Latest Cosmological constant Stories

Dark Energy Hidden Behind Phantom Fields
2014-03-28 14:30:26

FECYT - Spanish Foundation for Science and Technology Quintessence and phantom fields, two hypotheses formulated using data from satellites, such as Planck and WMAP, are among the many theories that try to explain the nature of dark energy. Now researchers from Barcelona and Athens suggest that both possibilities are only a mirage in the observations and it is the quantum vacuum which could be behind this energy that moves our universe. Cosmologists believe that some three quarters of...

Dark Energy Theory Challenged
2013-01-10 09:15:38

[ Listen to the Podcast “The Search For Dark Energy” ] redOrbit Staff & Wire Reports - Your Universe Online A popular theory that relies on dark energy, thought to be the main contributor to the accelerating expansion of the Universe does not fit newly obtained data with regards to one fundamental constant — the proton to electron mass ratio. Rodger Thompson, a University of Arizona astronomy professor, disclosed his findings Wednesday at the American...

New Data Supports Einstein's Explanation For Dark Matter
2012-04-03 08:07:50

New information obtained by scientists using a 10-meter telescope located in Antarctica has strengthened the most widely accepted explanation for the mysterious force that is behind the increasingly rapid expansion of the universe, according to a pair of press releases published this week. According to a statement from the National Science Foundation (NSF), the most recent South Pole Telescope (SPT) data "strongly" supports Albert Einstein's cosmological constant, said to be the leading...

2010-04-21 14:45:00

Narrower constraints from the newest analysis aren't quite narrow enough The international Supernova Cosmology Project (SCP), based at the U.S. Department of Energy's Lawrence Berkeley National Laboratory, has announced the Union2 compilation of hundreds of Type Ia supernovae, the largest collection ever of high-quality data from numerous surveys. Analysis of the new compilation significantly narrows the possible values that dark energy might take"”but not enough to decide among...

2010-03-12 13:10:00

A team led by Princeton University scientists has tested Albert Einstein's theory of general relativity to see if it holds true at cosmic scales. And, after two years of analyzing astronomical data, the scientists have concluded that Einstein's theory, which describes the interplay between gravity, space and time, works as well in vast distances as in more local regions of space. The scientists' analysis of more than 70,000 galaxies demonstrates that the universe -- at least up to a distance...

2009-05-09 07:15:37

New dark energy model includes cosmological phase transition Imagine a time when the entire universe froze. According to a new model for dark energy, that is essentially what happened about 11.5 billion years ago, when the universe was a quarter of the size it is today. The model, published online May 6 in the journal Physical Review D, was developed by Research Associate Sourish Dutta and Professor of Physics Robert Scherrer at Vanderbilt University, working with Professor of Physics Stephen...

2008-12-16 13:58:26

U.S. astronomers say they have, for the first time, clearly observed the effects of dark energy on the most massive collapsed objects in the universe. National Aeronautics and Space Administration astronomers using the agency's Chandra X-ray Observatory tracked how dark energy has stifled the growth of galaxy clusters. Combining that information with previous studies, scientists say they have obtained the best clues yet about what dark energy is and what the destiny of the universe might be....

2007-01-17 09:45:16

Researchers at the University of Copenhagen's Dark Cosmology Centre at the Niels Bohr Institute have brought us one step closer to understanding what the universe is made of. As part of the international collaboration ESSENCE they have observed distant supernovae (exploding stars), some of which emitted the light we now see more than half the age of the universe ago. Using these supernovae they have traced the expansion history of the universe with unprecedented accuracy and sharpened our...

2005-11-23 13:39:38

The genius of Albert Einstein, who added a "cosmological constant" to his equation for the expansion of the universe but later retracted it, may be vindicated by new research published today in the journal Astronomy and Astrophysics. The enigmatic "dark energy" that drives the acceleration of the Universe behaves just like Einstein's famed cosmological constant, according to the Supernova Legacy Survey (SNLS), an international team of researchers in France and Toronto and Victoria in Canada,...

Latest Cosmological constant Reference Libraries

2004-10-19 04:45:41

Quintessence (Dark Energy) -- Quintessence or dark energy is a hypothetical form of energy postulated to exist in order to explain observations of an accelerating universe. This energy would act like a vacuum pressure, pushing things apart. Other attempts to explain these recent observations involve a non-zero cosmological constant, which has the same effect. Indeed, sometimes quintessence is said to result in a non-zero cosmological constant, and conversely a non-zero cosmological...

2004-10-19 04:45:41

Cosmological Constant -- The cosmological constant (usually denoted by the Greek capital letter lambda: Λ) is a value occurring in Einstein's theory of general relativity. The units of Λ are 1/second2; its value is unknown but believed to be positive based on recent observations. The constant is proportional to the energy density of the vacuum ρ, where π is Pi, G is the gravitational constant and c is the speed of light in vacuum. The term can be postive, negative, or...

2004-10-19 04:45:41

Inflation -- Inflation is the idea - first proposed by Alan Guth (1981) - that the nascent universe passed through a phase of exponential expansion that was driven by a negative vacuum energy density (positive vacuum pressure). This expansion can be modelled by a non-zero cosmological constant. As a direct consequence of this expansion, all of the observable universe is posited to have originated in a small, initially causally-connected region. Quantum fluctuations in this microscopic...

2004-10-19 04:45:41

Accelerating universe -- In the late 1990s, observations of type I supernova produced the unexpected result that the expansion of the universe appears to be accelerating. These observations appear more firm as new data has appeared. This means that the speed with which a distant galaxy recedes from us increases over time. If this trend continues, eventually we won't be able to see any other galaxies any more. This new theory of the end of the Universe has been called the Big Rip....

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Word of the Day
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