A Single Oxygen Atom's Odyssey from the Big Bang to Life on Earth...and Beyond
As he did in The Physics of Star Trek, Lawrence Krauss will blow you away in his new bestseller, Atom -A Single Oxygen Atom's Odyssey from the Big Bang to Life on Earth...and Beyond".
In an interview in a recent issue of Astrobiology online Krauss relates that "one of the most poetic aspects of all of science is the fact that we are all star children, literally, as each and every atom in our bodies was once inside of a star, perhaps several stars, and the very elements that make us up were forged inside fiery stellar furnaces."
One of the most fascinating facts Kruass reveals is that present-day life evolved out of bacteria that thrived on the early Earth for two billion years, were there was no free oxygen, and, in the absence of oxygen, there was no ozone layer to protect life against the extreme ultraviolet radiation coming from the sun.
Recent advances in biochemical evolution Krauss points out suggests that sulfur-eating bacteria, or methane-producing fermenters, are likely to have predated more sophisticated photosynthetic bacteria. In fact, before photosynthesis there was quite likely chemosynthesis. Here primordial life forms would have lived without oxygen and in the dark. They would not have been powered, as plants are, by the sun, but rather by the heat of the Earth.
Krauss finds the existence of extremophiles the most compelling new development in astrobiology with its profound implications for the existence of life throughout the Universe:
"The first cells were probably more accustomed to the darkness and the putrid smell of sulfur assicatied with hydrothermal vents. Every year one reads of new forms of life discovered in places ranging from the relatively benign hydrothermal vents to the acidic, toxic, sweaty regions at the bottom of deep oil wells. Most compelling of all, perhaps, is the recent discovery that the tree of life has merely three branches, not five [plants, animals, fungi, bacteria and protists (sophisticated single-celled animals)], and that the one closest to the root involves bacteria that live in hot environments, the hyperthermophiles. Hyperthermophiles defy all conventional wisdom. These forms of life not only can thrive in environments that normalize sterilize materials, in excess of the normal boiling temperature of water at sea level, 100 degrees Celsius, they require such temperatures. These arguments suggest that all life on Earth today descended from species that liked it hot."
The two most profound developments in the history of life on the planet, Krauss concludes, were photosynthesis and, later, respiration. By these two processes, not only would life be forever changed but so would the Earth.
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