The Earliest Time of Life in Universe

[Chalnoth]

Chalnoth, looks like my hypothesis of comets from other solar systems is believed possible by others:


In 1950, the idea was independently revived by Dutch astronomer Jan Hendrik Oort as a means to resolve a paradox:[7] over the course of the Solar System's existence, the orbits of comets are unstable; eventually, dynamics dictate that a comet must either collide with the Sun or a planet, or else be ejected from the Solar System by planetary perturbations.


"In June 2010 Harold F. Levison and others have suggested on the basis of enhanced computer simulations that the Sun "captured comets from other stars while it was in its birth cluster." Their results imply that "a substantial fraction of the Oort cloud comets, perhaps exceeding 90%, are from the protoplanetary disks of other stars." [28]"


http://en.wikipedia.org/wiki/Oort_cloud

Well, I think the key point there is "while it was in its birth cluster," which is a whole other ballgame. In any event, while it was in its birth cluster, every star system would have been approximately the same age as our own, so that the comets would still be about the same age as the Earth.

 

[lowing99]

re the in solar system seeding, I wondered if the comets were smaller, even although they were formed at the same time as the solar system, would they not have cooled down earlier because of their small size and perhaps generated the conditions for primitive life earlier than say a planet. Just a stray thought.

I remember reading about a theory of comets carrying primitive viruses in a library book about 30 years ago, I can't remember much after all this time but I remember it was a convincing postulation, (I might go and see if the library still has the book and list the details here).

I've never had the time to actually check new flu strain appearance dates to see if there is a relationship with passing comets however Halley passed in 1910 was it Spanish Flu in 1918? The next time it passed was 1986, Bird flu, Swine flu, Sars all started after 1986.

That's extremely weak evidence I agree but if you assume there is a variable delay of some months to years between the comet passing and the tail dust fully permeating the atmosphere and any potential organism then mutating into a variety of new flu bugs in any number of locations. The variable delay would disguise the culprit as it would be an irregular interval between strains. I guess the delay would have to be associated with atmospheric conditions and sun activity at the time of the tail passing.

Then again that might be rubbish, apologies if it is ;)

 

[Chalnoth]

re the in solar system seeding, I wondered if the comets were smaller, even although they were formed at the same time as the solar system, would they not have cooled down earlier because of their small size and perhaps generated the conditions for primitive life earlier than say a planet. Just a stray thought.

Certainly they would have cooled more rapidly, but also by virtue of being so much further away from any energy source, any chemical reactions on them would have progressed much more slowly.

It's far more likely that comets may have seeded various complex organic molecules (e.g. amino acids) than full-blown organisms (even simple viruses).

I've never had the time to actually check new flu strain appearance dates to see if there is a relationship with passing comets however Halley passed in 1910 was it Spanish Flu in 1918? The next time it passed was 1986, Bird flu, Swine flu, Sars all started after 1986.

Now that is just not possible. Flu viruses are very specific beasts, with very specific genomes. All flu viruses have a very clear hereditary relationship with existing flu viruses. This is how we know that they are, indeed, flu viruses and not something else. And the specific evolutionary mechanisms that surround the production of new flu viruses are well-known. A primary mechanism comes from the fact that if two separate viruses infect the same cell, the viruses that result will be a random mixing of the components of the parent viruses.

So if you have a person (or animal) infected with two different strains of the flu, you end up with a number of cells infected with the two different strains, and end up with a huge number of random mixings of the two strains. After a number of generations of this random mixing and reproduction, the most successful mixings will come to dominate, and be more likely to be passed on to the next person/animal.

Finally, let me just point out that even in the unlikely event that there were some virus-like organisms on comets, they would not be anywhere close to being as adapted as organisms living here on Earth. So they would simply become food for existing microbes. By contrast, viruses that are actually able to infect people are quite complex, highly-efficient little beasties that have all sorts of different mechanisms for getting past our formidable defenses.

 

[lowing99]

I must go and see if that book is still there, perhaps I've remembered it incorrectly, it was 30 years ago I read it. :)

 

[Tanelorn]

It's far more likely that comets may have seeded various complex organic molecules (e.g. amino acids) than full-blown organisms (even simple viruses).


This is also what I am thinking, the whole galaxy could be full of the same complex organic molecules hitching a ride on comets just looking for a new planet with the right conditions to kick start the process of life and therefore actually life that would end up being somewhat similar to our own.


Another long shot possibility is that intelligent life could seed and thus terraform other newly formed planets with the right kind of single celled organisms.

 

[lowing99]

I found this link relating to the flu conversation

http://scienceray.com/astronomy/do-diseases-come-from-space-comet-controversy/

There seems to be some conflicting opinions out there on the subject

 

[Chalnoth]

I found this link relating to the flu conversation

http://scienceray.com/astronomy/do-diseases-come-from-space-comet-controversy/

There seems to be some conflicting opinions out there on the subject

Yes, well, you can find places on the Internet dedicated to a belief that the world is flat. This doesn't exactly mean much.

 

[lowing99]

I had a brief look through the material relating to Hoyle and Wickramasinghe, I think the book I read years ago might have been by Hoyle. They do seem to have done some work on the subject. I'm not advocating the theory, i just think it's an interesting idea.

Personally I still think that everytime we place limits on the adaptability of life it just keeps stretching those limits. I'll keep an open mind on this one, at least until they check out the organic composition of the most of the closest passing comets.

"The World Health Organization (WHO) has declared that smallpox has been completely eradicated. But past epidemics seem to have followed definite cycles of a few hundred years. Hoyle and Wickramasinghe believe that smallpox will reappear, carried by an as yet undiscovered comet that returns every few centuries."

I really hope they are wrong in respect to this in particular.

 

[Chalnoth]

"The World Health Organization (WHO) has declared that smallpox has been completely eradicated. But past epidemics seem to have followed definite cycles of a few hundred years. Hoyle and Wickramasinghe believe that smallpox will reappear, carried by an as yet undiscovered comet that returns every few centuries."

I really hope they are wrong in respect to this in particular.

They're as wrong as flat-earthers. It's completely ridiculous. There is no possible physical mechanism that could come close to explaining this.

 

[lowing99]

It's far more likely that comets may have seeded various complex organic molecules (e.g. amino acids) than full-blown organisms (even simple viruses).

I think this is the most likely outcome, if indeed the Earth was seeded in the first place, I think the probability is that it originated here, as you say.

 

[Oldfart]

It's far more likely that comets may have seeded various complex organic molecules (e.g. amino acids) than full-blown organisms (even simple viruses).

Have biologists managed to theoretically assemble these molecules (and amy other needed local materials) in a manner that results in something that resembles a lifeform?

 

[Chalnoth]

Have biologists managed to theoretically assemble these molecules (and amy other needed local materials) in a manner that results in something that resembles a lifeform?

That really depends upon what you mean. We have managed to produce some very simple self-replicating molecules (that is, if you put one of these molecules in a bath with a number of the components of said molecule, after a while you end up with a lot of the original molecule after periodically heating and cooling the bath down a few times).

 

[Oldfart]

That really depends upon what you mean. We have managed to produce some very simple self-replicating molecules (that is, if you put one of these molecules in a bath with a number of the components of said molecule, after a while you end up with a lot of the original molecule after periodically heating and cooling the bath down a few times).

Thanks, I was sort of afraid of my usual sin on this forum, which is not asking the question in a correct, sensible way. I suppose that the lifeform that I referred to should have the capability to evolve. Simple self-replication sounds to me like crystals.

 

[Chalnoth]

Thanks, I was sort of afraid of my usual sin on this forum, which is not asking the question in a correct, sensible way. I suppose that the lifeform that I referred to should have the capability to evolve. Simple self-replication sounds to me like crystals.

Oh, they definitely did evolve. The difficulty in this particular case is that the building blocks themselves were somewhat complex. But it is expected that this sort of self-replication was one step along the way to life.

Edit: Btw, here's a blog post describing the specific research I'm talking about:
http://scienceblogs.com/pharyngula/2009/01/chemical_replicators.php

 

[Oldfart]

Edit: Btw, here's a blog post describing the specific research I'm talking about:
http://scienceblogs.com/pharyngula/2009/01/chemical_replicators.php

Many thanks, Chalnoth, quite interesting. I was a little surprised at the "live" approach, thought they'd be modeling this stuff on a supercomputer. You know, trying billions of initial conditions, find some primitive lifeforms, and then cleverly speed up their theoretical evolution along a million different pathways. First to make a mammal wins the Nobel...

 

[Chalnoth]

First to make a mammal wins the Nobel...

Haha, not only would replicating billions of years of evolution be a little bit difficult, but it couldn't ever happen the same way twice :)