For example : tonne mass of a blue whale; million tonnes of global human biomass. Power and energy : 1 watt of power uses 1 joule of energy per second; about watts in 1 horsepower; 3, kilojoules kJ or kilocalories kcal in 1 kWh of energy, sustaining 1, watts for 1 hour. For example , a watt incandescent light bulb illuminates a room; 80 watts sustain human basal metabolic rate, using 6, kJ or 1, kcal or 1. Patrick Doncaster , 7 November , one of the then 7,,, rising by per minute, 79 million per year.
Evolution of life on Earth 4,,, earliest life on Earth: single-celled prokaryotic Archaea Hadean Eon , 3. Human evolution 2,, earliest human, Homo sp. Years ago. Evolution of life on Earth. This brings us back to the fatalistic view. The Standard Model of physics presumes that we are all made of elementary particles with no additional constituents.
As such composite systems, we do not possess freedom at a fundamental level, because all particles and their interactions follow the laws of physics. These uncertainties are substantial on the scale of an individual but average out when dealing with a large sample. Humans and their complex interactions evade a sense of predictability at the personal level, but perhaps the destiny of our civilization as a whole is shaped by our past in an inevitable statistical sense. The forecast of how much time we have left in our technological future could then follow from statistical information about the fate of civilizations like ours that predated us and lived under similar physical constraints.
Most stars formed billions of years before the sun and may have fostered technological civilizations on their habitable planets that perished by now.
If we had historical data on the life span of a large number of them, we could have calculated the likelihood of our civilization to survive for different periods of time. The approach would be similar to calibrating the likelihood of a radioactive atom to decay based on the documented behavior of numerous other atoms of the same type. In principle, we could gather related data by engaging in space archaeology and searching the sky for relics of dead technological civilizations. This would presume that the fate of our civilization is dictated by the physical constraints.
But once confronted with the probability distribution for survival, the human spirit may choose to defy all odds and behave as a statistical outlier. For example, our chance for survival could improve if some people choose to move away from Earth. Currently, all our eggs are in one basket. Venturing into space offers the advantage of preserving our civilization from a single-planet disaster. Establishing multiple communities of humans on other worlds would resemble the duplication of the Bible by the Gutenberg printing press around , which prevented loss of precious content through a single-point catastrophe.
Of course, even a short-distance travel from Earth to Mars raises major health hazards from cosmic rays, energetic solar particles, UV radiation, lack of a breathable atmosphere and low gravity. Finding technosignatures in space is an extreme long shot, but Wright argues that the effort is worthwhile. Such studies might reveal new details about the history and evolution of the solar system, for instance, or about resources that might be useful to future spacefarers.
IE 11 is not supported. For an optimal experience visit our site on another browser. Share this —. By Corey S. Scientists detect signals from what could be the oldest stars in the universe March 23,
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