Tuesday, July 22, 2008

Are We Living in a Giant Void?

As a science fiction fan, I have come across something that annoys me. There seem to be a limited number of things that can happen in a series, and episodes start repeating themselves from series to series. One such occurrence is the idea of a ship being trapped in a void of stars; being literally nowhere near another star, and thus, all in black.

This void, as most episodes are entitled, is similar to the descriptions that filter out of Antarctica. When explorers are traversing miles and miles of white, they begin to lose the ability to determine where they are, and if they are moving.

The idea of an astronomical void is not just science fiction fodder however, and rather, according to Timothy Clifton and colleagues Pedro G. Ferreira and Kate Land at the University of Oxford, a possible explanation for why it looks as if our universe is expanding at an accelerated pace.

So far, the general consensus has been that dark energy – though unfound and unproven – is to blame for this acceleration. And although corroboration has been found from several independent sources, such as the cosmic microwave background and large scale structure, as well as improved measurements of the supernovae, this consensus is filled with uncertainties, considering that the observed value of dark energy is 120 orders of magnitude smaller than what is predicted from quantum physics.

At this point, Timothy Clifton’s paper, entitled ‘Title: Living in a Void: Testing the Copernican Principle with Distant Supernovae’, can be brought in to play as the basis of an alternative theory explaining what we are witnessing outside our proverbial window.

The opening line of their paper, states that “a fundamental presupposition of modern cosmology is the Copernican Principle”.

The Copernican Principle states that the Earth is not in a central, specially favored position, according to Herman Bondi in his 1952 book Cosmology. Clifton and co want to challenge this principle scientific theory, with an explanation that would also help us understand what we are seeing.

Their theory posits that if in fact Earth and our surrounding neighbors are in fact in an unusual or special region of space, ie, a void, then our perspective on the universe would be severely challenged. The local geometry of space-time would be different than expected. The curvature of space around us would affect how light from those distant supernovae that originally saw us explain their dimness as an ever accelerating and expanding universe. In fact, if the proposed void were large enough, it could do away entirely with the scientific need for dark energy to explain what we cannot.

It is no surprise that Clifton’s theories are speculative, but the best science always starts out that way. But one aspect of this paper, that at least one writer – Amanda Gefter, opinion editor at New Scientist – has picked up on, is that by blinding adhering to a scientific principle because to do otherwise is too hard, is tantamount to crime. Without making this a “rattle the cages” message, rules are there to be broken, and in science this is even more the case than elsewhere.

Posted by Josh Hill.

Original here

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