"The First Trillionth of a Second of Time" --Will CERN's LHC Reveal a "Dark Sector" of the Universe?
One of the most fascinating discoveries of our new century may be imminent if the Large Hadron Collider outside Geneva produces nano-blackholes. According to the best current physics, such nano blackholes could not be produced with the energy levels the LHC can generate, but could only come into being if a parallel universe were providing extra gravitational input. Versions of multiverse theory suggest that there is at least one other universe very close to our own, perhaps only a millimeter away. This makes it possible that some of the effects, especially gravity, "leak through," which could be responsible for the production of dark energy and dark matter that make up 96% of the universe.
At a CalTech roundtable conference on the possible impact of the LHC on physics, Neal Weiner of New York University, who is a proponent of the existence of forces as well as particles on the dark side, said that until recently our theories about dark matter were driven by ideas about particle theory rather than data. “Ultimately we learn that perhaps it has very little to do with us at all,” Dr. Weiner said. “Who knows what we will find in the dark sector?”
The Milky Way and Andromeda galaxies are the dominant structures in a galaxy cluster called the Local Group which is, in turn, an outlying member of the Virgo supercluster. Andromeda--about 2.2 million light-years from the Milky Way--is speeding toward our galaxy at 200,000 miles per hour.
This motion can only be accounted for by gravitational attraction, even though the mass that we can observe is not nearly great enough to exert that kind of pull. The only thing that could explain the movement of Andromeda is the gravitational pull of a lot of unseen mass--perhaps the equivalent of 10 Milky Way-size galaxies--lying between the two galaxies.
Meanwhile, our entire Local Group is hurtling toward the center of the Virgo Cluster (image above) at one million miles per hour.
The Milky Way and its neighboring Andromeda galaxy, along with some 30 smaller ones, form what is known as the Local Group, which lies on the outskirts of a “super cluster”—a grouping of thousands of galaxies—known as Virgo, which is also pulled toward the Great Attractor. Based on the velocities at these scales, the unseen mass inhabiting the voids between the galaxies and clusters of galaxies amounts to perhaps 10 times more than the visible matter.
Even so, adding this invisible material to luminous matter brings the average mass density of the universe still to within only 10-30 percent of the critical density needed to "close" the universe. This phenomena suggests that the universe be "open." Cosmologists continue to debate this question, just as they are also trying to figure out the nature of the missing mass, or "dark matter."
It is believed that this dark matter dictates the structure of the Universe on the grandest of scales. Dark matter gravitationally attracts normal matter, and it is this normal matter that astronomers see forming long thin walls of super-galactic clusters.
Recent measurements with telescopes and space probes of the distribution of mass in M31 -the largest galaxy in the neighborhood of the Milky Way- and other galaxies led to the recognition that galaxies are filled with dark matter and have shown that a mysterious force—a dark energy—fills the vacuum of empty space, accelerating the universe's expansion.
Astronomers now recognize that the eventual fate of the universe is inextricably tied to the presence of dark energy and dark matter.The current standard model for cosmology describes a universe that is 70 percent dark energy, 25 percent dark matter, and only 5 percent normal matter.
We don't know what dark energy is, or why it exists, or if it even does exist. On the other hand, particle theory tells us that, at the microscopic level, even a perfect vacuum bubbles with quantum particles that are a natural source of dark energy. But a naïve calculation of the dark energy generated from the vacuum yields a value 10120 times larger than the amount we observe. Some unknown physical process is required to eliminate most, but not all, of the vacuum energy, leaving enough left to drive the accelerating expansion of the universe.
A new theory of particle physics is required to explain this physical process.
The universe as we see it contains only the stable relics and leftovers of the big bang: unstable particles have decayed away with time, and the perfect symmetries have been broken as the universe has cooled, but the structure of space remembers all the particles and forces we can no longer see around us.
Discovering what it is that makes up the heart of the Great Attractor -- will surely rank as one of the greatest discoveries in the history of science.
CERN’s Large Hadron Collider, the most powerful particle accelerator ever built, has begun colliding protons and generating sparks of primordial fire in an effort to recreate conditions that ruled the universe in the first trillionth of a second of time after the Big Bang. Physicists have been speculating for 30 years what they will see.
A major hope is an explanation for why gravity is so weak compared with the other forces of nature. How is it that a refrigerator magnet can hold itself up against the pull of the entire Earth? Perhaps they will discover what physicists call the “wimp miracle,” previously undiscovered particles — known collectively as wimps, for weakly interacting massive particles, that supersymmetry predicts could explain the mysterious dark matter that astronomers believe makes up 25 percent of the universe.
Image at top of page: a combined radio/optical image shows the galaxy cluster Abell 3376 in visible light (blue) and radio (red) images. The giant radio arcs surrounding the cluster were discovered using the Very Large Array. The visible-lightimage is from the Digitized Sky survey
The Daily Galaxy via nytimes.com http://www.nytimes.com/2010/01/26/science/26essay.html
Image credit: Galaxy Cluster Abell 3376 (Radio/Optical) Joydeep Bagchi, IUCAA, NRAO/AUI/NSF
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