Is There Life On Mars?

EnolaGaia

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Going back to the start of this thread, anyone know what happened to the Martian meteorite from 20 years ago that was supposed to contain fossilised microbes and therefore "proof" of life on Mars? They went really quiet on that one.

I'm pretty certain you're referring to the meteorite Allan Hills 84001(aka ALH84001), discovered in 1984 in Antarctica and widely publicized as displaying structures suggestive of microbial life in the mid to late 1990s. Even though most of the features underlying the claims of biological evidence have been explained in non-biological terms the dispute continues to this day.

https://en.wikipedia.org/wiki/Allan_Hills_84001
 

gordonrutter

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Going back to the start of this thread, anyone know what happened to the Martian meteorite from 20 years ago that was supposed to contain fossilised microbes and therefore "proof" of life on Mars? They went really quiet on that one.
Have you not seen the documentary on that by John Carpenter?
 

GNC

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I'm pretty certain you're referring to the meteorite Allan Hills 84001(aka ALH84001), discovered in 1984 in Antarctica and widely publicized as displaying structures suggestive of microbial life in the mid to late 1990s. Even though most of the features underlying the claims of biological evidence have been explained in non-biological terms the dispute continues to this day.

https://en.wikipedia.org/wiki/Allan_Hills_84001

No wonder with such an unexciting name as Allan Hills. Should have called it Wondiferous Lifeproofer or something.

I might have known it would come to nothing. Bill Clinton was summoned for no reason!
 

EnolaGaia

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Newly published research results suggest there's a simple reason for a lack of life on Mars - it's too damned small.
There Could Be an Extremely Simple Reason Why Mars Isn't as Suitable For Life

We often talk about the strong similarities between Earth and Mars, but it's the differences that are likely behind why one planet has life and the other doesn't – at least, no life we've found so far.

Specifically, new research suggests it could be down to the size discrepancy. The diameter of Mars is just 53 percent that of Earth's (just over half the size), and that would make it impossible for Mars to hang onto volatiles that we know are vital for life – such as water.

"Mars's fate was decided from the beginning," says planetary scientist Kun Wang of Washington University in St. Louis.

"There is likely a threshold on the size requirements of rocky planets to retain enough water to enable habitability and plate tectonics, with mass exceeding that of Mars." ...

The team studied the isotope compositions of potassium in 20 Mars meteorites, chosen because they seem to be representative of Mars's bulk silicate composition. These compositions were then compared to the known bulk silicate compositions of three other inner Solar System objects of varying masses – Earth, the Moon, and the asteroid Vesta.

The results showed that Mars lost more volatiles than Earth did during its formation, but retained more than the Moon and Vesta, both of which are significantly smaller and drier than Mars. ...

This has implications for our understanding of the planet's history, the researchers said. Previous research has found that Mars was once very soggy indeed. This new correlation between gravity and volatile retention might help place constraints on just how much water Mars once had.

Additionally, the finding has implications for our search for habitable worlds outside the Solar System. One factor that influences the presence of liquid water on a planetary surface is its temperature, related to its proximity to the host star. Too close and water evaporates; too far, and it freezes. ...
FULL STORY: https://www.sciencealert.com/there-...might-have-limited-habitability-its-tiny-size
 

EnolaGaia

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Here are the bibliographic details and abstract for the published research ...

Tian, Zhen et al.
"Potassium isotope composition of Mars reveals a mechanism of planetary volatile retention."
Proceedings of the National Academy of Sciences 118.39 (2021): e2101155118.
21 Sept 2021.
https://doi.org/10.1073/pnas.2101155118

Abstract
The abundances of water and highly to moderately volatile elements in planets are considered critical to mantle convection, surface evolution processes, and habitability. From the first flyby space probes to the more recent “Perseverance” and “Tianwen-1” missions, “follow the water,” and, more broadly, “volatiles,” has been one of the key themes of martian exploration. Ratios of volatiles relative to refractory elements (e.g., K/Th, Rb/Sr) are consistent with a higher volatile content for Mars than for Earth, despite the contrasting present-day surface conditions of those bodies. This study presents K isotope data from a spectrum of martian lithologies as an isotopic tracer for comparing the inventories of highly and moderately volatile elements and compounds of planetary bodies. Here, we show that meteorites from Mars have systematically heavier K isotopic compositions than the bulk silicate Earth, implying a greater loss of K from Mars than from Earth. The average “bulk silicate” δ41K values of Earth, Moon, Mars, and the asteroid 4-Vesta correlate with surface gravity, the Mn/Na “volatility” ratio, and most notably, bulk planet H2O abundance. These relationships indicate that planetary volatile abundances result from variable volatile loss during accretionary growth in which larger mass bodies preferentially retain volatile elements over lower mass objects. There is likely a threshold on the size requirements of rocky (exo)planets to retain enough H2O to enable habitability and plate tectonics, with mass exceeding that of Mars.

SOURCE: https://www.pnas.org/content/118/39/e2101155118
 

Trevp666

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Mars scientists now know where to look for life

"....From Perseverance's observations, it's now certain that where the river system met the lake water, the flows suddenly slowed and the sediment in suspension fell out to form a delta - the kind of wedge-shaped "landform" you'll see all over the Earth.
It's in such an environment that micro-organisms could have thrived and their chemical traces been preserved."


BBC article contains reproductions of the pictures of sedimentary rock layers.

https://www.bbc.co.uk/news/science-environment-58852236
 

Victory

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"MITZPE RAMON (ISRAEL) - Inside a huge crater in Israel's sun-baked Negev desert, a team wearing space suits ventures forth on a mission to simulate conditions on Mars."

c1_4111987.jpg



https://www.bangkokpost.com/world/2196115/life-on-mars-simulating-red-planet-base-in-israeli-desert
 

Trevp666

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a team wearing space suits
Blimey I hope they get to wear something better than the shonky 'cardboard and tinfoil' stuff they appear to be wearing in this pic!
 

charliebrown

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After many rovers and billions of dollars spent, nothing has been found on Mars.

It is possible a civilization could have been on Mars many years in the past, maybe ?
 

charliebrown

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Plasma specialist, Dr. John Brandenburg, claims Mars had a life ending war because of NASA finding radioactive potassium, besides other radioactive materials.
 

charliebrown

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I have read a theory that a race of small people live in the many underground caves on Mars that NASA thinks exists.

These surviving Martians living in caves would have water and be protected from the fierce surface radiation.

Mars is a true enigma.
 

Sabresonic

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I wonder if there was life on Mars did they have Music, Sport, Hospitality, Ghosts, Time Slips and MarsDonalds ?
 

charliebrown

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It makes you wonder why China, Russia, and the U.S. are killing each trying to get to Mars if it is a dead planet ?
 

EnolaGaia

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As our capabilities for seeking signs of current or past life on Mars evolve, it becomes more important to remain vigilant against confusing non-biological pseudofossils for evidence of biological life and / or lifeforms. The full version of this newly published article can be accessed at the link below.
Scientists Warn About 'False Fossils' Present on Mars

When looking for signs of life on Mars, we need to look out for 'false fossils' that may be abundant on the Red Planet, according to a new study.

Mars rover Perseverance lists, among its mission objectives, a first for red planet exploration. The robotic explorer has been tasked with searching for signs of ancient microbial life on the dusty, dry planet – tiny microfossils that would be evidence that Mars was once habitable.

That would indeed be an astounding, incredible discovery – but the new paper urges caution in interpreting what we find, in both this and future sources.

According to astrobiologist Sean McMahon of the University of Edinburgh and geobiologist Julie Cosmidis of the University of Oxford in the UK, scientists will have to keep an eye out for non-biological mineral deposits that look a heck of a lot like fossils.

In a new paper, the pair have outlined dozens of non-biological, or abiotic, processes that can produce pseudofossils – structures that look like fossils of microscopic organisms like those that may have once existed on Mars. ...

"For every type of fossil out there, there is at least one non-biological process that creates very similar things, so there is a real need to improve our understanding of how these form."

This notion is not exactly surprising. Mars is an absolute feast for pareidolia and conspiracies. All you need is one funny-looking rock and the rumors run riot. ...

"We have been fooled by life-mimicking processes in the past," Cosmidis said.

"On many occasions, objects that looked like fossil microbes were described in ancient rocks on Earth and even in meteorites from Mars, but after deeper examination they turned out to have non-biological origins. This article is a cautionary tale in which we call for further research on life-mimicking processes in the context of Mars, so that we avoid falling into the same traps over and over again." ...
FULL STORY: https://www.sciencealert.com/false-fossils-could-confuse-the-search-for-life-on-mars


PUBLISHED ARTICLE:
Sean McMahon, Julie Cosmidis
False biosignatures on Mars: anticipating ambiguity.
Journal of the Geological Society 2021
doi: https://doi.org/10.1144/jgs2021-050

SOURCE: https://pubs.geoscienceworld.org/jg...-biosignatures-on-Mars-anticipating-ambiguity
 

Mythopoeika

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Yeah, that skeleton... it's just a rock. Honest.
 

EnolaGaia

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I'm pretty certain you're referring to the meteorite Allan Hills 84001(aka ALH84001), discovered in 1984 in Antarctica and widely publicized as displaying structures suggestive of microbial life in the mid to late 1990s. Even though most of the features underlying the claims of biological evidence have been explained in non-biological terms the dispute continues to this day. ...

Here's the latest contribution to the study of ALH84001. A multi-faceted chemical analysis failed to find anything that couldn't be explained by known abiotic geological processes.
Latest Study Finds No Trace of Aliens in 4-Billion-Year-Old Martian Meteorite

To date, we've found over a hundred precious Mars rocks that have travelled from the red planet and landed on Earth at some point. Among those, specimen ALH84001 might well be one of the most enigmatic.

This meteorite fragment was picked up during a snowmobile ride in the ice field of Alan Hills in Antarctica in 1984, and is thought to have formed on Mars around 4 billion years ago. ...

What has especially intrigued scientists since its discovery are the minuscule traces of organic carbon detected as part of the rock's composition. Could this point to early alien life back on Mars all those billions of years ago?

Well, probably not, according to the latest study of the fragment. Instead, the organic molecules found in the meteorite are most likely the result of particular fluid and rock interactions similar to those that happen on Earth. ...

To study the tiny carbon globules found within ALH84001, the team gained access to a thin section and a chip of the meteorite, obtained from NASA Johnson Space Center.

They subjected these fragments to a variety of techniques, including nanoscale-level imaging, an analysis of the isotopes present in the rock, and spectroscopy (using light to study the chemical composition of matter).

Their results showed that the characteristics of the rock indicate it could have easily formed in the presence of non-biological or abiotic processes that are known to produce organic carbon molecules here on Earth. The first one is serpentinization, which happens when igneous rocks (solidified from lava or magma) that are rich in iron or magnesium interact with circulating water, producing hydrogen.

The second process is carbonation, where rocks react with slightly acidic water that has dissolved carbon dioxide in it, resulting in carbonate materials. It's not clear if both processes happened simultaneously, but the study suggests they weren't happening over an extended period of time. ...
FULL STORY: https://www.sciencealert.com/organi...-abiotic-processes-not-alien-life-study-shows
 

Paul_Exeter

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Here's the latest contribution to the study of ALH84001. A multi-faceted chemical analysis failed to find anything that couldn't be explained by known abiotic geological processes.

FULL STORY: https://www.sciencealert.com/organi...-abiotic-processes-not-alien-life-study-shows
Sad news.

In 1996 the world seemed full of hope, finding life on Mars would have been the icing on the cake. Since then we've had the illegal Blair/Bush Gulf war, 911, 711, climate crisis, Brexit, Covid etc...etc...

Still, it remains possible that some microbial life exists deep underneath the Martian surface
 

Cochise

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Sad news.

In 1996 the world seemed full of hope, finding life on Mars would have been the icing on the cake. Since then we've had the illegal Blair/Bush Gulf war, 911, 711, climate crisis, Brexit, Covid etc...etc...

Still, it remains possible that some microbial life exists deep underneath the Martian surface
If you think things looked good in 1996 you wouldn't believe how wonderful the future looked in 1968. But I agree its all gone down the toilet, especially since 9/11.

I won't go into why I think 9/11 is pivotal here, but hopefully by the end of this year I will have resolved a number of personal encumbrances, whereupon I will set up a Fortean Politics forum, buy myself some asbestos underpants, and set myself up as referee.
 
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EnolaGaia

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Results of carbon isotope testing by the Curiosity rover do not rule out the possibility of biotic activity in Mars' carbon cycle, but neither do they clearly point to a biological process having occurred.
NASA's Curiosity Rover Drilled Holes Into Mars, And Found Something Very Strange

As it's the foundation for all life on Earth, discovering carbon on other planets always gets scientists excited – and the Curiosity Rover on Mars has found an unusual mix of the chemical element that could hypothetically point to the existence of alien life.

That's by no means certain, but it's a possibility. It's one of three different scenarios that experts think might have produced the carbon found in sediment in the Gale crater, collected across nine years from August 2012 to July 2021.

A total of 24 powder samples were heated by Curiosity to separate individual chemicals, revealing a wide variation in terms of the mix of carbon 12 and carbon 13 isotopes: the two stable carbon isotopes that can reveal how the carbon cycle may have changed over time. ...

What makes these variations particularly fascinating – some samples enriched with carbon 13, and some extremely depleted – is that they point to unconventional processes different to those created by the carbon cycle in Earth's modern era. ...

One explanation for the carbon signatures is a giant, molecular cloud of dust. The Solar System passes through one of these every couple of hundred million years or so, and the cooling effect it creates leaves carbon deposits in its wake. This is a plausible scenario, the team says, but one that needs more investigation.

Alternatively, the conversion of CO2 to organic compounds (like formaldehyde) through abiotic (non-biological) processes could explain what Curiosity has found – in this case, ultraviolet light might have been the trigger. It's something scientists have hypothesized about before, but again further study is required to confirm whether or not this is actually what's happening.

That leaves the third explanation, which is that either ultraviolet light or microbes once upon a time converted methane produced by biological processes – that we're looking at carbon created as a result of life. As with the other two possibilities, we're going to need more surrounding evidence to know for sure, but there are some parallels on Earth. ...
FULL STORY: https://www.sciencealert.com/really...on-mars-and-it-could-point-to-biological-life
 
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