found dozens of
millimeter-sized splotches, each surrounded by a black ring and mimicking the
appearance of leopard spots. These rings contain iron and phosphate, which are
also seen on Earth as a result of microbe-led chemical reactions. On Earth, these types of features in rocks
are often associated with the fossilized record of microbes living in the
subsurface.
-
- Cheyava Falls sits at the edge of an
ancient, 400-meter-wide river
valley. Scientists suspect this ancient
channel was carved out long ago due to water gushing into Jezero Crater;
Neretva Vallis runs along the inner wall of this region. In one possible
scenario, mud that already possessed organic compounds got dumped into the
valley and later cemented into the Cheyava Falls rock. A second episode of water oozing into the
formed rock would have created the object's calcium sulfate veins and black-ringed
spots the team sees today.
-
- It is possible that the observed calcium
sulfate entered the rock at uninhabitably high temperatures, perhaps during a
nearby volcanic event. However, whether such non-biological chemical reactions
could have resulted in the observed black-ringed spots is an open question.
-
-
August 29, 2024 EXOPLANET
LIFE 4544
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--------------------- --- Friday, August 30, 2024
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