Could we actually be Martians?

[TriangleMan]

With all of the talk of water on Mars. . . .

Does anyone remember an ATM theory from years ago which proposed that if simple life evolved on Mars it's possible that a collision with an asteroid could have sent some of the bacteria to Earth and "seeded" our planet? Something to do with a hypothesis that Mars would have cooled faster than the Earth so simple life could have developed there before it developed on Earth.

It still seems like a long shot - and we would have to find the Martian life to prove it.

[Glom]

That all depends on what you mean by Martian. Is BA really American?

[Drakheim]

With all of the talk of water on Mars. . . .

Does anyone remember an ATM theory from years ago which proposed that if simple life evolved on Mars it's possible that a collision with an asteroid could have sent some of the bacteria to Earth and "seeded" our planet? Something to do with a hypothesis that Mars would have cooled faster than the Earth so simple life could have developed there before it developed on Earth.

It still seems like a long shot - and we would have to find the Martian life to prove it.

It is a probable theory. Earth was not a very nice planet at the time of life starting, so if a bacteria could survive 1) the impact nessesary to throw something out of Mars's gravity and 2) intersteller space for who knows how long... then yes it is possible.

[harlequin]

I guess someone has read The Martian Chronicles....

[Kaptain K]

I guess someone has read The Martian Chronicles....

Yup!

[TriangleMan]

I guess someone has read The Martian Chronicles....

Yup!

Nope.

[JohnOwens]

I guess someone has read The Martian Chronicles....

Yup!

Nope.

But you're reading them right now!

[TriangleMan]

Well, at least I now know where the theory probably came from.

[Dancar]

I'd consider that highly speculative.

I think its more probably that life developed under the conditions that existed then (perhaps in a more favorable microclimate somewhere in the sea) and later evolved to match changing conditions. If you postulate that life fell from the sky on a metiorite, you have to explain how it survived hostile space conditions en route, as well as how it originated wherever it came from.

Dancar

[TriangleMan]

I'd consider that highly speculative.

Absolutely. I just brought it up because all of the talk about water on Mars reminded me of it. We would have to find life (or remnants thereof) on Mars, confirm that it is similar/same to some ancient terrestrial life and even then that doesn't mean that it couldn't have developed parallel to terrestrial life or that the "seeding" wasn't the other way around.

[Drakheim]

If it developed on a simular scale as ours, then it could stand to reason that life develops the same on all water worlds.

It could be that the movie makers of the 1950's had it right... the aliens could pass for Ward and June Clever...

But I doubt it :wink:

[George]

I'd consider that highly speculative.

Absolutely. I just brought it up because all of the talk about water on Mars reminded me of it. We would have to find life (or remnants thereof) on Mars, confirm that it is similar/same to some ancient terrestrial life and even then that doesn't mean that it couldn't have developed parallel to terrestrial life or that the "seeding" wasn't the other way around.

Mars, being smaller, would have cooled much sooner than Earth allowing liquid water to ineract with the environment. I would guess that a, possibly common, large impact hit a water area, escape velocity might be reached.
As for survivability, bacteria was found on a lunar camera lens after two years of moon time (according to my Bill Bryson cd).

It would be interesting to see ejection profiles for land and sea impacts.

[frogesque]

I'd consider that highly speculative.

Absolutely. I just brought it up because all of the talk about water on Mars reminded me of it. We would have to find life (or remnants thereof) on Mars, confirm that it is similar/same to some ancient terrestrial life and even then that doesn't mean that it couldn't have developed parallel to terrestrial life or that the "seeding" wasn't the other way around.

Mars, being smaller, would have cooled much sooner than Earth allowing liquid water to ineract with the environment. I would guess that a, possibly common, large impact hit a water area, escape velocity might be reached.
As for survivability, bacteria was found on a lunar camera lens after two years of moon time (according to my Bill Bryson cd).

It would be interesting to see ejection profiles for land and sea impacts.

I have some problems with this. Not only would a Martian meteor have to contend with a hard life in space, vacuum, radiation etc. for X= (pick your own number) millions of years but it also has to survive the launch process (? asteroid impact, Y = ??? deg C) but it then has its surface layer vapourised on entry to Earth's atmosphere. I know some primitive life-forms are tough cookies but that's a tall order. Having done all that and survived it then finds itself in an enviroment that is at best sterile or worst poisonous to it. For life to be seeded and thrive conditions have to be right for colonisation.

[Argos]

Maybe OT, but what about the contrary? Earth microbes colonizing Mars? The collision rate on Earth is higher than on Mars, given Earth´s size. Also, the chunck of space rock bound to Mars could have taken precious life supporting substances with it, known to be abundant in the primeval Earth. Besides, Mars atmospheric reentry would be less dramatic in terms of heat.

[frogesque]

Bigger mass of Earth=larger escape velocity=larger event to eject material=higher temperatures of ejected material.

There could be/have been life on Mars ( or ex solar planets) but I think as our knowledge base increases we shall see that life is not a strictly one off thing that relies on planet hopping microbes hitching a lift on impact debris.

[George]

I have some problems with this. Not only would a Martian meteor have to contend with a hard life in space, vacuum, radiation etc. for X= (pick your own number) millions of years but it also has to survive the launch process (? asteroid impact, Y = ??? deg C) but it then has its surface layer vapourised on entry to Earth's atmosphere. I know some primitive life-forms are tough cookies but that's a tall order. Having done all that and survived it then finds itself in an enviroment that is at best sterile or worst poisonous to it. For life to be seeded and thrive conditions have to be right for colonisation.

I am considering more of a water (becoming ice) ejection scenario. I am guessing a greater chance of water-born organism vs. land plus the added bonous of an ice cocoon for the trip. Once melted in the atmosphere, the impact is rain (assuming a small ice chunk).

Origins last nite got me wondering more about this. It was found that the added energy of an impact would advance a primitive structure. Here, they impacted amino acids and got peptides.

If pansperima is true, it only helps the "life clock" not likely life formation itself, of course. Mars might of had a head start on Earth.

[frogesque]

I'm open to correction here but impact ejected water at escape velocity would more likely be in its vapour phase rather than ice at the temperature and pressure of near Earth space. I'm no expert but it may well disassociate and ionise a la comet tail - not a good environment for biological systems.

[George]

I'm open to correction here but impact ejected water at escape velocity would more likely be in its vapour phase rather than ice at the temperature and pressure of near Earth space. I'm no expert but it may well disassociate and ionise a la comet tail - not a good environment for biological systems.

It would be nice to know just what both land and sea ejections would look like. At 1 atm, water will expand about 1700 times it's volume as it vaporizes. Mars might have had less pressure, increasing the expansion. This expansion might work to "turbo-boost" the cooler liquid in front of it (or within it). I am curious about it but can't really say if this is possible or not.

[eburacum45]

The theory is that life could just about survive the impact necessary to send a lifebearing rock into space from the surface of Mars, but not from the surface of Earth or Venus;

so, if we find life on Mars that is genetically related to Earth life (or if we find it on Europa, or Titan, or elsewhere)
then that life must have shared an origin with Earth life- but that origin can not have been on Earth.
(or Venus).

Mars is a good candidate for abiogenesis; during the Noachian period it may have had all the required conditions.
So- it remains to be seen.