(Press-News.org) A new paradigm for understanding the earliest eras in the history of the universe has been developed by scientists at Penn State University. Using techniques from an area of modern physics called loop quantum cosmology, developed at Penn State, the scientists now have extended analyses that include quantum physics farther back in time than ever before -- all the way to the beginning. The new paradigm of loop quantum origins shows, for the first time, that the large-scale structures we now see in the universe evolved from fundamental fluctuations in the essential quantum nature of "space-time," which existed even at the very beginning of the universe over 14 billion years ago. The achievement also provides new opportunities for testing competing theories of modern cosmology against breakthrough observations expected from next-generation telescopes. The research will be published on 11 December 2012 as an "Editor's Suggestion" paper in the scientific journal Physical Review Letters.
"We humans always have yearned to understand more about the origin and evolution of our universe," said Abhay Ashtekar, the senior author of the paper. "So it is an exciting time in our group right now, as we begin using our new paradigm to understand, in more detail, the dynamics that matter and geometry experienced during the earliest eras of the universe, including at the very beginning." Ashtekar is the Holder of the Eberly Family Chair in Physics at Penn State and the director of the university's Institute for Gravitation and the Cosmos. Coauthors of the paper, along with Ashtekar, are postdoctoral fellows Ivan Agullo and William Nelson.
The new paradigm provides a conceptual and mathematical framework for describing the exotic "quantum-mechanical geometry of space-time" in the very early universe. The paradigm shows that, during this early era, the universe was compressed to such unimaginable densities that its behavior was ruled not by the classical physics of Einstein's general theory of relativity, but by an even more fundamental theory that also incorporates the strange dynamics of quantum mechanics. The density of matter was huge then -- 10 to the 94 grams (10^94) per cubic centimeter, as compared with the density of an atomic nucleus today, which is only 10 to the 14 grams (10^14).
In this bizarre quantum-mechanical environment -- where one can speak only of probabilities of events rather than certainties -- physical properties naturally would be vastly different from the way we experience them today. Among these differences, Ashtekar said, are the concept of "time," as well as the changing dynamics of various systems over time as they experience the fabric of quantum geometry itself.
No space observatories have been able to detect anything as long ago and far away as the very early eras of the universe described by the new paradigm. But a few observatories have come close. Cosmic background radiation has been detected in an era when the universe was only 380-thousand years old. By that time, after a period of rapid expansion called "inflation," the universe had burst out into a much-diluted version of its earlier super-compressed self. At the beginning of inflation, the density of the universe was a trillion times less than during its infancy, so quantum factors are much less important in ruling the large-scale dynamics of matter and geometry.
Observations of the cosmic background radiation show that the universe had a predominantly uniform consistency after inflation, except for a light sprinkling of some regions that were more dense and others that were less dense. The standard inflationary paradigm for describing the early universe, which uses the classical-physics equations of Einstein, treats space-time as a smooth continuum. "The inflationary paradigm enjoys remarkable success in explaining the observed features of the cosmic background radiation. Yet this model is incomplete. It retains the idea that the universe burst forth from nothing in a Big Bang, which naturally results from the inability of the paradigm's general-relativity physics to describe extreme quantum-mechanical situations," Agullo said. "One needs a quantum theory of gravity, like loop quantum cosmology, to go beyond Einstein in order to capture the true physics near the origin of the universe."
Earlier work with loop quantum cosmology in Ashtekar's group had updated the concept of the Big Bang with the intriguing concept of a Big Bounce, which allows the possibility that our universe emerged not from nothing but from a super-compressed mass of matter that previously may have had a history of its own.
Even though the quantum-mechanical conditions at the beginning of the universe were vastly different from the classical-physics conditions after inflation, the new achievement by the Penn State physicists reveals a surprising connection between the two different paradigms that describe these eras. When scientists use the inflation paradigm together with Einstein's equations to model the evolution of the seed-like areas sprinkled throughout the cosmic background radiation, they find that the irregularities serve as seeds that evolve over time into the galaxy clusters and other large-scale structures that we see in the universe today. Amazingly, when the Penn State scientists used their new loop-quantum-origins paradigm with its quantum-cosmology equations, they found that fundamental fluctuations in the very nature of space at the moment of the Big Bounce evolve to become the seed-like structures seen in the cosmic microwave background.
"Our new work shows that the initial conditions at the very beginning of the universe naturally lead to the large-scale structure of the universe that we observe today," Ashtekar said. "In human terms, it is like taking a snapshot of a baby right at birth and then being able to project from it an accurate profile of how that person will be at age 100."
"This paper pushes back the genesis of the cosmic structure of our universe from the inflationary epoch all the way to the Big Bounce, covering some 11 orders of magnitude in the density of matter and the curvature of space-time," Nelson said. "We now have narrowed down the initial conditions that could exist at the Big Bounce, plus we find that the evolution of those initial conditions agrees with observations of the cosmic background radiation."
The team's results also identify a narrower range of parameters for which the new paradigm predicts novel effects, distinguishing it from standard inflation. Ashtekar said, "It is exciting that we soon may be able to test different predictions from these two theories against future discoveries with next-generation observational missions. Such experiments will help us to continue gaining a deeper understanding of the very, very early universe."
INFORMATION:
The research was supported by the National Science Foundation.
[ Barbara K. Kennedy ]
CONTACTS
Abhay Ashtekar: 814-863-9601, ashtekar@gravity.psu.edu
Barbara Kennedy (PIO): 814-863-4682, science@psu.edu
IMAGES
A high-resolution illustration related to this research is online at
http://www.science.psu.edu/news-and-events/2012-news/Ashtekar11-2012
The beginning of everything: A new paradigm shift for the infant universe
2012-11-29
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
Precisely engineering 3-D brain tissues
2012-11-29
CAMBRIDGE, MA -- Borrowing from microfabrication techniques used in the semiconductor industry, MIT and Harvard Medical School (HMS) engineers have developed a simple and inexpensive way to create three-dimensional brain tissues in a lab dish.
The new technique yields tissue constructs that closely mimic the cellular composition of those in the living brain, allowing scientists to study how neurons form connections and to predict how cells from individual patients might respond to different drugs. The work also paves the way for developing bioengineered implants to replace ...
Running too far, too fast, and too long speeds progress 'to finish line of life'
2012-11-29
Vigorous exercise is good for health, but only if it's limited to a maximum daily dose of between 30 and 50 minutes, say researchers in an editorial published online in Heart.
The idea that more and more high intensity exercise, such as marathons, can only do you good, is a myth say the US cardiologists, and the evidence shows that it's likely to more harm than good to your heart.
"If you really want to do a marathon or full distance triathlon, etc, it may be best to do just one or a few and then proceed to safer and healthier exercise patterns," they warn.
"A routine ...
Can a genetic variation in the vitamin D receptor protect against osteoporosis?
2012-11-29
New Rochelle, NY, November 29, 2012—Osteoporosis, or reduced bone mineral density that can increase the risk of fractures, may affect as many as 30% of women and 12% of men worldwide. One risk factor for osteoporosis is vitamin D deficiency. A modified form of the vitamin D receptor present in some individuals may lower their risk for developing osteoporosis, according to an article in Genetic Testing and Molecular Biomarkers, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The article is available on the Genetic Testing and Molecular Biomarkers website.
To ...
Post-divorce journaling may hinder healing for some
2012-11-29
Following a divorce or separation, many people are encouraged by loved ones or health-care professionals to keep journals about their feelings. But for some, writing in-depth about those feelings immediately after a split may do more harm than good, according to new research.
In a study of 90 recently divorced or separated individuals, psychological scientist David Sbarra of the University of Arizona and colleagues found that writing about one's feelings can actually leave some people feeling more emotionally distraught months down the line, particularly those individuals ...
Drug may offer new approach to treating insomnia
2012-11-29
MINNEAPOLIS – A new drug may bring help for people with insomnia, according to a study published in the November 28, 2012, online issue of Neurology®, the medical journal of the American Academy of Neurology.
The drug, suvorexant, blocks the chemical messengers in the brain called orexins, which regulate wakefulness. Other drugs for insomnia affect different brain receptors.
Taking the drug suvorexant increased the amount of time people spent asleep during the night, according to the study. The study involved 254 people ages 18 to 64 who were in good physical and ...
Tiny algae shed light on photosynthesis as a dynamic property
2012-11-29
One of the first chemical reactions children learn is the recipe for photosynthesis, combining carbon dioxide, water and solar energy to produce organic compounds. Many of the world's most important photosynthetic eukaryotes such as plants did not develop the ability to combine these ingredients themselves. Rather, they got their light-harnessing organelles -- chloroplasts -- indirectly by stealing them from other organisms. In some instances, this has resulted in algae with multiple, distinct genomes, the evolutionary equivalent of a "turducken*."
Chloroplasts originally ...
Morality-based judgments are quicker, more extreme than practical evaluations
2012-11-29
Judgments made after a moral evaluation are quicker and more extreme than the same judgment based on practical considerations, but morality-based evaluations can be more easily shifted and made with other considerations in mind, according to research published November 28 in the open access journal PLOS ONE by Jay Van Bavel and colleagues from New York University.
Previous research has suggested that moral reasoning usually occurs after a person makes a decision, as a post hoc justification of their choice, rather than the basis for the decision itself. This new study ...
More omnivore dilemmas: Seasonal diet changes can cause reproductive stress in primates
2012-11-29
When seasonal changes affect food availability, omnivores like blue monkeys adapt by changing their diets, but such nutritional changes may impact female reproduction, according to research published November 28 in the open access journal PLOS ONE by Steffen Foerster from Barnard College, and colleagues from Columbia University and the Smithsonian Institution.
The authors found that levels of fecal glucocorticoids (fGC), a stress marker, increased when female monkeys shifted their diet towards lower quality fallback foods, whereas the levels decreased when the monkeys ...
Skeletons in cave reveal Mediterranean secrets
2012-11-29
Skeletal remains in an island cave in Favignana, Italy, reveal that modern humans first settled in Sicily around the time of the last ice age and despite living on Mediterranean islands, ate little seafood. The research is published November 28 in the open access journal PLOS ONE by Marcello Mannino and colleagues from the Max Planck Institute for Evolutionary Anthropology, Germany.
Genetic analysis of the bones discovered in caves on the Egadi islands provides some of the first mitochondrial DNA data available for early humans from the Mediterranean region, a crucial ...
Scientists identify depression and anxiety biomarker in youths
2012-11-29
Scientists have discovered a cognitive biomarker – a biological indicator of a disease – for young adolescents who are at high risk of developing depression and anxiety. Their findings were published today, 28 November, in the journal PLOS ONE.
The test for the unique cognitive biomarker, which can be done on a computer, could be used as an inexpensive tool to screen adolescents for common emotional mental illnesses. As the cognitive biomarker may appear prior to the symptoms of depression and anxiety, early intervention (which has proven to be one of the most effective ...