Transferal of life

DeepSpace9

Signs point to life on Mars, billions of years ago, even before Earth..
Is it possible that Asteroid impacts, launched rocks to Earth from Mars, and the bacteria in these rocks evolved on Earth? If so how likely is this scenario?

mjacobsca

IF evidence of life is
found on Mars, and IF it shares similar bio-chemical properties, then the odds will be higher than what we can estimate today. For now, your idea falls in the realm of theoretically possible, and nothing more. Life could form anywhere and be blasted in to space by asteroid impacts. But until we see evidence for this, how can anyone say how likely it is?

DeepSpace9

Well take into consideration, it is our closest neighbor.. There was a period of heavy bombardment. And the fact is, it would be impossible for the Earth not to contain thousands of LBS of Mars rocks.. And since Mars did have water, and if it had DNA based bacteria. It was transferred to Earth, because Mars would of had life before Earth did. And if we ever find DNA based life on Mars in a rock etc.. That would mean we are Martians..

Chronos

Why would you think martian life predated life on earth?

Ryan_m_b

What makes you think abiogenesis on Mars was more likely to happen than on Earth? This question is entirely unanswerable at the moment. Firstly because we don't yet have a comprehensive theory of abiogenesis and secondly because our knowledge of martian history is so incomplete.

someGorilla

Martian predators running wild

HallsofIvy

No, it isn't. Not counting the moon, Venus is our closest neighbor. Venus is about half as far from the earth as Mars.

How does that follow?

d3mm

I have heard people refer to Mars in this way before. I think he meant "closest" as in most similar, and not physical distance. I also think people need to write more clearly to prevent misunderstanding! :-)

Ryan_m_b

Is it though? I don't know the answer to that I'm genuinely curious.

d3mm

I don't know either. I was explaining a common alternative meaning of that phase in popular culture.

Of the two neighbours, Mars and Venus, Mars would be my first bet for human habitation and for what we might recognise today as life. I will have to research if Venus today is similar to the climate of primordial Earth. In terms of colonisation, I don't know if I prefer Mars or the moon, but I will take either over Venus. Mars is further than Luna but water means greater potential for self-sufficiency.

mfb

In our solar system, probably, if mars really had an atmosphere and liquid water over significant timescales and if venus was not completely different before. Mercury is too close to the sun, all other planets are gas giants (and too far away from sun, so the moons do not help) and all minor planets are too small or way too far away from sun.
In other planetary systems, there are planets more similar to earth than mars ;).

LastTimelord

There are actually small creatures called "Tardigrades" that are able to survive for extended periods of time in space, and some scientists think that this may be how life got on earth. There is a word for this theory, but I can't remember it...

Ryan_m_b

I think you hit the nail on the head with popular culture. I'm always sceptical when people trump the colonise Mars idea. With a bit more water at the poles and a wisp of an atmosphere the Moon would be just as habitable. Bear in mind the Martian atmosphere is a small fraction of the pressure of Earth's and Mars has no biosphere at all for us to survive in. In fact we still don't have any real evidence to suggest how healthy land animals are if they are conceived, born and raised in low gravity let alone how well ecosystems would work.

The whole habitability comparison seems to be like arguing whether it is more survivable to be shot in the face at point blank or blown up with a MOAB six feet away.
Panspermia.

d3mm

Both Mars and Moon would need domes to live in.

I believe the argument for Mars was:

2H₂O (drink) → 2H₂ (fuel) + O₂ (breathe)

Ryan_m_b

Agreed, domes and closed ecosystems. Plus a large society to fill a specialised labour pool and a wealth of industries to support them...
Pretty weak argument IMO.

mfb

You do not have to produce this from water, and you need the oxygen to burn hydrogen anyway. Both O₂ + C <-> CO₂ (food/breathing) and 2H₂O <-> 2H₂ + ₂2 (as energy storage) can be used as closed cycles.

d3mm

I'm not keen on either Mars or moon. Priority 1 has to be large asteroids approaching Earth.