Confirmation of the Isotropy (Lack of Any Special Direction) of the Universe

[Recusant]

There were already good confirmations of one of the basic principles of modern cosmology, but this study seems to nail it down beyond any reasonable doubt.

"It's official: You're lost in a directionless universe" | Science

Ever peer into the night sky and wonder whether space is really the same in all directions or if the cosmos might be whirling about like a vast top? Now, one team of cosmologists has used the oldest radiation there is, the afterglow of the big bang, or the cosmic microwave background (CMB), to show that the universe is "isotropic," or the same no matter which way you look: There is no spin axis or any other special direction in space. In fact, they estimate that there is only a one-in-121,000 chance of a preferred direction—the best evidence yet for an isotropic universe. That finding should provide some comfort for cosmologists, whose standard model of the evolution of the universe rests on an assumption of such uniformity.

"It's a much more comprehensive analysis than in previous cases," says Anthony Challinor, a cosmologist at the University of Cambridge in the United Kingdom who was not involved in the work. "The question of how isotropic is the universe is of fundamental importance."

In 1543, Nicolaus Copernicus knocked Earth and humanity from the supposed center of the universe by noting that Earth goes around the sun, not the other way around. That observation gave birth to the Copernican principle, which holds that we have no special place in the infinite, centerless universe. In the early 20th century, with the advent of Albert Einstein's general theory of relativity and the observation that the universe is expanding in all directions, that idea evolved into the cosmological principle, which assumes that the universe is the same everywhere and in every direction. In fancier terms, the universe is both homogeneous and isotropic.

The principle has its limitations. As the existence of stars and galaxies shows, matter is not distributed exactly the same way everywhere. This, they assume, arises because the universe was born as a homogeneous soup of subatomic particles in the big bang. As the universe underwent an exponential growth spurt called inflation, tiny quantum fluctuations in that soup expanded to gargantuan sizes, providing density variations that would seed the galaxies. Yet, the standard model of cosmology rests on the assumption that, on the largest scales, these variations are insignificant, and space is homogeneous and isotropic.

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[Tank]

I do love your posts.

[Recusant]

  Thank you, Tank. 

[Icarus]

By all means, add me to the list of respectful admirers of your posts.