Just when we think we know something, we find a twist that could unravel it all. This morning I ran across an article from the November issue of New Scientist that challenges current thoughts on cosmology:
IT WAS the evolutionary theory of its age. A revolutionary hypothesis that undermined the cherished notion that we humans are somehow special, driving a deep wedge between science and religion. The philosopher Giordano Bruno was burned at the stake for espousing it; Galileo Galilei, the most brilliant scientist of his age, was silenced. But Nicolaus Copernicus’s idea that Earth was just one of many planets orbiting the sun – and so occupied no exceptional position in the cosmos – has endured and become a foundation stone of our understanding of the universe.
Could it actually be wrong, though?
Nearly everyone accepts the thought that our little corner of the universe is the same, more or less, as the rest of the universe. While some claim that Earth is uniquely designed for life, they still accept the thought that the universe is more or less homogeneous. The homogenous principle, along with the isotropic principle (that the universe looks essentially the same from any angle), are necessary to make Einstein’s theory of relativity work. As the article also states,
They were introduced into cosmology not because of any observational evidence, but to save face. In 1917, Albert Einstein had applied his theory of gravity – general relativity – to the dynamics of the universe. Without the simplifying assumptions of homogeneity and isotropy, Einstein’s fiendishly complex equations proved impossible to solve.
Author Marcus Chown goes on to explain how cosmological models had to change to incorporate new information, including inventing “dark energy” to make the pieces fit (an “energy of the gaps” theory), only to find that dark energy doesn’t really work, either.
That is grounds enough, says George Ellis, a leading cosmology theorist based at the University of Cape Town in South Africa, to take a hard look at our assumptions about the universe and our place in it. “If we analyse the supernova data by assuming the Copernican principle is correct and get out something unphysical, I think we should start questioning the Copernican principle.”
An interesting thought. An alternative model has been suggested by Ellis, that Earth could be sitting in what is essentially a large bubble of less density than what is outside of the bubble. And, to explain for the seemingly apparent isotropic universe that we can see, Earth would have to be very near the center of the bubble.
Here we go again. The full article is here.