Friday, January 27, 2006

Dark Matter

The latest in Universe Evolution Theories entails the ripping apart of everything in 20 billion years, caused by the force of Dark Matter on the expansion of the Universe. Ripping apart everything? Yes, everything. Even subatomic particles. Even strings. Ouch.

A rather harrowing new theory about the death of the universe paints a picture of "phantom energy" ripping apart galaxies, stars, planets and eventually every speck of matter in a fantastical end to time.

Scientifically it is just about the most repulsive notion ever conceived....

Driving the known acceleration of the universe's expansion is a mysterious thing is called dark energy, thought of by scientists as anti-gravity working over large distances.

Conventional wisdom holds that the acceleration will proceed at a constant rate, akin to a car that moves 10 mph faster with each mile traveled. With nothing to cap the acceleration, all galaxies will eventually recede from one another at the speed of light, leaving each galaxy alone in a cold, dark universe within 100 billion years. We would not be able to see any galaxies outside our Milky Way, even with the most powerful telescopes.

That's the conventional view, remarkable as it sounds.

The Big Rip theory has dark energy's prowess increasing with time, until it's an out-of-control phantom energy. Think of our car accelerating an additional 10 mph every half mile, then every hundred yards, then every foot.

Before long, the bumpers are bound to fly off. Sooner or later, our hypothetical engine will come apart, regardless of how much we spend on motor oil....

If our species survives... here are some signs that scientists of the future will want to look for.

  • A billion years before the end, all galaxies will have receded so far and so fast from our own as to be erased from the sky, as in no longer visible.
  • When the Milky Way begins to fly apart, there are 60 million years left.
  • Planets in our solar system will start to wing away from the Sun three months before the end of time.
  • When Earth explodes, the end is momentarily near.

At this point, there is still a short interval before atoms and even their nuclei break apart. "There's about 30 minutes left," Caldwell said, "But it's not quality time."

And then what? Does the universe recycle itself? Is there something after nothing?

"We're not sure what happens after that," Caldwell says. "On the face of it, it would look like time ends."

Nice. On the other hand, our sun is scheduled for demolition in only 7 billion years:

Just as sure as the Sun comes up every morning, it is scheduled to die. Experts give it some 7 billion years, when it will turn into a bloated red giant. As the name implies, a red giant is a star swelled to gargantuan proportions. Earth would be first engulfed in heat and light, then vaporized.

Well before then, things will turn real nasty. In just a billion years, the Sun could be 11-percent brighter, scientists say, rendering Earth an inhospitable greenhouse. In 3.5 billion years, the Sun could be 40-percent brighter than it is today.

With our demise so clear on the cosmic horizon, astrophysicist Fred Adams of the University of Michigan and NASA's Gregory Laughlin got to wondering in recent years how the planet might be saved by gravitational interaction with a passing star. They ran computer simulations of possible encounters over the next 3.5 billion years, finding last year that the odds of the Earth being completely ejected from the solar system are one-in-100,000.

Slim odds. And life in the frigidity of deep space would be no summer picnic.

So Adams and Laughlin, along with Don Korycansky of the University of California, Santa Cruz, began to discuss consider how human intervention might bring about a more suitable long-term orbit, one that gradually expands with the aging Sun.

Their idea, which evolved from interaction with a star to rerouting a giant space rock to save Earth, will be published in an upcoming issue of the journal Astrophysics and Space Science.

"This is not an urgent problem," Adams stressed.

And from Darksyde at Dailykos comes a more precise description of the end of the world:

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.

It's just something to think about, keep in the back of your mind for a few billion years before starting to actually worry about it.


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