Is a moon required to support life ?

The fossil record does not agree, it shows life as just beginning 3.5 to 4 billion years ago. The only forms of life that date back 4 billion years are procaryotic cells. The known fossil record is scarcely the last word here. Is it probable that we have just happened to find the remains of the very oldest life on Earth? Can we even be certain that the earliest life left fossils that still exist today? Even if the date is 4 billion years, this is early enough to have been completely destroyed in the Late Heavy Bombardment, ~ 100 million years later. If so, life would have had to start again, u... [More]

Look, I think you are making some strange statements. We know life evolved after it formed. What is your point? At some point life was able to not just expand but evolve. Evolution and diversity are two requirements for the long-term survival of life. Strange statement? Maybe if you haven't heard it before. I disagree with you. Life formed early and Thrived not simply survived. It transformed the planet into what we know today. i.e. a comfortable planet. I can't find any evidence that it thrived (why did you capitalize that?). We don't know how long it took before it covered the planet or when... [More]

The known fossil record is scarcely the last word here. I disagree. It shows us the development of life, as well as the progression life took. Is it probable that we have just happened to find the remains of the very oldest life on Earth? Well, yes, we have seen the remains of the oldest life on earth, and it is microbial. And with the model of life that we have today, that progression makes perfect sense. Can we even be certain that the earliest life left fossils that still exist today? Yes, we have a record of them, and the transitions made to the many complex forms we see today. Even if the... [More]

We don't know that life came into being only once on this planet, or that it could only do so during a short window of opportunity. That's true. We only know that we haven't found any traces of this other life but the odds of that are extremely small in any case. It is considered entirely possible that life existed as long ago as 4.5 billion years, was totally destroyed in the Late Heavy Bombardment at 3.9 billion years ago, and began again from scratch, perhaps as late as 3.5 billion years ago. This raises the possibility of a rather broad 'window' of up to a billion years, during which life ... [More]

I disagree with you. Life formed early and Thrived not simply survived. It transformed the planet into what we know today. i.e. a comfortable planet. I suspect in these early years there was still quite some bombardment, it strikes me that once life took hold, it would be hard to end life as billions and billions of tiny organisms. We know all water bodies on early earth were loaded with Coacervates, so you would have to near destroy the planet, or at least everything on it to wipe life out once it takes hold. It would be easy to destroy one big thing, but much harder to destroy billions of ti... [More]

The known fossil record is scarcely the last word here. Is it probable that we have just happened to find the remains of the very oldest life on Earth? Can we even be certain that the earliest life left fossils that still exist today? Even if the date is 4 billion years, this is early enough to have been completely destroyed in the Late Heavy Bombardment, ~ 100 million years later. If so, life would have had to start again, under different conditions than before, and probably several hundred million years after its original inception. Genetic evidence suggests life was present by 4.29 Ga, ther... [More]

Genetic evidence suggests life was present by 4.29 Ga, therefore life on Earth survived the Late Heavy Bombardment. http://www.evolbiol.ru/large_files/sheridan.pdf Top link mate We propose a date of 4.29 Ga for the Last Common Ancestor of the Bacterial and Archaeal Domains and a date of 3.46 Ga for the Bacterial and Archaeal Domain individual radiations. These divergence times do not conflict with geological evidence but call into question the interpretation of early Archean (»3.5 Ga) microfossils as evidence of cyanobacterial lineages Dated 2003! I Must keep up, I had only heard about the 4... [More]

Interesting article. It suggests the possibility that forms of life arose completely independently of ours, and persist to this day. Since most organisms remain genetically uncharacterized, we can scarcely rule this out. We wouldn't know if, or when they began. http://www.guardian.co.uk/science/2009/feb/15/microbes-earth-tree-of-life

Interesting article. It suggests the possibility that forms of life arose completely independently of ours, and persist to this day. Since most organisms remain genetically uncharacterized, we can scarcely rule this out. We wouldn't know if, or when they began. http://www.guardian.co.uk/science/2009/feb/15/microbes-earth-tree-of-life Is there any traces of anything that give rise to such reasoning? Or is it pie in the sky stuff?

Interesting article. It suggests the possibility that forms of life arose completely independently of ours, and persist to this day. Since most organisms remain genetically uncharacterized, we can scarcely rule this out. We wouldn't know if, or when they began. http://www.guardian.co.uk/science/2009/feb/15/microbes-earth-tree-of-life It sort of reminds me of the ideal of life on Europa. Even if we find life there, is it Alien? Not really if it carries the same signatures that life on earth does. We might have seeded life through panspermia. Even should we find life on another planet, there are... [More]