Author Topic: Oldest fossils ever discovered raises question of life on Mars  (Read 5946 times)

Offline Mongo62

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if you like Ward's writing, you should try Gorgon, all about the amazing mammal-like reptiles of the Permian and the Permo-Triassic extinction.

I like all of his writing. I think Peter Ward is a tremendous writer, who should be a lot better known than he is. His books DO tend to make the readers emotionally uncomfortable, though. For example The Medea Hypothesis, which lays out his anti-Gaia hypothesis that the Earth's biosphere is not stable, and keeps "trying" to revert to a microbe-dominated state with no higher life forms. Sounds a bit crazy, but he presents a lot of evidence in support of the idea.

This would possibly explain the Fermi Paradox, though, if biospheres containing higher life forms almost always revert to single-celled systems. And after the book was published, additional support for the hypothesis was found, in the form of fossils of an early multi-cellular organism ecosystem (~2.2 billion years ago) which died out shortly afterwards, with the Earth reverting to only single-celled organisms for over a billion years afterward.

The ALH84001 meteorite is 4.4 Ga, which is before the martian 4.1 - 3.8 Ga habitable window that is currently considered.

That date is no longer accepted, the bulk of the meteorite is now thought to be 4.091 billion years old: Oldest Mars Meteorite Younger Than Thought. The carbonate matrix containing the putative micro-fossils would have been deposited some time after this, but it seems to be very difficult to date.
« Last Edit: 09/07/2016 01:46 PM by Mongo62 »

Online notsorandom

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If I had to pick a single scientific question to know the answer to, it would be the Fermi paradox.  It would be interesting (yet probably not terribly useful) to know how the universe got started, and likewise to know how life got going here.  But understanding the Fermi paradox is all about the future.  You can have a solution to the Fermi paradox if the universe is full of algae, but with ourselves, as intelligent animals, being unique.  That would also make me sad, and I hope it's not the case, but my opinion isn't relevant to what's actually going on.
Well some intelligent species has to be the first to the party. It might be that we are the first to evolve and that the others will be along in short order. It's it kind of contrary to the Copernican principle but humans may be the first intelligent life at least in our little corner of the galaxy. I've heard some pretty interesting arguments that the universe is still pretty young and that we may have evolved close to the earliest our universe could support complex life. There are what about three generations of stars? The first generation was needed just to make the elements needed for life. Then things had to calm down a bit too. A close by supernova isn't good for life. For the first part of universe's existence it was uninhabitable for intelligent life. The question is when did it become habitable? If that happened not too long ago then intelligent life could be common but hasn't had time to become common.

Offline llanitedave

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The best answer to the Fermi Paradox that I've come across states simply that once a technological species advances enough to be able to use fusion power, then a planetary gravity well is no longer attractive to them.  A planet cannot easily provide the variety and availability of raw materials that the small icy bodies can, so that advanced life is more likely to inhabit the Oort Cloud equivalents of star systems.  A dominant, advanced species can expand to populate an entire galaxy without bothering  itself with any of the inner planets.

As for the Rare Earth hypothesis, I suspect that Ward and Brownlee's thesis is close to correct, but maybe for different reasons than they argued.  The number of ways that life can evolve without having to invent eukaryotic structures and multicellular tissues makes me think that life like ours probably arose by nothing more than pure dumb luck.  No real specific obstacles need be evoked.
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Offline Star One

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Oldest fossils ever discovered raises question of life on Mars
« Reply #43 on: 03/01/2017 06:12 PM »
Here's an update on this matter and a note of caution is struck.

World's oldest fossils found in Canada, say scientists

Quote
But not everyone is convinced by the new study, not least Frances Westall, an expert on ancient fossil bacteria at the French national centre for scientific research. “The thing that bothers me most about these structures is the fact that they all seem to be extremely oriented. They are parallel to each other and microbes don’t grow parallel to each other,” she said.

Westall said it remains possible that the haematite structures were formed as a result of the high temperatures and pressures experienced by metamorphic rocks. What’s more, she points out, the newly discovered filaments are far larger than the oldest known well-preserved microbial filaments previously found in 3.33bn-year-old rocks – a surprise given the lack of oxygen in the environment in which the newly proposed fossils are thought to have originated. “In an environment without oxygen, microbes grow – but they grow very slowly and they are small,” she said.

“What I am not saying is that there could not have been life at 3.8bn years ago,” Westall added. “But in rocks that have been so altered, like these have been, I think that morphological traces are unlikely to remain.”

Others, too, remain cautious, if more optimistic. David Emerson, a geomicrobiologist and expert in modern iron-oxidising bacteria at the Bigelow Laboratory for Ocean Sciences in the US said that the structures do not look like what would be expected from modern bacteria, but that he found it compelling that filaments are found in groups, suggesting a colony of microbes. But, he added, “I don’t think there is a smoking gun here that says this is clearly biological.”

https://www.theguardian.com/science/2017/mar/01/worlds-oldest-fossils-found-canada-say-scientists-quebec-haematite-377bn-428bn-years
« Last Edit: 03/01/2017 10:14 PM by Star One »

Offline Alpha_Centauri

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An aerobe oxidising iron? At this time? Surely that's not what the hydrothermal vent hypothesis is about?
« Last Edit: 03/01/2017 08:29 PM by Alpha_Centauri »

Offline Dalhousie

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Here's an update on this matter and a note of caution is struck.

World's oldest fossils found in Canada, say scientists

Quote
But not everyone is convinced by the new study, not least Frances Westall, an expert on ancient fossil bacteria at the French national centre for scientific research. “The thing that bothers me most about these structures is the fact that they all seem to be extremely oriented. They are parallel to each other and microbes don’t grow parallel to each other,” she said.

Westall said it remains possible that the haematite structures were formed as a result of the high temperatures and pressures experienced by metamorphic rocks. What’s more, she points out, the newly discovered filaments are far larger than the oldest known well-preserved microbial filaments previously found in 3.33bn-year-old rocks – a surprise given the lack of oxygen in the environment in which the newly proposed fossils are thought to have originated. “In an environment without oxygen, microbes grow – but they grow very slowly and they are small,” she said.

“What I am not saying is that there could not have been life at 3.8bn years ago,” Westall added. “But in rocks that have been so altered, like these have been, I think that morphological traces are unlikely to remain.”

Others, too, remain cautious, if more optimistic. David Emerson, a geomicrobiologist and expert in modern iron-oxidising bacteria at the Bigelow Laboratory for Ocean Sciences in the US said that the structures do not look like what would be expected from modern bacteria, but that he found it compelling that filaments are found in groups, suggesting a colony of microbes. But, he added, “I don’t think there is a smoking gun here that says this is clearly biological.”

https://www.theguardian.com/science/2017/mar/01/worlds-oldest-fossils-found-canada-say-scientists-quebec-haematite-377bn-428bn-years

I'd also note that the succession is poorly dated, it could be as old as 4.23 Ga, or as young as 3.77 Ga.  Now 3.77 isn't really young, but it is comparable with other, also rather questionable, evidence for life in the Isua greenstone belt in Greenland (3.8 Ga)
« Last Edit: 03/02/2017 04:18 AM by Dalhousie »
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Online Req

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The best answer to the Fermi Paradox that I've come across states simply that once a technological species advances enough to be able to use fusion power, then a planetary gravity well is no longer attractive to them.  A planet cannot easily provide the variety and availability of raw materials that the small icy bodies can, so that advanced life is more likely to inhabit the Oort Cloud equivalents of star systems.  A dominant, advanced species can expand to populate an entire galaxy without bothering  itself with any of the inner planets.

When I first read about Hair and Hedman's work and the Fermi paradox, it occurred to me that there is a very simple explanation, and that is that FTL travel and communication is not possible in this universe.  What Hair and Hedman talk about is completely true and does not rely on FTL at all from a topical perspective, but the motivation to expand and build such a galactic empire doesn't exist.

Think about it, our galaxy is over 100,000 light years in diameter.  The closest star to us is 4 light years away.  What motivation does this empire have to exist if there's a practical upper limit of 0.1c for travel and 1c for comms?  No trade, no military support, and not even the ability to have a central authority to drive any kind of imperative(such as colonize the entire galaxy.)  Let's say this authority is "conveniently" located near sag A*, it still takes over 50,000 years for any new directive to propagate, and that's assuming no response is necessary.  Let's say our friends at Proxima Centauri need something from us.  We won't even know for 4 years, and it'll take another 40 for us to get it there.

An entire solar system of raw materials is an awful lot.  It's not clear to me that the need for more space to live in or raw materials to consume alone would motivate such a civilization(or many civilizations) to expand across an entire galaxy given almost any amount of time.
« Last Edit: 03/02/2017 03:41 AM by Req »

Offline CuddlyRocket

An entire solar system of raw materials is an awful lot.  It's not clear to me that the need for more space to live in or raw materials to consume alone would motivate such a civilization(or many civilizations) to expand across an entire galaxy given almost any amount of time.

Think culture. The more sentient beings there are the more scientists, engineers and artists there are and the faster is scientific, technological and artistic advancement, to everyone's benefit, and which can be spread by radio. A one-in-a-trillion genius would appear every 100 generations on a planet of 10 billion, but ever generation on 100 such planets.

Then there's competition. Do you want those folks over there - who might even be of a separate species - to be colonising the galaxy spreading their weird ideas and genes and eclipsing your own? Think of the dash for empire among European powers in the 19th century. We might think we're too advanced to fall prey to such motivations, but so did many of them!

Offline meekGee

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The best answer to the Fermi Paradox that I've come across states simply that once a technological species advances enough to be able to use fusion power, then a planetary gravity well is no longer attractive to them.  A planet cannot easily provide the variety and availability of raw materials that the small icy bodies can, so that advanced life is more likely to inhabit the Oort Cloud equivalents of star systems.  A dominant, advanced species can expand to populate an entire galaxy without bothering  itself with any of the inner planets.

When I first read about Hair and Hedman's work and the Fermi paradox, it occurred to me that there is a very simple explanation, and that is that FTL travel and communication is not possible in this universe.  What Hair and Hedman talk about is completely true and does not rely on FTL at all from a topical perspective, but the motivation to expand and build such a galactic empire doesn't exist.

Think about it, our galaxy is over 100,000 light years in diameter.  The closest star to us is 4 light years away.  What motivation does this empire have to exist if there's a practical upper limit of 0.1c for travel and 1c for comms?  No trade, no military support, and not even the ability to have a central authority to drive any kind of imperative(such as colonize the entire galaxy.)  Let's say this authority is "conveniently" located near sag A*, it still takes over 50,000 years for any new directive to propagate, and that's assuming no response is necessary.  Let's say our friends at Proxima Centauri need something from us.  We won't even know for 4 years, and it'll take another 40 for us to get it there.

An entire solar system of raw materials is an awful lot.  It's not clear to me that the need for more space to live in or raw materials to consume alone would motivate such a civilization(or many civilizations) to expand across an entire galaxy given almost any amount of time.
Motivation is indeed the critical piece, for exactly these reasons.

What you need to do is replace "first evolved species" with "first evolved species that is inherently wired to expand" and the then argument remains the same.

So yeah, the first 1000 species may not propagate due to lack of motivation, but #1001 will, and then you can overrun the galaxy pretty quickly even with 0.01c or 0.001c
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Offline Ben the Space Brit

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Just a bit of context: This time is before the presumed 'Late Heavy Bombardment' that theory says created most of the Moon's (and presumably Mars's too) crater fields, which was about 3.8Gya. It has been previously assumed that this would have basically liquefied Earth's surface.

Taking this into consideration, it is probably going to be statistically difficult to find more samples on Earth, let alone the other terrestrial planets.
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Offline Dalhousie

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Just a bit of context: This time is before the presumed 'Late Heavy Bombardment' that theory says created most of the Moon's (and presumably Mars's too) crater fields, which was about 3.8Gya. It has been previously assumed that this would have basically liquefied Earth's surface.

Taking this into consideration, it is probably going to be statistically difficult to find more samples on Earth, let alone the other terrestrial planets.

Assuming the old dates are correct of course. There are a few pre LHB rocks in the Acasta complex in Canada.  Plus individual mineral grains in Australia and elsewhere.

Mars has preserved more of it's pre LHB crust.

IF these finds are genuinely biological and IF the rocks as as old as claimed then two things are possible.

1) Conditions during the LHB were not as severe as thought and some life survived through it. or 2) Life appeared twice.
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Online Req

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The best answer to the Fermi Paradox that I've come across states simply that once a technological species advances enough to be able to use fusion power, then a planetary gravity well is no longer attractive to them.  A planet cannot easily provide the variety and availability of raw materials that the small icy bodies can, so that advanced life is more likely to inhabit the Oort Cloud equivalents of star systems.  A dominant, advanced species can expand to populate an entire galaxy without bothering  itself with any of the inner planets.

When I first read about Hair and Hedman's work and the Fermi paradox, it occurred to me that there is a very simple explanation, and that is that FTL travel and communication is not possible in this universe.  What Hair and Hedman talk about is completely true and does not rely on FTL at all from a topical perspective, but the motivation to expand and build such a galactic empire doesn't exist.

Think about it, our galaxy is over 100,000 light years in diameter.  The closest star to us is 4 light years away.  What motivation does this empire have to exist if there's a practical upper limit of 0.1c for travel and 1c for comms?  No trade, no military support, and not even the ability to have a central authority to drive any kind of imperative(such as colonize the entire galaxy.)  Let's say this authority is "conveniently" located near sag A*, it still takes over 50,000 years for any new directive to propagate, and that's assuming no response is necessary.  Let's say our friends at Proxima Centauri need something from us.  We won't even know for 4 years, and it'll take another 40 for us to get it there.

An entire solar system of raw materials is an awful lot.  It's not clear to me that the need for more space to live in or raw materials to consume alone would motivate such a civilization(or many civilizations) to expand across an entire galaxy given almost any amount of time.
Motivation is indeed the critical piece, for exactly these reasons.

What you need to do is replace "first evolved species" with "first evolved species that is inherently wired to expand" and the then argument remains the same.

So yeah, the first 1000 species may not propagate due to lack of motivation, but #1001 will, and then you can overrun the galaxy pretty quickly even with 0.01c or 0.001c

It doesn't seem unlikely to me that such an imperative may originally exist, it just seems unlikely that it would persist over millions of years, during which time each colony is more or less irrelevant to one another.

Given that the speed of light is more accurately expressed as the speed of causality, when you start talking about galactic scales, they are literally irrelevant to each other in the sense that they don't even exist to each other in their current states, and won't for tens of thousands of years.

Edit to remind that I consider the notion that FTL is not possible as a hypothetical, and what I'm saying pre-supposes that it's not possible as a potential explanation to the Fermi paradox.
« Last Edit: 03/04/2017 04:57 AM by Req »

Offline Star One

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Complex Life Could Be Vastly Older Than Thought

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It was around 1.6 billion years ago that a community of small, bright red, plantlike life-forms, flitting around in a shallow pool of prehistoric water, were etched into stone until the end of time. Or at least until a team of Swedish researchers chipped their fossilized remnants out of a sedimentary rock formation in central India.
Research published this week in PLoS Biology suggests this collection of ancient, newly analyzed fossils—unearthed a few years back—are in all likelihood red algae. If that proves true, it would imply that complex, multicellular life evolved a lot earlier than previously thought—and that the evolutionary family tree of life on Earth might need a major pruning.

https://www.scientificamerican.com/article/complex-life-could-be-vastly-older-than-thought/#

Offline Star One

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Oldest fossils ever discovered raises question of life on Mars
« Reply #53 on: 03/17/2017 06:35 AM »
Fossil or inorganic structure? Scientists dig into early life forms

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An international team of researchers discovered that inorganic chemicals can self-organize into complex structures that mimic primitive life on Earth.

Florida State University Professor of Chemistry Oliver Steinbock and Professor Juan Manuel Garcia-Ruiz of the Consejo Superior de Investigaciones Cientificas (Spanish National Research Council) in Granada, Spain published an article in Wednesday's edition of Science Advances that shows fossil-like objects grew in natural spring water abundant in the early stages of the planet. But they were inorganic materials that resulted from simple chemical reactions.

This complicates the identification of Earth's earliest microfossils and redefines the search for life on other planets and moons.

"Inorganic microstructures can potentially be indistinguishable from ancient traces of life both in morphology and chemical composition," Garcia-Ruiz said.

Scientists had seen hints of this in past lab work, but now through Steinbock and Garcia-Ruiz's research, it is clear that this also happened in nature.

https://m.phys.org/news/2017-03-fossil-inorganic-scientists-early-life.html

As if such identifications weren't complicated enough already on Earth with access to a fully equipped laboratory, let alone on a distant world with just the instruments of an in situ rover or lander to call on.
« Last Edit: 03/17/2017 06:39 AM by Star One »

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