- 4625
- MARS - are
there signs of life? - On Earth, these types of features in rocks
are often associated with the fossilized record of microbes living in the
subsurface. NASA's Perseverance rover
may have found signs of ancient life in a rock on Mars.
-------------------------------------- 4625 - MARS - are there signs of life?
- See Review 4624 “Mars had water at one time”
. This Review asks, “What about life?”
Perseverance Mars rover finds possible signs of ancient Red Planet life
-
- 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, which scientists have
nicknamed "Cheyava Falls," 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, also 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.
-
- These spots are a big surprise. 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. 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.
-
- This trip through the Neretva Vallis
riverbed paid off as we found something we've never seen before, which will
give our scientists so much to study.
We have zapped that rock with lasers and X-rays and imaged it literally
day and night from just about every angle imaginable.
-
- To fully grasp what really unfolded in the
ancient river valley billions of years ago, 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.
-
-
November 26, 2024 MARS - are
there signs of life? 4625
------------------------------------------------------------------------------------------
-------- Comments appreciated and Pass it on to
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--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for
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--- to:
------
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------ “Jim Detrick” -----------
--------------------- --- Wednesday, November 27,
2024
---------------------------------
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