Just a couple of decades ago, many of the deepest mysteries of space and time were wrapped in a pretty box called the Inflationary Big Bang Model, itself a product of studying those spectral rainbows from distant galaxies. The Big Bang explained why our cosmos is expanding; the Inflationary part covered, among other items, how ripples of matter and energy could arise early on in the infant universe to form the first galaxies and stars. The looming question remaining in cosmology was exactly how fast the universe was growing in size and whether it will end in fire or ice.

In the old paradigm, if the mass of the universe is below a critical magnitude, it will keep growing forever. Our cosmos will end in the Big Freeze: A perpetual state of utter black emptiness and cold. The background temperature will asymptote to absolute zero and such will be the fate of the cosmos to the grim end of time. If it's above that critical mass, one day it will stop expanding and slowly begin to contract. It will grow hotter and denser until the pressure and temperature are unimaginable: The Big Crunch.

The history of our universe in slices of time. Left courtesy Wikipedia: A few fractions of a second after the Big Bang Singularity, the nascent universe undergoes the process of Inflation and then cools until it is transparent to light, eventually assuming its familiar appearance. If the universe continues to expand, it will eventually cool to absolute zero, the stars will finally burn out, and our cosmos will turn black as pitch forever. If the universe stops expanding and then collapses, it will roughly reverse the sequence of events above and end in the Big Crunch. Right courtesy NASA/JPL: The earliest image of the universe captured from the COsmic Background Explorer or COBE, the different colors are precursors to the very first proto-galaxies

But in the 1990s a more precise method of measuring the distance and velocity of galaxies was developed using the husks of once mighty stars as a stellar candle. And when those quantities were calculated for a number of galaxies, cosmologists were in for a big surprise. The universe was expanding alright, but it wasn't slowing down at all; in fact it may be speeding up!

The phenomena was dubbed Dark Energy. Another, even more stunning revelation was soon unveiled, this heretofore unsuspected force accounts for over 2/3 of the mass of the entire universe! What we think of as 'the cosmos', i.e. stars, planets, dust, protons, electrons, light, gravity, and heat, is nothing but a light froth, a mere afterthought of visible substances bubbling on the surface of a deep ocean of invisible Dark Energy.

Now using the brightest, most energetic stellar explosions known, called Silicon Star Hypernova AKA Gamma Ray Bursters, to further measure the rate of change in Dark Energy, cosmologists have found tentative evidence this strange repulsive force is increasing over time. And that's where it gets spooky: At present, this bizarre sort of antigravity works only over vast distances, hundreds of millions of light years or more. But if the mysterious force is increasing, it will become effective over shorter and shorter distances in the future.

Exponential growth is an inexorable process. No matter how humble the beginnings, a phenomenon that is growing exponentially will, sooner or later, reach for infinity. EG: Double a penny once a month and in a few years, you'll be a millionaire. What if Dark Energy is growing slowly, imperceptibly, but relentlessly in this manner?

In that case, over the next fifteen billion years, the galaxies will be pushed apart faster and faster, in fact that's already happening. But as the strange force of repulsion grows in magnitude, individual galaxies will begin to be affected. In the last few millions of years before the final cosmic apocalypse, stars in the outer reaches will begin drifting away from their parent galaxy. Then the gravitational glue holding the galaxies together will fail, whole spirals and elliptical conglomerations will come apart, each of the billions of stars within accelerating away from one another. The effect will build and build and build ... Eventually, the phantom force will over come the pull of stars on their own planets. The earth along with the rest of the solar system will decouple from the sun and each will go their separate ways. And it won't stop there!

The top red curve indicates a universe in which Dark Energy is causing the expansion of the universe to accelerate. There is growing evidence that our universe is following the red curve. For more detail see Cosmic Variance. Diagram courtesy of NASA

Dark Energy will keep growing; first stars and then planets will flatten like spinning pancakes and begin to throw off layer after layer of material. In the final year, the earth unravels in a high speed version of its original formation from space rocks, dust, and gas. Then the rocks, the individual dust grains, the larger molecules of gas, are sheared by the relentless, growing force. In the last few seconds, the very atoms are ripped asunder, the nuclei cut and cut again, reduced to lighter and lighter elements. Individual protons and neutrons are rendered into their constituent quarks and gluons. Perhaps the strings theorized to form the basis of all particles are then stretched and broken, photons, electrons, even theoretical gravitons, are destroyed.

Of particular interest is what might happen to Black Holes. When space is expanding considerably faster than the speed of light, General Relativistic solutions for all kinds of Black Holes are broken.

How long? Based on some estimates of the rate of growth in Dark Energy, in about 20 billion years the universe will be riven to quantum bits and beyond. It's not just matter which will be destroyed: The fabric of space-time itself will be shattered, liberating hitherto unheard of energies whisked away in the escalating, superluminal explosion! The universe would be shredded, not even empty space as we know it would remain: It will be violent, it will be glorious; it will be The End.

And maybe the beginning of a whole new era, one completely alien to our familiar cosmos of matter and energy, space and time. Or maybe it means the end of everything that ever was for all eternity.

If the universe is accelerating, in 20 billion years the fabric of space time may be torn into shards. There would be nothing left, not even empty space. Illustration used with permission, copyright © 1998-2006 Lynette Cook, all rights reserved. Check out more of Lynette's space artwork here, lots of exosolar planets and SETI art. Well worth the look!

What is Dark Energy? An aberration of observational techniques? A Cosmological Constant or a property of space-time, or something entirely new? Could the phantom force be a temporary phase, similar to the initial Cosmic Inflation theorized to have arisen and vanished in the first seconds after the Big Bang? Or is it an unstoppable, growing process? Cosmologists simply don't know the answers at this time.

But it does seem clear that the discovery of evolving Dark Energy, if confirmed, will rank as the most important find in cosmology since Edwin Hubble first measured the Universal Expansion almost eighty years ago. Research into this phenomenon could well lend as much insight into the fundamental physics of our cosmos as when Newton was conked on the head by an apple.

For now, this intriguing and disturbing hypothesis of complete, universal destruction looks like something worth exploring further. And if it holds up, the Big Freeze is comatose, the Big Crunch is dead: Long live The Big Rip!