I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.
Isaac Newton
The grand aim of all science is to cover the greatest number of empirical facts by logical deduction from the smallest number of hypotheses or axioms.
Albert Einstein
COSMOLOGY
Nothing exists except atoms and empty space; everything else is opinion.
Democritus
A New Explanation
In the beginning there was neither space nor time as we know them, but shifting foam of strings and loops, as small as anything can be. Within the foam, all of space, time and energy mingled in a grand unification. But the foam expanded and cooled. And then there was gravity, and space and time, and a universe was created. There was a grand unified force that filled the universe with a false vacuum endowed with a negative pressure. This caused the universe to expand exceedingly rapidly against gravity. But this state was unstable, and did not last, and the true vacuum reappeared, the inflation stopped, and the grand unified force was gone forever. In its place were the strong and electroweak interactions, and enormous energy from the decay of the false vacuum. The universe continued to expand and cool, but at a much slower rate. Families of particles, matter and antimatter, rose briefly to prominence and then died out as the temperature fell below that required to sustain them. Then the electromagnetic and the weak interaction were cleaved, and later the neutrinos were likewise separated from the photons. The last of the matter and antimatter annihilated, but a small remnant of matter remained. The first elements were created, reminders of the heat that had made them. And all this came to pass in three minutes, after the creation of time itself. Thereafter the universe, still hot and dense and opaque to light, continued to expand and cool. Finally the electrons joined to the nuclei, and there were atoms, and the universe became transparent. The photons which were freed at that time continue to travel even today as relics of the time when atoms were created, but their energy drops ever lower. And a billion years passed after the creation of the universe, and then the clouds of gas collapsed from their own gravity, and the stars shone and there were galaxies to light the universe. And some galaxies harbored at their centers giant black holes, consuming much gas, and blazing with exceeding brightness. And still the universe expanded. And stars created heavy elements in their cores, and then they exploded, and the heavy elements went out into the universe. New stars form still and take into themselves the heavy elements from the generations that went before them.
And more billions of years passed, and one particular star formed, like many others of its kind that had already formed, and would form in the future. Around this star was a disk of gas and dust. And it happened that this star formed alone, with no companion close by to disrupt the disk, so the dust did condense, and formed planets, and numerous smaller objects. And the third planet was the right size and the right distance from its star so that rain fell upon the planet and did not boil away, nor did it freeze. And this water made the planet warm, but not too warm, and was yet a good solvent, and many compounds formed. And some of these compounds could make copies of themselves. And these compounds made a code that could be copied and passed down to all the generations. And then there were cells, and they were living. And billions of years elapsed with only the cells upon the planet. Then some of the cells joined together and made animals which lived in the seas of the planet. And finally some cells from the water began to live upon the rocks of the land, and they joined together and made plants. And the plants made oxygen, and other creatures from the seas began to live upon the land. And many millions of years passed, and multitudes of creatures lived, of diverse kinds, each kind from another kind. And a kind of animal arose and spread throughout the planet, and this animal walked upon two feet and made tools. And it began to speak, and then it told stories of itself, and last it told this story. But all things must come to their end, and after many billions of years, the star will swell up and swallow the third planet, and all will be destroyed in the fire of the star. And we know not how the universe will end, but it may expand forever, and finally all the stars will die and the universe will end in eternal darkness and cold.
Source : © 1998, 2005 OUP; © 2005 John F Hawley
It is a capital mistake to theorize before one has data. -Sherlock Holmes
The glorious Sun, stays in his course, and plays the alchemist
Shakespeare, King John, III, 1
We begin with the mythological roots of cosmology, but our overriding theme will be that modern cosmology is not just today's creation myth. The historical development of the scientific method, the tremendous improvements in our data gathering abilities, and the development of physical theory set the modern cosmological picture apart......
The steps in formulating and testing scientific hypotheses:
The process of induction leads to a general principle consistent with the observations. From this principle one can deduce what specific events should follow. The process is continuous as better and better hypotheses are developed.
The scientific method has very specific rules. It is based on objective data, observations that are independent of who made those observations. Once sufficient data are collected, a hypothesis is framed to explain and unify them. In order to be regarded as scientific, the hypothesis must meet at minimum five characteristics: it must be relevant, testable, consistent, simple, and have explanatory power. Of these, the quality of testability particularly defines the scientific method. A hypothesis that does not contain the potential to be falsified is not scientific. Once a hypothesis has met success at explaining data and has proven itself useful in predicting new phenomena, it is generally called a theory.
What are examples of cosmological questions?
What are examples of common themes within cosmological mythology?
Can you find an example of an uncommon cosmological theme or concept in a mythological story?
The Aristotelian cosmological system was consistent with his physics. Although Aristotle's cosmology is quite different from the modern point of view, in what ways is it consistent with modern ideas? How did it differ?
During the Renaissance, humanity's cosmological model changed dramatically. The first blow in the "Scientific Revolution" was struck by Copernicus, whose Sun-centered model of the heavens gained rapid ascendancy in Renaissance Europe. What were some of the motivations for Copernicus to propose such a grand change to the prevailing concepts of the universe?
Tycho Brahe's observations of a supernova that appeared in 1572 helped to end the belief in the Aristotelean unchanging perfection of the celestial realm. How would you feel if you observed something that so challenged a basic tenet of your world view? In Tycho's own words:
Amazed, and as if astonished and stupefied, I stood still, gazing for a certain length of time with my eyes fixed intently upon it and noticing that same star placed close to the stars which antiquity attributed to Cassiopeia. When I had satisfied myself that no star of that kind had ever shone forth before, I was led into such perplexity by the unbelievability of the thing that I began to doubt the faith of my own eyes.
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