The origin of life remains one of the most open scientific questions in Astrobiology. While there's been great headway in both laboratory and theoretical understanding in how life may have originated, we still don't know when, where or how life originated.
Today's post revolves around this paper by Eva Stueken and others (mostly from the Univ. of Washington) I just reviewed in a seminar on a theory for the origin of life that looks at the early Earth as a global chemical reactor that could have led to the right reactants coming together to make life. The paper is open access, meaning anyone can go ahead and download it. The punchline of the paper is that instead of being a random event that occurred on the early Earth in one habitat, the origin of life was a more gradual process relying on multiple reactions from all over the Earth.
Most theories for the origin of life assume that life originated in one fairly limited region of the early Earth. This new theory looks at the exact opposite idea - what if life couldn't have formed in an isolated habitat? What if it required chemical reactions and transport schemes occurring all over the planet, perhaps not even at the same time?
The authors look at 8 different locales on the early Earth - the atmosphere, lakes and rivers, beaches, sea-ice, sea-surface micro layer, marine sediments, hydrothermal vents, and the oceanic crust. Each local has certain chemical reactions that are favored. For example, only places on or very near the surface have access to sunlight, which is important for a lot of the reactions believed to be necessary for life to form. On the other hand, hydrothermal vents are major sources of metals into the ocean, and therefore could play an essential role in the origin of life. Some people have even gone as far as to say that hydrothermal vents alone are where life originated.
Once the reactions occurred in each environment, there need to be various transport mechanisms to get the reaction products from one area to another. Thankfully, between winds, currents, tectonic outgassing and even convection in the crust, there's no reason to believe that this wasn't the case. So you could have molecule A form in a lake on the surface, molecule B form near a hydrothermal vent, molecule C from the sea-surface micro layer, and they all get together on the beach and suddenly...A+B+C = life.
Scientifically and theologically, the implications of this are profound. This is a hard theory to test, but if it were true, that would change the origin of life from a somewhat random event that relied on a specific chemical reaction occurring in one location to a more gradual, deterministic event that doesn't seem so improbable, if you have the right conditions.
What are the right conditions? It seems to be that you need a wide variety of environments. So perhaps if you have a planet like the Earth in the habitable zone of another star, life would have a high probability of forming. But what about a world like Europa, where the ocean is (mostly) cut off from the surface? Well, if there might be mechanisms to transport products from the surface to the ocean, but it doesn't seem as likely as life originating on an Earth-like planet.
What does this mean theologically? That's a bit more speculative, but we know that we are created in God's image, so it would make sense if God put a system in place to have life originate in places like the Earth. It's not scientifically obvious that evolution would automatically lead to homo sapiens (most scientists would argue it wouldn't) but there's still so much we don't understand about this topic.
Today's post revolves around this paper by Eva Stueken and others (mostly from the Univ. of Washington) I just reviewed in a seminar on a theory for the origin of life that looks at the early Earth as a global chemical reactor that could have led to the right reactants coming together to make life. The paper is open access, meaning anyone can go ahead and download it. The punchline of the paper is that instead of being a random event that occurred on the early Earth in one habitat, the origin of life was a more gradual process relying on multiple reactions from all over the Earth.
Most theories for the origin of life assume that life originated in one fairly limited region of the early Earth. This new theory looks at the exact opposite idea - what if life couldn't have formed in an isolated habitat? What if it required chemical reactions and transport schemes occurring all over the planet, perhaps not even at the same time?
The authors look at 8 different locales on the early Earth - the atmosphere, lakes and rivers, beaches, sea-ice, sea-surface micro layer, marine sediments, hydrothermal vents, and the oceanic crust. Each local has certain chemical reactions that are favored. For example, only places on or very near the surface have access to sunlight, which is important for a lot of the reactions believed to be necessary for life to form. On the other hand, hydrothermal vents are major sources of metals into the ocean, and therefore could play an essential role in the origin of life. Some people have even gone as far as to say that hydrothermal vents alone are where life originated.
Once the reactions occurred in each environment, there need to be various transport mechanisms to get the reaction products from one area to another. Thankfully, between winds, currents, tectonic outgassing and even convection in the crust, there's no reason to believe that this wasn't the case. So you could have molecule A form in a lake on the surface, molecule B form near a hydrothermal vent, molecule C from the sea-surface micro layer, and they all get together on the beach and suddenly...A+B+C = life.
Scientifically and theologically, the implications of this are profound. This is a hard theory to test, but if it were true, that would change the origin of life from a somewhat random event that relied on a specific chemical reaction occurring in one location to a more gradual, deterministic event that doesn't seem so improbable, if you have the right conditions.
What are the right conditions? It seems to be that you need a wide variety of environments. So perhaps if you have a planet like the Earth in the habitable zone of another star, life would have a high probability of forming. But what about a world like Europa, where the ocean is (mostly) cut off from the surface? Well, if there might be mechanisms to transport products from the surface to the ocean, but it doesn't seem as likely as life originating on an Earth-like planet.
What does this mean theologically? That's a bit more speculative, but we know that we are created in God's image, so it would make sense if God put a system in place to have life originate in places like the Earth. It's not scientifically obvious that evolution would automatically lead to homo sapiens (most scientists would argue it wouldn't) but there's still so much we don't understand about this topic.
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