8.19.2009

Dark Energy or God?


We've known for a century that the universe is expanding. We've known for just over a decade, that not only is it expanding but that the expansion is accelerating - at least that's what observations seem to be telling us. The Big Bang theory was sufficient to account for simple expansion, but to have accelerated expansion, there must be something more, something we have called Dark Energy. While the name is ominous, it seemed to be nothing more than adding a correction to Einstein's equations of General Relativity, akin to adding an exertion of pressure which happens to get larger as the density of the universe decreases.

However, a new model published in the Proceedings of the National Academy of Sciences (PNAS)(abstract free, article free after a few months past publication date), proposes a "simpler" explanation: that we are in the midst of a density wave caused by the Big Bang. As often happens with modern physics theories, the concept is not so easy to visualize, even though the equations work out. Essentially, it boils down to where and when galaxies form in high and low energy densities. If the Milky Way forms in the center of a low-density trough, distant galaxies will be forming at higher-density peaks. The outward expanding wave will 'push' these galaxies away from us with a rate of expansion that appears to be accelerating.

This theory had been proposed early on as a means of explaining away dark energy, but the PNAS article is the first time equations have been solved to show that the theory can be made consistent with observation.

The biggest criticism so far is that, for the theory to hold water, we (the observer) must be in the center of the density wave. The density wave is like the outward expanding wave we see from a pebble being dropped into the pond. We might think of the Big Bang as the pebble - the source of the ripples in space and time. However, the observer must be at the center of the ripples in order for observations to be consistent. That is, in the simplest case, the Milky Way galaxy must have formed right at the center of the Big Bang. This, of course, runs counter to all the lessons we've learned in the past which tell us there is nothing special about our location in time and space. It would be an extreme coincidence for us lowly observers to inhabit the most "special" place in the universe - which naturally leads one to believe that there is purpose behind all this. In other words, taking the theory in the most simple case is an argument for God or some intelligent design agent.

To be fair, the authors say that there may have been multiple ripples with different locations throughout the universe and we may be at one of these minor sources. And they aren't saying this is truth - only that this theory may be an explanation. I, however, have no doubt that this will be quickly latched onto by believers as further "scientific evidence" for the existence of God. They will quickly abandon whatever interpretations and creative constructs they've developed from their reading of the bible to find new passages that support humans as the center of all creation. They will ignore the possibility of existences in some lowly side ripple - what's the point in that? They will ignore that the theory isn't even fully vetted. As a model, it has to explain many other observed characteristics of the universe - not just accelerated expansion.

I, for one, am grabbing the popcorn and ready to watch them spin.

Other sources:
National Geographic
Space.com
USA Today

1 comment:

William said...

Hello,

It is good to see your endeavors for skepticism about religion and god. Everything starts with thinking and questioning. I did so. If you question enough, you will see that every do's and dont's that religion brings are for the situation we face after we taste death. If you think enough you will be tired due to the magnificence of the only God. I recommend you to check Az-Zariyat verse:47

The dark energy we discuss today was mentioned 1400 years ago in Quran by Almighty ALLAH and its style is like a wind scattering the universe by way of expanding it thus below are the verses from Quran

Quran chapter Az-Zariyat (The Winds that Scatter)

51:47 AND IT IS We who have built the universe with [Our creative] power; and, verily, it is We who are steadily expanding it.

I appreciate your skepticism and quest for knowledge.

Your Brother

Son of Adam