- 4106 - LIFE ON MARS - Perseverance explorations? What happens if Perseverance finds life on Mars? On February 18, 2023, NASA’s Perseverance rover set landed in the Jezero crater on Mars and almost immediately transmitted its first image of the Martian.
-------------- 4106 - LIFE ON MARS - Perseverance explorations?
- The Perseverance rover is NASA’s ninth
mission to land on Mars and is tasked with characterizing the geology,
atmosphere, and climate of Mars and help pave the way for human exploration.
But the rover is also focused on “astrobiology”, the study of life throughout
the Universe. As the next most-habitable place in our Solar System beyond
Earth, Mars is a major focus of astrobiological efforts.
-
- Billions of years ago Mars was a much
different place than it is today. Its atmosphere was denser, its climate
warmer, and liquid water flowed on its surface. This led to many of the
features that are observable today, like the preserved river delta in the
Jezero crater.
-
- This feature indicates that 3.5 billion
years ago, Jezero was a lakebed that had water flowing into it. This caused
sediment to build up over time, leading to the formation of a river delta that
is rich in clays. While the lake may be long gone, scientists theorize that
there could be biosignatures somewhere in this
28 mile wide crater.
-
- Given the relatively brief window Mars had
for habitability, odds are that only simple lifeforms (like single-celled bacteria)
would have emerged. On Earth, some of the most ancient evidence for life comes
in the form of microbialites, sedimentary deposits composed of carbonate mud
that form.
-
- We expect the best places to look for
biosignatures would be in Jezero’s lakebed or in shoreline sediments that could
be encrusted with carbonate minerals, which are especially good at preserving
certain kinds of fossilized life on Eartth.
-
- Using its advanced suite of scientific
instruments, Perseverance will collect rock core samples in metal tubes and
place them in a supply cache which will be retrieved by a future mission sent
by the ESA. These instruments include the rover’s suite of cameras, especially
the one located on the rover’s mast that’s capable of zooming in to inspect
targets (Mastcam-Z).
-
- The SuperCam instrument, which is also
located on the mast and can use a small laser to examine promising research
targets. This is done by using the laser to create small clouds of plasma
clouds, which will then be analyzed to determine the target’s chemical
composition. If the data it obtains reveals something interesting, the rover
will be able to examine it more closely with its two turret-mounted
instruments.
-
- These are known as the Planetary Instrument
for X-ray Lithochemistry (PIXL) and the Scanning Habitable Environments with
Raman & Luminescence for Organics & Chemicals (SHERLOC) instruments.
The PIXL relies on small x-ray bursts to search for chemical biosignatures
while SHERLOC uses its own laser to detect concentrations of organic molecules
and minerals that have been formed in watery environments.
-
- Together, these two instruments will
effectively create high-resolution maps of elements, minerals, and molecules in
Martian rocks and sediments, which astrobiologists will use to determine which
to collect and eventually send back to Earth.
-
- The instrumentation required to
definitively prove microbial life once existed on Mars is too large and complex
to bring to Mars. That is why NASA is partnering with the European Space Agency
on a multi-mission effort, called Mars Sample Return, to retrieve the samples
Perseverance collects and bring them back to Earth for study in laboratories
across the globe.
-
- We have strong evidence that Jezero Crater
once had the ingredients for life. Even if we conclude after returned sample
analysis that the lake was uninhabited, we will have learned something
important about the reach of life in the cosmos. Whether or not Mars was ever a living planet,
it’s essential to understand how rocky planets like ours form and evolve. Why
did our own planet remain hospitable as Mars became a desolate wasteland?
-
- Discovering life would raise some very
important questions, the answers to which would have some rather drastic
implications. There’s the question of
whether or not life on Mars is related to life on Earth. If the answer to this
question is yes, then scientists would have solid evidence that life is
distributed between planets in a star system. Alternately, it could be an
indication or where life is distributed throughout the cosmos by celestial
bodies like asteroids and comets.
-
- In this case, it could be argued that Earth
and Mars were seeded from the same source (though that would be extremely
difficult to prove). The most direct
test of the genetic relatedness of any martian and terrestrial life would come
from the comparisons of the information molecules (DNA, RNA) and the presence
of such molecules.
-
- However, if we see something that looks like
fossil cells upon sample return, and detect some organic biosignatures, that
would automatically support the similarities between past life on Mars and life
on Earth.
-
- The discovery of evidence for past life on
Mars is likely to lend some credibility to the theory that life still exists
there today. Much like the disappearance of Mars’ surface water, it is
theorized that microbial life could have also migrated underground as a result
of changes in the planet’s climate.
Microbes could survive beneath the surface in briny patches of water.
-
- Modern surface life on Mars is highly
unlikely, hence why Perseverance aims to collect samples that will preserve
evidence of past life. Nevertheless, the existence of past life will make the
issue of planetary protection all the more pressing when crewed missions to
Mars commences, especially if they lead to an enduring human presence there.
-
- Already, robotic missions are forced to
exercise care in the vicinity of potential sites for microbial life, a good
example of which is the time Curiosity came upon a discolored patch of sand
(thought to be a surface brine) and was forced to divert its path to go around
it.
-
- If human habitats are ever built on Mars,
the possibility that we could be causing harm to Martian organisms will always
be there.
-
-
July 29, 2023 LIFE
ON MARS -
Perseverance explorations? 4106
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