Panspermia Question

[gmacrider]

As I understand, the current concept of Panspermia involves the seeding of young planets by bacteria transported across space on rocks blasted out of life-bearing planets by collisions with other rocks.

 

I'm wondering how many bacteria would have to survive the trip (and the rough landing) to successfully seed a barren planet. I guess the answer would depend on many variables, but for a young Earth what would be the absolute minimal number of bacteria required?

 

Would ONE be enough? Or would a large herd of bacteria be required?

 

Are the "Common Ancestor" theorists looking for that ONE bacteria?

 

Thanks for your thoughts.

[Boerseun]

Seeing as bacteria divides, reproducing asexually, one should indeed be enough.

 

If you keep in mind the rough treatment bacteria can survive, panspermia is by no means impossible.

[Jay-qu]

im guessing you got that from the book angels and demons by Dan Brown... its a good book

[CraigD]

I'm wondering how many bacteria would have to survive the trip

Panspermia doesn’t necessarily require bacteria, or anything as complicated as cellular life. Viral DNA or even RNA could be enough. And while cellular life can be very tough, the ruggedness of some viruses is amazing.

[gmacrider]

Panspermia doesn’t necessarily require bacteria, or anything as complicated as cellular life. Viral DNA or even RNA could be enough. And while cellular life can be very tough, the ruggedness of some viruses is amazing.

 

But don't virii need host cells to reproduce? At any rate, it appears some primitive forms of life are capable of surviving space travel on rocks, and the violent take-off's and landings. I can imagine how this seeding might happen within a solar system, but what about the vast distances between stars? Or between galaxies? Could rocks really transport bacteria across these incredible distances?

 

It seems to me there are four possibilities:

 

1. Abiogenesis occurred on Earth.

2. Abiogenesis occurred somewhere else.

3. Both of the above.

4. None of the above (as in Abiogenesis did not occur).

 

I'm leaning towards #3, but it's just a gut feel.

[alxian]

those are theory for now (that life developed only on earth, mars and europa might have very similar fossil records to early earths)

 

imo panspermia is a way for intelligent life to traverse interstellar space without leaving home. bacteria would survive the trip where more complex creatures would not. if life exists here it may be because some ancient race seeded by intention or through the destruction of their worlds the comets that orbit beyond the reaches of their stars.

 

what happens when a star goes nova? sure it explodes and ruins its close planets, long before they are obliterated in that final coup de gras the star would have ballooned to a tremendous size and boiled off the standing solvents of her closer planets. that moisture could contain life, once away from the influence of the planets gravity the boiled off solvent could condense (over millions of years perhaps) into those icy bodies, then once the star went postal it would blow those icy bodies out, repeat that step often enough and you get a kuiper belt full of such objects. which interacting with each other and newly formed planetoids with eratic orbits like 2003 el61/ub313 and thousands other similar rogues you could get infall of icy objects often... like when passing through the pleiades boiled off solvent solidfying over cold meteorids could have fallen back on newly formed planetoids like earth and the Galilean moons...

 

until europa, io, titan, mars and venus are proven utterly sterile (now and in their ancient past, earth should not be considered the originator and sole bastian of life in our small corner of this arm of our galaxy.

 

 

europa also may not have spawned life originally but before it froze over it would have made a much better habitat than earth (earth technically speaking is cold and over wet) that water must have come from somewhere, infall of planetesimals would generate areas of energy convertion potential (hot to cold) as well as chemical conversions, the extra solvent also would mean very high amounts of different minerals and complex compounds but still without those flowing oceans spreading primordial life, life would have baked off the planets surface without gaining a foothold. some argue that life at that stage would have been hardy enough to tough out drouts but even they would require some standing water (or other solvent, the cooling earth would become progressively more accomodating but life could not have endured onthe surface. cave bacteria then the water born microbiotic life would have had a better time once the oceans filled up. extremophiles sucking nutrients out of superheating oceanic vents, at the fringes of those extreme environments they'd adapt to the cooler water and return to the surface of the water to suck in free sunlight.

 

so, there a good chance that life did evolve on earth... even with the evidence i say that life lay dormant within those comets and once the water started rising they were able to reawaken and seek out those oceanic vents.

 

the first life forms on earth being extremeophiles, whether they were the UV soakers or oceanic vent smokers, or cave carving bacteria (metabolizing escaping gases from the bowels of the earth, there wasn't much room for weak organisms.

 

if they were so extreme imo they could have survived the trip on those comets and then the otherwise horribly poisnous transition phases on earth, from UV anaerobic to weaker IR and oxygen rich atmosphere, from acidic fast flowing quickly drying rivers to vast oceans, it must have been some place to find a toe hold. however being that the earth was writihing almost from volcanism cometary bombardment and then the formations of the oceans life in those times had an over abundance of nutrients. it would have been a banquet in every nook and crany for hardy bacteria to feast upon and grow.

 

 

will wright at maxis is designing a new game, spore, which aims to simulate that world. of course the early planet won't be anything like the early days of life on earth (i highly doubt they will simulate phototrophs nor will will EA allow him to simulate cometary bombardment. but i you could imagine such things while playing the early stages of the game.

 

 

i had asked before, could early life have nurished itself on such extreme things as UV light and radioactive isotopes? would that have gained early earth bacteria an advantage over other species? specifically the radioactive isotope munchers would have had access to near limitless amounts of energy if they could properly metabolise the isotopes without the decaying high energy particles ruining there genes. UV based phototrophs would also have had a marked advantage in that UV light would have made metabolising minerals more easy.

 

earth imo then was seeded by comets with extremophiles who lay dormant within the icy conveyances. arriving on earth those that survived and adapted would have had a whale of a time. ones they oversaturated the oceans and filled the atmosphere with oxygen and adapted the metabolise it as well then life trully began evolution in earnest, exploding inside the ocean and out into all kinds of new forms.

 

 

now that we are able to do it for ourselves though.. should we focus some of our efforts toward designing pods full of our genetic potential and nonamachine (artificial bacteria), launching those pods to the most likely star systems to have planets like earth, such as 37 geminorum in the hopes that these early efforts could seed those planets within the next few thousand years. once we manage to travel faster than light and go to investigate wouldn't it be fun to have a welcoming commity already in place?

[gmacrider]

what happens when a star goes nova? sure it explodes and ruins its close planets, long before they are obliterated in that final coup de gras the star would have ballooned to a tremendous size and boiled off the standing solvents of her closer planets. that moisture could contain life, once away from the influence of the planets gravity the boiled off solvent could condense (over millions of years perhaps) into those icy bodies, then once the star went postal it would blow those icy bodies out, repeat that step often enough and you get a kuiper belt full of such objects. which interacting with each other and newly formed planetoids with eratic orbits like 2003 el61/ub313 and thousands other similar rogues you could get infall of icy objects often... like when passing through the pleiades boiled off solvent solidfying over cold meteorids could have fallen back on newly formed planetoids like earth and the Galilean moons...

 

Thanks for the interesting post. I'm curious about the idea that novas could be a mechanism for transporting bacterial life across inter-stellar distances. Is this a popular theory? Are there any ideas being bounced around that might explain the transportation of bacterial life across inter-galactic distances? Or is that just too unlikely?