A five-year survey of 200,000 galaxies, stretching back seven billion years in cosmic time, has led to one of the best independent confirmations that dark energy is driving our universe apart at accelerating speeds.This last point is a fascinating detail. All that we can see with our telescopes makes up only 4% of what's out there. The rest is invisible to us because it doesn't interact with light the way normal matter does.
The findings offer new support for the favored theory of how dark energy works -- as a constant force, uniformly affecting the universe and propelling its runaway expansion.
"The action of dark energy is as if you threw a ball up in the air, and it kept speeding upward into the sky faster and faster," said Chris Blake of the Swinburne University of Technology in Melbourne, Australia.
Dark energy is thought to dominate our universe, making up about 74 percent of it. Dark matter, a slightly less mysterious substance, accounts for 22 percent. So-called normal matter, anything with atoms, or the stuff that makes up living creatures, planets and stars, is only approximately four percent of the cosmos.
Here's another interesting detail. We don't know what the cosmic dark energy is, but we do know that its density is fine-tuned to one part in 10^120. That means that if the value of the density of this mysterious stuff deviated from its actual value by as little as one part in 10^120 a universe that could generate and sustain intelligent life would not exist. That level of precision is absolutely breathtaking.
Add to that the fact that the mass density, the total mass in the universe, is itself calibrated to one part in 10^60, and it is simply astonishing to realize that a universe in which life could exist actually came into being.
Imagine two dials, one has 10^120 calibrations etched into its dial face and the other has 10^60.
Now imagine that the needles of the two dials have to be set to just the mark they in fact are. If they were off by one degree out of the trillion trillion trillion, etc. degrees on the dial face the universe wouldn't exist. In fact, to make this analogy more like the actual case of the universe there would be dozens of such dials, all set to similarly precise values.
So how do scientists explain the fact that such a universe does, against all odds, exist? Some of them assume that there must be a near infinite number of different worlds, a multiverse. If the number of universes is sufficiently large (unimaginably large), and if they're all different, then as unlikely as our universe is, the laws of probability say that one like ours must exist among the innumerable varieties that are out there.
The other possibility, of course, is that our universe was purposefully engineered by a super intellect, but given the choice between believing in a near infinity of worlds for which there's virtually no evidence and believing that our universe is the product of intentional design, a belief for which there is much evidence, guess which option many modern scientists choose.
The lengths people go to in order to avoid having to believe that there's something out there with attributes similar to those traditionally imputed to God really are remarkable.
