Monday 28 May 2007

The Story of the Universe: Part 2

By the time evolution brought forth a species called Homo Sapiens, on an undistinctive planet called Earth, the universe had already existed for over ten billion (10,000,000,000) years. This species spent most of the next 600,000 years eeking out a meager existence, battling with the other cohabitants of the planet for mere survival, but eventually, after most of that 600,000 years had passed, they briefly gained the upper hand over all other species of the Earth and managed to dominate them in spectacularly successful and brutal fashion.

Compared with the eons that had preceeded it, at only a handful of millenia, the reign of Homo Sapiens was pitifully short, and despite the enormous amount of energy and enthusiasm they collectively dedicated to making an impression on the universe, in the end the existence of Homo Sapiens amounted more or less to nothing at all.

Following their demise, the ecology of Earth gradually regained its balance and evolution continued to bring forth a widely varied array of organisms for a further 2 billion years. None of these organisms happened to possess the same level of intelligence Homo Sapiens had, and no-one noticed, or was by any means the worse-off for it. Eventually the Sun, the star around which the Earth had been orbiting for six and a half billion years, began to exhaust its reserves of hydrogen, and as this was taking place the concentration of helium at its core rose, causing in turn a dramatic increase in its production of heat and light. On Earth this caused a runaway greenhouse effect, by consequence of which all the oceans evaporated, and practically all life became extinct. In this sterile environment only thermophilic bacteria were able to cling to life, but after a time even these hardy organisms were extinguished as the Sun continued to swell.

Once all the helium at the Sun's core had been completely extinguished it became a red giant, loosing much of its mass to evaporation in the process, which caused the planets, including Earth to slip into more remote orbits. The Sun continued to grow and at its largest, was 100 times its earlier size. At this time the surface of the Earth was completely molten. Eventually the Sun exploded into a planetary nebula, which, had there been any sentient life forms around to observe it, would have appeared quite picturesque. After this the Sun assumed it's penultimate form of a white dwarf and subsequently, very very slowly, faded to black.

100 trillion (10 to the power of 14) years after the extinction of Homo Sapiens, all the stars in the universe had exhausted their fuel supply, and the only remaining objects were dead stars in the form of brown dwarfs, white dwarfs, neutron stars and black holes. The protons that formed the atoms from which the matter of these dead stars were composed then started decaying. For another 10 trillion, trillion (10 to the power of 25) years, the only thing that happened in the universe was the unbelievably slow, inexorable decay of dead stars.

Eventually this process too, was complete and the only things left in the universe were black holes. The black holes also decayed, even more slowly than the dead stars. The decay of black holes took place over such an unimaginably huge span of time that words do not exist to describe the amount of years it took, we can only use numbers: After 10 to the power of 100 years, all the black holes in the universe had evaporated, and there was nothing remaining in the entire cold, dark expanse except the occasional stray, lonely photon, neutrino, electron or positron, flying about in meaningless, random patterns, hardly ever encountering one another, forever .....

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