Life on Mars and Drake's

[Vexer]

(Wasn't sure where this topic would fit).

 

 

 

I used to be keenly interested in the prospects of Life on Mars (or anywhere else in our system).

 

I thought that the discovery of life on Mars would be a major indication of what we could plug into the Drake Equation.

 

But things changed when it was realistically proposed that planets could ‘seed’ each other via impact ejecta.

 

Now, as far as Drake and its implications, life on Mars (or anywhere in your Solar system) means nothing.

 

Right?

[ajb]

I would agree with that conclusion.

 

Finding life in our solar system would be amazing, but I don't think that it would "prove" that life exists somewhere else out there. I drew a similar conclusion years ago based on the same arguments as you. It would be possible if not likely that we would share some common ancestor, even if that was just some bacteria spore that survived the journey.

 

Now, the Drake equations talks about finding other life in the universe as a whole and says nothing about life on other bodies in our solar system. I don't see how finding something on Mars would mean anything for the Drake equation.

[Sayonara]

The Drake equation is intended to allow the uncertainty factors to be quantified in the question of how many civilizations we might expect to detect by virtue of intelligent communication phases (that's in OUR GALAXY ajb, not the universe). If changing the variables due to new information won't affect the outcome, what's the point of using it?

 

Look at what variable go into the equation:

 

R* is the average rate of star formation in our galaxy

fp is the fraction of those stars that have planets

ne is the average number of planets that can potentially support life per star that has planets

fℓ is the fraction of the above that actually go on to develop life at some point

fi is the fraction of the above that actually go on to develop intelligent life

fc is the fraction of civilizations that develop a technology that releases detectable signs of their existence into space

L is the length of time such civilizations release detectable signals into space.

 

 

Estimates we plug into the equation for the variables I italicised might well be revised if we find evidence of Martian life, past or present. These revisions would clearly have an effect on the answer that pops out the other end.

 

Personally I think that Drake's original working values were a bit silly. fi was orders too high and fc was far too low.

[ajb]

(that's in OUR GALAXY ajb, not the universe)

 

 

Ok, I stand corrected.

[Vexer]

Not quite getting my point then.

 

fℓ is the fraction of the above that actually go on to develop life at some point

 

 

Early scenario: life on Mars indicates ‘t’ is 100%. I.e; two out of two examples. 100% on each sample. That’s er, “statistically significant”.

 

Late scenario (life can be seeded): life on Mars means: nothing. Life on Mars: statistically insignificant.

[Ophiolite]

Personally I think that Drake's original working values were a bit silly. fi was orders too high and fc was far too low.

While Drake's figures now appear out of line with current thinking we need to recall context. Drake did not seriously entertain the idea that his equation would provide an meaningful estimate of the number of galactic civilisations. Rather he used it to frame the agenda of a meeting held at Greenbank Observatory in the early 1960s to discuss communication with extraterrestrial intelligences. Each factor in the equation formed a topic for dicsussion.

Now' date=' as far as Drake and its implications, life on Mars (or anywhere in your Solar system) means nothing.

 

[/quote']That depends upon its character. I agree its meaning is minor if it can be shown that life on Mars and life on Earth share a common ancestor. However, if Martian life is based upon something other than DNA, or uses quite different amino acids, then that finding would be significant.

[Sayonara]

Not quite getting my point then.

fℓ is the fraction of the above that actually go on to develop life at some point

Early scenario: life on Mars indicates ‘t’ is 100%. I.e; two out of two examples. 100% on each sample. That’s er, “statistically significant”.

Late scenario (life can be seeded): life on Mars means: nothing. Life on Mars: statistically insignificant.

 

Well, by the same token, life on Earth means nothing to the Drake equation. Or rather, you can't be certain that it does.

 

Let me ask you this: Does the distinction between life originating on a planet or being seeded there from elsewhere have any effect on whether or not such life can eventually produce a communicating civilisation such as those which the Drake equation estimates?

[Ophiolite]

Let me ask you this: Does the distinction between life originating on a planet or being seeded there from elsewhere have any effect on whether or not such life can eventually produce a communicating civilisation such as those which the Drake equation estimates?

Yes.

If life evolved independently on Mars it increases estimates of the range of conditions under which life might arise (and be sustained) and thereby tends to increase the estimates for the number of extant civilisations.

[Sayonara]

I like your reasoning there, and I agree on the range of conditions front, but I don't think you see what I was trying to address.

 

What I was getting at is that all life on Earth might (for all we know) have been seeded by matter from a now extinct Martian biosphere. However, is we were to suddenly discover this tomorrow, we would not suddenly become incapable of releasing detectable signals into space.

[Vexer]

Let me ask you this: Does the distinction between life originating on a planet or being seeded there from elsewhere have any effect on whether or not such life can eventually produce a communicating civilisation such as those which the Drake equation estimates?

 

Yes. That’s my entire point. But I see yours.

 

Ah… but I see yours.

 

But my original point was that (the new idea of) ‘seeded’ life cuts down the Drake equation by orders of magnitude.

 

You’re saying that ‘seeded’ worlds can up the Drake Number. I’m saying that the ‘seed’ idea downs the Drake number by some orders of magnitude. With regard to original genesis.

[Sayonara]

But my original point was that (the new idea of) ‘seeded’ life cuts down the Drake equation by orders of magnitude.

 

You’re saying that ‘seeded’ worlds can up the Drake Number. I’m saying that the ‘seed’ idea downs the Drake number by some orders of magnitude. With regard to original genesis.

The thing is, the Drake equation doesn't make any statement about genesis, and genesis is not a specified variable. It just estimates the population of races which are capable of communicating in a particular way.

 

If anything, seeding is going to deliver to worlds which might otherwise remain lifeless the chance to produce such a civilisation.

 

This is possibly something which we could model experimentally as a community. The problem lends itself well to study by simulation and we have plenty of programming skills between us.

 

I had a really important point to make on this last week shortly after making my last post, but I was unable to get to a PC and I forget what I was thinking about. I'll try and remember!

[Vexer]

If anything, seeding is going to deliver to worlds which might otherwise remain lifeless the chance to produce such a civilisation.

 

That's a point.

 

But only if life can 'seed' interstellar.