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panspermia
It’s a tiny eight-legged animals survived exposure to the harsh environment of space on an Earth-orbiting mission is further support for the idea that simple life forms could travel between planets. For instance, rocks regularly get blasted off Mars by cosmic impacts, and a number of Martian meteorites have been found on Earth that some researchers have controversially suggested brought microbes over here, potentially making us all Martians originally.
Simple Beginnings
These might have been contained in simple capsules akin to cell membranes, and over time more complex molecules that performed these reactions better than the smaller ones could have evolved, scenarios dubbed "metabolism-first" models, as opposed to the "gene-first" model of the "RNA world" hypothesis.
RNA World
RNA which can store information like DNA, serve as an enzyme like proteins, and help create both DNA and proteins. Later DNA and proteins succeeded this "RNA world," because they are more efficient. RNA still exists and performs several functions in organisms, including acting as an on-off switch for some genes.
Chilly Start
Ice might have covered the oceans 3 billion years ago, as the sun was about a third less luminous than it is now. This layer of ice, possibly hundreds of feet thick, might have protected fragile organic compounds in the water below from ultraviolet light and destruction from cosmic impacts.
Deep-Sea Vents
The deep-sea vent theory suggests that life may have begun at submarine hydrothermal vents, spewing key hydrogen-rich molecules. Even now, these vents, rich in chemical and thermal energy, sustain vibrant ecosystems.
Community Clay
The first molecules of life might have met on clay according to an idea elaborated by organic chemist Alexander Graham Cairns-Smith. these surfaces might not only have concentrated these organic compounds together, but also helped organize them into patterns much like our genes do now.
It’s a tiny eight-legged animals survived exposure to the harsh environment of space on an Earth-orbiting mission is further support for the idea that simple life forms could travel between planets. For instance, rocks regularly get blasted off Mars by cosmic impacts, and a number of Martian meteorites have been found on Earth that some researchers have controversially suggested brought microbes over here, potentially making us all Martians originally.
Simple Beginnings
These might have been contained in simple capsules akin to cell membranes, and over time more complex molecules that performed these reactions better than the smaller ones could have evolved, scenarios dubbed "metabolism-first" models, as opposed to the "gene-first" model of the "RNA world" hypothesis.
RNA World
RNA which can store information like DNA, serve as an enzyme like proteins, and help create both DNA and proteins. Later DNA and proteins succeeded this "RNA world," because they are more efficient. RNA still exists and performs several functions in organisms, including acting as an on-off switch for some genes.
Chilly Start
Ice might have covered the oceans 3 billion years ago, as the sun was about a third less luminous than it is now. This layer of ice, possibly hundreds of feet thick, might have protected fragile organic compounds in the water below from ultraviolet light and destruction from cosmic impacts.
Deep-Sea Vents
The deep-sea vent theory suggests that life may have begun at submarine hydrothermal vents, spewing key hydrogen-rich molecules. Even now, these vents, rich in chemical and thermal energy, sustain vibrant ecosystems.
Community Clay
The first molecules of life might have met on clay according to an idea elaborated by organic chemist Alexander Graham Cairns-Smith. these surfaces might not only have concentrated these organic compounds together, but also helped organize them into patterns much like our genes do now.