December 06, 2012

Attribution

The idea of natural selection itself began as a just-so story, more than two millennia before Darwin. Darwin belatedly learned this when, a few years after the publication of “On the Origin of Species,” in 1859, a town clerk in Surrey sent him some lines of Aristotle, reporting an apparently crazy tale from Empedocles. According to Empedocles, most of the parts of animals had originally been thrown together at random: “Here sprang up many faces without necks, arms wandered without shoulders ... and eyes strayed alone, in need of foreheads.” Yet whenever a set of parts turned out to be useful the creatures that were lucky enough to have them “survived, being organised spontaneously in a fitting way, whereas those which grew otherwise perished.” In later editions of “Origin,” Darwin added a footnote about the tale, remarking, “We here see the principle of natural selection shadowed forth.”
From Just So Stories.
The solution to the paradox* (why is the night sky dark?) could be due to several different possibilities:

1.The universe is finite, that is, it ends at some point.
2.The stars run out at large distances.
3.There hasn't been enough time for the light to reach us from the most distant stars.

We will find out shortly that we can actually estimate the age of our universe. Because the universe is not infinitely old, the answer is number 3 listed above. Since light takes time to reach us, we can see only those objects that are near enough to us that their light has reached us. Curiously enough, the first published solution to Olbers' Paradox is attributed to Edgar Allan Poe. In his essay Eureka, Poe says:
Were the succession of stars endless, then the background of the sky would present us an uniform luminosity, like that displayed by the Galaxy - since there could be absolutely no point, in all that background, at which would not exist a star. The only mode, therefore, in which, under such a state of affairs, we could comprehend the voids which our telescopes find in innumerable directions, would be by supposing the distance of the invisible background so immense that no ray from it has yet been able to reach us at all.
*That'd be Olber’s paradox.