The light of life still eludes us.

• Author: Braffman-Miller, Judith
• Position: Science & Technology

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WHEN YOU LOOK up at the night sky, it blazes with luminous objects such as stars and galaxies. However, most of the universe is dark, composed mainly of invisible material, the nature of which we do not understand. The stars--that we barely understand--compose only a tiny fraction of our universe. We are made of star-stuff. The stars cooked the elements that compose our bodies deep in their nuclear-fusing hearts, and then blew up when they ran out of fuel, seeding the universe with the ingredients of life. The ordinary atoms that compose such objects as stars, planets, and people represent only a small fraction of the mass and energy content of the universe.

As beautiful as the stars are, as much as we depend on them for our existence, they merely are the frosting on the cake--but what a cake it is. The unimaginably gigantic and luminous starlit galaxies and immense galaxy clusters and superclusters are embedded in halos of mysterious dark mailer, which is a hypothetical form of mailer that has been determined to exist--albeit indirectly--because it exerts gravitational effects on objects that can be seen, such as galaxies. However the true nature of dark matter is not known, although it forms immense, web-like filaments throughout space and time. and it is believed to be composed of exotic particles that do not interact with light. The starlit galaxies are suspended throughout Ibis complex, invisible structure, like glistening dewdrops on the web of some enormous spider.

Even more abundant, and more mysterious, is so-called dark energy, a bizarre force that is causing our universe to accelerate in its expansion. Some scientists even speculate that, billions and billions of years from now, the dark energy literally will rip our universe apart--even shredding atoms into nothingness. This is only one way that scientists propose the universe will end. There are other theories of how the universe may die--if indeed it does expire.

Most scientists believe that the universe was born 13,700,000,000 years ago in the Big Bang. It started as an exquisitely small patch, much smaller than a proton, and then--in the tiniest fraction of a second--expanded exponentially to attain macroscopic size. Something--we do not know precisely what--made that tiny patch undergo this runaway inflation. This patch that was far too small for a human being to see, so small that it was almost, but not exactly, nothing, was, in fact, so dense and hot that all that we are and all that we ever will know, sprung from it. Time itself, many believe, was born at that same instant.

However, other cosmologists speculate that there very well may have been something undiscovered and, perhaps, undiscoverable, existing before the Big Bang. What this might have been purely is a matter of speculation. The baby universe was filled with extremely energetic radiation, a writhing sea of hot particles of light that we call photons. The entire ancient universe glowed brilliantly like the surface of the sun. What we see now, almost 14,000,000,000 years later, is the fading--greatly expanded and expanding--aftermath of that primordial conflagration. As our universe grew to its present enormous size, the fires of its formation cooled, and now we watch from our obscure, rocky little world as our universe grows larger and larger, colder and colder, darker and darker, fading like the eerie grin of the Cheshire Cat.

The neonatal universe is thought to have experienced an accelerated expansion that we call inflation. Although inflation remains a theory, recent observations and measurements indicate that it is the most likely event (currently being considered) that could have caused our universe to develop in the way that it has. In the tiniest fraction of a second, inflation is believed to have blown up like a fantastic balloon each and every part of our tiny patch of space by a factor of at least [10.sup.27] (10 followed by 26 zeroes). Before inflation blew up this patch, the portion of the cosmos that we can see today--the visible universe--was a smooth little crumb...