Why we came from Mars (rationally)
I developed some comments watching this video here:
http://www.youtube.com/watch?v=9RExQFZzHXQ
These are two well-established scientists and media personalities (yes this works). I thought it was interesting that Tyson seriously entertained the idea that life could have come from Mars.
The argument is that there are 100,000s of Martian rocks that should have fallen to Earth over the years, during the period of heavy bombardment (100s of tons). He makes the point that Mars would have been fertile for life before Earth, which I understand very very well. Then he says that it would be a disappointment to find fossils of life on Mars that was made of the same DNA, because that would not constitute a separate development of life.
I want to take this concept and run with it. Notably, I'm much more interested in the specialness of the idea of life on Earth coming from Mars. One would say, "but that's fantastically improbable". I agree. That's why it's a good theory.
The reality of our universe contains a number of peculiarities. Notably, let's look into these ideas.
1. Our Universe is fine-tuned for life, which is reasonable by the anthropic principle
2. Space is, as far as we know, dark with respect to life around us - we're alone as far as we know
3. We had more time than we need to evolve
4. The time scales needed for humans to develop from language to the LHC were virtually nothing
These 4 comprise the evidence I will need to make my claim. Most of them need some more explanation so I will be returning to all of them. Firstly, Tyson made some interesting points in the video about the elements of life being roughly the same elements that are the most common to the universe. This resulted in the observation that Silicon based life is possible, but completely unnecessary. Generally, the existence of Carbon is just one of the many reasons our universe is fertile for life, very much so in fact. One would expect that given a fertile universe for life, the universe would be teeming with life, but it gets more complicated, continuing...
My 2 point is certainly one of contention. We have the question of the observability of life at hand. I think that we should be able to see life if 1, 3, and 4 hold strongly true, but unfortunately I will need all those 3 to make the argument effectively. We can only theoretically detect radio waves from civilization from a local bubble as Search for Extra Terrestrial Intelligence (SETI) has been attempting, but we need to dig more into the argument here. How would we expect to detect life. I would propose:
- radio waves from industrial communications
- observational evidence from ordinary life/presence (2 kinds)
- they just come here and visit us
It's getting complicated here, but I'll note that a certain number of observable stars exist for each one of these interaction methods. SETI looks at the first one, and the number of stars is some number of 100,000s. By most reasonable constructions of the Drake Equations, it is more probable than not that SETI will fail. So this observation does not preclude the idea of the universe being teeming with life. The observation from ordinary presence will be possible for an advanced civilization but non-technological civilization should be within our reach in 100 years or so, but there's a more important part to this. The concept of a Dyson Sphere is rather nonsense in itself, but the idea of a mega-scale society is not. This goes back to my previous point 4. We may predict that advanced civilizations are basically explosions, and if intelligent life comes to be, they will almost instantaneously on universal scales, colonize all the local stars and expand infinitely.
My point 3 is something I don't hear other people argue very often. The Precambrian explosion happened 500 million years ago, and it is thinkable that advanced life like us could have evolved somewhere in the universe anytime after that time. It could have evolved before this! Think about this, the light bubble for 500 million years ago is absolutely monstrous. I put forth the observation that no civilization within 500 million light-years of us has come to visit us. That has huge implications for the Drake Equation. It is premature to say that our civilization is on the verge of a technological singularity, but that is not important. it is important that a civilization like us could hit a technological singularity. There is a valid observation probably no civilization within a billion light-year radius of us has hit a singularity.
My conclusion from that observation is that life, period, is highly unlikely to evolve. That is to say, abiogenesis leading to intelligent life is improbable. I admit, I'm applying my personal experience as a human in human society to say that the probability of hitting a technological singularity given intelligent life is not much less than 1. People could very easily disagree with my point, which would paint a picture that many intelligent but non-prolific civilizations are out there.
Let's revisit the Drake Equation. I will write it twice, representing two different forms.
The Drake Equation:
( # of intelligent life instances in Milky way ) = ( # of stars ) * sum( ( probability of success of i_th stage of life ) , i=1, ..., N )
( # of ppl who've visited us ) = ( # of stars in 1 Gly ) * sum( ( probability of success of i_th stage of life ) , i=1, ..., N ) * ( probability of singularity, N+1 )
nu_l = sum( ( probability of success of i_th stage of life )
nu_s = ( probability of singularity, N+1 )
The reality is that a coherent physical theory of the universe NEEDS the sum in these equations to be impossibly low. Our evolutions needs to be infinitely unlikely looking from afar. There is a balance between the two terms nu_l and nu_s, the probabilities of a star hosting life and the probability of intelligent beings explosively expanding to new celestial bodies, respectively.
The point where is disagree with most commentators on this matter is that nu_l being anything other than almost zero to the point of most prohibiting life in the universe is folly. Practically the product nu_s * nu_l < ( about 5 ) / (1.2x10^9).
3 to 7 × 10^22 = I'l say 3 x 10^22
then
(3 * (10^22) * (1^3)) / (13.75^3) = 1.2 × 10^19 --> number of stars in 1 Gly radius (with fuzzy math ;)
Milky Way has 1-4 x 10^11 stars.
The assertion that a technological singularity is unlikely must be, generally, less than the number of the Milky Way's stars divided by the 1 Gly stars. That comes out to be around 10^-8. I'm going out on a limb to say that the probability of humans killing ourselves is less than 1 in 100 million (although I could be wrong). A technological singularity is simply inevitable in a universe that is abundant in intelligent life.
Our universe is simply not abundant in intelligent life. How do we exist then?
Because life could not have evolved in Earth unless the more fertile conditions of primitive mars had not evolved the first forms of cellular life. Why?
Tectonics.
In Earth's early days it was a magma soup that nothing could have survived on. Mars also started out like this, but it cooled off much faster and the Goldilocks period of it's tectonic evolution came much earlier. Furthermore, change of environment in which life is living will very commonly spur an explosion in more advanced and new kinds of life.
This model would allow basic life to be common, but life advanced enough to attain intelligence totally rare. That explains well how large and complex life could have existed on Earth for 100s of millions of years without being disturbed by other visitors who developed more quickly. So this solves what I might call the "Dinosaur problem" in our model of the universe.
I've explained why we need a tool to identify a transition in the evolution of life to be very unlikely. To wrap this up, I need to explain why it WAS very unlikely that life flew on a space journey from Mars to Earth (as if you needed that explained). Solar systems with 8 nicely arranged planets are probably rare. Just the relative proximity of Earth and Mars is not a normal thing, and the movement of material from Mars (the perfect nursery) to Earth (the perfect home) requires the evolution of TWO 'perfects' in the same solar system as well as a meteor bombardment history that allowed a large transfer of Martian mass to Earth. ADDITIONALLY it require that spore-like life evolved on Mars and survived the journey. That's pretty obscenely unlikely. But this makes sense actually.
While it may seem self-defeating for this model to require a low probability of intelligent life evolving, it's actually not. Looking backward from our perspective, we've only observed ONE case of life like us, and therefore, the probability of such life evolving may be ARBITRARILY SMALL. As far as we can tell, a theory that places that probability lower than another theory is to be preferred rationally. In addition to the massive (known) expanses of space, the multi-verse theories dictate that fertile conditions (to the degree that they are) for life could have existed for an arbitrarily large amount of time. There could have been INFINITE trials and there is no logical fallacy if we are the only intelligent life in the universe. There is also no logical fallacy if rapid industrialization and evolution to a space-faring race is also near inevitable.
Is this a more 'dismal' view of the universe than Tyson prefers? Absolutely so, but it's highly credible. Indeed, if we find that life developed on Mars SEPARATE from life on Earth, we may as well prepare to join our galactic community, for advanced life is certainly common. We have every reason to prefer that view from a humanist perspective. We would like to find that we're not alone.
But we probably are alone. And I have described a model consistent with that.
http://www.youtube.com/watch?v=9RExQFZzHXQ
These are two well-established scientists and media personalities (yes this works). I thought it was interesting that Tyson seriously entertained the idea that life could have come from Mars.
The argument is that there are 100,000s of Martian rocks that should have fallen to Earth over the years, during the period of heavy bombardment (100s of tons). He makes the point that Mars would have been fertile for life before Earth, which I understand very very well. Then he says that it would be a disappointment to find fossils of life on Mars that was made of the same DNA, because that would not constitute a separate development of life.
I want to take this concept and run with it. Notably, I'm much more interested in the specialness of the idea of life on Earth coming from Mars. One would say, "but that's fantastically improbable". I agree. That's why it's a good theory.
The reality of our universe contains a number of peculiarities. Notably, let's look into these ideas.
1. Our Universe is fine-tuned for life, which is reasonable by the anthropic principle
2. Space is, as far as we know, dark with respect to life around us - we're alone as far as we know
3. We had more time than we need to evolve
4. The time scales needed for humans to develop from language to the LHC were virtually nothing
These 4 comprise the evidence I will need to make my claim. Most of them need some more explanation so I will be returning to all of them. Firstly, Tyson made some interesting points in the video about the elements of life being roughly the same elements that are the most common to the universe. This resulted in the observation that Silicon based life is possible, but completely unnecessary. Generally, the existence of Carbon is just one of the many reasons our universe is fertile for life, very much so in fact. One would expect that given a fertile universe for life, the universe would be teeming with life, but it gets more complicated, continuing...
My 2 point is certainly one of contention. We have the question of the observability of life at hand. I think that we should be able to see life if 1, 3, and 4 hold strongly true, but unfortunately I will need all those 3 to make the argument effectively. We can only theoretically detect radio waves from civilization from a local bubble as Search for Extra Terrestrial Intelligence (SETI) has been attempting, but we need to dig more into the argument here. How would we expect to detect life. I would propose:
- radio waves from industrial communications
- observational evidence from ordinary life/presence (2 kinds)
- they just come here and visit us
It's getting complicated here, but I'll note that a certain number of observable stars exist for each one of these interaction methods. SETI looks at the first one, and the number of stars is some number of 100,000s. By most reasonable constructions of the Drake Equations, it is more probable than not that SETI will fail. So this observation does not preclude the idea of the universe being teeming with life. The observation from ordinary presence will be possible for an advanced civilization but non-technological civilization should be within our reach in 100 years or so, but there's a more important part to this. The concept of a Dyson Sphere is rather nonsense in itself, but the idea of a mega-scale society is not. This goes back to my previous point 4. We may predict that advanced civilizations are basically explosions, and if intelligent life comes to be, they will almost instantaneously on universal scales, colonize all the local stars and expand infinitely.
My point 3 is something I don't hear other people argue very often. The Precambrian explosion happened 500 million years ago, and it is thinkable that advanced life like us could have evolved somewhere in the universe anytime after that time. It could have evolved before this! Think about this, the light bubble for 500 million years ago is absolutely monstrous. I put forth the observation that no civilization within 500 million light-years of us has come to visit us. That has huge implications for the Drake Equation. It is premature to say that our civilization is on the verge of a technological singularity, but that is not important. it is important that a civilization like us could hit a technological singularity. There is a valid observation probably no civilization within a billion light-year radius of us has hit a singularity.
My conclusion from that observation is that life, period, is highly unlikely to evolve. That is to say, abiogenesis leading to intelligent life is improbable. I admit, I'm applying my personal experience as a human in human society to say that the probability of hitting a technological singularity given intelligent life is not much less than 1. People could very easily disagree with my point, which would paint a picture that many intelligent but non-prolific civilizations are out there.
Let's revisit the Drake Equation. I will write it twice, representing two different forms.
The Drake Equation:
( # of intelligent life instances in Milky way ) = ( # of stars ) * sum( ( probability of success of i_th stage of life ) , i=1, ..., N )
( # of ppl who've visited us ) = ( # of stars in 1 Gly ) * sum( ( probability of success of i_th stage of life ) , i=1, ..., N ) * ( probability of singularity, N+1 )
nu_l = sum( ( probability of success of i_th stage of life )
nu_s = ( probability of singularity, N+1 )
The reality is that a coherent physical theory of the universe NEEDS the sum in these equations to be impossibly low. Our evolutions needs to be infinitely unlikely looking from afar. There is a balance between the two terms nu_l and nu_s, the probabilities of a star hosting life and the probability of intelligent beings explosively expanding to new celestial bodies, respectively.
The point where is disagree with most commentators on this matter is that nu_l being anything other than almost zero to the point of most prohibiting life in the universe is folly. Practically the product nu_s * nu_l < ( about 5 ) / (1.2x10^9).
3 to 7 × 10^22 = I'l say 3 x 10^22
then
(3 * (10^22) * (1^3)) / (13.75^3) = 1.2 × 10^19 --> number of stars in 1 Gly radius (with fuzzy math ;)
Milky Way has 1-4 x 10^11 stars.
The assertion that a technological singularity is unlikely must be, generally, less than the number of the Milky Way's stars divided by the 1 Gly stars. That comes out to be around 10^-8. I'm going out on a limb to say that the probability of humans killing ourselves is less than 1 in 100 million (although I could be wrong). A technological singularity is simply inevitable in a universe that is abundant in intelligent life.
Our universe is simply not abundant in intelligent life. How do we exist then?
Because life could not have evolved in Earth unless the more fertile conditions of primitive mars had not evolved the first forms of cellular life. Why?
Tectonics.
In Earth's early days it was a magma soup that nothing could have survived on. Mars also started out like this, but it cooled off much faster and the Goldilocks period of it's tectonic evolution came much earlier. Furthermore, change of environment in which life is living will very commonly spur an explosion in more advanced and new kinds of life.
This model would allow basic life to be common, but life advanced enough to attain intelligence totally rare. That explains well how large and complex life could have existed on Earth for 100s of millions of years without being disturbed by other visitors who developed more quickly. So this solves what I might call the "Dinosaur problem" in our model of the universe.
I've explained why we need a tool to identify a transition in the evolution of life to be very unlikely. To wrap this up, I need to explain why it WAS very unlikely that life flew on a space journey from Mars to Earth (as if you needed that explained). Solar systems with 8 nicely arranged planets are probably rare. Just the relative proximity of Earth and Mars is not a normal thing, and the movement of material from Mars (the perfect nursery) to Earth (the perfect home) requires the evolution of TWO 'perfects' in the same solar system as well as a meteor bombardment history that allowed a large transfer of Martian mass to Earth. ADDITIONALLY it require that spore-like life evolved on Mars and survived the journey. That's pretty obscenely unlikely. But this makes sense actually.
While it may seem self-defeating for this model to require a low probability of intelligent life evolving, it's actually not. Looking backward from our perspective, we've only observed ONE case of life like us, and therefore, the probability of such life evolving may be ARBITRARILY SMALL. As far as we can tell, a theory that places that probability lower than another theory is to be preferred rationally. In addition to the massive (known) expanses of space, the multi-verse theories dictate that fertile conditions (to the degree that they are) for life could have existed for an arbitrarily large amount of time. There could have been INFINITE trials and there is no logical fallacy if we are the only intelligent life in the universe. There is also no logical fallacy if rapid industrialization and evolution to a space-faring race is also near inevitable.
Is this a more 'dismal' view of the universe than Tyson prefers? Absolutely so, but it's highly credible. Indeed, if we find that life developed on Mars SEPARATE from life on Earth, we may as well prepare to join our galactic community, for advanced life is certainly common. We have every reason to prefer that view from a humanist perspective. We would like to find that we're not alone.
But we probably are alone. And I have described a model consistent with that.